7 Cortex I

Question 1

What is a clinicoanatomical correlation?

Answer 1

Correlating a lesion observed at autopsy with premortem clinical signs to infer function

Question 2

What area of the cortex was the first to be formulated using clinicoanatomical correlation?

Answer 2

Broca’s area

Question 3

Where is Broca’s area located and what is its function?

Answer 3

inferior frontal convolutions; language expression

Question 4

What is the most common type of neuron in the cerebral cortex?

Answer 4

pyramidal cells

Question 5

Name the six layers of the cortex.

Answer 5

I. Plexiform II. outer granular III. outer pyramidal IV. inner granular V. inner pyramidal VI. multiform

Question 6

What are the horizontal fibers in layers IV and V of the cortex called?

Answer 6

Band of Baillerger

Question 7

What do you call the interneurons that make connections between layers and within layers of the cortex?

Answer 7

Granule cells

Question 8

In which layers of the cortex can you find pyramidal cells?

Answer 8

All layers except layer I, predominant in layers II, III, and V

Question 9

Are granule cells usually inhibitory or excitatory?

Answer 9

inhibitory

Question 10

Which layer(s) of the cortex do interhemispheric arise from and what do they form?

Answer 10

Layer III, corpus callosum and anterior commissure

Question 11

Which areas of the cortex does the corpus callosum connect?

Answer 11

all areas except the temporal poles, which are connected by the anterior commissure

Question 12

What are the two types of intrahemispheric axons?

Answer 12

long association and short association axons

Question 13

Which layer(s) of the cortex do long association axons arise from and what do they connect?

Answer 13

layers III and V; they connect lobes

Question 14

Which layer(s) of the cortex do short association axons arise from and what do they connect?

Answer 14

layer II; they connect gyri

Question 15

What do local intrinsic axons connect?

Answer 15

they connect cortical layers together

Question 16

What do local circuit axons connect together, and what makes them chemically unique?

Answer 16

they connect columns; they are typically peptidergic

Question 17

what is the difference between corticofugal and corticopetal axons?

Answer 17

corticofugal axons originate in the cortex and end in other subcortical brain sturctures, whereas corticopetal originate in subcortical structures and end in the cortex

Question 18

what are the different divisions of projection/corticofugal axons?

Answer 18

corticothalamic, corticobulbar, corticospinal, corticostriate, corticopontine

Question 19

Which layer(s) of the cortex do corticothalamic axons arise from?

Answer 19

layer VI

Question 20

Which layer(s) of the cortex do corticobulbar and corticospinal axons arise from?

Answer 20

layers III and V

Question 21

Which layer(s) of the cortex do corticostriate and corticopontine axons arise from?

Answer 21

V

Question 22

What happens in the first half of gestation in regards to brain development?

Answer 22

formation of the cortical plate and of all cortical neurons

Question 23

what are the components of the undeveloped or undifferentiated part of the telencephalic neural tube?

Answer 23

a plexiform zone and a layer of neuroblasts known as the matrix zone or ventricular zone

Question 24

What event triggers neuroblast migration into the plexiform zone during neural development?

Answer 24

the arrival of noradrenergic axons in the plexiform zone

Question 25

how many waves of neuroblast migration occur during cortical development?

Answer 25

five

Question 26

which layer of the cortex does the first wave of neuroblasts form?

Answer 26

layer VI

Question 27

which layer of the cortex does the last wave of neuroblasts form?

Answer 27

layer II

Question 28

which wave of neuroblast migration forms layer I of the cortex?

Answer 28

none; layer I, the outermost acellular layer, was present before the waves began

Question 29

what is the fate of neuroblasts left in the matrix zone after the five waves?

Answer 29

they form the ependymal lining of the lateral ventrical

Question 30

what forms as the result of differential intracortical forces during development?

Answer 30

gyri and sulci

Question 31

What pathological condition is characterized by small and numerous gyri and sulci and poorly organized cell layers?

Answer 31

polymicrogyria

Question 32

which cortical layers are affected in lissencephaly?

Answer 32

layer II is absent and layers III and IV are reduced

Question 33

which pathological condition is characterized by a smooth cortex?

Answer 33

lissencephaly

Question 34

which condition is a milder form of lissencephaly?

Answer 34

pachygyria

Question 35

which developmental disorder is associated with displaced cortical layers in wernicke’s area

Answer 35

dyslexia

Question 36

what are ectopic foci and what condition are they associated with?

Answer 36

small nests of incorrectly positioned cortical neurons; epilepsy