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168-407: Sleep is a state of reduced mental and physical activity in which consciousness is altered and certain sensory activity is inhibited. During sleep, there is a marked decrease in muscle activity and interactions with the surrounding environment. While sleep differs from wakefulness in terms of the ability to react to stimuli , it still involves active brain patterns, making it more reactive than

336-405: A coma or disorders of consciousness . Sleep occurs in repeating periods , during which the body alternates between two distinct modes: REM and non-REM sleep . Although REM stands for "rapid eye movement", this mode of sleep has many other aspects, including virtual paralysis of the body. Dreams are a succession of images, ideas, emotions, and sensations that usually occur involuntarily in

504-404: A 24-hour cycle, whereas in monophasic sleep this occurs all at once. Under experimental conditions, humans tend to alternate more frequently between sleep and wakefulness (i.e., exhibit more polyphasic sleep) if they have nothing better to do. Given a 14-hour period of darkness in experimental conditions, humans tended towards bimodal sleep, with two sleep periods concentrated at the beginning and at

672-433: A better understanding of the properties of surface EMG recording. Surface electromyography is increasingly used for recording from superficial muscles in clinical or kinesiological protocols, where intramuscular electrodes are used for investigating deep muscles or localized muscle activity. There are many applications for the use of EMG. EMG is used clinically for the diagnosis of neurological and neuromuscular problems. It

840-407: A brain area directly above the optic chiasm , is presently considered the most important nexus for this process; however, secondary clock systems have been found throughout the body. An organism whose circadian clock exhibits a regular rhythm corresponding to outside signals is said to be entrained ; an entrained rhythm persists even if the outside signals suddenly disappear. If an entrained human

1008-454: A concept of consciousness. He does not use any single word or terminology that is clearly similar to the phenomenon or concept defined by John Locke . Victor Caston contends that Aristotle did have a concept more clearly similar to perception . Modern dictionary definitions of the word consciousness evolved over several centuries and reflect a range of seemingly related meanings, with some differences that have been controversial, such as

1176-400: A distinct type of substance not governed by the laws of physics), and property dualism (which holds that the laws of physics are universally valid but cannot be used to explain the mind). The three main types of monism are physicalism (which holds that the mind consists of matter organized in a particular way), idealism (which holds that only thought or experience truly exists, and matter

1344-410: A factor which may exacerbate disruption of the circadian cycle. Scientific studies on sleep have shown that sleep stage at awakening is an important factor in amplifying sleep inertia . Determinants of alertness after waking up include quantity/quality of the sleep, physical activity the day prior, a carbohydrate-rich breakfast, and a low blood glucose response to it. Sleep timing is controlled by

1512-605: A full eight hours. Researchers have found that sleeping 6–7 hours each night correlates with longevity and cardiac health in humans, though many underlying factors may be involved in the causality behind this relationship. Sleep difficulties are furthermore associated with psychiatric disorders such as depression , alcoholism , and bipolar disorder . Up to 90 percent of adults with depression are found to have sleep difficulties. Dysregulation detected by EEG includes disturbances in sleep continuity, decreased delta sleep and altered REM patterns with regard to latency, distribution across

1680-403: A function of the amount of time elapsed since the last adequate sleep episode) must be balanced against the circadian element for satisfactory sleep. Along with corresponding messages from the circadian clock, this tells the body it needs to sleep. The timing is correct when the following two circadian markers occur after the middle of the sleep episode and before awakening: maximum concentration of

1848-409: A good night's sleep. The American Academy of Sleep Medicine (AASM) divides NREM into three stages: N1, N2, and N3, the last of which is also called delta sleep or slow-wave sleep . The whole period normally proceeds in the order: N1 → N2 → N3 → N2 → REM. REM sleep occurs as a person returns to stage 2 or 1 from a deep sleep. There is a greater amount of deep sleep (stage N3) earlier in the night, while

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2016-436: A grasp of what consciousness means. Many fall into the trap of equating consciousness with self-consciousness —to be conscious it is only necessary to be aware of the external world. Consciousness is a fascinating but elusive phenomenon: it is impossible to specify what it is, what it does, or why it has evolved. Nothing worth reading has been written on it. Using 'awareness', however, as a definition or synonym of consciousness

2184-574: A highly specialized muscle of the electric ray fish ( Electric Eel ) generated electricity. By 1773, Walsh had been able to demonstrate that the eel fish's muscle tissue could generate a spark of electricity. In 1792, a publication entitled De Viribus Electricitatis in Motu Musculari Commentarius appeared, written by Luigi Galvani , in which the author demonstrated that electricity could initiate muscle contraction. Six decades later, in 1849, Emil du Bois-Reymond discovered that it

2352-579: A joystick-controlled wheelchair. Surface EMG recordings may also be a suitable control signal for some interactive video games. A joint project involving Microsoft , the University of Washington in Seattle , and the University of Toronto in Canada has explored using muscle signals from hand gestures as an interface device. A patent based on this research was submitted on June 26, 2008. In 2016

2520-502: A means of analyzing peak force and force generated by target muscles. According to the article "Peak and average rectified EMG measures: Which method of data reduction should be used for assessing core training exercises?", it was concluded that the "average rectified EMG data (ARV) is significantly less variable when measuring the muscle activity of the core musculature compared to the peak EMG variable." Therefore, these researchers would suggest that "ARV EMG data should be recorded alongside

2688-452: A more specialized question is how to square the subjective notion that we are in control of our decisions (at least in some small measure) with the customary view of causality that subsequent events are caused by prior events. The topic of free will is the philosophical and scientific examination of this conundrum. Many philosophers consider experience to be the essence of consciousness, and believe that experience can only fully be known from

2856-440: A motor unit fires, the impulse (called an action potential ) is carried down the motor neuron to the muscle. The area where the nerve contacts the muscle is called the neuromuscular junction , or the motor end plate . After the action potential is transmitted across the neuromuscular junction, an action potential is elicited in all of the innervated muscle fibers of that particular motor unit. The sum of all this electrical activity

3024-414: A muscle twitch or by surface electrodes. Fibrillations, however, are detected only by needle EMG, and represent the isolated activation of individual muscle fibers, usually as the result of nerve or muscle disease. Often, fibrillations are triggered by needle movement (insertional activity) and persist for several seconds or more after the movement ceases. After assessing resting and insertional activity,

3192-401: A pair of electrodes or by a more complex array of multiple electrodes. More than one electrode is needed because EMG recordings display the potential difference (voltage difference) between two separate electrodes. Limitations of this approach are the fact that surface electrode recordings are restricted to superficial muscles, are influenced by the depth of the subcutaneous tissue at the site of

3360-417: A particular frequency corresponds to various points in the sleep-wake cycle, such as being asleep, being awake, or falling asleep. Alpha, beta, theta, gamma, and delta waves are all seen in the different stages of sleep. Each waveform maintains a different frequency and amplitude. Alpha waves are seen when a person is in a resting state, but is still fully conscious. Their eyes may be closed and all of their body

3528-502: A person to a computer. In this project, an EMG signal is used to substitute for mechanical joysticks and keyboards. EMG has also been used in research towards a "wearable cockpit", which employs EMG-based gestures to manipulate switches and control sticks necessary for flight in conjunction with a goggle-based display. Unvoiced or silent speech recognition recognizes speech by observing the EMG activity of muscles associated with speech. It

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3696-409: A safety hazard. However, there are theoretical concerns that electrical impulses of nerve conduction studies (NCS) could be erroneously sensed by devices and result in unintended inhibition or triggering of output or reprogramming of the device. In general, the closer the stimulation site is to the pacemaker and pacing leads, the greater the chance for inducing a voltage of sufficient amplitude to inhibit

