Patterns of Memory Reactivation
In our search for the engram, our group has been conducting several studies assessing neural reactivation, the phenomemon according to which patterns of brain activity elicited when an event is experienced are reactivated when this same event is remembered. Our studies have made use of rich audio-visual film clips to capture the complexity of real-life experiences and elicit brain-wide patterns of activation, which we capture with functional magnetic resonance imaging (fMRI). We have applied a variety of multivariate data analysis techniques to our data, such as multivoxel pattern analysis (MVPA), Barycentric Discriminant Analysis (BADA), and Partial Least Squares (PLS), and have successfully identified widespread patterns of stimulus-specific activity elicited during perception that are reactivated during memory retrieval. Our approach provides a novel way to measure the faithfulness and quality of memory representations that is both objective and subject-independent. We are now using it to assess how individual differences, experience and other forms of experimental manipulation influence the nature and quality of the memory trace. We are also using our approach with senior and clinical populations in order to determine the mechanisms through which aging and pathology can deteriorate memory representations.
St-Laurent M., Bondad A., Abdi H., Buchsbaum B.R. 2014. Memory reactivation in healthy aging: evidence of stimulus-specific dedifferentiation. Journal of Neuroscience, 34(12), 4175-4186.
Buchsbaum B.R., Lemire-Rodger S, Fang C., Abdi H. 2012. The neural basis of vivid memory is patterned on perception. Journal of Cognitive Neuroscience, 24(9), 1867-1883.
St-Laurent M., Abdi H., Buchsbaum B.R., Hippocampal activity and memory performance predict classification accuracy for stimuli recalled from long-term memory (2014, April). Poster presented to the Annual Meeting of the Cognitive Neuroscience Society, Boston, MA. [View the poster here]