Mental navigation in the primate entorhinal cortex.

Area of Science:

• Neuroscience
• Cognitive Science
• Computational Neuroscience

Background:

• Cognitive maps enable novel computations from past experiences, like planning routes.
• Previous research demonstrated cognitive maps with external sensory input in spatial and non-spatial domains.
• The study investigates if cognitive maps function endogenously, without external input.

Purpose of the Study:

• To test if cognitive maps support endogenous computations without external sensory input.
• To investigate the role of the entorhinal cortex in endogenous cognitive map recruitment.
• To explore how the brain recalls landmarks internally during mental navigation.

Main Methods:

• Recorded neural activity from the entorhinal cortex of monkeys performing a mental navigation task.
• Monkeys used a joystick to create vectors between visual landmarks without seeing intermediate points.
• Utilized a continuous attractor network model with Hebbian learning to simulate endogenous landmark recall.

Main Results:

• Monkeys' task performance and generalization indicated reliance on structured landmark representations.
• Task-modulated neurons showed periodicity and ramping, consistent with continuous attractor networks.
• A computational model explained endogenous landmark recall and predicted transient slowing of path integration.

Conclusions:

• Findings link entorhinal cortex activity patterns to endogenous cognitive map recruitment.
• The study provides evidence for cognitive maps supporting internal computations.
• The research elucidates mechanisms of endogenous landmark recall and its effect on navigation.