November 22, 2019 – Fritjof Helmchen – Neocortical dynamics during sensory discrimination behavior

Neuroscience Seminar Series

Friday, November 22, 2019, 11:30, R229 (2e étage), Centre Universitaire des Saints Pères, 45 rue des Saints Pères, 75006 Paris

Fritjof Helmchen, Professor , Brain Research Institute, University of Zurich, Switzerland

Neocortical dynamics during sensory discrimination behavior

Abstract:

Through the combination of in vivo optical imaging and chronic expression of genetically encoded
calcium indicators it is now feasible to directly ‘watch’ neuronal population dynamics in the
neocortex of awake, head-restrained mice during specific behaviors. Here, I will present results

from calcium imaging experiments in mouse neocortex while the animals perform whisker-
based or auditory sensory discrimination tasks. We used wide-field calcium imaging to resolve
spatiotemporal activation patterns across large parts of the neocortex during individual trials. We
also chronically monitored cortical dynamics over weeks and across task learning. We observed
wide-spread, coordinated activation of multiple cortical areas, which correlated with various
behavioral aspects such as whisking, body movements, and licking. In particular, we identified
highly distinct patterns of persistent cortical activity during a short-term memory phase, which
were contingent of the animal’s behavior (active versus passive). We also found that posterior
parietal cortex (PPC) presumably acts as a routing hub, with distinct subdivisions being activated
for tactile versus auditory discriminations. During learning we identified two salient phases
framing the effective learning period, which in particular reorganized the signal flow through
posterior association areas, including PPC. Our results contribute to the understanding of the
principles of large-scale activation patterns supporting sensory discrimination and of how these
patterns emerge during learning.

Those interested in meeting with the speaker please contact

bruna.rubino@parisdescartes.fr