3864-443: A screen before bed may interfere with sleep. Modern humans often find themselves desynchronized from their internal circadian clock, due to the requirements of work (especially night shifts ), long-distance travel, and the influence of universal indoor lighting. Even if they have sleep debt, or feel sleepy, people can have difficulty staying asleep at the peak of their circadian cycle. Conversely, they can have difficulty waking up in

4032-562: A self taught electrical engineer, developed a machine that could be moved from the EMG Lab, and was relatively easy to use. As oscilloscopes had no "store" or "print" features at the time, a Polaroid camera was affixed to the front on a hinge. It was synchronized to photo the scan. Fellows studying at Mayo soon learned that this was a tool they wanted, too. As Mayo has no interest in marketing their inventions, Schmidt went on to continue to develop them in his basement for decades, selling them under

4200-438: A set of rituals such as reading a bedtime story, a bath, brushing teeth, and can also include a show of affection from the parent to the child such a hug or kiss before bed. A bedtime routine will also include a consistent time that the child is expected to be in bed ready for sleep. Having a reliable bedtime routine can help improve a child's quality of sleep as well as prepare them to make and keep healthy sleep hygiene habits in

4368-493: A strong intuition for the existence of what they refer to as consciousness, skeptics argue that this intuition is too narrow, either because the concept of consciousness is embedded in our intuitions, or because we all are illusions. Gilbert Ryle , for example, argued that traditional understanding of consciousness depends on a Cartesian dualist outlook that improperly distinguishes between mind and body, or between mind and world. He proposed that we speak not of minds, bodies, and

4536-609: A subjective point of view. Objective sleep quality refers to how difficult it is for a person to fall asleep and remain in a sleeping state, and how many times they wake up during a single night. Poor sleep quality disrupts the cycle of transition between the different stages of sleep. Subjective sleep quality in turn refers to a sense of being rested and regenerated after awaking from sleep. A study by A. Harvey et al. (2002) found that insomniacs were more demanding in their evaluations of sleep quality than individuals who had no sleep problems. Homeostatic sleep propensity (the need for sleep as

4704-404: A surface reference, in this case, however, the metal shaft of a hypodermic needle, insulated so that only the tip is exposed, is used both to record signals and to inject. Slightly more complex in design is the concentric needle electrode. These needles have a fine wire, embedded in a layer of insulation that fills the barrel of a hypodermic needle, that has an exposed shaft, and the shaft serves as

4872-446: A thorough analysis, the measured EMG signals can be decomposed into their constituent MUAPs. MUAPs from different motor units tend to have different characteristic shapes, while MUAPs recorded by the same electrode from the same motor unit are typically similar. Notably MUAP size and shape depend on where the electrode is located with respect to the fibers and so can appear to be different if the electrode moves position. EMG decomposition

5040-537: A transitional period is called slow-wave sleep or deep sleep. During this phase, body temperature and heart rate fall, and the brain uses less energy. REM sleep, also known as paradoxical sleep, represents a smaller portion of total sleep time. It is the main occasion for dreams (or nightmares ), and is associated with desynchronized and fast brain waves, eye movements, loss of muscle tone, and suspension of homeostasis . The sleep cycle of alternate NREM and REM sleep takes an average of 90 minutes, occurring 4–6 times in

5208-411: A very local picture of the activity of the whole muscle. Because skeletal muscles differ in the inner structure, the electrode has to be placed at various locations to obtain an accurate study. For the interpretation of EMG study is important to evaluate parameters of tested muscle motor units. This process may well be partially automated using appropriate software. Single fiber electromyography assesses

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5376-519: Is adenosine , a neurotransmitter that inhibits many of the bodily processes associated with wakefulness. Adenosine levels increase in the cortex and basal forebrain during prolonged wakefulness, and decrease during the sleep-recovery period, potentially acting as a homeostatic regulator of sleep. Coffee , tea, and other sources of caffeine temporarily block the effect of adenosine, prolong sleep latency, and reduce total sleep time and quality. Humans are also influenced by aspects of social time , such as

5544-406: Is awareness of internal and external existence . However, its nature has led to millennia of analyses, explanations, and debate by philosophers , scientists , and theologians . Opinions differ about what exactly needs to be studied or even considered consciousness. In some explanations, it is synonymous with the mind , and at other times, an aspect of it. In the past, it was one's "inner life",

5712-421: Is a common synonym for all forms of awareness, or simply ' experience ', without differentiating between inner and outer, or between higher and lower types. With advances in brain research, "the presence or absence of experienced phenomena " of any kind underlies the work of those neuroscientists who seek "to analyze the precise relation of conscious phenomenology to its associated information processing" in

5880-530: Is a monopolar needle electrode. This can be a fine wire inserted into a muscle with a surface electrode as a reference; or two fine wires inserted into muscle referenced to each other. Most commonly fine wire recordings are for research or kinesiology studies. Diagnostic monopolar EMG electrodes are typically insulated and stiff enough to penetrate skin, with only the tip exposed using a surface electrode for reference. Needles for injecting therapeutic botulinum toxin or phenol are typically monopolar electrodes that use

6048-450: Is access conscious; when we introspect , information about our thoughts is access conscious; when we remember , information about the past is access conscious, and so on. Although some philosophers, such as Daniel Dennett , have disputed the validity of this distinction, others have broadly accepted it. David Chalmers has argued that A-consciousness can in principle be understood in mechanistic terms, but that understanding P-consciousness

6216-555: Is accumulated against an individual's average sleep or some other benchmark. It is also unclear whether the prevalence of sleep debt among adults has changed appreciably in the industrialized world in recent decades. Sleep debt does show some evidence of being cumulative. Subjectively, however, humans seem to reach maximum sleepiness 30 hours after waking. It is likely that in Western societies , children are sleeping less than they previously have. One neurochemical indicator of sleep debt

6384-616: Is also debate over whether or not A-consciousness and P-consciousness always coexist or if they can exist separately. Although P-consciousness without A-consciousness is more widely accepted, there have been some hypothetical examples of A without P. Block, for instance, suggests the case of a " zombie " that is computationally identical to a person but without any subjectivity. However, he remains somewhat skeptical concluding "I don't know whether there are any actual cases of A-consciousness without P-consciousness, but I hope I have illustrated their conceptual possibility". Sam Harris observes: "At

6552-408: Is assessed with surface electrodes, but it should be recognized that these typically record only from muscle fibers in close proximity to the surface. Several analytical methods for determining muscle activation are commonly used depending on the application. The use of mean EMG activation or the peak contraction value is a debated topic. Most studies commonly use the maximal voluntary contraction as

6720-681: Is central to the animal rights movement , because it includes the ability to experience pain and suffering. For many decades, consciousness as a research topic was avoided by the majority of mainstream scientists, because of a general feeling that a phenomenon defined in subjective terms could not properly be studied using objective experimental methods. In 1975 George Mandler published an influential psychological study which distinguished between slow, serial, and limited conscious processes and fast, parallel and extensive unconscious ones. The Science and Religion Forum 1984 annual conference, ' From Artificial Intelligence to Human Consciousness ' identified

6888-649: Is dark. The diverse purposes and mechanisms of sleep are the subject of substantial ongoing research. Sleep is a highly conserved behavior across animal evolution, likely going back hundreds of millions of years. Humans may suffer from various sleep disorders , including dyssomnias , such as insomnia , hypersomnia , narcolepsy , and sleep apnea ; parasomnias , such as sleepwalking and rapid eye movement sleep behavior disorder ; bruxism ; and circadian rhythm sleep disorders . The use of artificial light has substantially altered humanity's sleep patterns. Common sources of artificial light include outdoor lighting and

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7056-496: Is defined roughly like English "consciousness" in the 1753 volume of Diderot and d'Alembert 's Encyclopédie as "the opinion or internal feeling that we ourselves have from what we do". About forty meanings attributed to the term consciousness can be identified and categorized based on functions and experiences . The prospects for reaching any single, agreed-upon, theory-independent definition of consciousness appear remote. Scholars are divided as to whether Aristotle had

