exam three (biorhythms) Flashcards
classical method of recording brain rhythms in cerebral cortex (hans berger)
EEG
timing of physiological function according to brain clock
circadian rhythm
to record brain waves voltage fluctuations between ___ ___ are measured
electrode pairs
electrode pairs measure electrical activity across what
two different cortical regions
eeg detects very small electrical fields generated by synaptic currents in ____ ____
cortical pyramidal
presynaptic release of _____ opens postsynaptic ion channels on cortical pyramidal cells
glutamate
positive current flows into pyramidal cell dendrite and leaves a slight _____ charge in extracellular fluid
negative
the positive current spreads through the dendrite and gradually escapes leaving ____ ___ more positive
intracellular fluid
activity across a ______ of cortical pyramidal cells is recorded by a single electrode and summed
population
small EEG signals generated by ______ activity
asynchronous
large EEG signals generated by _____ activity
synchronous
in the case of an EEG it is not the number of neurons activated but their _____
synchrony
quiet, waking state
alpha
light sleep
theta
deep sleep
delta
activated cortex
beta
activated, attentive cortex
gamma
high synchrony, high EEG amplitude, low frequency
deep sleep (delta)
low synchrony, low EEG, high frequency
alert and awake
records small differences in _____ signals generated by neural activity
magnetic
mechanisms of synchronous rhythms: a simple model oscillator with one ____ and ____ neuron
excitatory and inhibitory; constant excitatory inout will tend to trade back and forth creating a rhythm
there are two idea of what controls synchronous rhythms: the first idea is that cells take cues from a ____ _____;
master pacemaker
there are two idea of what controls synchronous rhythms: the second idea is ___ ____; many cells distribute timing function among themselves
collective collaboration
what structure is the master clock; has massive inputs to cortex
thalamus
_____ people will experience a seizure
7-10%
identified with a specific cause (infection, trauma, tumor, ect.)
symptomatic seizure
appears spontaneously in the absence of other CNS diseases
idiopathic seizures
repeated seizures- a level of synchrony generally not seen during normal behavior
epilepsy
entire cerebral cortex, complete behavioral disruption, loss of consciousness
generalized epilepsy
specific cortical area, may be associated with abnormal sensation or aura
partial or focal epilepsy
what are three symptoms of epileptic episodes
aura, motor component, loss of consciousness
originate mostly in temporal lobe, characterized by subjective experiences, automatisms or postural changes
complex partial seizure
patient H.M had a temporal lobectomy that had no effect onn
perception, intelligence, or personality
of brief duration, characterized by a loss of awareness with no motor activity except head or rolling eyes
petit mal
characterized by loss of consciousness and stereotypes motor activity
grand mal
stages of grand mal:
body stiffens and breathing stops
tonic stage
stages of grand mal: rhythmic shaking
clonic stage
stages of grand mal:
post seizure state of confusion
postictal depression
less than 30 sec. of generalized seizure, generally childhood from
absence seizure
during generalized epileptic seizure what is EEG signature
synchronized activity across scalp
these drugs inhibit discharge of abnormal neurons by stabilizing the neuronal membrane
anticonvulsant medications
readily reversible state of reduced responsiveness to and with environment
sleep
stages 1-4 of sleep are
non-REM
periods get longer over sleep cycle; more vivid dreams; atonia
REM sleep
humans average around ___ sleep cycles per night
90 minutes
sleep deprivation does lead to decreased cog. performance on tasks that require
attention
brief period of sleep lasting a second or so
microsleep
in sleep deprivation studies subjects show an increased tendency to
enter REM more readily in subsequent sleep sessions
subjects spend more time in REM after deprivation; what is this called?
REM rebound
process of shifitng a memory to new location occurs during sleep and is called
consolidation
____ memory consolidation in non REM
explicit (episodic)
____ memory consolidation in REM
implicit (motor skills)
hippocampal neuron that fires when a rat is in a certain location in an environment
place cell
during periods of ___ sleep after the food search activity of place cells become correlated
NREM
lesions in the midline structures (reticular activating system) of the brain stem produced states of consciousness like
NREM
when the midline (reticular activating system) is electrically stimulated it caused the cortex to from NREM to
aroused and alert state
(diffuse modulatory NT systems) what neurons are active during waking state and enhance waking state
noradrenergic and seratoninergic
(diffuse modulatory NT systems) active during waking state and also enhance REM events
cholinergic neurons
diffuse modulatory NT systems ___ rhythmic behavior of thalamus and ______ asynchronicity
decrease; increase
_____ has been associated with loss of hypocretin containing neurons (acetylcholine, seratonin, NE )
narcolepsy
progression of EEG changes ending in NREM sleep state
sleep
REM-on is due to ACh cells in pons, _____ firing just prior to REM sleep
increase
REM-off (5-HT and NE) cells in raphe and upper brainstem ____ firing just prior NREM sleep
increase
sleep promoting factor; accumulates over waking period, then decreases during sleep
adenosine
produced by wake-promoting Ach neurons; concentrations increase over waking period (stim. release of adenosine)
Nitric Oxide
synthesized in brain, stimulates immune system and peaks before sleep
cytokine (interleukin-1)
____% of genes exhibited differences of expression levels between sleeping and waking
0.5
cirelli and tononi found that genes which increased in sleeping rats are used for (changes were brain specific)
protein synthesis and plasticity related genes
circadian rhythms will continue even if daylight is removed; true or false?
true
name for environmental time cues that we become entrained to
zeitgebers
intact SCN produces rhythmic message: SCN cell firing rate varies with circadian rhythm, light input _____ clock
resets
action potentials are not keeping time in SCN because ___ applied to these neurons does not disrupt rhythm
TTX
a photoreceptor that is not a rod or cone that contains ____ slowly excited by light
melanopsin
the melanopsin synapses where
SCN neurons
if SCN is damaged what happens
daily activities occur haphazardly
the ___ is the master clock but almost every cell in the body has its own clock
SCN
the SCN neurons maintain ______ activity in the absense of output and input
rhythmic