Maria Wimber

How does the human brain recreate vivid mental images of past events? The talk will give an overview of our work investigating how memory reconstruction dynamically unfolds in time, using pattern analysis of electrophysiological and fMRI data as well as behavioural reaction time analyses. The results highlight two prominent characteristics of memory recall. First, when the hippocampus reactivates a previously stored visual memory, the information flow in neocortex tends to follow a reverse feature processing hierarchy compared to initial perception, starting with the reconstruction of high-level conceptual image features and ending with low-level perceptual detail. We also find consistent evidence for a representational shift towards conceptual features (“semanticisation”) over longer consolidation periods and with repeated, active recall. Second, memory reactivation is rhythmic, as visible in brain and behaviour, in line with models suggesting that the hippocampal theta rhythm orchestrates the timing of memory reactivation relative to incoming sensory input. Our most recent findings demonstrate that phase coding along the theta rhythm can help segregate overlapping, competing memories. Together, these findings emphasise the dynamic and reconstructive nature of our memories.

Maria Wimber is a Professor of Cognitive Neuroscience & Memory at the Centre for Cognitive Neuroimaging (CCNi), University of Glasgow. Her group’s work is centred around the question how the human brain reconstructs memories of past events, and how these memories adaptively change over time and with repeated use. Her group uses behaviour, EEG/MEG, fMRI, and intracranial EEG to isolate the neural footprints of memories and track their dynamic changes over time. Maria obtained her PhD from the University of Regensburg in 2008, working on neural mechanisms of forgetting. Following two postdocs, one at the University of Magdeburg and one at the MRC Cognition & Brain Science Unit in Cambridge, she took up a tenure-track position at the University of Birmingham in 2013, before moving to sunny Scotland in 2020.