Poster B13, Sunday, March 26, 8:00 – 10:00 am, Pacific Concourse
Dissociations between neural responses to external visual and auditory stimuli as a result of internal visual and auditory mind-wandering
Sophie Forster1, Charlotte Kemp1, Giulia Poerio2, Ben Dyson1; 1University of Sussex, UK, 2University of York, UK
Experience-sampling studies suggest that we spend around half of our waking lives engaging in task-unrelated mind wandering, which may often include rich sensory mental imagery. Here we examined how the sensory contents of mind wandering impact upon external perceptual processing. During EEG recording, participants were presented with an alternating visual fixation cross and an auditory noise burst, and instructed either to simply focus on this alone (direct attention; DA), or to engage with task-unrelated thought scenarios designed to elicit either auditory (AMW) or visual (VMW) mind wandering. Self-report of internal imagery confirmed that greater auditory imagery was generated for AMW and greater visual imagery was generated for VMW. Exogenous neural responses to the visual fixation cross (P1-N1-P2) and auditory noise (N1-P2-N2) were examined at parietal-occipital and fronto-central electrodes, respectively. For visual neural responses, latencies were faster during DA relative to any kind of mind wandering (AMW or VMW) whereas mean amplitudes for both P1 and N1 were reduced during VMW relative to AMW. For auditory neural responses, N2 mean amplitude was reduced during AMW relative to VMW. These data represent a dissociation between the modality-specific attenuation of exogenous responses to external stimuli as a result of the sensory nature of internal task-irrelevant imagery. The contribution of slower wave neural activity is also discussed. The study provides support for the notion that external perception and mental imagery draw on common, limited capacity, resources and, as such, may interfere with each other.
Topic Area: ATTENTION: Multisensory