reference-sleep disorder
Is it hard for you to fall asleep or stay asleep through the night? Do you wake up feeling tired or feel very sleepy during the day, even if you have had enough sleep? You might have a sleep disorder. The most common kinds are:
Insomnia - a hard time falling or staying asleep
Sleep apnea - breathing interruptions during sleep
Restless legs syndrome - a tingling or prickly sensation in the legs
Narcolepsy - daytime "sleep attacks"
Nightmares, night terrors, sleepwalking, sleep talking, head banging, wetting the bed and grinding your teeth are kinds of sleep problems called parasomnias. Parasomnias are a category of sleep disorders that involve abnormal movements, behaviors, emotions, perceptions, and dreams that occur while falling asleep, sleeping, between sleep stages, or during arousal from sleep. Sleepwalking is a common type of sleep disorder. Click on Learn More to learn more about sleepwalking.
[1] Simonds, John F., and Humberto Parraga. "Prevalence of sleep disorders and sleep behaviors in children and adolescents." Journal of the American Academy of Child Psychiatry 21.4 (1982): 383-388.
[2]Cartwright, Rosalind. "Sleepwalking violence: a sleep disorder, a legal dilemma, and a psychological challenge." American journal of psychiatry 161.7 (2004): 1149-1158.
[3]Schenck, Carlos H., Jeffrey L. Boyd, and Mark W. Mahowald. "A parasomnia overlap disorder involving sleepwalking, sleep terrors, and REM sleep behavior disorder in 33 polysomnographically confirmed cases." Sleep 20.11 (1997): 972-981.
[4]http://en.wikipedia.org/wiki/Parasomnia
System Review
Mental activity during sleep relates deeply with changes in consciousness and in brain activity. Actually, they have the same physiology basis.Because of the distributed organization of the primate brain and because of the inability to identify singular cortical or subcortical structures responsible for conscious experience, it is likely that the neuronal substrate that supports the functional states required for the constitution of conscious experience is distributed in nature. Based on the evidence that precise synchronization of oscillatory neuronal responses is likely to serve the binding of distributed computational results into coherent representations, we hypothesized that brain states compatible with conscious processing should be characterized by a high degree of synchrony, that is temporal coherence of activity.
In order to directly examine the relation between neuronal synchrony and conscious processing, we designed a paradigm that allowed us to identify the neuronal signatures that distinguish between conscious and unconscious processing of visual stimuli.[1] It calculate different lever of consciousness using the power and phase of gamma oscillations, which is a prevailing theory that indicate the mechanism of consciousness.
A simple model of Consciousness - machanism of gamma oscillations
Neurons are modeled as single-compartment integrate-and-fire units with membrane potential V. When V exceeds a threshold of 48 mV, a spike is recorded and transmitted to other neurons with an appropriate delay, and V is reset to 80 mV for a refractory period of 4 ms. The temporal
evolution of V, expressed in millivolts, is given by
where C =1 F/cm2 and currents are expressed in uA/cm2. The leak conductance is gleak= 0.1 ms/cm2, so that the membrane time constant Cgleak is 10 ms.
INaP and IKS are persistent sodium and slowly inactivating potassium currents, the interplay of which can generate intrinsic gamma-band oscillations.
IGABA, IAMPA, and INMDA are the total synaptic currents respectively from fast gabaergic, AMPA, and NMDA glutamatergic synapses.
ISRA is an additional current used to model spike-rate adaptation.
Iinput is the current applied during stimulus presentation to thalamic neurons of the lowest hierarchical level to simulate a visual or auditory input.
A final current, Ineuromodul, summarizes the known depolarizing effects of ascending activating
systems such as those from cholinergic, noradrenergic, and serotoninergic nuclei in the brainstem, basal forebrain, and hypothalamus (25). This parameter is used to control the level
of wakefulness. When Ineuromodul is low, membrane potentials converge to a stable asymptote in the absence of external stimulation. Beyond a threshold, individual neurons generate
intrinsic gamma-band membrane oscillations, first below the spiking threshold and then with an occasional occurrence of spikes.
[1]Melloni, Lucia, et al. "Synchronization of neural activity across cortical areas correlates with conscious perception." The Journal of neuroscience 27.11 (2007): 2858-2865.
[2]
Indeed, sleep brings about at once the most common and the most dramatic change in consciousness that healthy subjects are likely to witness – from the nearfading of all experience to the bizarre hallucinations of dreams. At the same time, the brain goes through an orderly progression of sleep stages, which can be identified by recording the electroencephalogram (EEG), eye movements (EOG, electroculogram), and muscle tone (EMG, electromyogram), and which indicate that major changes in brain activity are taking place.
