Directional tuning in the hippocampal formation of birds. Ben-Yishai et al.,

Here we used tetrodes to record neurons from the hippocampal formation of Japanese quails – a ground-dwelling species – while the quails roamed in an open-field arena. Whereas spatially-modulated cells (place-cells, grid cells, border-cells) were generally not encountered, the firing-rate of about 12% of the neurons was unimodally and significantly modulated by the head-azimuth – i.e. these were head-direction cells (HD cells).

Typically, HD cells were maximally active at one preferred-direction and minimally at the opposite null-direction, with preferred-directions spanning all 360o across the population. The preferred-direction was independent of the animal’s position and speed, and was stable during the recording session. The HD tuning was broader compared to that of HD cells in rodents, and most cells had non-zero baseline firing in all directions.

However, similarly to findings in rodents, the HD tuning usually rotated with the rotation of a salient visual cue in the arena. Thus, these findings support the existence of an allocentric head-direction representation in the quail hippocampal formation, and provide the first demonstration of head-direction cells in birds.