BIOL4100: BRAIN RHYTHMS AND SLEEP EXAM QUESTIONS
AND ANSWERS WITH COMPLETE SOLUTIONS VERIFIED
Electroencephalogram
Measures generalized activity in µV, requiring activation of many thousands of neurons
activated together to generate signal with sufficient strength to record
Electroencephalogram Signals
Come from synaptic excitation of dendrites on cortical pyramidal neurons
How Electroencephalogram Works
Afferent axon releases glutamate, depolarizes neuron, making extracellular fluid more
negative, and is based on comparison to nearby reference electrode
Electroencephalogram Activity
Must be synchronous
EEG Rhythms
Beta, alpha, theta, and delta
Beta Rhythm
Fastest, > 14 Hz, activated cortex
Alpha Rhythm
8-13 Hz, quiet waking state
Theta Rhythm
4-7 Hz, occurs during some sleep stages
Delta Rhythm
Slowest, < 4 Hz, large amplitude, deep sleep
, Source of Synchronous Rhythms
Cued by a central clock or pacemaker or distribute timing function by mutually exciting
or inhibiting one another
Mammalian Source of Synchronous Rhythms
Combination of both sources of rhythmic neuronal activity
Simple Two-Neuron Oscillator
Excitatory input is constant, E cell depolarizes and excites I cell, and I cells depolarizes
and inhibits E cell
Thalamus as a Pacemaker
Cells contain voltage-gated ion channels allowing for rhythmic, self-sustaining discharge
patterns even in the absence of external input, allowing cells to become synchronized
3 Potential Functions of Brain Rhythms
Brain's way of disconnecting cortex from sensory input during sleep, neural rhythms
coordinate activity between regions when awake, or just by-products which no purpose
Mechanisms of Seizures
Depend largely upon the type of seizure
Behavioral Features of Seizures
Associated largely with the location of seizure and pattern of seizure activity
Generalized Seizures
Involve most of the cortex and disrupt virtually all ongoing behavior during the seizure
Absence Seizures
Most frequent in childhood, ~ 30 sec of generalized 3 Hz EEG activity, and loss of
consciousness
AND ANSWERS WITH COMPLETE SOLUTIONS VERIFIED
Electroencephalogram
Measures generalized activity in µV, requiring activation of many thousands of neurons
activated together to generate signal with sufficient strength to record
Electroencephalogram Signals
Come from synaptic excitation of dendrites on cortical pyramidal neurons
How Electroencephalogram Works
Afferent axon releases glutamate, depolarizes neuron, making extracellular fluid more
negative, and is based on comparison to nearby reference electrode
Electroencephalogram Activity
Must be synchronous
EEG Rhythms
Beta, alpha, theta, and delta
Beta Rhythm
Fastest, > 14 Hz, activated cortex
Alpha Rhythm
8-13 Hz, quiet waking state
Theta Rhythm
4-7 Hz, occurs during some sleep stages
Delta Rhythm
Slowest, < 4 Hz, large amplitude, deep sleep
, Source of Synchronous Rhythms
Cued by a central clock or pacemaker or distribute timing function by mutually exciting
or inhibiting one another
Mammalian Source of Synchronous Rhythms
Combination of both sources of rhythmic neuronal activity
Simple Two-Neuron Oscillator
Excitatory input is constant, E cell depolarizes and excites I cell, and I cells depolarizes
and inhibits E cell
Thalamus as a Pacemaker
Cells contain voltage-gated ion channels allowing for rhythmic, self-sustaining discharge
patterns even in the absence of external input, allowing cells to become synchronized
3 Potential Functions of Brain Rhythms
Brain's way of disconnecting cortex from sensory input during sleep, neural rhythms
coordinate activity between regions when awake, or just by-products which no purpose
Mechanisms of Seizures
Depend largely upon the type of seizure
Behavioral Features of Seizures
Associated largely with the location of seizure and pattern of seizure activity
Generalized Seizures
Involve most of the cortex and disrupt virtually all ongoing behavior during the seizure
Absence Seizures
Most frequent in childhood, ~ 30 sec of generalized 3 Hz EEG activity, and loss of
consciousness
