Cerebral Cortex I

Question 1

How much of human brain is comprised of cerebral cortex

Answer 1

approx 80% of human brain comprised of cerebral cortex

Question 2

describe what human cortex is

Answer 2

Then sheet tissue
2-4mm in thickness
Basic architecture nearly identical over a broad range of species = like rat to human

Question 3

compare human cortex to other species

Answer 3

Same cells in same arrangement
But for humans =just more bc bigger = very large,huge surface area, but basic organizational motif the same

Question 4

what species have smooth or wrinkled brains

Answer 4

Rat brain = smooth,
Dog/cat=wrinkled a bit
Chimp/human/dolphin/elephant = very wrinkled

Question 5

Describe folds of human cortex

Answer 5

Cortex has many folds = enable large cortical surface area to fit inside skull
Allow to cram more sa into skull = grooves, can fit more cortical area inside skull

Question 6

what are folds called

Answer 6

Gyri (gyrus) = mounds

Question 7

what are grooves called

Answer 7

Sulci (sulcus or fissures) = grooves between gyri

Question 8

is the cerebral cortex the same in every person

Answer 8

No! = can show substantial structural variability in diff people
But can still identify anatomical structures related to patterns of gyri and sulci
Macro-anatomically defined regions correspond to diff functional regions = specialized, boundaries bewteen tehse areas line up with pattern of gyri and sulci

Question 9

name the prominent landmarks on human brain

Answer 9

Identifiable sulci and gyri =
Central sulcus (Rolandic fissure)
Lateral sulcus (Sylvain fissure)
(Key anatomical landmarks - bc embryology= why its shaped that way)

Question 10

describe lateral surface of cerebral cortex

Answer 10

Divided into 4 lobes
= frontal lobe (anterior to central sulcus, dorsal to lateral sulcus)
Temporal lobe
Parietal lobe
Occipital lobe

Question 11

where is a lot of the cerebral cortex hidden

Answer 11

within longitudinal fissure
4 lobes represented within this medial surface and a 5th lobe = limbic lobe, bounded by cingulate sulcus
Lots of cortex on medial surface
V1=on medial surface

Question 12

describe Limbic lobe

Answer 12

Defined by cingulate sulcus
Cortex under cingulate sulcus
Connects cognition thinking and feeling

Question 13

what are the 2 cerebral hemispheres separate by

Answer 13

Deep groove called longitudinal fissure

Question 14

what connects the 2 cerebral hemispheres

Answer 14

Corpus callosum
Sheet myelinated axons, connecting the 2 hemispheres so can talk to each other

Question 15

describe systems to name diff regions of cerebral cortex

Answer 15

various systems have been developed to name the diff regions of cerebral cortex
Most influential = korbinian brodmann 1909 = dived cortex into 52 numbered areas
System still widely used
4=m1
18=higher order visual processing area
17=v1

Question 16

how many layers of cortex

Answer 16

Thin sheet has 6 layers

Question 17

name all the laters of cortex from outside to inside

Answer 17

Layer 1 = molecular layer
Layer 2 = external granule layer
Layer 3 = external pyramidal layer
Layer 4 = internal granule layer
Layer 5= internal pyramidal layer
Layer 6= multi form layer

Question 18

name the 3 diff stains for Cortex

Answer 18

Golgi stain
Nissl stain
Weigert stain

Question 19

describe golgi stain

Answer 19

Only stains small random number of neurons
Stains whole neuron = cell bodies, dendrites and axons
See shape of cell more - best for seeing morphology

Question 20

describe Nissl stain

Answer 20

Stains cell bodies = neurons stand out best for seeing layers

Question 21

describe weigert stain

Answer 21

Stains myelinated axons

Question 22

Describe cortex layer 1 = molecular layer

Answer 22

Not many cells
Mainly dendrites, axons and synapses

Question 23

Describe cortex layer 2= external granule layer

Answer 23

Small densely packed cells filled with granule cells - little cells

Question 24

Describe cortex layer 3 = external pyramidal layer

Answer 24

Prominent cell type = cells with cell bodies shaped like pyramids = pyramidal cells
See that pyramidal neuron dendrites extends to layer 1 and see branching

Question 25

Describe cortex layer 4 =internal granule layer

Answer 25

Little cells See dendrites

Question 26

Describe cortex layer 5=internal pyramidal layer

Answer 26

A lot larger pyramidal cells

Question 27

Describe cortex layer 6 = multi form layer

Answer 27

Many diff cells

Question 28

What do the 6 layers do

Answer 28

Diff layers are talking to each other