Speaker 1: Ramon Nogueira (Fusi Lab)

Title: Nonlinear mixed selectivity in mouse barrel cortex: a compromise between complex discrimination and generalization

Abstract: Adaptive behavior requires the integration over time of multiple sensory inputs. In this study, mice were trained to actively integrate information from different whiskers to report the curvature of an object. The analysis of high-speed videos revealed that the task could be solved by integrating linearly the whisker contacts on the object. However, neural representations in the barrel cortex are high dimensional as the inputs from multiple whiskers are non-linearly mixed. The observed high dimensional representation could allow the animal to perform a broad class of significantly more complex tasks, with minimal disruption of the ability to generalize to novel situations in simpler tasks. Our work suggests that the barrel cortex operates in a regime that represents an efficient compromise between generalization and discrimination.

Speaker 2: Sami Hassan (Siegelbaum Lab)

Title: Odor representations in hippocampal area CA2

Abstract: Recent work in our lab identified a crucial role of the CA2 subregion of the hippocampus in social memory in rodents. Silencing CA2 resulted in the loss of the encoding, consolidation and recall of social memory and also suppressed social aggression. An important next step is the characterization of the underlying dynamics and processing of sensory cues that take place during social recognition in CA2. Olfactory stimuli are one candidate salient cue that may enable mice to recognize conspecifics. We are using an olfactory discrimination task involving both social and non-social odors in awake, head-fixed mice while performing 2-photon imaging of CA2 neuron activity. Our preliminary results indicate that mice are able to discriminate social odors from individual conspecifics and that these odors trigger robust CA2 activation. Experiments in progress explore whether CA2 activity can distinguish social from non-social odor cues.