Poster Session B, Sunday, March 24, 8:00 – 10:00 am, Pacific Concourse
Dynamical neural similarity tracks shifts of stimulus features and memory fluctuations
Yi Zhu1, Qun Ye1, Yi Hu1; 1East China Normal University
Neural similarity of a group of audience has been found to be indicative of stimulus engagement by measuring inter-subject correlations (ISC) with fMRI or EEG signals. However, there has been little evidence to directly characterize the three-dimensional relationships between shifts of stimulus features, fluctuation of neural responses and the resulting behavioural performances. We measured brain activity with electroencephalograph (EEG) from 35 participants while they viewed ten 76-second nature documentary excerpts, each of which involved two storylines (A & B) and was segmented into four parts (A1, A2, B1, B2). Excerpts were played half in a consecutive order and half in an interleaved order. After watching each of the excerpts, subjects completed a recognition memory task to judge whether frames were extracted from the excerpts. Neural similarity is assessed by the correlation between a participant’s neural response and peers’ to the same stimuli. Consistent with the stimulus shift between segments in both play orders, we observed a dynamical neural responses (ISC) corresponding to the segment shift: (i) ISC decreased gradually while viewing the same storyline and (ii) ISC increased while shifting from one storyline to another. Furthermore, such dynamical neural similarity subserved the recognition memory: the higher the ISC in video viewing was, the better its subsequent memory judged. Thus, our findings provide direct evidence of ISC in tracking stimulus processing, and implicate a mediated mechanism of ISC between stimulus encoding and subsequent memory retrieval.
Topic Area: PERCEPTION & ACTION: Multisensory