Lecture 16 - Spatial Navigation

Question 1

When were cognitive/spatial maps initially proposed?

Answer 1

Tollman was the first to suggest cognitive/spatial maps and provided evidence for this using rats in the 1940s.

Question 2

There is evidence for place cells in which area of the brain?

Answer 2

The hippocampus.

Question 3

Aside from place cells, what other cells are important for creating a cognitive map?

Are these cells all in the hippocampus?

Answer 3

Grid cells, head direction cells, and border/boundary cells.

No. Whilst place cells are found in the hippocampus, these other cells are found in other areas of the brain, but are close to the hippocampus.

Question 4

A lot of work around understanding how we engage with navigation and form cognitive maps is based on experiments using rodents.
Why is it difficult do measure navigation in humans and how is it currently done?

Answer 4

With rodents neurons and cortical activity can be measured directly using electrodes. Due to ethical reasons the same cannot be done with humans. This means when we want to measure brain activity in humans we need to use more indirect measures, such as fMRI, which are less accurate more limiting.

Question 5

Where in the brain are ‘scenes’ processed (proposed area)? Scenes include landscapes, rooms etc.

Answer 5

The parrahippocampal place area (PPA). Proposed by Kanwisher.

Question 6

What aspects of a scene is the PPA encoding?

Answer 6

The PPA encodes for global geometry of a scene (that is, the layout of a scene as dictated by the larger structures, or lack there of, in the scene), not the objects themselves.

Question 7

The PPA encodes for the global geometry of a scene not the objects within the scene.
True or False?

Answer 7

True.
There is a broad range of evidence to support this statement.

Question 8

What areas encode for the objects within a scene?

Answer 8

The areas in the brain that responsible for encoding for/processing information regarding objects in our visual field are the Lateral Occipital Complex and the fusiform gyrus.

Question 9

What would a person with damage to the PPA experience a scene as?

Answer 9

People with damage to the PPA report being able to see and identify objects within a scene, but do not have a sense the layout of the scene, i.e where these objects are in relation to one another.

Question 10

What do border/boundary cells encode for/what aspect of vision are they responsive to?

Answer 10

Border/boundary cells encode for information about how far away we are from objects/landmarks.

Question 11

The border/boundary cells in the hippocampus are not playing a role in recognising objects/landmarks, but rather are only encoding for information in regards to how far from a landmark/object one is.
True or false.

Answer 11

True.

Question 12

Where in the brain are the border/boundary cells that encode for distance from and between objects/landmarks?

Answer 12

Border/boundary cells are located in the hippocampus.

Question 13

There has been evidence to show that humans also have place-responsive/place cells in the hippocampus.
True or false.

Answer 13

True.

Question 14

What is encoded in the retrosplenial complex?

Answer 14

Allocentric heading

Question 15

What is allocentric heading and where in the brain is this aspect of vision encoded/processed?

Answer 15

The Retrosplenial Complex.

Question 16

What is a euclidian distance and what is a path distance?

Hint: as the crow flies

Answer 16

EUCLIDIAN DISTANCE refers to the distance as the crow flies.
PATH DISTANCE refers to the distance a route will take.

Question 17

Are euclidian distances encoded in the posterior or anterior region of the hippocampus.

Answer 17

The anterior area of the hippocampus.

Question 18

Where are path distances encoded? The posterior or anterior are of the hippocampus?

Answer 18

Posterior.

Question 19

Do euclidian distances correspond to a cognitive map?

Answer 19

Yes.

Question 20

What is encoded in the posterior parietal cortex?

Answer 20

In the RETROSPENIAL CORTEX it is thought that allocentric heading.

Question 21

Taxi drivers in London that had been working for a long time showed increases growth in their hippocampus. What does this suggest about the hippocampus.

What areas of the hippocampus were found have increased volume and what area had decreased volume?

Did London bus drivers show this same change in hippocampus volume?

Answer 21

The hippocampus is responsible for spatial navigation and cognitive maps, at least partially.

The anterior of the hippocampus had decreased volume and the posterior had increased volume.

No.

Question 22

What is Unilateral Spatial Neglect?