7224-481: Is generally taken to be the first philosopher to use conscientia in a way less like the traditional meaning and more like the way modern English speakers would use "conscience", his meaning is nowhere defined. In Search after Truth ( Regulæ ad directionem ingenii ut et inquisitio veritatis per lumen naturale , Amsterdam 1701) he wrote the word with a gloss : conscientiâ, vel interno testimonio (translatable as "conscience, or internal testimony"). It might mean

7392-400: Is increased, more and more muscle fibers produce action potentials. When the muscle is fully contracted, there should appear a disorderly group of action potentials of varying rates and amplitudes (a complete recruitment); this can be described as an interference pattern . EMG findings vary with the type of disorder, the duration of the problem, the age of the patient, the degree to which

7560-618: Is intrinsically incapable of explaining the holistic aspects of consciousness, but that quantum theory may provide the missing ingredients. Several theorists have therefore proposed quantum mind (QM) theories of consciousness. Notable theories falling into this category include the holonomic brain theory of Karl Pribram and David Bohm , and the Orch-OR theory formulated by Stuart Hameroff and Roger Penrose . Some of these QM theories offer descriptions of phenomenal consciousness, as well as QM interpretations of access consciousness. None of

7728-399: Is isolated in a bunker with constant light or darkness, he or she will continue to experience rhythmic increases and decreases of body temperature and melatonin, on a period that slightly exceeds 24 hours. Scientists refer to such conditions as free-running of the circadian rhythm. Under natural conditions, light signals regularly adjust this period downward, so that it corresponds better with

7896-445: Is known as a "natural short sleeper". This condition is not to be confused with intentional sleep deprivation, which leaves symptoms such as irritability or temporarily impaired cognitive abilities in people who are predisposed to sleep a normal amount of time but not in people with FNSS. The genes DEC2 , ADRB1 , NPSR1 and GRM1 are implicated in enabling short sleep. The quality of sleep may be evaluated from an objective and

8064-409: Is known as a motor unit action potential (MUAP). This electrophysiologic activity from multiple motor units is the signal typically evaluated during an EMG. The composition of the motor unit, the number of muscle fibres per motor unit, the metabolic type of muscle fibres and many other factors affect the shape of the motor unit potentials in the myogram. Nerve conduction testing is also often done at

8232-470: Is linked to some kind of "selfhood", for example to certain pragmatic issues such as the feeling of agency and the effects of regret and action on experience of one's own body or social identity. Similarly Daniel Kahneman , who focused on systematic errors in perception, memory and decision-making, has differentiated between two kinds of mental processes, or cognitive "systems": the "fast" activities that are primary, automatic and "cannot be turned off", and

8400-454: Is merely an illusion), and neutral monism (which holds that both mind and matter are aspects of a distinct essence that is itself identical to neither of them). There are also, however, a large number of idiosyncratic theories that cannot cleanly be assigned to any of these schools of thought. Since the dawn of Newtonian science with its vision of simple mechanical principles governing the entire universe, some philosophers have been tempted by

8568-458: Is monitored using surface EMG and patients have an auditory or visual stimulus to help them know when they are activating the muscle (biofeedback). A review of the literature on surface EMG published in 2008, concluded that surface EMG may be useful to detect the presence of neuromuscular disease (level C rating, class III data), but there are insufficient data to support its utility for distinguishing between neuropathic and myopathic conditions or for

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8736-585: Is much more challenging: he calls this the hard problem of consciousness . Some philosophers believe that Block's two types of consciousness are not the end of the story. William Lycan , for example, argued in his book Consciousness and Experience that at least eight clearly distinct types of consciousness can be identified (organism consciousness; control consciousness; consciousness of ; state/event consciousness; reportability; introspective consciousness; subjective consciousness; self-consciousness)—and that even this list omits several more obscure forms. There

8904-433: Is non-trivial, although many methods have been proposed. Rectification is the translation of the raw EMG signal to a signal with a single polarity , usually positive. The purpose of rectifying the signal is to ensure the signal does not average to zero, due to the raw EMG signal having positive and negative components. Two types of rectification are used: full-wave and half-wave rectification. Full-wave rectification adds

9072-457: Is not a simple matter: If awareness of the environment . . . is the criterion of consciousness, then even the protozoans are conscious. If awareness of awareness is required, then it is doubtful whether the great apes and human infants are conscious. Many philosophers have argued that consciousness is a unitary concept that is understood by the majority of people despite the difficulty philosophers have had defining it. Max Velmans proposed that

9240-454: Is not necessary to explain what we observe. Some philosophers, such as Daniel Dennett in a research paper titled "The Unimagined Preposterousness of Zombies", argue that people who give this explanation do not really understand what they are saying. More broadly, philosophers who do not accept the possibility of zombies generally believe that consciousness is reflected in behavior (including verbal behavior), and that we attribute consciousness on

9408-444: Is now the dominant position among contemporary philosophers of mind. For an overview of the field, approaches often include both historical perspectives (e.g., Descartes, Locke, Kant ) and organization by key issues in contemporary debates. An alternative is to focus primarily on current philosophical stances and empirical Philosophers differ from non-philosophers in their intuitions about what consciousness is. While most people have

9576-420: Is observed to be a necessary behavior across most of the animal kingdom, including some of the least cognitively advanced animals which have no need for other functions of sleep, such as memory consolidation or dreaming. It has been widely accepted that sleep must support the formation of long-term memory, and generally increasing previous learning and experiences recalls. However, its benefit seems to depend on

9744-528: Is physically indistinguishable from a human being and behaves like a human being in every way but nevertheless lacks consciousness. Related issues have also been studied extensively by Greg Littmann of the University of Illinois, and by Colin Allen (a professor at the University of Pittsburgh) regarding the literature and research studying artificial intelligence in androids. The most commonly given answer

9912-591: Is produced. This enables definition of a class of subtle motionless gestures to control interfaces without being noticed and without disrupting the surrounding environment. These signals can be used to control a prosthesis or as a control signal for an electronic device such as a mobile phone or PDA . EMG signals have been targeted as control for flight systems. The Human Senses Group at the NASA Ames Research Center at Moffett Field , CA seeks to advance man-machine interfaces by directly connecting

10080-441: Is profoundly influenced by changes in light, since these are its main clues about what time it is. Exposure to even small amounts of light during the night can suppress melatonin secretion, and increase body temperature and wakefulness. Short pulses of light, at the right moment in the circadian cycle, can significantly 'reset' the internal clock. Blue light, in particular, exerts the strongest effect, leading to concerns that use of

10248-445: Is raw experience: it is moving, colored forms, sounds, sensations, emotions and feelings with our bodies and responses at the center. These experiences, considered independently of any impact on behavior, are called qualia . A-consciousness, on the other hand, is the phenomenon whereby information in our minds is accessible for verbal report, reasoning, and the control of behavior. So, when we perceive , information about what we perceive

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10416-399: Is regulated by a process called homeostasis . Induced or perceived lack of sleep is called sleep deprivation . Process S is driven by the depletion of glycogen and accumulation of adenosine in the forebrain that disinhibits the ventrolateral preoptic nucleus , allowing for inhibition of the ascending reticular activating system . Sleep deprivation tends to cause slower brain waves in

10584-443: Is resting and relatively still, where the body is starting to slow down. Beta waves take over alpha waves when a person is at attention, as they might be completing a task or concentrating on something. Beta waves consist of the highest of frequencies and the lowest of amplitude, and occur when a person is fully alert. Gamma waves are seen when a person is highly focused on a task or using all their concentration. Theta waves occur during

10752-412: Is targeted for use in noisy environments, and may be helpful for people without vocal cords , with aphasia , with dysphonia , and more. EMG has also been used as a control signal for computers and other devices. An interface device based on an EMG Switch can be used to control moving objects, such as mobile robots or an electric wheelchair . This may be helpful for individuals that cannot operate

