Nb2 - Structure Of Cerebral Hemispheres

Front 1

Development of cerebral hemispheres - what is formed by week 4 and 5

Back 1

A. At 4 weeks of human development, there are three primary brain vesicles, with the anterior-most part called the forebrain, or prosencephalon.

B. By 5 weeks of human development, the forebrain divides into telecephalon, which forms the cerebral hemispheres, and diencephalon, which forms the thalamus, hypo-, epi-, and subthalamus, and retina.

Front 2

Cytoarchitectural maps - how many areas identified

Back 2

Brodmann (1909) mapped areas of cerebral cortex based on the differences observed in Nissl-stained cerebral cortex; 46 areas identified, and numbered.

Front 3

Sensory cortical areas include what 3 areas?

Back 3

Sensory cortical areas include primary, secondary and association areas

Front 4

Primary sensory areas receive impulses about what (3) and from what areas

Back 4

Primary sensory areas receive impulses about specific sensory modalities.
somatosensory: area 3,1,2
visual: area 17
auditory: area 41
*Each area shows a distorted representation of the body
surface (somatotopic, retinotopic, tonotopic representation).

Front 5

Primary sensory areas form connections with what nuclei and an ablation (elimination or removal) in these areas results in what

Back 5

Forms connections with specific thalamic nuclei.

Ablation results in dramatic deficits in sensory appreciation.

Front 6

Secondary sensory areas are identified for what (2) and in what areas?

Back 6

Somesthesia (skin senses and proprioception) in area S2

Audition (hearing) in area 42.

Front 7

Where are secondary sensory areas located and ablation here results in what?

Back 7

• Located near the primary sensory area.

• Ablation results in lesser deficits than primary
sensory area lesions.

Front 8

Sensory association areas identified for what and in what areas?

Back 8

• Identified for the somatosensory system, area
5,7 of superior parietal lobule.

• Identified for visual system, areas 18,19.

• Identified for the auditory system, area 22.

• These areas are called UNIMODAL (referring to one main direction or influence) association
areas.

Front 9

Association cortex - found where (3), what types of connections/functions does it have, unimodal or multimodal?

Back 9

• Found mainly in parietal, temporal and frontal lobes.

• Has sensory and motor connections, but even more
important are the integrative and cognitive functions.

• Unimodal association areas are devoted to
processing signals mainly from one primary area.

• Multimodal association areas are influenced mostly
by other regions of cortex and are concerned with
processing higher intellectual functions.

Front 10

Sensory cortical area - Primary somesthetic area - serves what functions, receives projections from where, damage/lesion of it results in what

Back 10

(parietal lobe, postcentral gyrus, Brodmann areas 3, 1, 2);
serves general somatic sensibility, superficial and deep (pain, temperature, and touch).

Receives projections from VPL, VPM thalamus.

Damage results in localized sensory
loss contralateral.

Front 11

Sensory cortical area - Somesthetic association area - serves what functions, damage/lesion of it results in what

Back 11

(superior parietal lobule, areas 5, 7); integrates impulses
associated with somatic sensations for recognition of body parts, position, and
appreciation of sensations.

Damage results in defective recognition of sensory
impressions, astereognosis (failure to recognize objects by touch), loss of body image.

Front 12

Sensory cortical area - Primary visual cortex

Back 12

(area 17) is the terminal area for fibers from LGN thalamus.
Visual cortex borders the calcarine sulcus.

Front 13

Sensory cortical area - Visual association areas

Back 13

(areas 18, 19) are essential for interpreting visual impressions
and integrating visual inputs with other sensory inputs.

Front 14

Sensory cortical area - Primary auditory cortex - serves what functions, receives projections from where, damage/lesion of it results in what

Back 14

(temporal lobe, transverse gyri of Heschl, area 41); located on
dorsal surface of superior temporal gyrus. Receives input from MGN thalamus;
tonotopically organized; one-sided lesions of auditory cortex result in difficulty in
localizing sounds and hearing loss mainly in the contralateral ear.

Front 15

Sensory cortical area - secondary auditory area.

Back 15

Area 42 is the secondary auditory area. Auditory association area is represented by the
posterior part of area 22. Auditory association cortex is involved in interpreting what is
heard.

Front 16

Sensory cortical area - Wernicke's area - serves what functions, damage/lesion of it results in what

Back 16

(parietal and temporal lobes, inferior parietal lobule); supramarginal
gyrus (area 40), angular gyrus (area 39), and superior temporal gyrus (area 22) is
related to language. Damage in dominant hemisphere results in aphasia, a language
disorder of understanding speech.

Front 17

Sensory cortical area - Broca's area

Back 17

(inferior frontal gyrus; areas 44, 45); in dominant hemisphere, this area is
concerned with speech; lesion results in difficulty in producing fluent sentences.

Front 18

Dominant cerebral hemisphere is for...(right and left)

Back 18

Language.

The left hemisphere is concerned usually with understanding and producing speech.

