Thalamocortical Physiology

Question 1

Slow wave sleep is one of the stages of sleep
characterized by a pattern of slow wave
oscillation of the EEG at a frequency called the _____

Answer 1

delta (δ) wave ~3 Hz.

Question 2

______ epilepsy is a type of epilepsy prevalent in children where the child has sudden staring
spells. The child will stop the activity he/she is doing, will stare briefly (a few seconds), and will
then resume

Answer 2

Absence

Question 3

Thalamic relay (TR) neurons are cells located in
the thalamus that receive an input from a ______ and relay that information to cortex via ________
synapses onto pyramidal cortical neurons with soma in layer _______ of cortex

Answer 3

sensory system,
excitatory glutamatergic,
IV

Question 4

Thalamic relay (TR) neurons, When awake, receive
little inhibitory input and their membrane
potential rests at _____. When these cells are
depolarized under these conditions the neurons
fire a series of action potentials at high frequency.

Answer 4

~-55 mV,

Question 5

Thalamic relay (TR) neurons, when asleep in the slow wave stage, the _______ neurons inhibit the TR neurons by releasing the inhibitory neurotransmitter GABA. Under these conditions the resting membrane potential of the TR cell is _______ and they fire bursts of action potentials riding on top of a Ca2+ spike.

Answer 5

thalamic reticular,

~-85 mV

Question 6

Absence seizures cannot be induced in mice where the gene for the ______ has been removed genetically.

Answer 6

T type Ca2+ channel

Question 7

In mice that have mutations in the T type Ca2+ channel gene that alter the voltage dependence of the inactivation gate –making it possible for the
thalamic relay neurons to fire slow Ca2+ spikes at depolarized resting potentials (~-60 mV).
These mutant mice exhibit ______ absence-like seizures and display slow waves in the EEG
during the seizures

Answer 7

spontaneous

Question 8

In humans there is a predisposition for absence seizures in families with specific mutations in genes encoding for _______

Answer 8

T-type Ca2+ channels

Question 9

anticonvulsants known to be clinically effective against absence epilepsy are ________, they block T-type
Ca2+ channels.

Answer 9

ethosuximide and valproic acid

Question 10

When an animal is asleep, stimulation of _______ neurons in the reticular activating system results in awakening of the animal and interruption of slow waves in the EEG.
Stimulation of these neurons releases ______in the thalamus.

Answer 10

cholinergic ,

acetylcholine

Question 11

Noradrenergic neurons from the ______ release noradrenaline in the thalamus. Activation of these
neurons takes place during ________ behaviors.

Answer 11

locus coeruleus,

fight or flight

Question 12

serotonergic neurons from the _______ release serotonin in the thalamus. All these nuclei can exert direct as well as indirect effects on the overall thalamocortical activity that determines sleep and wakefulness.

Answer 12

raphe nuclei

Question 13

_______ enhances inhibition between reticular cells

Answer 13

Clonazepam

Question 14

Clonazepam (AKA Klonopin) is a _______ that specifically enhances GABAA receptors that are
expressed in cells in the reticular nucleus neurons (and not relay cells).

Answer 14

benzodiazepine

Question 15

what is Halorhodopsin?

Answer 15

Light-activated chloride pump used in optogenetics

Question 16

The thalamic relay neuron’s axon
connects to the ________ cell, the burst of firing of action potentials in the TR cell elicits
firing of these cells at a δ frequency eliciting the slow wave EEG that is recorded during slow wave sleep.

Answer 16

cortical pyramidal