Exam 4 Part VI Flashcards
(112 cards)
Alpha waves:
8-13 cps (=Hz)
Alpha waves: 8-13 cps (=Hz)
Awake, restful state generated thalamus → cortex, strongest in occipital cortex. Usually said to come from visual cortex when it’s generating its
own rhythm, not receiving input from
outside (eyes open – α is gone)
Beta waves:
Beta waves: above 14 cps→25→50→
Beta waves: above 14 cps→25→50→
During activation of CNS, attention to a particular activity, REM sleep or during tension (above parietal & frontal).
Delta waves: below 3.5 cps
In deep (slow-wave) sleep (can be generated by cortex alone)
Theta waves:
Theta waves: 4-7 cps Hippocampus, ant. cingulate: problem-solving, spatial learning, navigation, anxiety, but also some stages of sleep
The degree of activity of the brain is proportional to the frequency of
brain waves
Evoked potentials.
Usually sensory stimuli of some kind. Visual, auditory, somatosensory, etc. Used clinically to detect intactness and features of pathway to cortex.
Slow-wave sleep,
Slow-wave sleep, restful sleep, most during night in adults, fall into this after sleep deprivation. Sleep-walking is in this stage
REM sleep –
REM sleep – rapid eye movement sleep. About 25% of sleep in young adults recurring about every 90 min., usually associated with dreaming. (In neonates about 90% of sleeping is REM.) The EEG is like wakefulness (Beta waves). Loss of muscle tone is characteristic of this type of sleep.
Active theory of sleep:
some center or centers below the midpons actively causes sleep by inhibiting other parts of the brain.
[orexin =
[orexin = hypocretin, found in lat. hypothalamus, 1 type of receptor absent in narcoleptic dogs. Orexin knockout mice = narcoleptic.
Modafinil activates
Modafinil activates orexin neurons and keeps one awake]
C. Epilepsy
Characterized by uncontrolled, excessive activity in part or all of CNS.
Generalized seizures:
Generalized seizures: loss of consciousness:
Grand mal:
tonic-clonic convulsion of entire body
grand mal is a
generalized seizure
Most people who exhibit generalized seizures have a
Most people who exhibit it have a hereditary predisposition for it.
Factors that can precipitate epilepsy include:
strong emotional stimuli
alkalosis caused by overbreathing → hyperexcitability of neurons
drugs (insulin hypoglycemia)
fever
loud noises or flashing lights → resonating frequency
Traumatic lesions are also capable of eliciting
Traumatic lesions are also capable of eliciting grand mal. →scarring → excessive excitability locally spreads
Petit mal
Petit mal (absence seizures): a few seconds of unconsciousness,
Partial seizures:
Partial seizures: without loss of consciousness:
includes focal epilepsy
Focal epilepsy:
Focal epilepsy: can come from a scar, necrosis, tumor or unknown etiology. One type is a psychomotor seizure; it usually involves the limbic system of the brain.
Vegetative and endocrine control functions of the hypothalamus CV regulation
↑ P & HR (post. & lat.): “expansive” ↓ P & HR (preoptic): “contractive”