Two UCLA-led studies offer fresh insights into how human brain neurons represent time and space. Researchers recorded single-neuron activity in patients with depth electrodes for intractable epilepsy treatment.
“Place cells” and “grid cells,” the brain’s GPS system, were initially found in rodents and later in humans by Dr. Itzhak Fried and colleagues. “Time cells” have been more recently identified.
One study investigated how the brain tracks space and time simultaneously, revealing that “time cells” activate during transitions in a timed navigation game. Another study explored the brain’s ability to track time during continuous events, finding periodic neuron activity during movie-watching.
These findings illustrate the coexistence of time and place cells in the human brain, forming the basis for a spatiotemporal cognitive map that encodes memories. Temporal periodicity complements spatial periodicity, aiding the encoding and retrieval of human experiences.