Exam 2- week 7 ppt 2 Cereburm layers and columns

Question 1

The majority of the cerebral cortex has _ layers

Answer 1

6 identifiable

Question 2

What parts does not have 6 layers?

Answer 2

hippocampal and parahippocampal cortex

Question 3

How many layers are in the hippocampus?

Answer 3

older phylogenic regions such has hippocampus (archicortex or allocortex) has 3 layers

Question 4

How many layers are in the parahippocampal cortex?

Answer 4

the parahippocampal gyrus (mesocortex) has 3-5 layers as it transitions from archi- to neurocortex

Question 5

How are the cerebrum’s cortical layers numbered?

Answer 5

~from most superficial (I) which is dendrite and axon rich, but poor cell body
~deepest layer (VI) with a number of smaller neurons and a few larger pyramidal cells

Question 6

What is another name for layer I?

Answer 6

molecule layer

Question 7

Details for layer I

Answer 7

~few scattered neurons
~consists mainly of extensions of apical dendrites of pyramidal neurons
~horizontally oriented axons with input from other cortical regions

Question 8

What is another name for layer II

Answer 8

external granular layer

Question 9

Details for layer II

Answer 9

~Contains small pyramidal neurons and numerous stellate neurons

Question 10

What is another name of layer III

Answer 10

external pyramidal layer

Question 11

Details for layer III

Answer 11

Contains mostly:
~small and medium sized pyramidal neurons
~non-pyramidal neurons
~vertically oriented intracortical axons

Question 12

Layers I-III are the main target of

Answer 12

corticocortical afferents

Question 13

Layer III is the principal source of

Answer 13

corticocortical efferents

Question 14

Another name for layer IV is

Answer 14

internal granular layer

Question 15

Details for layer IV

Answer 15

~contains different types of stellate and pyramidal neurons

~ Main target of thalamocortical afferents & intra-hemispheric corticocortical afferents

Question 16

Another name of layer V

Answer 16

internal pyramidal layer

Question 17

Details for layer V

Answer 17

~contains large pyramidal neurons
~largest cortical neurons- Betz cells are located in motor cortex layer V
~give rise to corticofugal axons
~Betz cells in motor cortex layer V are the largest of these corticospinal neurons

Question 18

Another name for layer VI

Answer 18

polymorphic or multiform layer

Question 19

Details for layer VI

Answer 19

~contains few large pyramidal neurons but many small spindle-like pyramidal and multiform neurons
~efferent fibers to the thalamus for reciprocal communication
~connection to thalamus are both excitatory and inhibitory

Question 20

Details for layer VI: connections to thalamus

Answer 20

~excitatory fibers directly to thalamus
~collateral to thalamic reticular nucleus that inhibit
~provides the brainstem with adjustable gain control for the relay of lemniscal and spinothalamic inputs

Question 21

Neurons of similar function are organized into

Answer 21

functional cortical columns

Question 22

Where to the cortical columns extend from/to?

Answer 22

from pial surface to white matter

Question 23

Are the neurons connected between the columns?

Answer 23

Yes, within each column are heavily interconnected between layers in the column

Question 24

Columns with specific functions are only seen in

Answer 24

primary sensory cortex

Question 25

all cells in a particular cortical column respond to the same..

Answer 25

stimulus
~same type of receptor
~same receptive field
~same pattern of stimulation

Question 26

Other details of the cortical columns

Answer 26

~are only this distinct in primary sensory and motor cortices
~role of this pattern of response not clear in how it relates to overall cortical functioning
~vast majority of neocortical neurons are not this input specific