The Virtual Tray of Objects Task as a novel method to electrophysiologically measure visuo-spatial recognition memory

We explored a novel method to electrophysiologically measure visuo-spatial recognition memory using a modified version of the Virtual Tray of Objects Task (VTOT). Event-related potentials (ERP) were recorded from 18 healthy volunteers during performance in the VTOT. Participants were required to detect random repetitions of three-dimensional visual stimuli (OLD) and to refrain from responding to non-repeated stimuli (NEW). Differences in ERP between the NEW and OLD conditions were tested for statistical significance using assumption-free non-parametric analyses. Further, a correlation between ERP and behavioral measures was sought. Significant OLD-NEW effects were found for four ERP components showing distinct spatio-temporal characteristics: a posterior positive component appearing at 100 ms (P100), a left-lateralized negative component peaking at≈250ms (N250), a frontal negative component at≈300–450ms (FN400), and a right late frontal negativity (rLFN) at≈500–720ms.Moreover, individual differences in the OLD-NEWeffect computed for the rLFN positively correlatedwith repeated stimulus recognition efficiency.However, therewere no late left parietal P600 old/neweffects. These findings suggest that the P100 componentmight reflect early visual perception processes taking place during performance in the task, whereas the N250 and FN400 components could be linked to stimulus-dependent access to visual memory representations and familiarity-related processes, respectively. In contrast, we propose that the rLFN component could be associated with higher-level cognitive functions, such as attention and monitoring processes. Altogether, our results suggest that the ERP version of the VTOT could play a role in the electrophysiological assessment of visuo-spatial memory and related sub-processes.