Stimulation of teleost pallium elicits an integrated feeding kinematic pattern important for prey capture.

Abstract

The precise control of jaw movements during vertebrate predatory behaviour is crucial for successful prey capture. In mammals, the movement patterns associated with orofacial movements have been investigated via long-lasting intracortical microstimulation, and have revealed a cortical contribution of integrated jaw movements to prey capture. However, little is known regarding the role of the pallium, a homologue of the mammalian cortex, in the control of jaw movements in anamniotes, such as fish and amphibians. Here, I therefore investigated the pallial involvement in the orobranchial movements using Odontobutis obscura, a bottom-dwelling fish, as a case study. Electrical microstimulation of the pallial surface elicited an integrated feeding motor programme with a jaw opening-closure sequence combined with closure of the operculums (gills). Sustained jaw closure could also be evoked. Furthermore, the effective stimulation sites for the two kinematic patterns were found to be primarily distributed in the caudomedial part of the dorsal pallium. I also observed associations between opercular movements and the two kinematic patterns, and recorded prey capture composed of several distinct phases: approach, fixation, snapping and withdrawal backwards. In the snapping phase, jaw opening and closure were combined with gill movements. These findings suggest evolutionary continuity in the neural mechanisms underlying predatory behaviours across vertebrates, from teleosts to mammals.