Intro To Cerebral Cortex

Question 1

Frontal Anatomy

Answer 1

Superior Frontal
Middle Frontal
Inferior Frontal: Or, T, O,

Precentral gyrus

Question 2

Temporal Anatomy

Answer 2

Superior
Middle
Inferior

Question 3

Occipital Anatomy

Answer 3

D

Question 4

Parietal Anatomy

Answer 4

F

Question 5

Cortical Divisions

Answer 5

ISOCORTEX: 6 layered (neocortex)

ALLOCORTEX: 3 layered

• paleocortex - olfactory
• archicortex - hippocampus

Question 6

Neocortical Layers

Answer 6

1 = molecular  
2= external granular 
3= external pyramidal
4= INTERNAL GRANULAR
5= internal pyramidal 
6= fusiform 

Granular=4
Infragranular= 5, 6

Question 7

Types of Neurons in Cortex

Answer 7

1. Spiny Stellate Cells
2. Pyramidal Cells
3. Nonpyramidal Cells

Question 8

Spiny Stellate Cells

Answer 8

Look like stars
-dendrites all directions

Dendrites largely layer 4

Dendrites have spines

Excitatory neurons: use glutamate

Axons project (info) to layers 2/3 `

Question 9

Pyramidal Neurons

Answer 9

Soma shaped like pyramid

Apical dendrite

• to layer 1
• ends in apical tuft
• oblique dendrites come off

Basal dendrites

Excitatory: use glutamate

Cell bodies in layers 2/3, 5, and 6

Question 10

Nonpyramidal

Answer 10

Inhibitory neurons

ALL layers

20% of cortical neurons

GABA

Lack spines on dendrites

Very specialized

Question 11

Feed Forward

Answer 11

Shapes impact of afferent input

Ex, Gaba neuron gets side signal from excitatory afferent, sends feed forward inhibitory signal to common downstream target

Question 12

Feed-back inhibition

Answer 12

Dampens local excitation in proportion to output

Ex. GABA neuron receives signal from pyramidal neuron and sends inhibitory signal back

Question 13

Cost/Benefit of cortex

Answer 13

Rich substrate of excitatory synapses

BENEFIT: rich substrate for learning, memory and cognition
-allows for plasticity

COST: too much excitation can injure or kill neurons: excitotoxicity

Question 14

How does the cortex work?

Answer 14

Compares expectations with reality

Question 15

Supragranular Layer

Answer 15

Layers 1, 2, 3

Primary origin and termination of intra cortical connections

Permits communication

ASSOCIATIONAL: communicate with areas in same hemisphere

COMMISSURAL: connect to opposite hemisphere

Question 16

Granular Layer

Answer 16

Mostly Thalamocortical input, esp from specific thalamic nuclei

Impt primary sensory cortices

(Motor cortex usually “agranular”)

Question 17

Infragranular Layer

Answer 17

Layers 5 and 6

Connect cerebral cortex with subcortical regions

Most developed in MOTOR cortex

Layer 5: projects to basal ganglia, brain stem, and spinal chord
-also to thalamus and other cortex

Layer 6: projects primarily to thalamus

Question 18

Top-Down

Answer 18

Predictive information

Information from higher cortical areas or non-specific thalamic nuclei that go to integration neurons

What is expected

Question 19

Bottom Up

Answer 19

Perceptive information

Info from lower cortical areas or sensory thalamic nuclei

new data/what is happening

Question 20

Integration Centers

Answer 20

Usually pyramidal neurons

Gets top-down info through apical dendrite/tuft (expected)

Gets bottom-up info from oblique or basal dendrites (new data)

Synthesize and compare inputs

Question 21

Synergy

Answer 21

Pyramidal neurons receive simultaneous input from both dendritic fields

Large electrical event

Long lasting plateau potential from ca currents

Burst of action potentials

Question 22

General Cortex Anatomy

Answer 22

Longitudinal fissure
Lateral Fissure

Frontal

Parietal (back top)

Temporal (side)

Occipital (back)