Neuroanatomy (Part 2)

Question 1

What are the names of the 6 layers of the cerebral cortex?

Answer 1

• Layer 1: Molecular (plexiform) Layer
• Layer 2: External granular layer
• Layer 3: External pyramidal layer
• Layer 4: Internal granular layer
• Layer 5: Internal pyramidal layer (ganglionic)
• Layer 6: Multiform layer

Question 2

What is found in the Molecular (plexiform) layer of the cerebral cortex?

Answer 2

• Very few neuronal somata.
• Apical dendrites of cells located in deeper cortical layers.
• Axons passing through or making connections in this layer.
• Axons arising from within this layer often travel parallel to the pia.

Question 3

What is found within the external granular layer of the Cerebral cortex?

Answer 3

• Small granule cells (local interneurons that inhibit other cortical cells) and some slightly larger pyramidal cells.
• Communications with ipsilateral cortical areas (via association fibers).

Question 4

What is found in the external pyramidal layer of the Cerebral Cortex?

Answer 4

• Primarily small-to-medium-sized pyramidal neurons projecting from the cortex.
• Communications with homotopic contralateral cortices (via commissural fibers).

Question 5

What is found within the internal granular layer of the Cerebral cortex?

Answer 5

• No pyramidal neurons.
• Interneurons receiving ascending sensory (thalamocortical) input and projecting to layers II/III.
• Contains dense band of tangential axons that form the outer band of Baillarger, which is hypertrophic and visible to the naked eye in a discrete occipital region (forming the stria Gennari of the striate cortex).

Question 6

What is contained in the internal pyramidal (ganglionic) layer of the Cerebral Cortex?

Answer 6

• Medium-to-very-large pyramidal neurons.
• A major source of cortical output to the brainstem and spinal cord.
• Contains a dense band of tangential axons (i.e., inner band of Baillarger).

Question 7

What is contained within the multiform layer of the Cerebral cortex?

Answer 7

• An assortment of cell types, including a few pyramidal cells.
• Small cells receive input from the thalamus and from cortical layers II, III, and V.
• Axons of the cells in this layer project to superficial cortical layers and also subcortically, for example, to the thalamus.

Question 8

What cells form the output pathway from the Cerebral cortex?

Answer 8

Pyramidal cells (layers II, III, V, and VI)

Question 9

Which cerebral layer are the largest pyramidal cells of the primary motor cortex that can make synaptic connections with caudal spinal motor neurons found?

Answer 9

Layer 5

Question 10

Where do axons of most thalamo-cortical neurons end?

Answer 10

Layer IV of cerebral cortex

Question 11

Where do axons of cortical association neurons end?

Answer 11

may end in any of the layers but mainly in layers II, III and IV.

Question 12

Deep within the cerebral white matter are nuclei forming what?

Answer 12

Basal Ganglia

Question 13

The BASAL GANGLIA are groups of neurons that are concerned with what?

Answer 13

The initiation and organization of movement.

Question 14

What are the major components of the basal ganglia?

Answer 14

o Caudate nucleus
o Putamen
o Globus pallidus
o Claustrum

Question 15

The caudate nucleus + putamen of the basal ganglia make up what?

Answer 15

Striatum

Question 16

The putamen + globus pallidus of the basal ganglia make up what?

Answer 16

Lentiform nucleus

Question 17

The basal ganglia lie close to the ______ and to the functionally linked _______and_______.

Answer 17

• lateral ventricles
• thalamus
• subthalamus

Question 18

The thalamus relays virtually all sensory input to ____. It also processes___ from the ____ and _____to regulate the _____ and hence movement.

Answer 18

• sensory cortices
• output
• basal ganglia
• cerebellum
• motor cortex

Question 19

The hippocampus is a collection of neurons that processes much _____ that is destined for long-term storage in memory within ____.

Answer 19

• Sensory information

- cortical circuitry

Question 20

The amygdala participates in _____, perhaps assigning an ____.

Answer 20

• emotional regulation

- emotional valence to memory

Question 21

What are the 3 forms of white matter?

Answer 21

• Projection
• Association
• Commisural

Question 22

What is the function of Association white matter?

Answer 22

Connects one cortical region to another within the same hemisphere (e.g., superior longitudinal fasciculus).

Question 23

What is the function of commisural white matter?

Answer 23

Connects homotopic cortical sites between hemispheres (e.g., corpus callosum).

Question 24

What is the function of projection white matter?

Answer 24

Connects cortical and subcortical sites (e.g., internal capsule).

Question 25

What are the components of the brainstem?

Answer 25

midbrain, pons (cerebellum may be included), and medulla oblongata.

Question 26

What are prominent landmarks in a horizontal slice of the midbrain?

Answer 26

• cerebral peduncle,
• substantia nigra,
• medial lemniscus
• red nucleus.

Question 27

What are prominent landmarks in a horizontal slice of the pons?

Answer 27

• corticospinal tract,
• medial lemniscus
• middle cerebellar peduncles

Question 28

What are prominent landmarks in a horizontal slice of the medulla oblongata?

Answer 28

• pyramid
• olive
• medial lemniscus

Question 29

The shape of the horizontal slices of the spinal cord vary with the rostro-caudal level of the section (T/F)

Answer 29

TRUE!!
-For example, there is only one dorsal column on either side at lumbar and lower thoracic levels, but there are two dorsal columns bilaterally at cervical levels.

Question 30

The more ____of the ______ carries sensory information from the legs, while the more _____ of the _____ carries sensory information from the arms

Answer 30

• medial
• dorsal columns
• lateral
• dorsal columns

Question 31

Where are the two enlargements of the spinal chord located?

Answer 31

• Cervical enlargement

- Lumo-sacral enlargement

Question 32

What do the enlargements of the spinal chord reflect?

Answer 32

greater numbers of cells required at these levels to process sensory and motor signals for the arms and legs.