Abstract
Contralateral Delay Activity (CDA) has been studied extensively as a marker of visual short-term memory (VSTM) capacity (Vogel, McCollough and Machizawa, 2005). Amongst others, the scalp topography of this ERP component and its contra-versus-ipsilateral nature suggest that the storage and maintenance of information in VSTM are cognitive operations modulating the activity in the same neural networks that are initially involved with the (biased) perceptual processing of the visual input. Hence, one would naturally predict that the quality of the initial encoding of visual information influences our ability to operate on that information for maintaining it in memory. Here, we present a latency dynamic in the early ERPs that correlates with VSTM capacity (K) and CDA amplitudes, observable when contamination of the early signal by spatial pre-cuing is adequately prevented. Our participants (N=34) verbally reported briefly shown letters in an 'early pre-cue' and 'absent pre-cue' version of a lateralized "whole report" experiment (Wiegand et al., 2014), with always five targets shown in the announced hemifield at variable exposure durations. Estimates of VSTM capacity were obtained by modeling of the accuracy data by the Theory of Visual Attention (Bundesen, 1990). Unlike a previous report, we do not replicate direct correlations between VSTM capacity and CDA amplitudes. However, we find strong correlations between memory capacity and the succession of P1 and N1 peak latency: the faster N1 follows P1, the higher a person's capacity. Interestingly, this is true for targets presented in either hemifield, but only prominent for P1 and N1 components measured at the right hemisphere – contralateral to the hemifield where the performance is weakest. In turn, this P1-N1 interplay correlates (modestly) with CDA amplitudes. Together, these results underline the role of initial encoding abilities in individuals' visual memory performance and their related CDA amplitudes.
Meeting abstract presented at VSS 2017