CEREBRUM

Question 1

Types of brain cortex

Answer 1

Isocortex (Neocortex or Homogenetic Cortex)

Allocortex (Paleocortex, Archicortex, or Heterogenetic Cortex)

Mesocortex (Periallocortex, Periarchicortex)

Question 2

Isocortex in which the six layers are clearly evident (such as the primary sensory cortex) is termed ___________

Answer 2

homotypical cortex.

Question 3

Isocortex in which some of the six layers are obscured (such as the motor cortex and visual cortex) is termed _______

Answer 3

heterotypical cortex

Question 4

The visual cortex is also known as granular cortex or _______

Answer 4

koniocortex

Question 5

It is subdivided into paleocortex (rostral insular cortex, piriform cortex, and primary olfactory cortex) and archicortex (hippocampal formation).

Answer 5

allocortex

Question 6

This type of cortex is found in much of the cingulate gyrus, entorhinal, parahippocampal, and orbital cortices and is intermediate in histology between the isocortex and allocortex

Answer 6

mesocortex

Question 7

The neurons of the cerebral cortex are of two functional categories: _____________

Answer 7

(1) principal (projection) neurons: corticocortical and corticosubcortical outputs.
(2) interneurons: local information processing.

Question 8

types of Principal (Projection) Neurons

Answer 8

PYRAMIDAL NEURONS

FUSIFORM, SPINDLE NEURONS

Question 9

The apex is directed toward the cortical surface. Apical dendrite directed toward the surface of the cortex and several horizontally oriented basal dendrites that arise from its base

Answer 9

PYRAMIDAL NEURONS

Question 10

types of Interneurons

Answer 10

STELLATE OR GRANULE NEURONS: only type of excitatory interneurons in the cortex. Inh: GABA, stim: ACH

HORIZONTAL CELLS OF CAJAL: found only in lamina I and disappear or are rare after the neonatal period.

CELLS OF MARTINOTTI: multipolar with short branching dendrites and an axon that projects to more superficial layers,

Question 11

__________consists primarily of a dense network of nerve cell processes among which are scattered sparse interneurons (horizontal cells of Cajal) and neuroglia

Answer 11

LAYER I (MOLECULAR, PLEXIFORM)

Question 12

________consists of a dense packing of small and medium-sized pyramidal neurons and interneurons intermingled with axons from other cortical layers of the same and opposite hemispheres (association and commissural fibers), as well as axons and dendrites passing through this layer from deeper layers

Answer 12

Layer II (EXTERNAL GRANULAR)

Question 13

This layer receives primarily axons of neurons in other cortical areas (association and commissural fibers), as well as axons of neurons in extracortical regions such as the thalamus.

Answer 13

LAYER III EXTERNAL PYRAMIDAL

Question 14

Layer IV is especially well developed in __________

Answer 14

primary sensory cortical areas.

Question 15

In the primary visual (striate) cortex, this layer is traversed by a dense band of horizontally oriented tha-lamocortical nerve fibers known as the ________

Answer 15

as the external band of Baillarger or the stripe of Gennari

Question 16

________consists of large and medium-sized pyramidal cells, stellate cells, and cells of Martinotti.

Answer 16

layer 5

Question 17

he largest pyramidal cells in the cerebral cortex_________ are found in this layer

Answer 17

(cells of Betz)

Question 18

_______ consists of cells of varying shapes and sizes, including fusiform cells and the cells of Martinotti, which are prominent in this layer.

Answer 18

Layer VI

Question 19

Layers ______are present in all types of cortex (neocortex, paleocortex, and archicortex).

Answer 19

I, V, and VI

Question 20

Neurons in lamina V give rise to corticofugal fibers that target _________. Neurons in lamina VI give rise to corticofugal fibers ______

Answer 20

subcortical areas (brain stem and spinal cord)

to the thalamus.

Question 21

Inputs to the cerebral cortex

Answer 21

Thalamus
Extrathalamic modulatory
Cortex of the same hemisphere (association fibers)
Cortex of the contralateral hemisphere (commissural fiber

Question 22

Extrathalamic Modulatory Input

Answer 22

Serotonin
Dopamine
Histamine
Noradrenergic
Cholinergic
GABA

Question 23

_____project widely in the cerebral cortex with the visual cortex receiving an especially rich serotonergic innervation

Answer 23

serotonin fibers

Question 24

function of serotonin fibers

Answer 24

pain control, emotion, and sleep.

