Cerebral Cortex Flashcards
granular vs agranular cortices
- granular = sensory/afferent function- layer 4
- agranular = motor (BA 4) and premotor cortex (BA 6) pyramidal layers; prominent function for output
The summation of electrical potential changes in the cerebral cortex occurs mainly at the vertically oriented _______.
pyramidal cells
What is feedforward relay of information?
- passing info from layer 3 to the higher layers- up the chain
- bottom up
- observed responses to stimuli
If the layers of the cortex are analogous to an email system, what are layers 2/3, 4, and 5/6?
- 2/3 = interoffice mail (relays)
- 4 = inbox (pathways arrive here)
- 5/6 = outbox (pathways leave via here- motor and thalamus)
Large ____ cells are most common in layers 5 and 6.
pyramidal
Recall from a previous lecture on the thalamus that rhythmic burst firing in the thalamus is prevalent during periods of _____, _____, and _____, and is thought to represent a temporary detachment of thalamic relay cells from their sensory inputs.
- slow wave sleep
- deep anesthesia
- absence seizures
_____ depolarizes thalamic relay neurons but this inhibits the thalamic reticular nucleus.
ACh
Cholinergic agonists and antagonists can have significant effects seen on ______.
EEG rhythms
What is predictive coding?
- compression of information into more simple form for storage
- gives difference btw observation and expectation in feedforward vs feedback flow
- basically only sending novel/unexpected information
Large pyramidal cells are most commonly found in layers _____.
5 and 6
The electroencephalogram measures electrical potential fluctuations at the scalp surface. These fluctuations of are produced mainly by ________ induced in neurons of the cerebral cortex.
temporal and spatial summation of electrical currents caused by EPSPs and IPSPs
Acetylcholine acts to open the thalamocortical gate to sensory information, consistent with its known effects on _____ and ______.
attention and arousal
synchrony
- the idea that neurons firing in close proximity will induce each other to synchronize their activity
- individual neurons have variable responses, but as a group the information is greater, more accurate, and gives the bigger picture
- neurons that oscillate together/fire together, wire together!
_______ acts to open the thalamocortical gate to sensory information, consistent with its known effects on attention and arousal.
Acetylcholine
______ cells of the reticular formation release thalamic cells from the rhythmic calcium spikes that generate the sleep rhyhms/spindles.
Cholinergic
Ach depolarizes ______ but this inhibits the ______.
- depolarizes = thalamic relay neurons
- inhibits = thalamic reticular nucleus
Cholinergic cells of the reticular formation release thalamic cells from the ______ that generate the sleep rhyhms/spindles.
rhythmic calcium spikes
____ are critical for the balance of cerebral cortex activity.
GABA-ergic neurons
______ cells are concentrated in layer 4 of the cortex.
Granular
The primary visual cortex has a large layer ____. Why?
4 because there’s so much sensory information coming into the eyes!
Stimulation of the brainstem reticular formation converts the _____ rhythms of sleep into the _____ activity of wakefulness (with behavioral correlate of wakefulness in the animal).
- slow oscillatory = sleep
- fast = awake
Stimulation of the _______ converts the slow oscillatory rhythms of sleep into the fast activity of wakefulness (with behavioral correlate of wakefulness in the animal).
brainstem reticular formation
Granular cells are concentrated in layer ___ of the cortex.
4
What is feedback flow of information?
- from the top-down- layers 2, 5, 6 to layers 1, 5, 6
- feedback- the response
Inhibitory interneurons make up _____% of all the cells in the cerebral cortex.
20%
______ make up 20% of all the cells in the cerebral cortex.
Inhibitory interneurons
The characteristic frequency bands or ranges of the EEG are? What physiology do they each correlate with?
- Delta: ?
- Theta: ?
- Alpha: ?
- Beta: ?
- Gamma: ?
- Delta: below 3.5Hz (slow wave sleep, deepest non-REM sleep, sleepwalking, bedwetting, night terrors here)
- Theta: 4-7.5 Hz (sleep onset/light sleep, inhibition of elicited responses)
- Alpha: 8-13 Hz (awake/waking up, eyes closed, coma)
- Beta: 14-30 Hz (awake, alert, active thinking, focus AND REM sleep)
- Gamma: 30-100 Hz (cross-modal sensory processing)
- *** BATs Drink Blood = from awake –> sleep
- Identify the basic classification of EEG rhythms, and their rough correspondence to different behavioral states.
- Delta: below 3.5Hz (slow wave sleep, deepest non-REM sleep, sleepwalking, bedwetting, night terrors here)
- Theta: 4-7.5 Hz (sleep onset/light sleep, inhibition of elicited responses)
- Alpha: 8-13 Hz (awake/waking up, eyes closed, coma)
- Beta: 14-30 Hz (awake, alert, active thinking, focus AND REM sleep)
- Gamma: 30-100 Hz (cross-modal sensory processing)
- *** BATs Drink Blood = the order from awake –> sleep
Recall from a previous lecture on the thalamus that rhythmic burst firing in the thalamus is prevalent during periods of slow wave sleep, deep anesthesia, or absence seizures, and is thought to represent ______.
a temporary detachment of thalamic relay cells from their sensory inputs
Distinct patterns of oscillation implies that a large number of neurons in a given location are experiencing simultaneous depolarization alternating with hyperpolarization, which is to say their activity is ______.
synchronized
How many layers are in the neocortex?
6 layers
