PT  - JOURNAL ARTICLE
AU  - An T. Nguyen
AU  - Matthew A. Albrecht
AU  - Ottmar V. Lipp
AU  - Welber Marinovic
TI  - Motor Output Matters: A Study on the Neural Correlates of Failed Inhibitory-Control
AID  - 10.1101/706978
DP  - 2019 Jan 01
TA  - bioRxiv
PG  - 706978
4099  - http://biorxiv.org/content/early/2019/07/18/706978.short
4100  - http://biorxiv.org/content/early/2019/07/18/706978.full
AB  - Motor actions can be suppressed with varying degrees of success, but this variability is not often captured in traditional experiments where inhibitory-control is conceptualised as an all-or-none process. Although the Stop/No-go P300 (a frontocentral positivity in the event-related potential (ERP) occurring around 300 ms after a Stop/No-go stimulus) has been implicated as a measure of inhibitory-control, it is unclear how the range of motor outputs relates to the P300. We examined the nature of this association in two experiments using an Anticipatory Timing and a Go/No-go Task. Force, response onset time, and the P300 were measured.In both experiments, P300 amplitude was reduced and ERP onset latencies were delayed on Failed compared to Successful Inhibitions. On Failed Inhibitions, our results show that responses with higher force (reflecting a greater degree of error) were associated with smaller P300 amplitudes. Although the binary categorisation of inhibition-success (Successful vs. Failed) accounted for more variance in the data compared to force, it misses a reliable linear relationship that can mbe captured by continuous measures of motor output. Overall, the results provide strong evidence that inhibitory-control is not an all-or-none process, and that the engagement of inhibitory-control is reflected by the P300. We present an activation-to-threshold model of inhibitory-control to explain our results, which offers a new conceptual framework for describing the implementation of inhibitory-control in highly prepared motor responses. Our results also highlight the importance of studying the spectrum of motor outputs and the need for future models of inhibitory-control to account for motor output, and not just the presence and absence of responses.