The neural substrate of navigation using hydrostatic cues in goldfish.

Hydrostatic pressure is a global sensory cue exploited by fish to navigate in the vertical dimension. Unlike other navigational cues in the horizontal plane that usually require learning and memory to determine location, hydrostatic pressure signals the absolute position along the vertical axis. Recently, it was shown that fish can use hydrostatic signals to navigate. It remains unclear, however, which brain regions are involved in processing this signal. Here, we tested whether the dorsomedial and lateral parts of the pallium, two regions that were found to be critical in horizontal navigation, are also critical for hydrostatic cue detection in goldfish. The results show that lesions to both these regions cause fish performance to deteriorate to chance values, indicating that both regions play an important role in processing hydrostatic pressure cues. These findings thus contribute to the rapidly growing body of knowledge on teleost navigation in space.