Hippocampus

Question 0

Where is it?

Answer 0

Central temporal lobe
Rostral to amygdala and caudal to end of corpus callosum
The entorhinal cortex is below it

Question 1

Why is the hippocampus important?

Answer 1

Learning new declarative names
Lowest threshold to seizure
Greatest vulnerability to ischemia
Area of continued neurogenesis
First area identified functional/morphological plasticity
Hormone responsive cells

Question 2

What are the two cell layers

Answer 2

Pyramidal

Granule cell layer - cell layer of the dentate gyrus

Question 3

Hippocampal organization

Dentate gyrus - 3 parts?

Answer 3

Granule cell layer
Molecular layer (contains dendrites of granule layer)
Hilus (inside curve of the granule layer)

Question 4

Hippocampal organization
CA (cornu ammonis)
Field of hippocampus proper?

Answer 4

Pyramidal cell layer - cells in all the same direction
Apical dendrites to the inside of the structure
Basal dendrites to the outside of the strucure

Question 5

Hippocampal organization

Subiculum

Answer 5

Appears continuous with both pyramidal fields of both hippocampus and entorhinal cortex

Question 6

Hippocampal pyramidal cell nt?

Answer 6

Glut

Question 7

Major hippo input?

Answer 7

Entorhinal cortex

Question 8

Hippo inputs?

Answer 8

entorhinal cortex
septal nuclei via fornix
contralateral hippo (commissural projections via C3)
Supramammillary hypothalamus
brainstem monoaminergic afferents (DA, 5HT, NE all via fornix)

Question 9

Hippo outputs?

Answer 9

Nucleus accumbens *not an input
entorhinal cortex
septal nuclei via fornix
contralateral hippo (to dentate, CA fields)
Hypothalamus (mammillary bodies via fornix but really subiculum via fornix)

Question 10

Prime circuit of hypothalamus
How many relays?
Nt?

Answer 10

4

glutamate, so excitatory

Question 11

Prime circuit of hypothalamus

Answer 11

1. entorhinal cortex to dentate gyrus via perforant path
2. granule cells of dentate gyrus to CA3 via mossy fibers
3. CA3 to CA1 via shaffer collaterals (go to contralateral hippo too)
4. CA1 to subiculum to out

Question 12

Hippo connections form recurrent excitatory loops, which may predispose to:

Answer 12

seizure

Question 13

Projection neurons within the hippocampus give rise to axons that terminate in the

Answer 13

contralateral hippocampus and entorhinal cortex

Question 14

The type of memory the hippocampus is involved in forming?

Answer 14

Declarative (long term) and working memories

Question 15

Full biolateral damage vs partial bilateral damage (w MI)?

Answer 15

Anterograde amnesia

Rapid forgetting

Question 16

which cells in particular are vulnerable to ischemia?

Answer 16

CA1

Question 17

The neurons are highly responsive to what hormones?

Answer 17

Glucocorticoids and estrogen

Question 18

CA3 cells are vulnerable to death by

Answer 18

seizures

Question 19

What does estrogen do for the cells?

Answer 19

pyramidal cell spine elaboration and new memory formation

Question 20

What is long term potentiation?

Answer 20

A mechanism of memory formation

Question 21

What is kindling

Answer 21

torturing animals by giving them seizures that eventually lower their threshold for having seizures

Question 22

glucocorticoids ___________ and antidepressants __________ neurogenesis

Answer 22

Reduce, increase

Question 23

Is the hippocampus really needed in forming olfactory cues?

Answer 23

no