10920-428: Is that we attribute consciousness to other people because we see that they resemble us in appearance and behavior; we reason that if they look like us and act like us, they must be like us in other ways, including having experiences of the sort that we do. There are, however, a variety of problems with that explanation. For one thing, it seems to violate the principle of parsimony , by postulating an invisible entity that

11088-409: Is the fact that consciousness of some sort goes on. 'States of mind' succeed each other in him . [...] But everyone knows what the terms mean [only] in a rough way; [...] When I say every 'state' or 'thought' is part of a personal consciousness , 'personal consciousness' is one of the terms in question. Its meaning we know so long as no one asks us to define it, but to give an accurate account of it

11256-438: Is the most difficult of philosophic tasks. [...] The only states of consciousness that we naturally deal with are found in personal consciousnesses, minds, selves, concrete particular I's and you's. Prior to the 20th century, philosophers treated the phenomenon of consciousness as the "inner world [of] one's own mind", and introspection was the mind "attending to" itself, an activity seemingly distinct from that of perceiving

11424-399: Is used diagnostically by gait laboratories and by clinicians trained in the use of biofeedback or ergonomic assessment. EMG is also used in many types of research laboratories, including those involved in biomechanics , motor control, neuromuscular physiology, movement disorders, postural control, and physical therapy . EMG can be used to sense isometric muscular activity where no movement

11592-399: Is used for functional diagnosis and during instrumental motion analysis. EMG signals are also used as a control signal for prosthetic devices such as prosthetic hands, arms and lower limbs. An acceleromyograph may be used for neuromuscular monitoring in general anesthesia with neuromuscular-blocking drugs , in order to avoid postoperative residual curarization (PORC). Except in

11760-486: The unconscious processes of cognition such as perception , reactive awareness and attention , and automatic forms of learning , problem-solving , and decision-making . The cognitive science point of view—with an inter-disciplinary perspective involving fields such as psychology , linguistics and anthropology —requires no agreed definition of "consciousness" but studies the interaction of many processes besides perception. For some researchers, consciousness

11928-805: The Journal of Consciousness Studies , along with regular conferences organized by groups such as the Association for the Scientific Study of Consciousness and the Society for Consciousness Studies . Electromyography EMG testing has a variety of clinical and biomedical applications. Needle EMG is used as a diagnostics tool for identifying neuromuscular diseases , or as a research tool for studying kinesiology , and disorders of motor control. EMG signals are sometimes used to guide botulinum toxin or phenol injections into muscles. Surface EMG

12096-580: The Zhuangzi. This bird's name is Of a Flock ( peng 鵬 ), yet its back is countless thousands of miles across and its wings are like clouds arcing across the heavens. "Like Of a Flock, whose wings arc across the heavens, the wings of your consciousness span to the horizon. At the same time, the wings of every other being's consciousness span to the horizon. You are of a flock, one bird among kin." Mental processes (such as consciousness) and physical processes (such as brain events) seem to be correlated, however

12264-409: The amplitude and duration of the muscle action potential and an overall shift to lower frequencies. Monitoring the changes of different frequency changes the most common way of using EMG to determine levels of fatigue. The lower conduction velocities enable the slower motor neurons to remain active. A motor unit is defined as one motor neuron and all of the muscle fibers it innervates. When

12432-486: The circadian clock (Process C), sleep-wake homeostasis (Process S), and to some extent by the individual will. Sleep timing depends greatly on hormonal signals from the circadian clock, or Process C, a complex neurochemical system which uses signals from an organism's environment to recreate an internal day–night rhythm. Process C counteracts the homeostatic drive for sleep during the day (in diurnal animals) and augments it at night. The suprachiasmatic nucleus (SCN),

12600-435: The frontal cortex , shortened attention span, higher anxiety, impaired memory, and a grouchy mood. Conversely, a well-rested organism tends to have improved memory and mood. Neurophysiological and functional imaging studies have demonstrated that frontal regions of the brain are particularly responsive to homeostatic sleep pressure. There is disagreement on how much sleep debt is possible to accumulate, and whether sleep debt

12768-430: The mind during certain stages of sleep. During sleep, most of the body's systems are in an anabolic state, helping to restore the immune , nervous , skeletal , and muscular systems; these are vital processes that maintain mood , memory , and cognitive function , and play a large role in the function of the endocrine and immune systems . The internal circadian clock promotes sleep daily at night , when it

12936-619: The "contents of conscious experience by introspection and experiment ". Another popular metaphor was James's doctrine of the stream of consciousness , with continuity, fringes, and transitions. James discussed the difficulties of describing and studying psychological phenomena, recognizing that commonly-used terminology was a necessary and acceptable starting point towards more precise, scientifically justified language. Prime examples were phrases like inner experience and personal consciousness : The first and foremost concrete fact which every one will affirm to belong to his inner experience

13104-439: The "everyday understanding of consciousness" uncontroversially "refers to experience itself rather than any particular thing that we observe or experience" and he added that consciousness "is [therefore] exemplified by all the things that we observe or experience", whether thoughts, feelings, or perceptions. Velmans noted however, as of 2009, that there was a deep level of "confusion and internal division" among experts about

13272-485: The "slow", deliberate, effortful activities of a secondary system "often associated with the subjective experience of agency, choice, and concentration". Kahneman's two systems have been described as "roughly corresponding to unconscious and conscious processes". The two systems can interact, for example in sharing the control of attention. While System 1 can be impulsive, "System 2 is in charge of self-control", and "When we think of ourselves, we identify with System 2,

13440-464: The "structure" of the mind by analyzing its "elements". The abstract idea of states of consciousness mirrored the concept of states of matter . In 1892, William James noted that the "ambiguous word 'content' has been recently invented instead of 'object'" and that the metaphor of mind as a container seemed to minimize the dualistic problem of how "states of consciousness can know " things, or objects; by 1899 psychologists were busily studying

13608-456: The 'outer world' and its physical phenomena. In 1892 William James noted the distinction along with doubts about the inward character of the mind: 'Things' have been doubted, but thoughts and feelings have never been doubted. The outer world, but never the inner world, has been denied. Everyone assumes that we have direct introspective acquaintance with our thinking activity as such, with our consciousness as something inward and contrasted with

13776-556: The 17th century, and the first recorded use of "conscious" as a simple adjective was applied figuratively to inanimate objects ( "the conscious Groves" , 1643). It derived from the Latin conscius ( con- "together" and scio "to know") which meant "knowing with" or "having joint or common knowledge with another", especially as in sharing a secret. Thomas Hobbes in Leviathan (1651) wrote: "Where two, or more men, know of one and

13944-415: The 1930s through the 1950s, and researchers began to use improved electrodes more widely for the study of muscles. The AANEM was formed in 1953 as one of several currently active medical societies with a special interest in advancing the science and clinical use of the technique. Clinical use of surface EMG (sEMG) for the treatment of more specific disorders began in the 1960s. Hardyck and his researchers were

14112-420: The EMG signal below the baseline to the signal above the baseline to make a conditioned signal that is all positive. If the baseline is zero, this is equivalent to taking the absolute value of the signal. This is the preferred method of rectification because it conserves all of the signal energy for analysis. Half-wave rectification discards the portion of the EMG signal that is below the baseline. In doing so,

14280-462: The active muscle directly below the surface decreased. As adipose tissue increased, the amplitude of the surface EMG signal directly above the center of the active muscle decreased. EMG signal recordings are typically more accurate with individuals who have lower body fat, and more compliant skin, such as young people when compared to old. Muscle cross talk occurs when the EMG signal from one muscle interferes with that of another limiting reliability of

