Poster B37, Sunday, March 26, 8:00 – 10:00 am, Pacific Concourse
Knowledge of temporal delay instantiates distinct neural pathways for proactive cognitive control
Jacqueline Janowich1, James Cavanagh1; 1University of New Mexico
Dot Pattern Expectancy evaluates expectancy in cognitive control. We performed two experiments elucidating the role of temporal delay on proactive initiation of control, each using EEG to resolve neural mechanisms of control initiation. In Experiment 1 (n=25), we manipulated delay length between informative cue and test probe block-wise, such that delay length was known/regular. Participants performed less accurately on trials demanding a modified response to an unexpected probe in Short versus Long Delay, but equally well between delay lengths for trials requiring the maintenance of a cued response rule, suggesting stronger use of Proactive control in Short versus Long delay. Frontal N2 amplitude, associated with task/response switching, showed a significant interaction between delay and regular/control-demanding cue type, with pronounced N2 for short, control-demanding cues, indicating a distinct signal for temporally-imminent control needs. To resolve how this temporally-mediated preparatory activity is modulated by predictability, and explore how control is optimized during unknown delay, in Experiment 2 (n=24) we varied delay length on a trial-wise basis, with cues “delay-informative” or “delay-unknown” by trial. Known short delays evoked similar accuracy decrements as in Experiment1, but this was ameliorated in unknown short delays, indicating less preparation of prepotent response. In addition, accuracy for maintenance/control-demanding trials was greater in Long versus Short delay, irrespective of delay knowledge. EEG Contingent Negative Variation (CNV) varied significantly by cue type, helping to explain the lesser prepotent response for regular cues and successful maintenance of control-demanding cues. Overall, distinct mechanisms were initiated for high/low control demands over known/unknown delays.
Topic Area: EXECUTIVE PROCESSES: Goal maintenance & switching