Question 25

he dopaminergic input to the cortex is believed to play a role in: _________

Answer 25

orienting behavior.

Question 26

This is believed to enhance the selectivity and vigor of cortical responses to sensory stimuli or other synaptic inputs to the target neurons in the cortex.

Answer 26

Noradrenergic Input.

Question 27

the histaminergic input to the cerebral cortex originates from the ______in the posterolateral hypothalamus

Answer 27

tuberomamillary nucleus

Question 28

for cortical arousal and motivation. It has been implicated in the genesis of memory deficit in Alzheimer’s disease.

Answer 28

cholinergic input

Question 29

GABAergic input to the cerebral cortex terminates in the________

Answer 29

hippocampus

Question 30

The association fibers arise from nearby (short association u-fibers) and distant (long association fibers) regions of the _______hemisphere. T

Answer 30

same

Question 31

The long association fiber system includes such bundles as the ___________

Answer 31

cingulum, superior longitudinal fasciculus, arcuate fasciculus, inferior longitudinal fasciculus, occipitofrontal fasciculus, and the uncinate fasciculus.

Question 32

The cingulum is the white matter core of the cingulate gyrus. It connects the _______and the __________

Answer 32

anterior perforated substance

parahippocampal gyrus.

Question 33

_________ arise from corresponding and noncorresponding regions in the contralateral hemisphere, travel via the corpus callosum and project on neurons in all laminae but mostly laminae I, II, and III

Answer 33

The commissural fibers

Question 34

OUTPUTS OF CEREBRAL CORTEX

Answer 34

(1) the association fiber system,
(2) the commissural fiber system, and
(3) the corticofugal fiber system.

Question 35

This __________ connects the cerebral cortex directly with motor neurons in the spinal cord and is concerned with highly skilled volitional movement

Answer 35

corticofugal fiber tract

Question 36

_____________ constitutes the majority of the descending corticospinal fibers and decussates in the pyramids (motor decussation);

____________ is smaller and crosses at segmental levels in the spinal cord.

Answer 36

(lateral corticospinal)

anterior corticospinal)

Question 37

This fiber tract separates from the corticospinal fiber system in the cerebral peduncle and joins the medial lemniscus in the caudal midbrain extending through the pons to the middle medulla oblongata, where it becomes undetectable

Answer 37

Aberrant Pyramidal Tract

Question 38

It is thus responsible for the reported supranuclear cranial nerve palsies in lesions of medial lemniscus.

Answer 38

Aberrant Pyramidal Tract

Question 39

The__________constitute by far the largest component of the corticofugal fiber system.

Answer 39

corticopontine fibers

Question 40

The_________ projection comprises the most massive striatal afferents.

Answer 40

corticostriate

Question 41

Corticostriatal fibers are organized topographically into three distinct striatal territories:

Answer 41

(1) sensorimotor, (2) associative, and (3) limbic.

Question 42

Corticostriate pathways are also organized somatotopically such that cortical association areas project to the _______, whereas sensorimotor cortical areas preferentially project to the ________

Answer 42

caudate nucleus

putamen

Question 43

Brodmann areas 13 and 14 refer to the anteriorly placed two ______and areas 15 and 16 refer to the posteriorly placed two _______

Answer 43

insulae breves,

insulae longes.

Question 44

The primary somesthetic area receives nerve fibers from the________

Answer 44

ventral posterolateral and ventral posteromedial nuclei of the thalamus

Question 45

In addition to thalamic afferents, the primary somesthetic cortex receives commissural fibers through the _______from the contralateral primary somesthetic cortex and short association fibers from the adjacent _________

Answer 45

corpus callosum

primary motor cortex

Question 46

It is believed that pain and temperature sensations are determined at the _________whereas the source, severity, and quality of such sensations are perceived in the ________

Answer 46

thalamic level,

postcentral gyrus.

Question 47

__________is located on the most inferior aspect of the postcentral gyrus and in the superior bank and depth of the lateral sulcus (parietal operculum)

Answer 47

Secondary Somesthetic Area (SII)