Exploring Stop Signal Reaction Time Over Two Sessions of the Anticipatory Response Inhibition Task

Abstract

Various behavioural tasks can measure the motor component of impulse control, response inhibition. Response inhibition encompasses the ability to cancel unwanted actions and is evaluated via stop signal reaction time (SSRT). The current study explored the effect of two sessions on SSRT within the anticipatory response inhibition task (ARIT) and how this compared to the stop signal task (SST). Forty-four participants completed two sessions of the ARIT and SST, 24 hours apart. SSRT and its constituent measures (Go trial reaction time, stop signal delay) were calculated. SSRT reflecting non-selective inhibition was consistent between sessions in both tasks (both p > .293). Reaction time and stop signal delay also remained stable across sessions in the ARIT (all p > .063), whereas in the SST, both reaction time (p = .013) and stop signal delay (p = .009) increased. Across the two sessions, SSRT reflecting partial inhibition improved (p < .001), which was underpinned by changes to reaction time (p < .001) and stop signal delay (p < .001). The maximal efficiency of non-selective inhibition remained stable across two sessions in the ARIT. Results of the SST confirmed that non-selective inhibition can however be affected by more than inhibitory network integrity when Go trial reaction times are not constrained in task design. Partial response inhibition measures changed across sessions, suggesting the sequential process captured by the SSRT occurred more quickly in session two. These findings highlight the absence/extent of inherent SSRT changes possible during multiple-session study designs e.g., pre/post, or active/sham comparisons.