ERP paper on sequential effects of selective attention (Primed DL)

During my ambitious young PhD years in cognitive neuroscience I collected more data than I had time to publish on. For example, I equipped participants with 61 scalp electrodes and let them perform the "primed dichotic listening" experiment that I had developed. My previous studies had established a priming effect, and fMRI neuroimaging had indicated that cognitive control and inhibition may be involved in producing the effect. As ERP has a finer temporal resolution, this could be used to examine the time course of such an effect. Unfortunately, I didn't have time to analyse the data during my PhD time, so the data was left unused for several years. I later got in touch with René Huster whom I went to graduate school with, and we analysed the data together during a research visit to his research group in Oldenburg.

As before, in each trial of the experiment a single syllable was played followed by a dichotic syllable pair, and in some cases one of the syllables in the pair repeated the prime syllable. The trials were categorized based on whether the repeated syllable was selected or not, as shown in the figure below.

A strong behavioural effect was seen as in the previous studies. The ERP analysis was optimized to identify differences in the early attention processing (i.e. the N200s) between the different response categories. ERPs were extracted for three midline electrodes from four relevant time-windows and compared between the conditions using repeated measures ANOVA. Significant effects were seen in both the prime-related (left in the figure below) and in the dichotic target-related activity (right in the figure below). 

Trials where the participant reported the non-primed syllable (prime ignored trials) showed more negative ERPs at prime presentation, which may indicate inhibition of the prime representation. Trials where the participant reported the primed syllable (prime reported trials) showed more negative ERPs at target presentation, which may indicate cognitive conflict and effortful response selection. In reference to the theoretical framework presented previously, the data suggest that the interplay of a proactive inhibition bias (during prime presentation) and a reactive potential for conflict (during target presentation) is involved in causing the primed dichotic listening effect.

Sætrevik, Huster & Herrmann (2013) Proactive and reactive sequential effects on selective attention - Brain and Cognition

There is also a second data set, with EEG recorded from a larger data set doing a sequence of dichotic listening trials which we will hopefully go on to publish some day.