The neural representation of self and others

The ability to distinguish self from others plays a crucial role in social interactions in humans and animals. Deficits with self-recognition are observed in psychiatric disorders such as schizophrenia. How the brain processes sensory signals related to self and others to enable social recognition is currently not well understood. I address this question in mice, the genetically most tractable mammal. In rodents, social information transmitted through volatile compounds is detected by the main olfactory system. Novel social and non-social odors evoke exploratory sniffing, which provides a behavioral readout of stimulus detection. Accordingly, I will present social (cage bedding) and nonsocial olfactory stimuli to head-restrained mice, while registering sniffing. In parallel, I will perform large-scale electrophysiological recordings in the prefrontal and orbitofrontal cortex, which have previously implicated in processing social stimuli. These experiments allow me to map the representations of self, social and non-social stimuli with high resolution. In a next step, I will specifically express inhibitory opsins in self-representing neuronal ensembles based on the inducible expression from an immediate early gene promoter. I will then selectively inhibit self-encoding ensembles during a social discrimination task. These experiments will provide causal evidence for the contribution of neural ensembles to self-recognition and opening new avenues to study psychiatric disease.