Thalamocortical Physiology Flashcards
When do the corticothalamic slow waves stop?
when the animal wakes up
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.
pyramidal cortical neurons
Serotonergic neurons from the ______ release serotonin in the thalamus.
raphe nuclei
When the Thalamic relay (TR) cells are depolarized, the neurons _____.
fire a series of APs at high frequency
What kind of channel is inactivated by depolarization?
T-type Ca++ channels
Slow wave EEG typical of absence seizures resembles ______.
the slow waves of stage IV sleep
Oscillations in neuronal activity in the _____ circuit play an important role in normal physiological activities such as sleep.
thalamocortical
Slow wave EEG typical of ______ resembles the slow waves of stage IV sleep.
absence seizures
The thalamic relay (TR) cell elicits firing of the ______ at a delta frequency.
cortical pyramidal cell
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.
cholinergic neurons
When do slow Ca++ spikes fire?
when the thalamic relay neuron is hyperpolarized
Absence epilepsy is a type of epilepsy prevalent in children, where the child _____.
has sudden staring spells
Name 2 anticonvulsants for absence epilepsy.
- ethosuximide
- valporic acid
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
What do the slow EEG waves recorded in absence epilepsy stem from?
thalamocortical oscillatory activity
Serotonergic neurons from the raphe nuclei release ______ in the _______.
serotonin; thalamus
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.
reticular activating system
Noradrenergic neurons from the locus coeruleus release _____ in the _______.
noradrenaline; thalamus
The ____ affects activity of cortical neurons through axonal connectivity btw it and the cortex.
thalamus
______ from the raphe nuclei release serotonin in the thalamus.
Serotonergic neurons
____ is a type of epilepsy prevalent in children, where the child has sudden staring spells.
Absence epilepsy
Noradrenergic neurons from the ______ release noradrenaline in the thalamus.
locus coeruleus
What are ethosuximide and valporic acid? How do they work?
txs for absence epilepsy; inhibit T-type Ca++ channels
What does the EEG pattern in absence epilepsy look like?
- similar to that of slow wave sleep
- delta waves of about 3 Hz
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.
cortex; excitatory glutamatergic synapses
The thalamic relay (TR) cell elicits firing of the cortical pyramidal cell at a ______.
delta frequency
T/F?: Because the thalamus is deep in the diencephalon, the EEG cannot report on its activity directly.
true
______ from the locus coeruleus release noradrenaline in the thalamus.
Noradrenergic neurons
What is the Thalamic relay (TR) potential when an animal is awake?
-55mV
What is the Thalamic relay (TR) potential when the animal is asleep?
-85mV
Thalamocortical circuit activity is regulated by _____.
axons ascending from the brainstem from cholinergic, noradrenergic, and serotonergic neurons
What is the contribution of the thalamus to an EEG due to?
thalamocortical connections
The ______ elicits firing of the cortical pyramidal cell at a delta frequency.
thalamic relay (TR) cell
______ typical of absence seizures resembles the slow waves of stage IV sleep.
Slow wave EEG
What are the EEG hallmarks of slow wave sleep?
- slow delta waves (3 Hz)
- in stage IV of sleep
What kind of channel makes the slow Ca++ spike? What is unique about it?
a T-type Ca++ channel; it’s inactivated by depolarization
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.
4
All sensory info with the exception of _____ must relay through thalamic nuclei.
olfactory input
EEG reports on _____.
collective activity of large neurons near the surface of the brain
Who gets absence seizures?
families w/ mutations of the T-type Ca++ channel genes
Why is the Thalamic relay (TR) potential more negative when the animal is asleep?
the thalamic reticular neurons inhibit the Thalamic relay (TR) neurons by releasing GABA
_____ activity is regulated by axons ascending from the brainstem from cholinergic, noradrenergic, and serotonergic neurons.
Thalamocortical circuit
____ 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.
Thalamic relay (TR)
What do Thalamic relay (TR) cells at -85mV resting membrane potential fire?
bursts of APs riding on top of a Ca++ spike @ a frequency of 3Hz
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.
is asleep
What causes hyperpolarization of the thalamic relay neurons?
inhibitory interneurons in the thalamic reticular nuclei