14448-754: The affected extremity, namely venipuncture, to prevent development or worsening of lymphedema or cellulitis. Despite the potential risk, the evidence for such complications subsequent to venipuncture is limited. No published reports exist of cellulitis, infection, or other complications related to EMG performed in the setting of lymphedema or prior lymph node dissection. However, given the unknown risk of cellulitis in patients with lymphedema, reasonable caution should be exercised in performing needle examinations in lymphedematous regions to avoid complications. In patients with gross edema and taut skin, skin puncture by needle electrodes may result in chronic weeping of serous fluid. The potential bacterial media of such serous fluid and

14616-614: The average of the data is no longer zero therefore it can be used in statistical analyses. Needle EMG used in clinical settings has practical applications such as helping to discover disease. Needle EMG has limitations, however, in that it does involve voluntary activation of muscle, and as such is less informative in patients unwilling or unable to cooperate, children and infants, and in individuals with paralysis. Surface EMG can have limited applications due to inherent problems associated with surface EMG. Adipose tissue (fat) can affect EMG recordings. Studies show that as adipose tissue increased

14784-448: The basis of behavior. A more straightforward way of saying this is that we attribute experiences to people because of what they can do , including the fact that they can tell us about their experiences. The term " qualia " was introduced in philosophical literature by C. I. Lewis . The word is derived from Latin and means "of what sort". It is basically a quantity or property of something as perceived or experienced by an individual, like

14952-591: The body surface" invites another criticism, that most consciousness research since the 1990s, perhaps because of bias, has focused on processes of external perception . From a history of psychology perspective, Julian Jaynes rejected popular but "superficial views of consciousness" especially those which equate it with "that vaguest of terms, experience ". In 1976 he insisted that if not for introspection , which for decades had been ignored or taken for granted rather than explained, there could be no "conception of what consciousness is" and in 1990, he reaffirmed

15120-412: The brain and body, the reduced rate of metabolism enables countervailing restorative processes. The brain requires sleep for restoration, whereas these processes can take place during quiescent waking in the rest of the body. The essential function of sleep may be its restorative effect on the brain: "Sleep is of the brain, by the brain and for the brain." This theory is strengthened by the fact that sleep

15288-463: The brain from metabolic end products generated during waking. Anabolic hormones, such as growth hormones , are secreted preferentially during sleep. The brain concentration of glycogen increases during sleep, and is depleted through metabolism during wakefulness. The human organism physically restores itself during sleep, occurring mostly during slow-wave sleep during which body temperature, heart rate, and brain oxygen consumption decrease. In both

15456-556: The brain restores its supply of adenosine triphosphate (ATP), the molecule used for short-term storage and transport of energy. In quiet waking, the brain is responsible for 20% of the body's energy use, thus this reduction has a noticeable effect on overall energy consumption. Sleep increases the sensory threshold . In other words, sleeping persons perceive fewer stimuli, but can generally still respond to loud noises and other salient sensory events. During slow-wave sleep , humans secrete bursts of growth hormone . All sleep, even during

15624-408: The brain. This neuroscientific goal is to find the "neural correlates of consciousness" (NCC). One criticism of this goal is that it begins with a theoretical commitment to the neurological origin of all "experienced phenomena" whether inner or outer. Also, the fact that the easiest 'content of consciousness' to be so analyzed is "the experienced three-dimensional world (the phenomenal world) beyond

15792-436: The brain. Many other neuroscientists, such as Christof Koch , have explored the neural basis of consciousness without attempting to frame all-encompassing global theories. At the same time, computer scientists working in the field of artificial intelligence have pursued the goal of creating digital computer programs that can simulate or embody consciousness . A few theoretical physicists have argued that classical physics

15960-655: The case of some purely primary myopathic conditions EMG is usually performed with another electrodiagnostic medicine test that measures the conducting function of nerves. This is called nerve conduction study (NCS). Needle EMG and NCSs are typically indicated when there is pain in the limbs, weakness from spinal nerve compression , or concern about some other neurologic injury or disorder. Spinal nerve injury does not cause neck, mid back pain or low back pain , and for this reason, evidence has not shown EMG or NCS to be helpful in diagnosing causes of axial lumbar pain, thoracic pain, or cervical spine pain . Needle EMG may aid with

16128-637: The conscious, reasoning self that has beliefs, makes choices, and decides what to think about and what to do". Some have argued that we should eliminate the concept from our understanding of the mind, a position known as consciousness semanticism. In medicine , a "level of consciousness" terminology is used to describe a patient's arousal and responsiveness, which can be seen as a continuum of states ranging from full alertness and comprehension , through disorientation, delirium , loss of meaningful communication, and finally loss of movement in response to painful stimuli . Issues of practical concern include how

16296-650: The day, is associated with the secretion of prolactin . Key physiological methods for monitoring and measuring changes during sleep include electroencephalography (EEG) of brain waves , electrooculography (EOG) of eye movements, and electromyography (EMG) of skeletal muscle activity. Simultaneous collection of these measurements is called polysomnography , and can be performed in a specialized sleep laboratory . Sleep researchers also use simplified electrocardiography (EKG) for cardiac activity and actigraphy for motor movements. The electrical activity seen on an EEG represents brain waves. The amplitude of EEG waves at

16464-920: The deepest period of sleep. Napping too long and entering the slow wave cycles can make it difficult to awake from the nap and leave one feeling unrested. This period of drowsiness is called sleep inertia . The siesta habit has recently been associated with a 37% lower coronary mortality, possibly due to reduced cardiovascular stress mediated by daytime sleep. Short naps at mid-day and mild evening exercise were found to be effective for improved sleep, cognitive tasks, and mental health in elderly people. Monozygotic (identical) but not dizygotic (fraternal) twins tend to have similar sleep habits. Neurotransmitters, molecules whose production can be traced to specific genes, are one genetic influence on sleep that can be analyzed. The circadian clock has its own set of genes. Genes which may influence sleep include ABCC9 , DEC2 , Dopamine receptor D2 and variants near PAX 8 and VRK2 . While

16632-430: The delay between the contractions of individual muscle fibers within a motor unit and is a sensitive test for dysfunction of the neuromuscular junction caused by drugs, poisons, or diseases such as myasthenia gravis. The technique is complicated and typically performed only by individuals with special advanced training. Surface EMG is used in a number of settings; for example, in the physiotherapy clinic, muscle activation

16800-408: The diagnosis of nerve compression or injury (such as carpal tunnel syndrome ), nerve root injury (such as sciatica), and with other problems of the muscles or nerves. Less common medical conditions include amyotrophic lateral sclerosis , myasthenia gravis , and muscular dystrophy . The first step before insertion of the needle electrode is skin preparation. This typically involves simply cleaning

16968-478: The diagnosis of specific neuromuscular diseases. EMGs may be useful for additional study of fatigue associated with post-poliomyelitis syndrome and electromechanical function in myotonic dystrophy (level C rating, class III data). Recently, with the rise of technology in sports, sEMG has become an area of focus for coaches to reduce the incidence of soft tissue injury and improve player performance. Certain US states limit

17136-422: The difficulty of producing a definition that does not involve circularity or fuzziness. In The Macmillan Dictionary of Psychology (1989 edition), Stuart Sutherland emphasized external awareness, and expressed a skeptical attitude more than a definition: Consciousness —The having of perceptions, thoughts, and feelings ; awareness. The term is impossible to define except in terms that are unintelligible without

17304-729: The distinction between inward awareness and perception of the physical world, or the distinction between conscious and unconscious , or the notion of a mental entity or mental activity that is not physical. The common-usage definitions of consciousness in Webster's Third New International Dictionary (1966) are as follows: The Cambridge English Dictionary defines consciousness as "the state of understanding and realizing something". The Oxford Living Dictionary defines consciousness as "[t]he state of being aware of and responsive to one's surroundings", "[a] person's awareness or perception of something", and "[t]he fact of awareness by

