Ventral Hippocampus

Question 1

What are the 3 roles of the ventral hippocampal projection to the PFC?

Answer 1

Flexible behaviour
Value-based decision making
Working memory

Question 2

Where do 1/3 of the PFC-projecting neurons from the ventral hippocampus originate?

Answer 2

Superficial layer

Question 3

Where do 2/3 of the PFC-projecting neurons from the ventral hippocampus originate?

Answer 3

Deeper layer

Question 4

How does the morphology of ventral hippocampal deep layer PFC-projecting neurons differ from that of superficial layer PFC-projecting neurons?

Answer 4

Deep layer - long sparse dendrites

Superficial layer - compact dendrites

Question 5

How does the activity of deep and superficial PFC-projecting ventral neurons differ?

Answer 5

Deep layer - more likely to fire in response to input, ~50% have bursting firing pattern
Superficial layer - small proportion have bursting firing pattern

Question 6

Which part of the hippocampus projects to the PFC?

Answer 6

Ventral

Question 7

How do the inputs to deep and superficial ventral hippocampus layers differ?

Answer 7

Deep layer - very few inputs from entorhinal cortex

Superficial layer - larger input from entorhinal cortex

Question 8

Are superficial vHPC layer projections to the PFC mainly excitatory or inhibitory?

Answer 8

Inhibitory

Question 9

Are deep vHPC layer projections to the PFC mainly excitatory or inhibitory?

Answer 9

Excitatory

Question 10

Which gene is expressed in superficial vHPC layer neurons but not deep layer vHPC neurons?

Answer 10

Calb

Question 11

What voltage enables the measurement of excitatory vHPC input onto PFC pyramidal cells?

Answer 11

-70mV

Question 12

What voltage enables the measurement of inhibitory vHPC input onto PFC pyramidal cells?

Answer 12

0mV

Question 13

How many distinct neuron populations project from the ventral hippocampus to the PFC?

Answer 13

2

Question 14

What are the 2 traditional views of hippocampal functional division?

Answer 14

Cold hippocampus - dorsal - spatial navigation and memory

Hot hippocampus - ventral - emotional processing and memory

Question 15

What are the effects of altered hippocampal function in rodents?

Answer 15

Impaired spatial navigation and memory
Impaired response to threatening stimulus
Impaired goal-directed behaviour
Anxiety level changes

Question 16

Where does the dorsal HPC project to and what is the shared role of these areas?

Answer 16

Entorhinal cortex, mammillary bodies, anterior thalamus, lateral NAc
Spatial localisation

Question 17

Where does the ventral HPC project to and what are the roles of these areas?

Answer 17

PFC, NAc, hypothalamus, amygdala, medial NAc

Reward, stress, threat

Question 18

Which subcortical hippocampal inputs are biased to the ventral HPC and what are the roles of these areas?

Answer 18

Amygdala, hypothalamus, VTA, raphe nuclei, locus coeruleus

Reward, stress, threat, mood

Question 19

Which cortical hippocampal input is biased to the ventral HPC?

Answer 19

mEC

Question 20

How do dHPC lesions affect mouse behaviour?

Answer 20

Impair spatial behaviour

Question 21

How do vHPC lesions affect mouse behaviour?

Answer 21

Impair reward and anxiety responses

Question 22

How do place cells in the vHPC differ from those in the dHPC?

Answer 22

Fewer

Lower resolution spatial tuning

Question 23

Is dHPC cell firing allocentric or egocentric?

Answer 23

Allocentric

Question 24

Is vHPC cell firing allocentric or egocentric?

Answer 24

Egocentric

Question 25

What does the dHPC mainly encode?

Answer 25

Prediction of place

Question 26

What does the vHPC mainly encode?

Answer 26

Prediction of reward/threat

Question 27

What are the similarities of vHPC and dHPC cells?

Answer 27

Predictive
Respond to combination of cues
Integrate inputs from multiple modalities - external and internal

Question 28

What is the overall role of the hippocampus?

Answer 28

Encodes relationships between different cues - to predict consequences of actions