Poster E68, Monday, March 26, 2:30-4:30 pm, Exhibit Hall C
Persistence of hippocampal activation patterns in post-encoding rest predicts subsequent voluntary, but not involuntary recall of distressing film clips
Renee M. Visser1, Richard N. Henson1, Emily A. Holmes1,2; 1Medical Research Council Cognition and Brain Sciences Unit, University of Cambridge, UK, 2Karolinska Institutet, Stockholm, Sweden
A key question in emotional memory research is how a traumatic event may result in intrusive, involuntary memories of that event – the core clinical feature of psychological disorders such as post-traumatic stress. Previous behavioural work shows that the strength of voluntary recall of traumatic events is not necessarily related to the frequency or vividness of the involuntary recall of those events, a dissociation that is not readily explained by mainstream episodic memory theories. Here, we investigated whether the two types of recall may be associated with distinct neural profiles at the time of encoding and shortly after. For this, 32 healthy participants underwent functional Magnetic Resonance Imaging while viewing clips of distressing events (the so-called ‘trauma film paradigm’), with periods of resting state in between consecutive clips. Next, we applied ‘multi-voxel correlation structure’ to assess the degree to which voxel-by-voxel connectivity profiles related to the encoding of a specific clip persisted during the immediately-following post-encoding rest period. In the hippocampus, higher similarity between post-encoding rest and encoding profiles, compared to immediately-preceding pre-encoding rest periods, predicted the voluntary recall (both verbal and visual recognition) of the distressing events, a week later. This neural profile was not however related to the frequency or variety of intrusive memories that participants recorded in a daily diary, which they kept for a week following film viewing. These findings corroborate behavioural observations and tentatively suggest that voluntary and involuntary memories of the same event may to some extent rely on separate neural systems.
Topic Area: LONG-TERM MEMORY: Episodic