17472-418: The electromyographer assess the activity of muscle during voluntary contraction. The shape, size, and frequency of the resulting electrical signals are judged. Then the electrode is retracted a few millimetres, and again the activity is analyzed. This is repeated, sometimes until data on 10–20 motor units have been collected in order to draw conclusions about motor unit function. Each electrode track gives only

17640-513: The end of the dark time. Bimodal sleep in humans was more common before the Industrial Revolution . Different characteristic sleep patterns, such as the familiarly so-called " early bird " and " night owl ", are called chronotypes . Genetics and sex have some influence on chronotype, but so do habits. Chronotype is also liable to change over the course of a person's lifetime. Seven-year-olds are better disposed to wake up early in

17808-556: The end of the sleep cycle. Awakening involves heightened electrical activation in the brain, beginning with the thalamus and spreading throughout the cortex . On a typical night of sleep, there is not much time that is spent in the waking state. In various sleep studies that have been conducted using the electroencephalography, it has been found that females are awake for 0-1% during their nightly sleep while males are awake for 0-2% during that time. In adults, wakefulness increases, especially in later cycles. One study found 3% awake time in

17976-480: The exact 24 hours of an Earth day. The circadian clock exerts constant influence on the body, affecting sinusoidal oscillation of body temperature between roughly 36.2 °C and 37.2 °C. The suprachiasmatic nucleus itself shows conspicuous oscillation activity, which intensifies during subjective day (i.e., the part of the rhythm corresponding with daytime, whether accurately or not) and drops to almost nothing during subjective night. The circadian pacemaker in

18144-537: The first (1966) practitioners to use sEMG. In the early 1980s, Cram and Steger introduced a clinical method for scanning a variety of muscles using an EMG sensing device. Research began at the Mayo Clinic in Rochester, Minnesota under the guidance of Edward H. Lambert , MD, PhD (1915–2003) in the early 1950s. Lambert, known as the "Father of EMG", with the assistance of his Research Technician, Ervin L Schmidt,

18312-528: The first ninety-minute sleep cycle, 8% in the second, 10% in the third, 12% in the fourth, and 13–14% in the fifth. Most of this awake time occurred shortly after REM sleep. Today, many humans wake up with an alarm clock ; however, people can also reliably wake themselves up at a specific time with no need for an alarm. Many sleep quite differently on workdays versus days off, a pattern which can lead to chronic circadian desynchronization. Many people regularly look at television and other screens before going to bed,

18480-471: The following example: It is difficult for modern Western man to grasp that the Greeks really had no concept of consciousness in that they did not class together phenomena as varied as problem solving, remembering, imagining, perceiving, feeling pain, dreaming, and acting on the grounds that all these are manifestations of being aware or being conscious. Many philosophers and scientists have been unhappy about

18648-406: The following medical conditions (please note this is not an exhaustive list of conditions that can result in abnormal EMG studies): Disorders of muscle: Disorders of the neuromuscular junction: Disorders of nerves: Plexus disorders: Root disorders: Motor neuron disease The first documented experiments dealing with EMG started with Francesco Redi 's works in 1666. Redi discovered

18816-481: The future. Children need many hours of sleep per day in order to develop and function properly: up to 18 hours for newborn babies, with a declining rate as a child ages. Early in 2015, after a two-year study, the National Sleep Foundation in the US announced newly revised recommendations as shown in the table below. Sleep may facilitate the synthesis of molecules that help repair and protect

18984-407: The highest rate of sleep. The hours that children spend asleep influence their ability to perform on cognitive tasks. Children who sleep through the night and have few night waking episodes have higher cognitive attainments and easier temperaments than other children. Sleep also influences language development. To test this, researchers taught infants a faux language and observed their recollection of

19152-445: The hormone melatonin, and minimum core body temperature. Human sleep-needs vary by age and amongst individuals; sleep is considered to be adequate when there is no daytime sleepiness or dysfunction. Moreover, self-reported sleep duration is only moderately correlated with actual sleep time as measured by actigraphy , and those affected with sleep state misperception may typically report having slept only four hours despite having slept

19320-474: The hours when other people are awake, the hours when work is required, the time on clocks, etc. Time zones , standard times used to unify the timing for people in the same area, correspond only approximately to the natural rising and setting of the sun. An extreme example of the approximate nature of time zones is China, a country which used to span five time zones and now officially uses only one (UTC+8). In polyphasic sleep , an organism sleeps several times in

19488-581: The idea that consciousness could be explained in purely physical terms. The first influential writer to propose such an idea explicitly was Julien Offray de La Mettrie , in his book Man a Machine ( L'homme machine ). His arguments, however, were very abstract. The most influential modern physical theories of consciousness are based on psychology and neuroscience . Theories proposed by neuroscientists such as Gerald Edelman and Antonio Damasio , and by philosophers such as Daniel Dennett, seek to explain consciousness in terms of neural events occurring within

19656-437: The inside, subjectively. The problem of other minds is a philosophical problem traditionally stated as the following epistemological question: Given that I can only observe the behavior of others, how can I know that others have minds? The problem of other minds is particularly acute for people who believe in the possibility of philosophical zombies , that is, people who think it is possible in principle to have an entity that

19824-595: The interaction between these two domains occurs inside the brain, perhaps in a small midline structure called the pineal gland . Although it is widely accepted that Descartes explained the problem cogently, few later philosophers have been happy with his solution, and his ideas about the pineal gland have especially been ridiculed. However, no alternative solution has gained general acceptance. Proposed solutions can be divided broadly into two categories: dualist solutions that maintain Descartes's rigid distinction between

19992-418: The irritation of needle insertion subsides, the electromyograph should detect no abnormal spontaneous activity (i.e., a muscle at rest should be electrically silent, with the exception of the area of the neuromuscular junction , which is, under normal circumstances, very spontaneously active). When the muscle is voluntarily contracted, action potentials begin to appear. As the strength of the muscle contraction

20160-532: The knowledge of the value of one's own thoughts. The origin of the modern concept of consciousness is often attributed to John Locke who defined the word in his Essay Concerning Human Understanding , published in 1690, as "the perception of what passes in a man's own mind". The essay strongly influenced 18th-century British philosophy , and Locke's definition appeared in Samuel Johnson 's celebrated Dictionary (1755). The French term conscience

20328-520: The laryngeal muscles, and subspecialists in urology, obstetrics and gynecology who have had selective training in performing EMG of muscles controlling bowel and bladder function. One basic function of EMG is to see how well a muscle can be activated. The most common way that can be determined is by performing a maximal voluntary contraction (MVC) of the muscle that is being tested. Each muscle group type has different characteristics, and MVC positions are varied for different muscle group types. Therefore,

20496-489: The latter have been found in a GWAS study that primarily detects correlations (but not necessarily causation), other genes have been shown to have a more direct effect. For instance, mice lacking dihydropyrimidine dehydrogenase (Dpyd) had 78.4 min less sleep during the lights-off period than wild-type mice. Dpyd encodes the rate-limiting enzyme in the metabolic pathway that catabolizes uracil and thymidine to β- alanine , an inhibitory neurotransmitter . This also supports

20664-480: The level of consciousness can be assessed in severely ill, comatose, or anesthetized people, and how to treat conditions in which consciousness is impaired or disrupted. The degree or level of consciousness is measured by standardized behavior observation scales such as the Glasgow Coma Scale . While historically philosophers have defended various views on consciousness, surveys indicate that physicalism

20832-460: The level of your experience, you are not a body of cells, organelles, and atoms; you are consciousness and its ever-changing contents". Seen in this way, consciousness is a subjectively experienced, ever-present field in which things (the contents of consciousness) come and go. Christopher Tricker argues that this field of consciousness is symbolized by the mythical bird that opens the Daoist classic

21000-532: The mind of itself and the world". Philosophers have attempted to clarify technical distinctions by using a jargon of their own. The corresponding entry in the Routledge Encyclopedia of Philosophy (1998) reads: During the early 19th century, the emerging field of geology inspired a popular metaphor that the mind likewise had hidden layers "which recorded the past of the individual". By 1875, most psychologists believed that "consciousness

