Revealing the neural basis of human memory with direct recordings of place and grid cells and traveling waves

The ability to remember spatial environments is critical for everyday life. In this talk, I will discuss my lab’s findings on how the human brain supports spatial memory and navigation based on our experiments with direct brain recordings from neurosurgical patients performing virtual-reality spatial memory tasks. I will show that humans have a network of neurons that represent where we are located and trying to go. This network includes some cell types that are similar to those seen in animals, such as place and grid cells, as well as others that have not been seen before in animals, such as anchor and spatial-target cells. I also will explore the role of network oscillations in human memory, where humans again show several distinctive patterns compared to animals. Whereas rodents generally show a hippocampal oscillation at ~8Hz, humans have two separate hippocampal oscillations, at low and high frequencies, which support memory and navigation, respectively. Finally, I will show that neural oscillations in humans are traveling waves, propagating across the cortex, to coordinate the timing of neuronal activity across regions, which is another property not seen in animals. A theme from this work is that in terms of navigation and memory the human brain has novel characteristics compared with animals, which helps explain our rich behavioural abilities and has implications for treating disease and neurological disorders.