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 Wed 06 June 2018 13:00
Sherrington Building, Library (map)
Dr Katharina Wilmes
Imperial College London
Interneuron circuits for top-down guided plasticity of sensory representations
Abstract: Humans and animals are remarkable at attending to stimuli that predict rewards. While the underlying neural mechanisms are unknown, it has been shown that rewards influence plasticity of sensory representations in early sensory areas. Hence, top-down reward signals can modulate plasticity in local cortical microcircuits. However, synaptic changes require time, but rewards are usually limited in time. Because the two happen on different time scales, it is unclear how reward signals interact with long-term synaptic changes. We hypothesise that interneuron circuits, which recently emerged as key players during learning and memory, bridge the timescales. We investigate how temporary top-down modulation by rewards can interact with local excitatory and inhibitory plasticity to induce long-lasting changes in sensory circuitry. We construct rate-based and spiking models of layer 2/3 mouse visual cortex consisting of excitatory pyramidal neurons, and different interneuron populations, corresponding to somatostatin (SST)-positive, parvalbumin (PV)-positive and vasoactive intestinal peptide (VIP)-expressing interneuron types. We demonstrate how interneuron networks could store information about the rewarded stimulus to instruct (subsequent or more slowly emerging) long-term changes in excitatory connectivity in the absence of further reward.

About the speaker: Katharina is a postdoc in the Clopath lab at Imperial College London since February 2017. She is broadly interested in understanding the cellular and circuit mechanisms that underlie learning and the regulation of synaptic plasticity. She obtained her PhD (2016) in Computational Neuroscience and Biophysics from the Bernstein Center and the Humboldt University in Berlin, where she worked with Susanne Schreiber and Henning Sprekeler. Prior to that, she studied Cognitive Science (BSc, Osnabrueck University) and Cognitive Neuroscience (MSc, University of Amsterdam).