Building internal models during periods of rest and sleep

Abstract: Every day we make decisions critical for adaptation and survival. We repeat actions with known consequences. But we can also infer associations between loosely related events to infer and imagine the outcome of entirely novel choices. In the first part of the talk I will show that during successful inference, the mammalian brain uses a hippocampal prospective code to forecast temporally structured learned associations. Moreover, during periods of rest, co-activation of hippocampal cells in sharp-wave/ripples represent inferred relationships that include reward, thereby “joining-the-dots” between events that have not been observed together but lead to profitable outcomes. Computing mnemonic links in this manner may provide an important mechanism to infer new relationships. In the second part of the talk I will test this hypothesis and show that in human participants performance on an inference task improves after memory reactivation is facilitated during periods of rest. Finally, I will discuss how neural activity across different brain regions may coordinate during periods of rest and sleep to build an internal model that extends beyond direct experience.

Bio: Helen studied Natural Sciences at University of Cambridge, before completing her PhD at University College London (UCL). During her PhD, Helen used Magnetic Resonance Imaging (MRI) to investigate mechanisms for memory and decision making in the human brain, with supervision from Prof. Tim Behrens and Prof. Ray Dolan at the Wellcome Trust Centre for Neuroimaging. In 2015, Helen was awarded a Junior Research Fellowship at the University of Oxford (Merton College). During this fellowship, and as a postdoctoral researcher, Helen worked with Prof. David Dupret at the MRC Brain Network Dynamics Unit (BNDU) where she developed a cross-species approach to gain new insights into the neural mechanisms that support inferential reasoning. In 2022, Helen was awarded a UKRI Future Leaders Fellowship to set up her own research group at the BNDU and the Wellcome Centre for Integrative Neuroimaging, University of Oxford. Helen’s group investigates how cells and circuits in the brain work together to perform computations that support memory in both health and disease.

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