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Flashcards in The Brain II Deck (53):

where is the neocortex? How many layers does it have?

it forms the majority of the cortex and it has 6 layers


list the layers in order of closest to pia mater till the one closest to subcortical white matter

I molecular, II external granular, III small pyramidal, IV internal granular, V large pyramidal, VI multiform


the I molecular layer is aka?

the plexiform layer. It has the least neurons


are most of the cells in the neocortex inhibitory or excitatory?

they are excitatory, (this is opposite to cerebellar cortex)


what are the 2 kinds of cortical neurons?

the pyramidal and the non-pyramidal neurons.


the spiny dendritic neurons are?



what are chandelier neurons?

the branches of the axon embrace the pyramidal cell axons


what are basket neurons?

the branch of the non-pyramidal cell branch onto the proximal part of the dendrites


where do non pyramidal cells originate from?

the ganglionic eminence


where do pyramidal cells originate from?

the neuroepithelium


how do pyramidal cells reach the cortex?

they perform interkinetic nuclear migration. hey move from the basal/Pial side to the ventricular/apical side


what are radial glia?

they are used as pole for the cells ,which are leaving the ventricular side, to wrap around and move up and down. They are both a migrating scaffold but also a proliferative precursor


the neurons which are on the radial glia can be called? They need which chemicals?

locomotion neurons, Multipolar neurons. Need Cdc42, Rac1, RhoA


which gene when mutated drastically mutates the cortex formation?

the Lis1 gene. A microtubule 'cage' surrounds the nucleus and links it with the centrosome using the microtubule network. The lissencephaly 1 protein (LIS1) functions as a bridge


what allows cells to move?

the link between the nucleus, the microtubule network and the centrosome to enable movement.





the walls of the neural tube are divided into?

the innermost (ventricular) ependymal layer, then mantle, marginal layer. In the center is the canal


explain the inside out formation of the cortical layers

there is the first wave migration of neurons and glia which exit the ventricular layer and they move and form the preplate area which is very superficial. These neurons start to extend some axons and they form an intermediate zone.
The second wave migration: it leads to formation of cortical plane, and causes the preplate to divide into an upper marginal zone and lower subplate.
Last: the later born neurons migrate through the intermediate zone, subplate, lamina V/VI and then they form lamina II,III,IV


the subplate forms which layer?

layer V/VI


where is the subventricular zone?

it is below the ventricular layer. It is an accessory germinative layer


what becomes the white matter?

the intermediate zone, MZ,CP,SP


note that the first born neurons in the lamina I ?

disappear and so does the subplate


what is reln?

it is a protein that is produced by cajal retzius cells, they are already present in the preplate before the first wave


what is the tangential migration and who performs it?

it is the outward and tangential migration of neurons and glia, it is done by the cells from the ganglionic eminence


which layer is targeted for thalmic projection? Which is the source for centrifugal cells

layer IV, layer V


what are the 3 layers of the cornu ammonis?

polymorph, pyramidal, molecular layer


what are the 3 layers of the dentate gyrus

the polymorph, the granular, molecular


the paleocortex is close to the ?

olfactory complex


what is the uncus?

it is the hooked part of the temporal lobe


name the structures found in/near the anterior horn of the lateral ventrical

septum pellucidum, forceps minor, rostrum of corpus callosum, caudate nucleus, tapetum of corpus callosum, thalamus (forms the floor)


what structures are near/in the posterior/occipital horn of the lateral ventrical?

the tapetum, forceps major, note that this is embedded in the white matter of the occipital lobe


name the structures in the inferior horn of the lateral ventrical?

the hippocampus, amygdala, tail of caudate nucleus, stria terminalis, associative fibers


name the parts of the diencephalon

the thalamus (metathalamus), hypothalamus, epithalamus, subthalamus


how can we see the epithalamus and the thalamus

by removing the corpus callosum and the body of the fornix


what is the point where the two thalamus lobes meet

the interthalmic adhesion


what it the large posterior part of the epithalamus and thalamus called

the pulvinar


what is the structure on the roof of the third ventrical?

the tele coroidea


what is the stria medullaris?

the connection between the limbic system


what is the foramina of Monroe?

the communication between the third and lateral ventrical


The epithalamus has which glands. What happens as we age?

It has the pineal glands, which produce melatonin and calcify as we age


When the pulvinar is displaced,what do we find under It?

The lateral and medial geniculate bodies : The metathalamus


Where is the trigone of habenular? What is It?

It is in the epithalamus, it contains the habenular nuclei, which function to help limbic system communication. Note that when we move anterior to it we find it's attachment to the stria medullaris


Where is the habenular commisure

At the epithalamus. It contains the habenular commisure and the posterior commisure


What is the purpose of the posterior commisure

It connects the 2 mesencephalon, it is involved in the papillary reflex, it connects the 2 colliculi (superior and inferior) , connects the prefectal nuclei.


Where is the prefectal area

It is the transition area from the base of the brain to the midbrain


The presence of which structure can explain why when a light is shone into one eye,both pupils constrict

The posterior commisure


Where is the subcommisural organ

It is in the wall of the mesencephalic aqueduct where it enters into the 3rd ventricle


What is the purpose of the subcommisural organ. An error in it leads to what illness?

It secretes a protein that keeps the mesencephalic aqueduct open and promotes neurogenesis, and binds to compounds that need to be cleared from the CSF.
It leads to congenital hydrocephaly : the CSF produced in the lateral ventricles and the 3rd ventricle cannot be drained through the fourth ventricle into the cisterna magna and eventually the sub arachnoid space


Explain the division of the thalamus

It is made mostly of Gray matter, yet it has 2 strips of white matter that help it's division. The internal lamina medullary, and the external medullary lamina.
The internal lamina is Y shaped, in the V of the Y we have the anterior thalamic nuclei.
Medial to the Y we have the median ( closer to thr other thalamus) and medial nuclei. And lateral to the Y is the lateral nuclei which is divided into many other sections .
Lateral to the external medullary lamina we have the reticular nucleus


What are the 3 types of nuclei in the thalamus

The specific relay nuclei, the association nuclei, the non specific nuclei


Refer to slide 69

For matching on thalamic region and type of neurons


What are thalamic peduncles

They are part of the internal capsule, and the corona radiata. It can be superior, inferior, posterior, anterior


Where is the subthalamus? What do we find here

It is under the thalamus, more specifically it is anterior to the tegmentum of the midbrain and behind the hypothalamus.
Here we have the most rostral part of the substania-nigra and the red nucleus. We also have the subthalamic nucleus also called the nucleus of Louis