Aim 

To understand the general principles of cognition, and to identify neural signals or biomarkers that can predict the onset of neurodegenerative diseases of learning and memory.

Background

Grid cells play a well-established role in map-like coding and spatial navigation. Less well understood, however, is the potential role that these map-like codes contribute to general cognition and complex processes such as learning, memory and decision making.

The Doeller Group is interested in investigating the idea that the brain uses map-like representations for cognition that extends beyond spatial navigation.

Key Research Questions

• Are map-like learning mechanisms, that are already known to play a role in spatial cognition, also important for cognition in general?

• What are the cognitive-level biomarkers that predict the onset of neurodegenerative diseases such as Alzheimer’s Disease?

Tools & Methods

The Doeller Group uses neuroimaging techniques such as functional magnetic resonance imaging (fMRI) and magnetoencephalography (MEG) to investigate brain systems that support learning, memory, and decision making.

The former technique boasts relatively good “spatial resolution” (the ability to detect where a signal is coming from) while the latter boasts good “temporal resolution” (the ability to detect when a signal occurs).

By combining this data with electrophysiological recordings from rodents, the team is able to paint a more comprehensive picture of the link between entorhinal brain signals and general cognition.

Research

Recent work in the Doeller lab has focused on the entorhinal cortex, the part of the brain where grid cells reside. In comparing data from human MEG recordings to electrophysiological recordings of grid cells in rodents, the group found a “grid-like” signal in the MEG recordings during a visual exploration/tracking task.

This discovery demonstrates that “grid coding” applies not only to spatial navigation tasks, as originally described, but may also play a critical role in other behaviors such as visual exploration or locomotion. The group proposes that the same systems which represent literal space are responsible for representing abstract/mental space.

The idea of cognitive space actually dates back to the 1940s, when Edward Tolman first proposed that goal-directed behavior was made possible through “cognitive maps”. Over two decades later, when place cells – cells that fire when an animal is in a particular region of space – were discovered by scientists O’Keefe and Nadel, many credited the discovery as a validation of Tolman’s cognitive map theory. Yet, since the discovery of spatially-selective cells (place cells, grid cells, head-direction cells, border cells, etc.), scientists have focused more on the use of these codes for physical navigation through space, and less so on the psychological space that is supported by these codes.

Research by the Doeller Group is bringing attention and experimental validation back to the cognitive map theory of psychological function. Whether we are discussing how to get from the grocery store back home, or whether we are figuring out how two ideas might be connected, we use the same map-like brain systems to fulfill our goal.

For more information please visit our labs' external website:

Doeller Lab