Ayala HerbertHuman memory is selective and there are many reasons for this. Neuroscientists have recently discovered a curious aspect of how our memory works. When the brain needs to recall information related to a specific location, individual neurons take aim at specific memories.
When asked to recommend a travel itinerary for a city you’ve been to often, selective snippets of memories of places from different trips may come to mind. Researchers from several universities, including Columbia University in New York and Emory University in Atlanta, USA, studied individual neurons – called “memory cells” – of 19 patients who had undergone brain surgery for epilepsy treatment.
The patients performed a task designed to assess spatial memory performance. During the task, the subjects were placed on a road using virtual reality (VR) goggles and asked to press a button when they encountered specific objects. In part of the task, the researchers asked participants to walk along a path and mark the location of a distant object. By examining the medial temporal lobe (MTL) and, in particular, the entorhinal cortex, the scientists found that memory-tracking cells were “spatially tuned” to the location and could then retrieve the location information that the person had to recall.
The scientists’ work shows that neurons in the human brain keep track of events we intentionally recall and can change their activity patterns to distinguish between memories. They’re like dots on a Google map that mark where important events in your life happened. This discovery could serve as a potential mechanism for our ability to selectively utilize different experiences from the past and help experts understand how these memories affect the spatial map of the human brain.
In the past, scientists have already tried to understand how this can be done. They found that the cells of the neural network are very important for the operation of spatial memory, as it works similarly to a GPS system. Spatial tuning of neurons is the idea that individual neurons are “activated to represent a location in the environment during navigation.” Previous work has suggested that spatially tuned cells reassign their triggering circuits in different environments, so events that occur in different locations are associated with different spatial maps,” the researchers explain.
Building on this work, the scientists suggested that individual neurons in the MTL, and especially in the entorhinal cortex, will demonstrate a kind of “spatial tuning of neurons” modeled by past experience. The implication is that the human brain creates the truest map of memories.
