Behavioral phenotyping of calcium channel (CACN) subunit α2δ3 knockout mice: Consequences of sensory cross-modal activation.

Sensory cross-activation is still ill-defined and research concerning the consequences of sensory mergence on normal brain function is very limited. Human studies describe behavioral benefits of people with synesthesia- a peculiar form of perception possibly due to cross-modal activation- regarding sensory and memory abilities. Here, we studied behavioral alterations in calcium channel (CACN) subunit α2δ3 knockout (KO) mice exhibiting pain-induced cortical cross-modal activation. Knockout mice exhibited an increased response upon touch of a pinna and impaired audition, while elementary olfaction, vision, somatosensation and motor function were not altered. In contrast to synesthetic humans for whom enhanced memory function had been described, α2δ3 KO mice might have developed defects for object-based memory. However, in a task requiring use of multiple modalities, mutant mice revealed an enhanced performance compared to wild-type controls. Furthermore, several tests revealed evidence for increased anxiety-like behavior of α2δ3 KO animals. In summary, deficits in single sensory abilities and a potential gain in processing simultaneous sensory information in α2δ3 KO mice might represent behavioral correlates of sensory cross-activation. Further, our data suggest a role of CACNα2δ3 within the functionality of the sensory system, but not the motor system and general health.