NAL: Cerebral Hemispheres and Cortex

What are the 5 vesicles formed on both sides of the embryonic tube? What does each develop into?

Telencephalon - cerebral hemispheres

Diencephalon - thalamus, epithalamus, and hypothalamus

Mesencephalon - mesencephalon

Metencephalon - pons and cerebellum

Myelencephalon - medulla oblongata

What are the three mapping methods for the cortex?

Anatomical (gyri, sulci, lobes), histological (52 brodmann areas), and functional (motor/premotor/visual/etc.)

Are the hemispheres equal? Why or why not?

No, left is larger (left handed individuals may have equal or larger right side)

What are the divisions of the frontal lobe?

Precentral gyrus, superior frontal gyrus, middle frontal gyrus, inferior frontal gyrus - opercular + triangular + orbital gyri

What are the divisions of the parietal lobe? What about functionally?

Post-central gyrus, superior parietal lobe, inferior parietal lobe - supramarginal gyrus + angular gyrus.

Primary sensory cortex

What are the divisions of the temporal lobe?

(Lateral) Superior/inferior temporal, superior/middle/inferior gyrus

(Inferior) inferior temporal gyrus, lateral occipitotemporal gyrus, medial occipitotemporal gyrus, and parahippocampal gyrus - uncus

What does the temporal lobe do?

Involved in language/hearing/visual ID

What line demarcates the occipital lobe from the parietal/temporal?

From parietooccipital sulcus to preoccipital notch

What divides the cuneus and lingual gyrus? What are each of these structures responsible for?

Calcarine sulcus. Cuneus = above (lower field of vision), lingual gyrus = below (upper field of vision)

The cortex is comprised of... with... internal to this.

Gray matter, white matter

What two cell types are present in the 6 cortical layers? What does each look like and what type of regions would you expect to find each one in?

Stellate and pyramidal. Stellate = numerous dendrites, input areas. Pyramidal = 1 apical, 2 basal dendrites + large axon, output areas.

What are the 6 layers of the cerebral cortex?

molecular, external granular, external pyramidal, internal granular, internal pyramidal, multiform

What does the molecular layer do?

Receives dendrites from internal layers to function as a coordinating center - like a water cooler.

What layer do all dendrites send back to?

1 - Molecular

What does the external granular layer do?

Receives input from other cortical regions

What does the external pyramidal layer do?

Sends output to other cortical areas

What layers are predominant in association and commissural fibers?

3 (sending) & 2 (receiving)

What does the internal granular layer do? What layer is this, where is it thickest, and what is it also known as?

Receives input from thalamus and other brainstem areas. Geniculocortical input layer. Very thick in sensory areas (vision, auditory, somatosensory). Also known as striate cortex (cause of thickness).

What does the internal pyramidal layer do? Where is it thickest?

Sends axons to brainstem/spinal cord. Thickest in motor areas of cortex.

What does the multiform layer do?

Sends axons (corticogeniculate fibers) back to thalamus. Modulates what info thalamus sends to cortex (attention)

Name the purpose of Brodmann areas 1, 2, 3, 4, 6, 8, 17, 18, 19, 22 (+39/40), 41, 42, 44 + 45. Also name the lobe they are located in and what type of aphasia damage would induce upon them if applicable.

1/2/3 = primary somatosensory cortex (frontal)

4 - primary motor (frontal)

6 - premotor (frontal)

8 - frontal eye fields (frontal)

17 - Primary vision cortex (V1) - input from the LGN general process (occipital)

18 - Association vision cortex (V2) - input from 17 to 19 (occipital)

19 - Association vision cortex (V3) - receive + process 18 (occip)

22/39/40 - Wernicke - jargon aphasia from damage (temporal/frontal/frontal)

41 - primary auditory - receive medial gen nuc and send to 42 (temporal)

42 - auditory association - receive 41, send to 22 (temporal)

44/45 - Broca's area - speech - expressive aphasia from damage

What do the prosencephalon/mesencephalon/rhombencephalon give rise to?

Telen/Diencephalon (forebrain)
Mesencephalon (midbrain)
Meten/Myelencephalon (hindbrain)

What is optic ataxia?

Can visually identify orientation but vision cannot drive motor movements accurately.

What is hemifield neglect?

Individual is completely oblivious to one side of their visual field.

What is an example of the following disconnections in the ventral pathway:
Visual to visual
Visual to verbal
Visual to limbic

Agnosia
Anomia/Alexia
Improper emotional-visual response

Define the following conditions:
a. Achromatopsia
b. Prosopagnosia
c. Simultagnosia
d. Object Agnosia
e. Pure Alexia

a. Inability to distinguish colors
b. Inability to recognize human faces
c. Inability to recognize multiple objects in a scene
d. Inability to recognize objects
e. Inability to read

What is alexia a defect in (structurally)?

Occipitotemporal corticofugal bundle or left inferior temporal gyrus