Abstract

We developed a new auditory working memory (WM) paradigm to dissect the role of perceptual “bottom-up” and “top-down” attention or inhibitory control processes inWM that would be of particular value in studies of cognitive function in schizophrenia. ERPs (72 sites) were recorded twice (1 wk retest) from 29 healthy adults during encoding, maintenance, and item retrieval in three auditory WM tasks (I: Ignore; S: Suppress; R: Remember) consisting of listening to a series of 4 letters alternately presented to left and right ear (LE/RE; 600 ms SOA), followed by a maintenance interval and a probe. Subjects selectively attended to letters presented to one ear and ignored those in the other ear (I), suppressed letters presented to one ear (S), or remembered all letters (R). The critical cue was provided either before (I) or after (S) the encoding series, or with the probe (R). Here we focus on correct monaural item presentations during encoding. Reference-free scalp current source densities of ERPs, quantified by temporal PCA, revealed a characteristic bi-hemispheric N1 sink-source dipole spanning auditory cortex (peak latency 104 ms) with a robust asymmetry (greater contralateral to stimulated ear). While attending to LE during I, the contralateral N1 dipole was enhanced with LE and reduced with RE presentations; these modulations were not seen when attending to RE, or for S and R tasks. These findings suggest that early top-down modulation of perceptual bottom-up asymmetries during auditory stimulus encoding are primarily under control of a right-lateralized attention network.

Desciptors: event-related potential (ERP), auditory WM, attention

[Supported by NIMH grant MH106905].