Dr Alexa Morcom – University of Sussex
Dr Zara Bergström – University of Kent
A longstanding question in memory research is how and when people are able to control what they recall. For instance, you may want to remember who you had a socially-distanced beer with last month, without recalling details about the beer itself.
At the time of recollection the brain’s hippocampus is thought to trigger the reinstatement of the same cortical patterns that were present during the original events. This reinstatement is thought to underpin the conscious experience of remembering the past. Can people select which aspects of events are reinstated (preretrieval control), or do selective processes operate later on the information recovered from memory (postretrieval control)? And how do these abilities change as people age when preretrieval or postretrieval control (or both) may be impaired?
Human functional magnetic resonance (fMRI) brain imaging has been used to measure reinstatement, with mixed evidence for selective recollection. But fMRI has very low time resolution so cannot fully separate early from late cognitive processes. More recently, dynamic measures of reinstatement have become possible using electroencephalography (EEG), which is better able to distinguish preretrieval from postretrieval control of recollection.
Understanding how selective recollection is achieved is essential for testing theoretical models of memory, and improving understanding of memory difficulties in groups with impaired recollection like healthy older people.
APPROACHES TO BE USED
This project will investigate the conditions under which preretrieval and postretrieval control can achieve selective recollection in younger and older adults. The student will learn and apply two complementary brain imaging modalities with advanced multivariate analysis techniques, alongside memory tasks developed to examine stages of memory control. You will examine the roles of the hippocampus and cortex in selective recollection using anatomically precise fMRI, and assess the dynamic emergence of selective memory representations with time-resolved EEG imaging.