Everyone experiences common events differently. This leads to personal memories that presumably provide neural signatures of individual identity when events are reimagined. We present initial evidence that these signatures can be read from brain activity. To do this, we progress beyond previous work that has deployed generic group-level computational semantic models to distinguish between neural representations of different events, but not revealed interpersonal differences in event representations. We scanned 26 participants’ brain activity using functional Magnetic Resonance Imaging as they vividly imagined themselves personally experiencing 20 common scenarios (e.g., dancing, shopping, wedding). Rather than adopting a one-size-fits-all approach to generically model scenarios, we constructed personal models from participants’ verbal descriptions and self-ratings of sensory/motor/cognitive/spatiotemporal and emotional characteristics of the imagined experiences. We demonstrate that participants’ neural representations are better predicted by their own models than other peoples’.The regions of the brain activated in the participants were pretty uniform; but the pattern of activation different considerably. Calling up memories of the last dance several people went to might require their drawing upon similar brain structures, but one person might remember mostly the music, another the lights and the crowds, and a third focused entirely on who (s)he is dancing with -- and between those three you'd see a pattern of neural firing that is dramatically different.
"One of the goals of cognitive science is to understand how memories are represented and manipulated by the human brain," said lead author Andrew Anderson, in an interview with Science Daily. "This study shows that fMRI can measure brain activity with sufficient signal to identify meaningful interpersonal differences in the neural representation of complex imagined events that reflect each individual's unique experience."