Schedule of Events | Symposia

Fixation-related ERPs (fERPs) to moving stimuli during visual search: Effects of training but not of neurostimulation (rDLPFC HD-tDCS)

Poster Session F - Tuesday, April 1, 2025, 8:00 – 10:00 am EDT, Back Bay Ballroom/Republic Ballroom

Jason R Taylor¹ (jason.taylor@manchester.ac.uk), Stephen J Ball¹, Johan Hulleman¹, Gorana Pobric¹; ¹University of Manchester

The potential of neurostimulation and cognitive training to improve visual search performance is of interest in both research and applied settings. Fixation-related event-related potentials (fERPs) may be more sensitive than behavioural measures and may help distinguish effects on component cognitive sub-processes. We report a large (N=110) double-blind study of the effects of training and neurostimulation on visual search performance and fERPs. Participants were randomly assigned to Stimulation (MRI-guided 4-1 HD-tDCS to rDLPFC for 20min/session), Sham (stimulation 1min/session), and Control (no equipment) groups. All received 5x 40-minute training sessions on a difficult visual search task: Stimuli were moving squares with smaller squares embedded in the top left corner (target present on 50% of trials) or top right corner (nontarget distractors; 8 or 16 per trial). The task was also performed during two EEG sessions, pre- and post-training (64-channel BioSemi ActiveTwo; eye-tracking via SR Research Eyelink DUO). Behavioural performance showed clear training effects (main effects of training session) but no effects of stimulation group. fERPs (P1, P300) time-locked to targets and non-targets showed expected targetness effects and training effects (larger targetness effects post-training), but no effects of stimulation. fERPs time-locked to pre-target fixations (N2 posterior-contralateral (N2pc), sustained posterior contralateral negativity (SPCN)) discriminated target location (contralateral vs. ipsilateral) and showed an effect of training (N2pc: larger target location effects post-training) but no effects of stimulation. Overall, training effects (but no stimulation effects) on visual search were evident in behaviour and fERPs associated with perceptual sensitivity (P1), target detection (P300), and spatial attention (N2pc).

Topic Area: PERCEPTION & ACTION: Vision