21168-535: The more body fat an individual has, the weaker the EMG signal. When placing the EMG sensor, the ideal location is at the belly of the muscle: the longitudinal midline. The belly of the muscle can also be thought of as in-between the motor point (middle) of the muscle and the tendonus insertion point. Cardiac pacemakers and implanted cardiac defibrillators (ICDs) are used increasingly in clinical practice, and no evidence exists indicating that performing routine electrodiagnostic studies on patients with these devices pose

21336-493: The morning than are fifteen-year-olds. Chronotypes far outside the normal range are called circadian rhythm sleep disorders. Naps are short periods of sleep that one might take during the daytime, often in order to get the necessary amount of rest. Napping is often associated with childhood, but around one-third of American adults partake in it daily. The optimal nap duration is around 10–20 minutes, as researchers have proven that it takes at least 30 minutes to enter slow-wave sleep,

21504-409: The muscle under observation. Typical repetition rate of muscle motor unit firing is about 7–20 Hz, depending on the size of the muscle (eye muscles versus seat (gluteal) muscles), previous axonal damage and other factors. Damage to motor units can be expected at ranges between 450 and 780 mV. Muscle tissue at rest is normally electrically inactive. After the electrical activity caused by

21672-400: The muscle. Normal muscles exhibit a brief burst of muscle fiber activation when stimulated by needle movement, but this rarely lasts more than 100ms. The two most common pathologic types of resting activity in muscle are fasciculation and fibrillation potentials. A fasciculation potential is an involuntary activation of a motor unit within the muscle, sometimes visible with the naked eye as

21840-428: The name ErMel Inc. It was not until the middle of the 1980s that integration techniques in electrodes had sufficiently advanced to allow batch production of the required small and lightweight instrumentation and amplifiers. At present, a number of suitable amplifiers are commercially available. In the early 1980s, cables that produced signals in the desired microvolt range became available. Recent research has resulted in

22008-498: The nature of consciousness as a matter for investigation; Donald Michie was a keynote speaker. Starting in the 1980s, an expanding community of neuroscientists and psychologists have associated themselves with a field called Consciousness Studies , giving rise to a stream of experimental work published in books, journals such as Consciousness and Cognition , Frontiers in Consciousness Research , Psyche , and

22176-401: The night and density of eye movements. Sleep duration can also vary according to season. Up to 90% of people report longer sleep duration in winter, which may lead to more pronounced seasonal affective disorder . By the time infants reach the age of two, their brain size has reached 90 percent of an adult-sized brain; a majority of this brain growth has occurred during the period of life with

22344-404: The night. Circadian rhythm exerts some influence on the nighttime secretion of growth hormone. The circadian rhythm influences the ideal timing of a restorative sleep episode. Sleepiness increases during the night. REM sleep occurs more during body temperature minimum within the circadian cycle, whereas slow-wave sleep can occur more independently of circadian time. The internal circadian clock

22512-409: The notion of quantum consciousness, an experiment about wave function collapse led by Catalina Curceanu in 2022 suggests that quantum consciousness, as suggested by Roger Penrose and Stuart Hameroff , is highly implausible. Apart from the general question of the "hard problem" of consciousness (which is, roughly speaking, the question of how mental experience can arise from a physical basis ),

22680-414: The outer objects which it knows. Yet I must confess that for my part I cannot feel sure of this conclusion. [...] It seems as if consciousness as an inner activity were rather a postulate than a sensibly given fact... By the 1960s, for many philosophers and psychologists who talked about consciousness, the word no longer meant the 'inner world' but an indefinite, large category called awareness , as in

22848-540: The pacemaker. Despite such concerns, no immediate or delayed adverse effects have been reported with routine NCS. No known contraindications exist for performing needle EMG or NCS on pregnant patients. Additionally, no complications from these procedures have been reported in the literature. Evoked potential testing, likewise, has not been reported to cause any problems when it is performed during pregnancy. Patients with lymphedema or patients at risk for lymphedema are routinely cautioned to avoid percutaneous procedures in

23016-659: The patient can be cooperative, the type of needle electrode used to study the patient, and sampling error in terms of the number of areas studied within a single muscle and the number of muscles studied overall. Interpreting EMG findings is usually best done by an individual informed by a focused history and physical examination of the patient, and in conjunction with the results of other relevant diagnostic studies performed including most importantly, nerve conduction studies, but also, where appropriate, imaging studies such as MRI and ultrasound, muscle and nerve biopsy, muscle enzymes, and serologic studies. Abnormal results may be caused by

23184-421: The peak EMG measure when assessing core exercises." Providing the reader with both sets of data would result in enhanced validity of the study and potentially eradicate the contradictions within the research. EMG can also be used for indicating the amount of fatigue in a muscle. The following changes in the EMG signal can signify muscle fatigue : an increase in the mean absolute value of the signal, increase in

23352-528: The performance of needle EMG by nonphysicians. New Jersey declared that it cannot be delegated to a physician's assistant. Michigan has passed legislation saying needle EMG is the practice of medicine. Special training in diagnosing medical diseases with EMG is required only in residency and fellowship programs in neurology, clinical neurophysiology, neuromuscular medicine, and physical medicine and rehabilitation. There are certain subspecialists in otolaryngology who have had selective training in performing EMG of

23520-465: The period of a person being awake, and they continue to transition into Stage 1 of sleep and in stage 2. Delta waves are seen in stages 3 and 4 of sleep when a person is in their deepest of sleep. Sleep is divided into two broad types: non-rapid eye movement (non-REM or NREM) sleep and rapid eye movement (REM) sleep. Non-REM and REM sleep are so different that physiologists identify them as distinct behavioral states. Non-REM sleep occurs first and after

23688-421: The phase of sleep and the type of memory. For example, declarative and procedural memory-recall tasks applied over early and late nocturnal sleep, as well as wakefulness controlled conditions, have been shown that declarative memory improves more during early sleep (dominated by SWS) while procedural memory during late sleep (dominated by REM sleep) does so. Consciousness Consciousness , at its simplest,

23856-403: The phenomenon of consciousness, because researchers lacked "a sufficiently well-specified use of the term...to agree that they are investigating the same thing". He argued additionally that "pre-existing theoretical commitments" to competing explanations of consciousness might be a source of bias. Within the "modern consciousness studies" community the technical phrase 'phenomenal consciousness'

24024-450: The proportion of REM sleep increases in the two cycles just before natural awakening. Awakening can mean the end of sleep, or simply a moment to survey the environment and readjust body position before falling back asleep. Sleepers typically awaken soon after the end of a REM phase or sometimes in the middle of REM. Internal circadian indicators , along with a successful reduction of homeostatic sleep need, typically bring about awakening and

24192-409: The quantum mechanical theories have been confirmed by experiment. Recent publications by G. Guerreshi, J. Cia, S. Popescu, and H. Briegel could falsify proposals such as those of Hameroff, which rely on quantum entanglement in protein. At the present time many scientists and philosophers consider the arguments for an important role of quantum phenomena to be unconvincing. Empirical evidence is against

24360-453: The range of descriptions, definitions or explanations are: ordered distinction between self and environment, simple wakefulness , one's sense of selfhood or soul explored by " looking within "; being a metaphorical " stream " of contents, or being a mental state , mental event , or mental process of the brain. The words "conscious" and "consciousness" in the English language date to

24528-411: The realm of consciousness and the realm of matter but give different answers for how the two realms relate to each other; and monist solutions that maintain that there is really only one realm of being, of which consciousness and matter are both aspects. Each of these categories itself contains numerous variants. The two main types of dualism are substance dualism (which holds that the mind is formed of

