Lecture 5: Cerebral Cortex

Question 1

Explain the Characteristics of the Cerebral Hemispheres (4)

Answer 1

1 * Cortex composed of GREY MATTER (cell bodies of neurons).

2 * LAYERED STRUCTURE of cortex REFLECTING FUNCTIONAL AREAS of the cortex.
- Korbinian Brodmann mapped the areas based on differences in cytoarchitecture. Later found that structural differences related to functional differences

3 * Entire AREA of the cerebral cortex is 1m2.

4 * 5 lobes: frontal, parietal, temporal, occipital and limbic.

5. Cerebral Cortex is comprised of 6 layers?

Question 2

UNDERSTAND THE HISTOLOGICAL ORGANISATION OF THE NEOCORTEX:

Older areas of cortex have only three layers, such as the paleocortex in the olfactory bulb and the archicortex in the hippocampus.

Answer 2

Older areas of the cortex have only three layers, such as the paleocortex in the olfactory bulb and the archicortex in the hippocampus.

Layers:
Molecular layer (i)
External Granular layer (ii)
External Pyramidal layer (iii)
Internal Granular Layer (iv)
Internal pyramidal layer (V)
Multiform layer (VI)

Question 3

Explain Pyramidal Neurons (3)

Answer 3

1. Found in layers III and V.
2. Main output cells of the cortex – the project from cortex to other regions of CNS.
3. Characteristic triangular structure, typically with one apical dendrite and abundant dendritic trees coming from cell body.

Question 4

In the….. cortex, there are more …? NEURONS?
Primary motor cortex
Primary sensory cortex

Answer 4

Primary motor cortex
Pyramidal > granular neurons

Primary sensory cortex
Granular > pyramidal neurons

Question 4

In the….. cortex, there are more …? NEURONS?
Primary motor cortex
Primary sensory cortex

Answer 4

Primary motor cortex
Pyramidal > granular neurons

Primary sensory cortex
Granular > pyramidal neurons

Question 5

Understand the Sensory Homunclus

Answer 5

In an image

Question 6

What is Association Fibres?
EXAMPLES? 3

Answer 6

1. Association fibres interconnect areas of the cortex within one hemisphere.

Examples:
* Superior longitudinal fasciculus
* Inferior front-occipital fasciculus
* Cingulum

Question 7

What are commissural fibres?

EXAMPLES (2)

Answer 7

1. Commissural fibres connect functional areas of the cortex in one hemisphere with corresponding functional areas in the other hemisphere.

Examples:
* Corpus callosum
* Anterior commissure

Question 8

What are Projection Fibres?
Examples? 2

Answer 8

Projection fibres travel to or from the cortex. Travel between the thalamus & cortex or descend from the cortex to basal ganglia.

Examples:
* Corona radiata
* Optic radiation

Question 9

Understand the Functional Areas of the Cortex
Understand the Association Areas of the Cortex
Understand Parietal Association Areas of the Cortex
Understand the Temporal Association Areas the Cortex

Answer 9

What is Parietal Association Areas: the area where somatic and visual sensations are integrated, resulting in the high-level interpretation of stimuli.

Recall Functions of Cortical Regions

Question 10

Neurobiology of language; Broca area, Wernicke area, Arcuate fasciculus

Answer 10

Broca area – links cortical areas together for the production of language.

Wernicke area – dedicated to the comprehension of language and assign meaning to symbols.

Arcuate fasciculus connects Broca and Wernicke areas.

Question 11

What is Aphasia?

Answer 11

Aphasia = inability to communicate effectively

Broca Aphasia:
Expressive or motor aphasia
Nonfluent Speech, difficulty with syntax,
grammar, repetition, and production of individual words. Comprehension is intact.

Wernicke Aphasia:
Receptive or sensory aphasia.
Fluent speech, syntax, grammar, and structure of words are intact.
Difficulty with comprehension of speech.
produces nonsensical words and phrases.

Conduction Aphasia:
Difficulty repeating words
Both comprehension and production of language are intact.

Question 12

Understand the Blood Supply to The Cortex. Blood supply to cortex & subcortical nuclei

Answer 12

and vascular territories.