Speaker
Description
Visually guided prey capture is an ethologically relevant behaviour that depends on the precise integration of sensory input and motor output. Postsynaptic density proteins 95 and 93 (PSD-95/93) are signalling scaffolds of the PSD of excitatory synapses with opposing function for critical period (CP) timing: PSD-95 promotes AMPA-silent synapse maturation which terminates the CP while PSD-93 inhibits CP-closure. Binocularity develops during visual CP and fully matures before CP-closure. Despite the livelong CP-plasticity of PSD-95 knock-out (KO) mice or the precocious CP-closure of PSD-93 KO mice, these animals exhibit relatively subtle sensory phenotypes in adulthood in standard cage housing. To assess the role of PSD-95 and PSD-93 in ethologically relevant binocular visual processing, we compared prey capture behaviour in KOs and their corresponding wild-type (WT) littermates. PSD-95 KO mice exhibited profoundly impaired predatory behaviour, but improved prey localisation under monocular conditions, indicating impaired binocular integration. On the other hand, PSD-93 KO mice exhibited minor deficits; under binocular conditions, WT and PSD-93 KOs performed similarly, with impairments observed under monocular conditions. Using monocular vision, both WT- and PSD-93 KO-mice were significantly slower, travelled greater distances, and showed a lower probability of contact given an approach, indicating failure in high-precision targeting. Our results highlight that the closure of CP is required for accurate hunting with binocular but not monocular vision, whereas precocious CP-closure results in minor impairments, primarily restricted to monocular vision. These findings highlight the importance of CP-closure for proper binocular vision in an ethologically relevant task.
