PS250 - Spatial Navigation

What is one of the most used navigational tasks?

The Morris Watermaze

Who invented the Morris Watermaze?

Richard Morris in 1981

Morris Watermaze

Large circular maze 2M in diameter with a submerged platform in the pool

Four strategies to find the platform

1. Random navigation 

2. Taxon navigation 

3. Praxic navigation

4. Locale navigation 

Random navigation

No information about the location of the platform = locate it randomly

Taxon navigation 

Animal can see (or locate by other sensory input) the cue towards which it always swims

Praxic navigation

Animal executes a constant motor program. If an animal always starts in the same position and the goal remains in a constant position

Locale navigation

Animal learns the location of a platform relative to a constellation of cues. Build up a cognitive map on which the location is known. Depends on where platform, cues etc relative to yourself and where platform, cues etc are relative to each other

What area is thought to be involved in spatial navigation, learning, and memory?

Hippocampal formation 

Where is the hippocampal formation?

The hippocampus is a medial temporal lobe structure, surrounded by cortical areas

What does lesions of the hippocampus do?

Disrupts spatial learning

What did Maguire (2000) find?

More time spent as a taxi driver the greater the activation of the anterior hippocampus

Properties of place cells

• Good stability across time

• Continues to fire in the dark or when cues are removed

• When distal landmarks move, place cells move in proportion 

Head-direction cells

Cells which fire depending on the direction of the head

What do lesions of the postsubiculum do?

Impairs spatial navigation