We employ a range of technologies including tetrode and high density neuropixels electrophysiological probes, two photon imaging in conjunction with virtual reality environment, and novel maze tasks to study the spatial correlates of hippocampal and medial entorhinal cortical cells. Figure 1 shows the fields of 12 entorhinal grid cells recorded 47 days after implantation of a neuropixels probe. 

In recent work we have shown that the grid structure is not uniform across the whole of a nonhomogeneous environment such as a trapezoid and that single fields can be manipulated by the movement of nearby walls of the enclosure. Figure 2 shows that the symmetrical grid pattern recorded from a grid cell in a square is distorted and much less gridlike in the trapezoid. This finding calls into question how useful the grid system is for providing a metric for the cognitive map and suggests that the grids are more responsive to the shape of the enclosure than had previously been suspected. 

Cells in the amygdala respond selectively to stimuli of ethological significance such as a conspecific or a specific food, and continue to fire after the removal of that stimulus for periods of minutes. We are trying to understand the mechanism underlying this short-term response and to understand its function. Does it provide a memory of the event or does it provide some other type of signal for example enabling other areas of the brain to consolidate information stored at the time of an important ethological event.