15 Intro to the Cerebral Cortex

Question 1

What is the importance of the central sulcus in relation to the topography of the brain?

Answer 1

central suclus devices the frontal and parietal lobe

Question 2

What do the longitudinal, transverse and sylvan/lateral fissure separate respectively?

Answer 2

longitudinal (two cerebral hemispheres) transfers (cerebrum and the cerebellum) and sylvan (divides temporal lobe and frontal/parietal lobes)

Question 3

What structure lies behind the transverse fissure?

Answer 3

insula

Question 4

Describe the variety of paths that are contained in the cortical white matter.

Answer 4

white matter is deep and axons can go locally or to other cortical/non cortical areas (corticortical, through commissure, cortico-spinal, cortico-bulbar, short association fibers, superior longitudinal fasciculus)

Question 5

What types of cells would you expect to see in the layers of the cortex?

Answer 5

pyramidal and stellate cells (excitatory- glutamate) and interneurons (inhibitory- GABA)

Question 6

Name two areas, that unlike the neocortex, do not have 6-layers

Answer 6

paleocortex (ie. pyriform cortex) and archicortex (hippocampus)

Question 7

Which Brodman’s areas represent areas that are now know as the optical and auditory cortex?

Answer 7

optical (17) auditory (41-42)

Question 8

What is important to remember about functional mapping of the cortex?

Answer 8

some functions are distributed between multiple areas and connections between areas play an important role in function

Question 9

Describe 4 different methods for determining cortical function experimentally.

Answer 9

1. create a lesion and observe the deficit 2. stimulate an area and observe the resulting action 3. record the amount of electrical activity based on given stimuli 4. watch for increased blood flow with given stimuli (fMRI)

Question 10

What are the four main types of functional regions?

Answer 10

primary sensory area, primary motor area, association area, and limbic area (** remember that many higher order processes are not confined to a single cortical area but instead distributed in a network)

Question 11

Name the 6 distinct areas of primary sensory cortex.

Answer 11

visual (occipital midline), auditory (lower lip of sylvan fissure), vestibular (insular and upper lip of sylvan fissure), somatosensory (posterior to central sulcus), gustatory (anterior to vetibular) and olfaction (base of brain)

Question 12

All input to the primary sensory cortex from the receptors is processed through the ________ before it reaches the primary sensory cortices (except for olfaction, which erectly goes to the olfaction cortex)

Answer 12

thalamus

Question 13

Where are the motor cortices located?

Answer 13

anterior to the central sulcus

Question 14

What is the function of association cortex?

Answer 14

process raw sensory signals into complex concepts that can be remembered and used to create new ideas that can be formulated into action (notice, assign significance and make meaningful response)

Question 15

Name the three major subdivisions of the association cortex.

Answer 15

unimodal motor, unimodal sensory and multimodal

Question 16

What is unimodal motor?

Answer 16

divided into supplementary motor cortex (SMA) and lateral premotor cortex (PMC) which both deal with more complex motor patterns generally internally generated selected movement – receives mostly input from the primary motor cortex and sends output to LMN

Question 17

What is unimodal sensory?

Answer 17

areas near primary sensory cortices that respond to more complex stimuli via communication within and to primary sensory cortices

Question 18

What does multimodal association cortex?

Answer 18

areas of higher cortical function that are distributed through networks that are still being figured out including preprocessed inputs from thalamus (not from sensory or motor thalamus), cortical areas or subcortical inputs

Question 19

How does spatial neglect demonstrate the function of the association cortex?

Answer 19

damage to the TPO junction causes the patient to ignore things in contralateral space: neglect may be due to disruption of the connection between the visual cortex dorsal (where) and ventral (what) areas (BONUS: TPO lesions are most prominent on the right side because its perception is bilateral and when interrupted, the left side provides only unilateral perception)

Question 20

What function does the frontal association cortex linked with?

Answer 20

two sections: dorsalateral prefrontal cortex (cognitive, executive functions and working memory) and ventromedial prefrontal cortex (emotional, affective functioning, planning and social restraint)

Question 21

Name the limbic areas (part of the limbic system)

Answer 21

parahippocampal gyrus, cingulate gyrus, septal area connected by the fiber pathway- cingulum

Question 22

What is the proposed function of the limbic system?

Answer 22

a conduit from the “thinking brain” to the “emotional” brain (described in the papez circuit)

Question 23

What is apraxia?

Answer 23

loss of the ability to perform complex motor tasks in the absence of paralysis

Question 24

What features would you find in the frontal lobe?

Answer 24

primary motor cortex, premotor cortex and supplementary motor areas, Broca’s (speech), working memory, personality, insight, foresight and reward

Question 25

What features would you find in the parietal lobe?

Answer 25

rostrally: primary and secondary somatosensory cortex; caudally: association areas, body image and spatial orientations and Wernicke’s area (language and reading skills)

Question 26

What features would you find in the occipital lobe?

Answer 26

primary visual on the medial surface, secondary and higher order visual association areas

Question 27

What features would you find in the insular lobe?

Answer 27

anterior and posterior: taste/flavor centers, body state awareness, regulation of autonomic function, time perception and more