Goal discrimination in hippocampal nonplace cells when place information is ambiguous

Abstract

Memory-guided navigation relies on hippocampal neurons, like place cells, that encode features of the environment. However, little is known about hippocampal place codes when spatial cues provide ambiguous information about finding goals. Nonplace cells, pyramidal cells that fire without strong spatial modulation in an environment, may be well-suited to carry task-relevant information when spatial information is ambiguous. We find that when spatial cues and goal information are conflicting, nonplace cell firing distinguishes between ambiguous spatial cues. On correct trials nonplace cells had higher firing rates and altered gamma-phase modulation at task-relevant cues than on incorrect trials, while place cells showed no such differences. Finally, this goal discrimination in nonplace cells is absent in a mouse model of Alzheimer's disease that has memory impairment. Our findings show that nonplace cells differentiate ambiguous goal information that place cells do not, revealing a special contribution to coding by these nonplace cells.