Hippocampus lecture 1

Question 1

Patient HM- anatomy

Answer 1

Bilateral removal of medial temporal lobes and hippocampus

Question 2

patient HM- memory

Answer 2

Anterograde amnesia- after surgery no new conscious memories

Partial retrograde amnesia.

Question 3

Functions of hippocampus

Answer 3

Anxiety
memory
spatial navigation

Question 4

Kirsch et al., (2008)

Answer 4

prefrotal cortex especially special to humans

Question 5

Scala naturae

Answer 5

“ladder of being” - with mammals at the top.

Question 6

Weir et al., (2002)

Answer 6

casual reasoning in birds- use tools to get food.

Question 7

Can we study complex cognitive abilities in animals?

Answer 7

Yes animals because also animals have impressive cognitive abilities. Even animals without cortex (birds), show evidence for insight related cognition. There might also be simpler “precursors” for cognitive abilities in some animals.

Question 8

Subregions of hippocampus

Answer 8

dendate gyrus, CA3, CA1 and subiculum

Question 9

projection neurons

Answer 9

(across subregions)

Question 10

Inhibitory interneurons

Answer 10

(within subregions)

Question 11

Dendate gyrus:

Answer 11

input region of the hippocampus, densely packed granule cells (excitatory projection neurons). Diverse inhibitory interneurons. High rates of neurogenesis.

Question 12

CA3 and CA1:

Answer 12

pyramidal projection neurons, inhibitory interneurons, dense recurrent network in CA3. Complex network of pyramidal neurons and interneurons. Cannabinoids act on these microcircuits through cannabinoid receptors.

Question 13

Subiculum:

Answer 13

output region of the hippocampus, two types of principal neurons: regular firing and bursting neurons. Overall less well studied area of the hippocampus.

Question 14

Hippocampal formation-

Answer 14

part of the limbic system (together with the amygdala), connection with entorhinal cortex and other structures, perforant pathway (layer II to CA3), tempero ammonic pathway (layer III to CA1).

Question 15

Action potentials

Answer 15

main form of communication between neurons. Brief, stereotypical changes in the membrane potential of a neuron. Due to the opening and closing of ion channels. Primarily due to the flux of sodium and potassium.

Question 16

how do we measure the flow of ions in the brain

Answer 16

Electrodes-
From the recorded signal we can determine the time when a certain neuron fired an action potential. The resulting spike trains are key to relate neuronal activity with behaviour.

Question 17

Hubel and Wiesel (1968)-

Answer 17

example of rate firing on stimulus orientation in the visual field.

Question 18

Hafting et al., (2008)

Answer 18

rate coding firing rate depends on the position of the animal.

Question 19

Correlation coding=

Answer 19

the relation of spike times across different neurons.