Thelencephalon. Cerebral Cortex Flashcards

1
Q

Telencephalon vesicles derives from

A

Rostral most prosencephalon: hypothalamo-telencephalic prosomeres hp1 and hp2

hp1-cerebral hemispheres
hp2-preoptic area

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2
Q

Telencephalic expansion or vesicles give rise to

A

Cerebral hemispheres

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3
Q

As the telencephalic vesicles develop, we distinguish 2 divisions within the vesicle

A

Pallium (roof and walls of the vesicle) - gives rise to cerebral cortex

Subpallium (floor of the vesicle) - gives rise to deep structures

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4
Q

Derivatives of the subpallium

A

Caudate nucleus
Putamen
Pallidal complex (Globus pallidus)

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5
Q

Derivatives of subpallium form

A

Basal ganglia

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6
Q

Location of caudate nucleus

A

Adjacent / lateral to the ventricle, forms its lateral walls and follows its shape during development

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7
Q

Developing of the caudate nucleus and putamen

A

Subpallium proliferates —> cortex fibers = projected to reach spinal cord (corticospinal & corticonuclear tracts)

These 2 tracts come together as they descend, = internal capsule, at 2 sides/lateral to thalamus. It passes through & pierces subpallium —> divided:

  • Dorsal structure (C shape) = Caudate nucleus
  • Ventral structure (circular) = the Putamen
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8
Q

Caudate nucleus + putamen =

A

Striatum

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9
Q

Striatum =

A

Caudate nucleus + putamen

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10
Q

Developing of Globus pallidus and location

A

From subpallium, a couple more structures develop (Globus pallidus) which divides into 2 nuclei: medial and lateral.

They are both medial to the putamen.

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11
Q

Hippocampus definition

A

Cortical structure derived from the pallium, but also ends up being subcortical.

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12
Q

Hippocampus origin

A

Cortical (medial wall of pallium) —> surrounds the ventricle.

It’s a piece of cortex that is also subject to shaping by ventricles. Fibres radiating from it (fornix) = C shape.

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13
Q

Amygdaloid complex origin

A

Mixed: from a set of nuclei which all together form it
- Part derive from the pallium
- Part of the subpallium

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14
Q

Amygdaloid complex location

A

Directly rostral to the hippocampus.

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15
Q

Cerebral cortex is derived from

A

The pallium

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16
Q

Cerebral cortex division according to location

A

Medial wall —> archicortex (becomes subcortical) —> hippocampal complex

Dorsal wall —> neocortex. The majority of cortex originates from dorsal pallium. It provides higher function.

Ventrolateral wall —> paleocortex, which’ll form the olfactory cortex. In the adult, we only see a very small area with that origin.

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17
Q

Archicortex

A

Very old. Its derivative is the hippocampus (memory.)

Key for life and survival.

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18
Q

Paleocortex

A

Very old. Olfaction is essential, greatly developed in animals. Very old in the phylogenetic scale.

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19
Q

Neocortex

A

Newest, phylogenetically recent.

20
Q

Cerebral cortex division according to structure

A

Isocortex
Allocortex

21
Q

Isocortex

A

Formed by 6 well differentiated layers of cells.

Phylogenetically recent.

It would correspond to the neocortex. In humans, 90-96% of the cortex is neocortex

22
Q

Allocortex

A

Variable nº of layers (3-6).

Older phylogenetically speaking.

Corresponds to hippocampus and olfactory cortex. They are structurally different, both have an organizational structure that is different to the typical neocortex = “allo”

23
Q

Cerebral lobes

A

Frontal lobe - until the central sulcus (Rolando sulcus)

Parietal lobe - from central to parieto-occipital sulcus. Clearly visible in the medial aspect, only hinted on the outside

Occipital lobe - form the parieto-occipital sulcus to the caudal end

Temporal lobe - Sylvian fissure or lateral sulcus. Where it joins to the parietal lobe, we extend a line = marks the boundary of the temporal lobe

24
Q

Gyri

A

Development is so fast that the parenchyma has to fold on itself, forming gyri

25
Q

Cingulate gyrus

A

Medial aspect: gyrus that surrounds the corpus callosum: cingulate gyrus.

26
Q

Limbic lobe

A

Cingulate gyrus + the one continuous with it below

27
Q

Parahippocampal lobe

A

The ventral part of the limbic lobe.
Contains the hippocampus within it (on the deep aspect).

28
Q

Insular lobe

A

Another lobe hidden under the frontal, parietal and temporal lobes.

It has short and long gyri + central sulcus. What separates the gyri are the sulci.

29
Q

White matter - short association fibers

A

Connect adjacent regions of the cortex, located in the same area.

30
Q

White matter - long association fibers

A

Connect distant cortical areas within the same hemisphere

31
Q

Bridging connections from one hemisphere to the other (within white matter)

A

Commissural fibers, biggest one = Corpus callosum. Also found anterior commissure and posterior commissure.

32
Q

Corona radiata

A

Fibers in the cerebral white matter that are not corticocortical projections, but going to subcortical structures.

33
Q

Fibers in the cerebral white matter that are not corticocortical projections, but going to subcortical structures.

A

Corona radiata

34
Q

Corona radiata fibers come to form…

A

Internal capsule

35
Q

Internal capsule will…

A

Form corticospinal and corticonuclear tracts
Separate the putamen from the caudate nucleus

36
Q

Internal capsule will compress even more at the level of midbrain to form

A

Crus cerebri

37
Q

Internal capsule will compress even more at the level of medulla to form

A

Pyramids

38
Q

Parts of the internal capsule

A

Anterior limb
Genu
Posterior limb

39
Q

Cells of the layers of the isocortex

A

Granular cells - layers 2 and 4
Pyramidal cells - layers 3 and 5

40
Q

Only cells that project out of the cortex

A

Pyramidal cells = cortical projection neurons
(Granular cells = inter neurons)

41
Q

Sensory nuclei specifically project to

A

Layer 4

42
Q

Difference between each region of the cortex

A

Changes in their respective cell layers

43
Q

Homotypical areas

A

6 typical layers are distinguishable

44
Q

Heterotypical granular areas

A

Huge, developed layer 4

45
Q

Heterotypical agranular areas

A

Almost no layer 4 and large pyramidal cells

46
Q

Brodmann areas

A

Heterotypical agranular cortical areas = motor cortex. Originate the descending pathway

Heterotypical granular cortical areas = sensory cortex. Area for projections from primary nuclei in the thalamus

Something in between = association cortices, receiving projections from the association nuclei in the thalamus. Integrate info from primary or secondary areas, and have a different structure

47
Q

Higher function correlates with

A

Increase in associative cortices