[028] Forebrain 1

Question 1

Is cerebral cortex grey or white matter?

Answer 1

Grey matter

Question 2

What is the neocortex?

Answer 2

Most of the cortex apart form olfactory and limbic areas

Question 3

How many layers are there in neocortex?

Answer 3

6

Question 4

What are pyramidal cells

Answer 4

Pyramidal neurons are the sole output (and major input ) of the cortex

Question 5

What types of pyramidal neurons are there
And what are their differences

Answer 5

1. Association fibres
   - leave cerebral cortex to go to other cortical areas in same hemispheres
2. Commissural fibres
   - leave cerebral cortex, go across midline and go to cerebral cortex at contralateral hemispheres
3. Projection fibres
   - leave cerebral cortex, go down into structures deep in forebrain or even into spinal cord eg corticospinal fibres

Question 6

Which layer does corticospinal axons arise from in neocortex

Answer 6

Layer V neurons

Question 7

Which layer does the thalamus project to in the neocortex?

Answer 7

Layer IV

Question 8

What are the lobes of the cerebral hemisphere

Answer 8

Frontal, parietal, temporal, occipital

Question 9

Which sulcus divides the frontal lobe and parietal lobe

Answer 9

Central sulcus

Question 10

Temporal lobe is below which sulci?

Answer 10

Lateral fissure aka Sylvian fissure

Question 11

What does The Central sulcus separate

Answer 11

Central sulcus (sulcus of Rolando) separates frontal lobes (located anteriorly) from the more posterior parietal lobe

Question 12

What separates the frontal lobe from the temporal lobe

Answer 12

Lateral sulcus

Question 13

Is there any demarcation between parietal and occipital lobe laterally?

Answer 13

NO! There is no specific demarcation between parietal and occipital lobe laterally.

But there is a sulcus on the medial aspect

Question 14

What demarcates the parietal lobe from the occipital lobe

Answer 14

Along medial aspect of hemispheres, parietal lobe and occipital lobe separated by parieto-occipital sulcus

Question 15

Do the lateral ventricles extend into each lobe of the cerebral hemisphere?

Answer 15

Yes
- Anterior frontal horn into frontal lobe
- Body within frontal and parietal lobe
- Posterior occipital horn projects into occipital lobe
- Inferior temporal horn extends inferiorly and anteriorly in temporal lobe

Question 16

Components of ventricular system

Answer 16

A. Lateral view
B. Posterior view

Question 17

What is this area

Answer 17

Insular cortex

Question 18

Name the gyrus pointed at

Answer 18

Question 19

Name the gyri in frontal lobe

Answer 19

Superior frontal gyrus
Middle frontal gyrus
Inferior frontal gyrus
Precentral gyrus

Question 20

Gyri of temporal lobe

Answer 20

Superior temporal gyrus
Middle temporal gyrus
Inferior temporal gyrus

Question 21

(Notable) Gyri in parietal lobe

Answer 21

Postcentral gyrus

In inferior parietal lobe:
Supramarginal gyrus (by definition, cuts off at end of lateral fissure)
Angular gyrus

Superior parietal lobe

Question 22

What is the intraparietal sulcus

Answer 22

One of two main sulci of parietal lobe (the other being post central sulci)

• runs from Postcentral sulcus towards occipital pole, dividing parietal lobe into superior and inferior parietal lobules

Question 23

What are Brodmann areas based off

Answer 23

Brodmann areas of cerebral cortex are based on histology but reflect function

Question 24

What is Broca’s area necessary for and where is it found in

Answer 24

Broca’s area found only in dominant hemisphere for language, usually left
- inferior frontal gyrus of the left side

Necessary for fluent speech

Question 25

Where is Broca Area located

Answer 25

Occupies par Opercular is and pars triangular is parts of inferior frontal gyrus

Question 26

Where is the primary motor cortex located

Answer 26

Also called M1, Generally in Precentral gyrus, but it is hard to define the anterior border of the primary motor cortex

Question 27

Where is premotor cortex located

Answer 27

Area 6 on lateral surface of hemisphere (In orange ) Active bilaterally, if at all

Question 28

Where is the somatosensory cortex located

Answer 28

- Just behind the motor cortex, M1 - in parietal lobe - occupies entire Postcentral gyrus - bilateral

Question 29

Representation of body parts in somatosensory cortex, S1

Answer 29

- somatotropin organisation - Representation of contralateral body parts is inverted (except for the face) - hand, lips and tongue have disproportionately large representation

Question 30

Does the motor cortex have a somatotopic organisation?

Answer 30

Yes But organisation of motor cortex is complex - not the case that each corticospinal neuron controls one muscle — have widespread terminals eg there is no corticospinal neuron specific for biceps brachii. Some corticospinal axons arise from neurons in parietal cortex.

Question 31

Where is primary auditory cortex located

Answer 31

Area 41 Bilaterally

Question 32

Where is the Wernicke’s area located

Answer 32

- Dominant hemisphere only - Area 22 in superior temporal gyrus of left hemisphere - Includes area 39, planum temporal (temporal plane) that comprises superior temporal gyrus (posterior portion of Brodman area 22) just posterior to primary auditory cortex and Supramarginal gyrus, area 40

Question 33

Function of Wernicke’s area

Answer 33

Concerned with understanding spoken word

Question 34

Function of planum temporal

Answer 34

Facilitates spatiotemporal discrimination and identification of auditory stimuli that are crucial for speech Involved in or modulated by auditory attention when selecting stimuli from left versus right ear

Question 35

Angular gyrus location

Answer 35

Area 39, Belongs descriptively to inferior parietal lobule Commonly included as part of Wernicke area In dominant hemisphere

Question 36

Function of angular gyrus

Answer 36

Reading (alexia) and Writing (agraphia)

Question 37

What are lesions involving Wernicke area in adults associated with

Answer 37

Wernicke or receptive aphasia, where comprehension is impaired to a greater extent than fluency of speech.

Question 38

Where is the posterior