Neural codes for 2-D and 3-D space in the hippocampal formation of bats

The work in our lab focuses on understanding the neural basis of behavior, particularly spatial cognition, in freely-moving, freely behaving mammals – employing the echolocating bat as a novel animal model.  I will describe our recent studies, including: (i) recordings of 3-D head-direction cells in the presubiculum of crawling bats, as well as recordings from hippocampal 3-D place cells in freely-flying bats, using a custom neural telemetry system – which revealed an elaborate 3-D spatial representation in the mammalian brain; and (ii) recordings of 'grid cells' in the bat's medial entorhinal cortex, in the absence of theta oscillations – which strongly argues against the prevailing computational model of grid formation.  I will also describe our recent studies of spatial memory and navigation of fruit bats in the wild, using micro-GPS devices, which revealed outstanding navigational abilities and provided the first evidence for a large-scale 'cognitive map' in a mammal.