Chapter 19: Brain Rhythms and Sleep Flashcards
The method of choice to study sleep is?
EEG Electroencephalography
For the most part an EEG measures voltages generated by what ?
By currents that flow during synaptic excitation of the dendrites of many pyramidal neurons in the cerebral cortex whih lies under the skull and makes up 80% of the brain mass
The amplitude of the EEG signal stringly depends of how….?
synchronous the activity of the underlying neuron is.
In what is MEG much better than EEG?
Detecting the source of neural activity in the brain expecially if deep below the surface.
The EEG rythms are categorized by their frequency range… beta rythms are?
fastest, anything greater than 14Hz and it signals an activated Cortex.
The EEG rythms are categorized by their frequency range…Alpha rythms are?
About 8-13 Hz and are associated with quiet, waking states.
The EEG rythms are categorized by their frequency range…Theta rhythms are?
4-7 Hz and occur during some sleep states.
The EEG rythms are categorized by their frequency range…Delta rhythms are?
Quite slow less than 4 Hz, often large in amplitude and are a hallmark of deep sleep.
In general high-frequency, low-amplitude rhythms are associated with….?
alertness and waking or the dreaming stages of sleep.
Low-frequency, high amplitude rhythms are associated with?
nondreaming sleep states or the pathological states of coma.
If the cortex is actively engaged in processing information > explain th steps that lead to what typ of EEG.
Activity level of cortical neurons is high but unsynchronized leading to low synchrony leading to low EEG amplitude and beta rhythms dominate,
Name the two mechanisms of synchronous behavior.
led by a pacemaker
arise from the collective behavior of all participants
Which brain area can function as a powerful pacemaker to the cortex.
The Thalamus
What is a generalized seizure?
It involves the entire cerebral cortex of both hemisspheres
What is a partail seizure?
It involves only a circumsribed are of the cortex.
What is the characteristic of a seizure?
Neuron of affected areas fire with a synchrony that never occurs during normal behavior. Seizures are accompanied by very large EEG patterns.
Drugs tha block GABA receptors are very potent convulsants which means…?
They are are seizure-promoting agents
What happens during REM-Sleep?
EEG looks more awake than asleep and vivid dreaming
What does Dement call non-rem-sleep ?
An idling brain in a movable body
What does Dement call rem-sleep?
An active, hallucinating brain in a paralyzed body
What happens to skeletal muscle during rem-sleep?
atonia / total loss of skeletal muscle
Name one example for ultraradian rhythms.
The 90 Minute cycle of non-rem rem non-rem sleep.
What happens after the K complex during Stage 2 of the sleep cycle?
Eye movements almost cease.
Each rem-sleep is followed by at least how many minutes of non-rem-sleep?
30 Minutes
The most reasonable theories about sleep fall into two general categories which are?
Restoration and Adaptation
Walking talking and screaming occur during which kind of sleep?
During non-rem-sleep.
What is somniloquy?
Sleep talking
How do sleep terrors differ from nightmares?
Sleep terrors happen during non-rem sleep nightmare happen during rem-sleep
What is rem rebound?
If a person is deprived from rem-sleep the person will have proportional higher rem-sleep when undisturbed
What is the activation-synthesis-hypothesis?
Dreams are seen as the associations and memories of the cerebral cortex that are elicited by the random discharges of the pons during rem-sleep.
Pontine neurons via the thalamus activate various areas of the cerebral cortex elicit well-known images or emotions, and the cortex then tries to synthesize the images into a whole
What is REM-sleep behavior disorder?
Dreamers who act out their dreams.
What are zeitgebers?
Envrionmental time cues such as light/dark temperature and humidity.
Mammals have a tiny pair of neuron clusters in the hypothalamus that serves a a biological clock..which is called?
The Suprachiasmatic nuclei SCN
When a person experiences repeated seizures, the condition is know as…?
epilepsy
The neurons most critical to the control of sleeping and waking are part ….
of the diffuse modulatory neurotransmitter system.
Sleep involves activity in descending branches of the diffuse modulatory system, such as….
the inhibition of motor neurons during dreaming
Which system controls the rhythmic behaviors of the thalamus, which in turn controls many EEG rhythms of th ecerebral cortex?
The diffuse modulatory system
Slow sleep related rhythms of the thalamus apparently block…?
the flow of sensory information up into the cortex
The brain stem modulatory neurons fire during waking and enhance the awake state. Which neurotransmitters are being used here?
Norepinephrine and serotonin
