Week 6: Recap of Place cells

Question 1

Across species (humans and rodents), we can identify different portions of the hippocampus (4)

Answer 1

• DG
• CA3
• CA2
• CA1

Question 2

Hippocampus receives main input from

Answer 2

EC (Enthorine cortex) which last stage of cortical processing prior to the hippocampus

Question 3

Remindar what we found in hippocampus diagram:

Answer 3

Question 4

Typical experiment to record neurons from hippocampal formation is from

Answer 4

single-cell recordings

Question 5

Reminder of single-cell recordings (3)

Answer 5

1. Microdrives with electrodes are chronically implanted
2. Once the animal has recovered from surgrey it performs a task or simple runs around a box to collect food pellets around the box to cover the entire space of maze
3. Electrodes are moved until they record spikes

Question 6

Diagram of single-cell recordings

Answer 6

Question 7

Neurons found in hippocampal formation (4)

Answer 7

1. Place cells
2. Head direction (HD) cells
3. Grid cells
4. Boudary cells

Question 8

The single-cell recordings allow us to have direct recordings from

Answer 8

rodent brain in behaving animal

Question 9

There is a visual cue (e.g., white card) in the box from single-cell recordings that help animal to

Answer 9

orientate itself in this box

Question 10

Remindar: Place cells

Answer 10

Place cells fire whenever an animal occupies a specific location in its environment, with each place cell firing at a different spot.

Question 11

Remindar: Grid cells (2)

Answer 11

A grid cell is a type of neuron within the entorhinal cortex that fires at regular intervals as an animal navigates an open area,

Grid cells generate virtual maps of the surroundings that resemble grids of repeating triangles.

Question 12

Location of place cells

Answer 12

Hippocampus

Question 13

Location of grid cells:

Answer 13

EC

Question 14

Diagram of place and grid cells:

Answer 14

Question 15

Remindar: HD cells

Answer 15

Head direction cells fire selectively when the rat’s head is pointed in a particular direction in allocentric space, regardless of its location (Ranck, 1985)

Question 16

Diagram of HD cells graph

Answer 16

Question 17

Boundary cells are measured the same way

Answer 17

as place cells (recording intensity of firing of a neuron, red = highest)

Question 18

Boundary cells have receptive fields and whenever the boundary cells is in that receptive field

Answer 18

that boundary cells fires an action potential

Question 19

Boundary cells respond to a specific

Answer 19

environmental boundary/objects at a particular distance and direction from an animal

Question 20

As an animal moves away from receptive field, that boundary cells

Answer 20

stops firing action potentials

Question 21

Boundary’s cells firing is

Answer 21

independent of the rat’s heading direction.

Question 22

Most of the neurons in hippocampal formation has been recorded in

Answer 22

humans as well

Question 23

Place fields are receptive fields for

Answer 23

space

Question 24

HD cells have receptive fields for

Answer 24

heading

Question 25

Place cell property 1

Answer 25

Location of a place field can not be predicted based on anatomical vicnity

Question 26

Location of the place field can not be predicted based on anatomical vincity means

Answer 26

Anatomically close place cells can have place fields far from each other (rather than close to each other) or one cell can be silent while other is active in different enviroments

Question 27

Place cell property 2 (3)

Answer 27

1. * Firing is independent of the rat's orientation in open field 2. * Firing is directional in narrow-armed mazes 3. * Firing is robust to the removal of sensory cues

Question 28

Firing of PC is independent of rat's orientation in open field = how? (2)

Answer 28

* Separated data according to movement direction * The activity of the place cell is still in the same location if the animal direction is west to east or east to west

Question 29

Firing of PC is directional in a narrow-armed maze (linear track = animal runs back and forth)

Answer 29

Meaning the animal only fires in one direction

Question 30

Firing of PC is robust to the removal of sensory cues (2) Nakazawa (2002)

Answer 30

If you have 4 sensory cues in enviroment, you can remove 3/4 and the PC cells still fire If you block the NMDA receptor, this is not the case, meaning formation of PC fields is important for plasicity by NMDA-receptor for these PC cells

Question 31

Place cell property 3 = Global remapping Individual PC cells at given enviroment fire at different locations or are silent and together all active PC cells

Answer 31

likely to cover the entire enviroment with their place fields

Question 32

Place cell property 3 Some PC cells are silent in one enviroment but

Answer 32

active in another

Question 33

Place cell property 3 If a PC cell is active in both enviroment it is so at

Answer 33

different locations

Question 34

Place cell property 3 what is global remapping?

Answer 34

The process of changing firing locaiton or turning on/off between enviroments

Question 35

Place property 3 (after def of glob remap) we can think of the set of active PC across an enviroment akin to

Answer 35

extended attractor network (current context recruits a given set)

Question 36

We can think that the set of active PC cells across enviroment akin to an extended attractor network but be careful... - (2)

Answer 36

If the set of active PC is bounded together by CA3 recurrence, it can't be via CA3 place cell with small receptive place fields Must be via CA3 cells that are active throughout the enviroment (i.e., not CA3 place cells)

Question 37

Place cell propertities (3)

Answer 37

1. Property 1 = location of place fields can not be predicted by anatomical vicinity 2. Property 2 = Firing is directional , independent or orientation and robust to removal of sensory cues 3. Property 3 = Global remapping

Question 38

Similar to Nakazawa paper, you need synaptic plasticity of the NMDA-receptor to have stable place fields (Kentros et al., 1998) - (2)

Answer 38

Inject saline , place field is stable Place field stability falls when NMDA receptors are blocked (i.e.,NMDAR anatgonist is injected in rat

Question 39

There is slow, experience-dependent changes to PC fields showing global remapping (Lever et al., 2002) is not the whole story (3)

Answer 39

* global remapping is akin to change between attractor * But the attractor 'is slowly deformed over time' * We need to keep these caveats in mind when building a model * Recall: question determines level of detial in model