Counterpart in the right hemisphere for speech areas on the left side are regions involved
in PROSODY, setting the emotional content of speech. This is the rhythmic or musical
aspect of speech, and conveys emotional tone.

Front 19

Producing prosody involved what gyrus and comprehending prosody involves what area of brain

Back 19

Producing prosody involves the right inferior frontal gyrus.
4. Comprehending prosody involves the right posterior temporal parietal area.

Front 20

What are the 2 Motor cortical areas?

Back 20

primary motor

premotor cortex

Front 21

Primary motor area - what area, receives input from where

Back 21

Primary motor area (frontal lobe, precentral gyrus, area 4); somatotopic representation;
receives input from premotor, somesthetic area, and VA and VL thalamus; considered a
motor-sensory area.

Front 22

Premotor cortex - what areas, produces what movements

Back 22

Premotor cortex (frontal lobe, areas 6 and 8); produces movements similar to those
obtained by stimulation of area 4, but requires stronger stimulation. Stimulations of
area 8 results in conjugate movements of eyes to opposite side; area 8 is called frontal
eye field; influences voluntary eye movements.

Front 23

Prefrontal cortex - what areas and what functions

Back 23

Prefrontal cortex (area 9, 10, 11, 12); functions in higher intellectual capacities such as
planning, ambition, drive, and personality.

Front 24

The gross neuropathological hallmark of Alzheimer’s disease is atrophy of what gyri and widening of what 4 lobes

Back 24

The gross neuropathological hallmark of Alzheimer’s disease is atrophy of the
cerebral gyri and widening of sulci in the superior frontal, inferior parietal, temporal,
and limbic lobes.

Front 25

Alzheimer’s disease is characterized by neuronal loss, most notably in what areas? (6)

Back 25

Alzheimer’s disease is characterized by neuronal loss, most notably in the
hippocampus, frontal, parietal and temporal cerebral cortex, amygdala, and olfactory
system.

Front 26

Nucleus basalis of Meynert - what are they and what happens when they are lost

Back 26

Nucleus basalis of Meynert is a group of neurons at the base of the brain, ventral to
globus pallidus, which represents a source of cholinergic innervation to the cerebral
cortex.

These neurons are lost, and there is a severe cholinergic deficit in the cerebral
cortex of Alzheimer’s patients.

Nucleus basalis projects to neocortex, hippocampus,
amygdala, olfactory bulbs, thalamus, and brainstem.

Front 27

What are the fiber bundles of cerebral hemispheres (3)

Back 27

A. Association fibers

B. Commissural fibers

C. Projection fibers

Front 28

Fiber bundles of cerebral hemispheres - Association Fibers

Back 28

Association fibers are confined to one hemisphere; most numerous fiber bundle class (ex.
arcuate fibers).

Front 29

Fiber bundles of cerebral hemispheres - Commisural Fibers - connect what

Back 29

Commissural fibers connect the cerebral cortex of two hemispheres (ex. corpus
callosum).

Front 30

Fiber bundles of cerebral hemispheres - Projection Fibers - connect what

Back 30

Projection fibers connect the cerebral cortex with subcortical structures: (ex. internal
capsule.

Front 31

What are the phylogenetic classes of cerebral cortex (3)

Back 31

Archicortex

Paleocortex

Neocortex

Front 32

Phylogenetic classes of cerebral cortex - Archicortex - refers to what

Back 32

Archicortex is the oldest phylogenetically; refers to three cell-layered cerebral cortex found
in hippocampus.

Front 33

Phylogenetic classes of cerebral cortex - Paleocortex - contains what layers, what is the associated area found here

Back 33

Paleocortex contains three-to-five cell layers; olfactory areas.

Front 34

Phylogenetic classes of cerebral cortex - Neocortex - contains what layers, found in what cortical areas (3)

Back 34

Neocortex is phylogenetically new and composed of six cell layers.

Constitutes about 95%
of cerebral cortex in man. Found in sensory, motor, and association cortical areas.

Front 35

Cerebral cortex contains two main cell types:

Back 35

(1) pyramidal cells
(2) stellate or
granule cells

Front 36

pyramidal cells - give rise to what, found in what 3 layers

Back 36

pyramidal cells give rise to projection, commissural, and association fibers and are found in layers 2, 3, and 5

Front 37

stellate or
granule cells - serve as what, and found in what 2 layers

Back 37

stellate or granule cells serve as interneurons for ntracortical connections, and found mainly in
layers 2 and 4.

Front 38

Layers of neocortex - what types of zones are found in these layers

Back 38

Neocortex has six layers; layers of 1, 2, 3, 4 are mainly afferent zones,
receiving information entering cerebral cortex, while layers 5 and 6 are mainly efferent
zones projecting outside the cerebral cortex, or to other regions of cerebral cortex.

Front 39

Vertical cortical columns are how wide, comprised of what

Back 39

Vertical cortical columns are functional columns of neurons about 50-500 μm wide;

Comprised of neurons activated by the same sensory stimulus, i.e. activated by touch,
position or visual stimuli.