Answer 22

Unilateral Spatial Neglect is the contralateral disturbance or absense of visual awareness of one side of the visual field.

Question 23

Why is unilateral spatial neglect caused mostly by damage to the right parietal lobe and why right-side spatial neglect rare?

Answer 23

The right hemisphere tends to be more responsible for spatial awareness and spatial encoding.
There is redundant processing of right visual spatial data in the left hemisphere, along with processing the right hemisphere as well, whereas left side visual data is only processed in the right visual field. This means that it is rare for unilateral spatial neglect of the right visual field.

Question 24

What is the frequency map of the basilar membrane in the cochlear?

Answer 24

Higher frequencies are mapped toward the base of the basilar membrane and lower frequencies are mapped toward the apex of the basilar membrane.

Question 25

Who won the Nobel Prize in 2014 for the discovery of place cells in the hippocampus?

Answer 25

O’Keefe , it was shared with Moser and Moser?

Question 26

What did Moser and Moser discover that lead them to jointly winning the Nobel Prize with O’Keefe in 2014?

Answer 26

Discovered Grid, Head Direction and Border/Boundary cells in the hippocampus and entohinal cortex in rats which fire when the rat is engaging in navigating their environment.

Question 27

What is Papez circuit?

Answer 27

Papez’s circuit is the brain/cognitive circuit associated with emotional expression.

Question 28

Why is it difficult to measure spatial navigation in humans compared ti animals?

Answer 28

Due to ethical limitations we cannot measure the brain in the same ways as we can measure the brains of animals. Direct measurement of brain activity can be performed on animals, whereas for humans we rely on more indirect measures such as fMRI. The problem with fMRI is that the participant must lay still and navigation generally involves moving around, looking around.

Question 29

What area did Kanwisher and Epstein coin in relation to spatial navigation/visual processing?

Answer 29

They generated evidence to support the idea that we have an area of cortex that is responsible for processing visual information in regards to scene recognition. They termed this part of the cortex the PARAHIPPOCAMPAL PLACE AREA.

Question 30

What aspects of a scene is the PARAHIPPOCAMPAL PLACE AREA encoding?

Answer 30

Global spatial geometry and not the objects within a space.

Question 31

What area is associated with recognising the objects within a scene?

Answer 31

The LATERAL OCCIPITAL LOBE has been indicated in recognition of objects within a scene.

Question 32

Studies have shown that the hippocampus in humans is activated when determining the distance (conscously/subconsciously) between landmarks, which is somewhat similar to the function of the border/boundary cells in the hippocampus of rats.
What does the hippocampus not activate in regards to spatial navigation?

Answer 32

Identification of landmarks does not cause activation in the hippocampus.
Identification of landmarks causes activation in the PPA and LOC.
Hippocampus is associated with WHERE not WHAT.

Question 33

Direct recording of neurons in pre-surgical epilepsy patients allowed for the discovery of what cells related to spatial navigation?

Answer 33

Place-responsive cells clustered in the hippocampus.

Question 34

What is the RETROSPLENIAL COMPLEX thought to be responsible for in regards to spatial navigation?

Answer 34

There is evidence to suggest that the RETROSPLENIAL COMPLEX is involved in the representation of/encoding allocentric heading.

Question 35

There has been evidence that suggests the hippocampus encodes for different spatial distances in different areas. What are the areas that are associated with EUCLIDIAN distance encoding and PATH DISTANCE encoding?

Answer 35

EUCLIDIAN DISTANCE (as the crow flies) encoded more ANTERIORLY and PATH DISTANCE encoded more POSTERIORLY in the hippocampus.

Question 36

In the iconic London Taxi Driver Experiment/Study of Hippocampal change and The Knowledge what was found?

Answer 36

It was found that after Taxi drivers acquired The Knowledge their anterior hippocampal volume decreased and their posterior hippocampal volume increased. It was also found that the longer the drivers were engaged in this occupation the greater the change/growth.

Question 37

Compared to Taxi drivers what was found about hippocampal volume in London Bus Drivers?

Answer 37

It was found that taxi drivers had more grey matter in their mid/posterior hippocampus compared to bus drivers and less grey matter in their anterior hippocampus compared to bus drivers.