24696-471: The recording of deeper muscles. Single fiber EMG needle electrodes are designed to have very tiny recording areas, and allow for the discharges of individual muscle fibers to be discriminated. To perform intramuscular EMG, typically either a monopolar or concentric needle electrode is inserted through the skin into the muscle tissue. The needle is then moved to multiple spots within a relaxed muscle to evaluate both insertional activity and resting activity in

24864-410: The recording which can be highly variable depending on the weight of a patient, and cannot reliably discriminate between the discharges of adjacent muscles. Specific electrode placements and functional tests have been developed to minimize this risk, thus providing reliable examinations. Intramuscular EMG can be performed using a variety of different types of recording electrodes. The simplest approach

25032-462: The reference electrode. The exposed tip of the fine wire serves as the active electrode. As a result of this configuration, signals tend to be smaller when recorded from a concentric electrode than when recorded from a monopolar electrode and they are more resistant to electrical artifacts from tissue and measurements tend to be somewhat more reliable. However, because the shaft is exposed throughout its length, superficial muscle activity can contaminate

25200-502: The researcher should be very careful while choosing the MVC position type to elicit the greater muscle activity level from the subjects. The types of MVC positions can vary among muscle types, contingent upon the specific muscle group being considered, including trunk muscles, lower limb muscles, and others. Muscle force, which is measured mechanically, typically correlates highly with measures of EMG activation of muscle. Most commonly this

25368-430: The role of β-alanine as a neurotransmitter that promotes sleep in mice. Familial natural short sleep is a rare, genetic, typically inherited trait where an individual sleeps for fewer hours than average without suffering from daytime sleepiness or other consequences of sleep deprivation . This process is entirely natural in this kind of individual, and it is caused by certain genetic mutations. A person with this trait

25536-500: The rules for that language. Infants who slept within four hours of learning the language could remember the language rules better, while infants who stayed awake longer did not recall those rules as well. There is also a relationship between infants' vocabulary and sleeping: infants who sleep longer at night at 12 months have better vocabularies at 26 months. Children can greatly benefit from a structured bedtime routine. This can look differently among families, but will generally consist of

25704-458: The same fact, they are said to be Conscious of it one to another". There were also many occurrences in Latin writings of the phrase conscius sibi , which translates literally as "knowing with oneself", or in other words "sharing knowledge with oneself about something". This phrase has the figurative sense of "knowing that one knows", which is something like the modern English word "conscious", but it

25872-421: The same time as an EMG to diagnose neurological diseases. Some patients can find the procedure somewhat painful, whereas others experience only a small amount of discomfort when the needle is inserted. The muscle or muscles being tested may be slightly sore for a day or two after the procedure. EMG signals are essentially made up of superimposed motor unit action potentials (MUAPs) from several motor units. For

26040-663: The scent of rose, the taste of wine, or the pain of a headache. They are difficult to articulate or describe. The philosopher and scientist Daniel Dennett describes them as "the way things seem to us", while philosopher and cognitive scientist David Chalmers expanded on qualia as the " hard problem of consciousness " in the 1990s. When qualia is experienced, activity is simulated in the brain, and these processes are called neural correlates of consciousness (NCCs). Many scientific studies have been done to attempt to link particular brain regions with emotions or experiences. Species which experience qualia are said to have sentience , which

26208-469: The screens of electronic devices such as smartphones and televisions, which emit large amounts of blue light, a form of light typically associated with daytime. This disrupts the release of the hormone melatonin needed to regulate the sleep cycle . The most pronounced physiological changes in sleep occur in the brain. The brain uses significantly less energy during sleep than it does when awake, especially during non-REM sleep. In areas with reduced activity,

26376-508: The signal of the muscle being tested. Surface EMG is limited due to lack of deep muscles reliability. Deep muscles require intramuscular wires that are intrusive and painful in order to achieve an EMG signal. Surface EMG can measure only superficial muscles and even then it is hard to narrow down the signal to a single muscle. The electrical source is the muscle membrane potential of about –90 mV. Measured EMG potentials range between less than 50 μV and up to 30 mV, depending on

26544-456: The skin with an alcohol pad. The actual placement of the needle electrode can be difficult and depends on a number of factors, such as specific muscle selection and the size of that muscle. Proper needle EMG placement is very important for accurate representation of the muscle of interest, although EMG is more effective on superficial muscles as it is unable to bypass the action potentials of superficial muscles and detect deeper muscles. Also,

26712-444: The specific nature of the connection is unknown. The first influential philosopher to discuss this question specifically was Descartes , and the answer he gave is known as mind–body dualism . Descartes proposed that consciousness resides within an immaterial domain he called res cogitans (the realm of thought), in contrast to the domain of material things, which he called res extensa (the realm of extension). He suggested that

26880-411: The suprachiasmatic nucleus has a direct neural connection to the pineal gland , which releases the hormone melatonin at night. Cortisol levels typically rise throughout the night, peak in the awakening hours , and diminish during the day. Circadian prolactin secretion begins in the late afternoon, especially in women, and is subsequently augmented by sleep-induced secretion, to peak in the middle of

27048-407: The traditional idea of the phenomenon called 'consciousness', writing that "its denotative definition is, as it was for Descartes , Locke , and Hume , what is introspectable". Jaynes saw consciousness as an important but small part of human mentality, and he asserted: "there can be no progress in the science of consciousness until ... what is introspectable [is] sharply distinguished" from

27216-419: The trough of the cycle. A healthy young adult entrained to the sun will (during most of the year) fall asleep a few hours after sunset, experience body temperature minimum at 6 a.m., and wake up a few hours after sunrise. Generally speaking, the longer an organism is awake, the more it feels a need to sleep ("sleep debt"). This driver of sleep is referred to as Process S . The balance between sleeping and waking

27384-416: The violation of skin integrity may increase the risk of cellulitis. Before proceeding, the physician should weigh the potential risks of performing the study with the need to obtain the information gained. There are two kinds of EMG: surface EMG and intramuscular EMG. Surface EMG assesses muscle function by recording muscle activity from the surface above the muscle on the skin. Surface EMG can be recorded by

27552-440: The world of introspection , of private thought , imagination , and volition . Today, it often includes any kind of cognition , experience , feeling , or perception . It may be awareness, awareness of awareness, metacognition , or self-awareness , either continuously changing or not. The disparate range of research, notions and speculations raises a curiosity about whether the right questions are being asked. Examples of

27720-488: The world, but of entities, or identities, acting in the world. Thus, by speaking of "consciousness" we end up leading ourselves by thinking that there is any sort of thing as consciousness separated from behavioral and linguistic understandings. Ned Block argued that discussions on consciousness often failed to properly distinguish phenomenal (P-consciousness) from access (A-consciousness), though these terms had been used before Block. P-consciousness, according to Block,

27888-507: Was also possible to record electrical activity during a voluntary muscle contraction. The first actual recording of this activity was made by Marey in 1890, who also introduced the term electromyography. In 1922, Gasser and Erlanger used an oscilloscope to show the electrical signals from muscles. Because of the stochastic nature of the myoelectric signal, only rough information could be obtained from its observation. The capability of detecting electromyographic signals improved steadily from

28056-440: Was but a small part of mental life", and this idea underlies the goal of Freudian therapy , to expose the unconscious layer of the mind. Other metaphors from various sciences inspired other analyses of the mind, for example: Johann Friedrich Herbart described ideas as being attracted and repulsed like magnets; John Stuart Mill developed the idea of "mental chemistry" and "mental compounds", and Edward B. Titchener sought

28224-537: Was rendered into English as "conscious to oneself" or "conscious unto oneself". For example, Archbishop Ussher wrote in 1613 of "being so conscious unto myself of my great weakness". The Latin conscientia , literally 'knowledge-with', first appears in Roman juridical texts by writers such as Cicero . It means a kind of shared knowledge with moral value, specifically what a witness knows of someone else's deeds. Although René Descartes (1596–1650), writing in Latin,

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