Insomnia - a hard time falling or staying asleep
Sleep apnea - breathing interruptions during sleep
Restless legs syndrome - a tingling or prickly sensation in the legs
Narcolepsy - daytime "sleep attacks"
Nightmares, night terrors, sleepwalking, sleep talking, head banging, wetting the bed and grinding your teeth are kinds of sleep problems called parasomnias. Parasomnias are a category of sleep disorders that involve abnormal movements, behaviors, emotions, perceptions, and dreams that occur while falling asleep, sleeping, between sleep stages, or during arousal from sleep. Sleepwalking is a common type of sleep disorder. Click on Learn More to learn more about sleepwalking.
[1] Simonds, John F., and Humberto Parraga. "Prevalence of sleep disorders and sleep behaviors in children and adolescents." Journal of the American Academy of Child Psychiatry 21.4 (1982): 383-388.
[2]Cartwright, Rosalind. "Sleepwalking violence: a sleep disorder, a legal dilemma, and a psychological challenge." American journal of psychiatry 161.7 (2004): 1149-1158.
[3]Schenck, Carlos H., Jeffrey L. Boyd, and Mark W. Mahowald. "A parasomnia overlap disorder involving sleepwalking, sleep terrors, and REM sleep behavior disorder in 33 polysomnographically confirmed cases." Sleep 20.11 (1997): 972-981.
[4]http://en.wikipedia.org/wiki/Parasomnia
System Review
Mental activity during sleep relates deeply with changes in consciousness and in brain activity. Actually, they have the same physiology basis.Because of the distributed organization of the primate brain and because of the inability to identify singular cortical or subcortical structures responsible for conscious experience, it is likely that the neuronal substrate that supports the functional states required for the constitution of conscious experience is distributed in nature. Based on the evidence that precise synchronization of oscillatory neuronal responses is likely to serve the binding of distributed computational results into coherent representations, we hypothesized that brain states compatible with conscious processing should be characterized by a high degree of synchrony, that is temporal coherence of activity.
In order to directly examine the relation between neuronal synchrony and conscious processing, we designed a paradigm that allowed us to identify the neuronal signatures that distinguish between conscious and unconscious processing of visual stimuli.[1] It calculate different lever of consciousness using the power and phase of gamma oscillations, which is a prevailing theory that indicate the mechanism of consciousness.
A simple model of Consciousness - machanism of gamma oscillations
Neurons are modeled as single-compartment integrate-and-fire units with membrane potential V. When V exceeds a threshold of 48 mV, a spike is recorded and transmitted to other neurons with an appropriate delay, and V is reset to 80 mV for a refractory period of 4 ms. The temporal
evolution of V, expressed in millivolts, is given by
 |
where C =1 F/cm2 and currents are expressed in uA/cm2. The leak conductance is gleak= 0.1 ms/cm2, so that the membrane time constant Cgleak is 10 ms.
INaP and IKS are persistent sodium and slowly inactivating potassium currents, the interplay of which can generate intrinsic gamma-band oscillations.
IGABA, IAMPA, and INMDA are the total synaptic currents respectively from fast gabaergic, AMPA, and NMDA glutamatergic synapses.
ISRA is an additional current used to model spike-rate adaptation.
Iinput is the current applied during stimulus presentation to thalamic neurons of the lowest hierarchical level to simulate a visual or auditory input.
A final current, Ineuromodul, summarizes the known depolarizing effects of ascending activating
systems such as those from cholinergic, noradrenergic, and serotoninergic nuclei in the brainstem, basal forebrain, and hypothalamus (25). This parameter is used to control the level
of wakefulness. When Ineuromodul is low, membrane potentials converge to a stable asymptote in the absence of external stimulation. Beyond a threshold, individual neurons generate
intrinsic gamma-band membrane oscillations, first below the spiking threshold and then with an occasional occurrence of spikes.
[1]Melloni, Lucia, et al. "Synchronization of neural activity across cortical areas correlates with conscious perception." The Journal of neuroscience 27.11 (2007): 2858-2865.
[2]
Indeed, sleep brings about at once the most common and the most dramatic change in consciousness that healthy subjects are likely to witness – from the nearfading of all experience to the bizarre hallucinations of dreams. At the same time, the brain goes through an orderly progression of sleep stages, which can be identified by recording the electroencephalogram (EEG), eye movements (EOG, electroculogram), and muscle tone (EMG, electromyogram), and which indicate that major changes in brain activity are taking place.
