Thalamocortical Physiology

Question 1

When do the corticothalamic slow waves stop?

Answer 1

when the animal wakes up

Question 2

Thalamic relay (TR) neurons are cells that receive an input from a sensory system and relay that info to the cortex via excitatory glutamatergic synapses onto ______ with soma in layer 4 of the cortex.

Answer 2

pyramidal cortical neurons

Question 3

Serotonergic neurons from the ______ release serotonin in the thalamus.

Answer 3

raphe nuclei

Question 4

When the Thalamic relay (TR) cells are depolarized, the neurons _____.

Answer 4

fire a series of APs at high frequency

Question 5

What kind of channel is inactivated by depolarization?

Answer 5

T-type Ca++ channels

Question 6

Slow wave EEG typical of absence seizures resembles ______.

Answer 6

the slow waves of stage IV sleep

Question 7

Oscillations in neuronal activity in the _____ circuit play an important role in normal physiological activities such as sleep.

Answer 7

thalamocortical

Question 8

Slow wave EEG typical of ______ resembles the slow waves of stage IV sleep.

Answer 8

absence seizures

Question 9

The thalamic relay (TR) cell elicits firing of the ______ at a delta frequency.

Answer 9

cortical pyramidal cell

Question 10

When an animal is asleep, stimulation of cholinergic neurons in the reticular activating system results in awakening of the animal and interruption of slow waves in the EEG.

Answer 10

cholinergic neurons

Question 11

When do slow Ca++ spikes fire?

Answer 11

when the thalamic relay neuron is hyperpolarized

Question 12

Absence epilepsy is a type of epilepsy prevalent in children, where the child _____.

Answer 12

has sudden staring spells

Question 13

Name 2 anticonvulsants for absence epilepsy.

Answer 13

• ethosuximide
• valporic acid

Question 14

When an animal is asleep, stimulation of cholinergic neurons in the reticular activating system results in ________.

Answer 14

awakening of the animal and interruption of slow waves in the EEG

Question 15

What do the slow EEG waves recorded in absence epilepsy stem from?

Answer 15

thalamocortical oscillatory activity

Question 16

Serotonergic neurons from the raphe nuclei release ______ in the _______.

Answer 16

serotonin; thalamus

Question 17

When an animal is asleep, stimulation of cholinergic neurons in the _______ results in awakening of the animal and interruption of slow waves in the EEG.

Answer 17

reticular activating system

Question 18

Noradrenergic neurons from the locus coeruleus release _____ in the _______.

Answer 18

noradrenaline; thalamus

Question 19

The ____ affects activity of cortical neurons through axonal connectivity btw it and the cortex.

Answer 19

thalamus

Question 20

______ from the raphe nuclei release serotonin in the thalamus.

Answer 20

Serotonergic neurons

Question 21

____ is a type of epilepsy prevalent in children, where the child has sudden staring spells.

Answer 21

Absence epilepsy

Question 22

Noradrenergic neurons from the ______ release noradrenaline in the thalamus.

Answer 22

locus coeruleus

Question 23

What are ethosuximide and valporic acid? How do they work?

Answer 23

txs for absence epilepsy; inhibit T-type Ca++ channels

Question 24

What does the EEG pattern in absence epilepsy look like?

Answer 24

• similar to that of slow wave sleep
• delta waves of about 3 Hz

Question 25

Thalamic relay (TR) neurons are cells that receive an input from a sensory system and relay that info to the _____ via ______ onto pyramidal cortical neurons with soma in layer 4 of the cortex.

Answer 25

cortex; excitatory glutamatergic synapses

Question 26

The thalamic relay (TR) cell elicits firing of the cortical pyramidal cell at a ______.

Answer 26

delta frequency

Question 27

T/F?: Because the thalamus is deep in the diencephalon, the EEG cannot report on its activity directly.

Answer 27

true

Question 28

______ from the locus coeruleus release noradrenaline in the thalamus.

Answer 28

Noradrenergic neurons

Question 29

What is the Thalamic relay (TR) potential when an animal is awake?

Answer 29

-55mV

Question 30

What is the Thalamic relay (TR) potential when the animal is asleep?

Answer 30

-85mV

Question 31

Thalamocortical circuit activity is regulated by _____.

Answer 31

axons ascending from the brainstem from cholinergic, noradrenergic, and serotonergic neurons

Question 32

What is the contribution of the thalamus to an EEG due to?

Answer 32

thalamocortical connections

Question 33

The ______ elicits firing of the cortical pyramidal cell at a delta frequency.

Answer 33

thalamic relay (TR) cell

Question 34

______ typical of absence seizures resembles the slow waves of stage IV sleep.

Answer 34

Slow wave EEG

Question 35

What are the EEG hallmarks of slow wave sleep?

Answer 35

• slow delta waves (3 Hz)
• in stage IV of sleep

Question 36

What kind of channel makes the slow Ca++ spike? What is unique about it?

Answer 36

a T-type Ca++ channel; it’s inactivated by depolarization

Question 37

Thalamic relay (TR) neurons are cells that receive an input from a sensory system and relay that info to the cortex via excitatory glutamatergic synapses onto pyramidal cortical neurons with soma in layer ____ of the cortex.

Answer 37

4

Question 38

All sensory info with the exception of _____ must relay through thalamic nuclei.

Answer 38

olfactory input

Question 39

EEG reports on _____.

Answer 39

collective activity of large neurons near the surface of the brain

Question 40

Who gets absence seizures?

Answer 40

families w/ mutations of the T-type Ca++ channel genes

Question 41

Why is the Thalamic relay (TR) potential more negative when the animal is asleep?

Answer 41

the thalamic reticular neurons inhibit the Thalamic relay (TR) neurons by releasing GABA

Question 42

_____ activity is regulated by axons ascending from the brainstem from cholinergic, noradrenergic, and serotonergic neurons.

Answer 42

Thalamocortical circuit

Question 43

____ neurons are cells that receive an input from a sensory system and relay that info to the cortex via excitatory glutamatergic synapses onto pyramidal cortical neurons with soma in layer 4 of the cortex.

Answer 43

Thalamic relay (TR)

Question 44

What do Thalamic relay (TR) cells at -85mV resting membrane potential fire?

Answer 44

bursts of APs riding on top of a Ca++ spike @ a frequency of 3Hz

Question 45

When an animal ______, stimulation of cholinergic neurons in the reticular activating system results in awakening of the animal and interruption of slow waves in the EEG.

Answer 45

is asleep

Question 46

What causes hyperpolarization of the thalamic relay neurons?

Answer 46

inhibitory interneurons in the thalamic reticular nuclei