Wadsley, C. G. | bioRxiv Science

bioRxiv2023

A global pause generates nonselective response inhibition during selective stopping

1Response inhibition is essential for terminating inappropriate actions. Selective response inhibition may be required when stopping part of a multicomponent action. However, a persistent response delay (stopping-interference effect) indicates nonselective response inhibition during selective stopping. This study aimed to elucidate whether nonselective response inhibition is the consequence of a global pause process during attentional capture or specific to a nonselective cancel process during selective stopping. We hypothesised that the stopping-interference effect would be larger in response to stop than ignore signals, owing to stronger nonselective response inhibition for explicit selective stopping. Twenty healthy human participants of either sex performed a bimanual anticipatory response inhibition paradigm with selective stop and ignore signals. Frontocentral and sensorimotor beta ({beta})-bursts were recorded with electroencephalography. Corticomotor excitability (CME) and short-interval intracortical inhibition (SICI) in primary motor cortex were recorded with transcranial magnetic stimulation. Behaviourally, responses in the non-signalled hand were delayed during selective ignore and stop trials. The response delay was largest during selective stop trials and indicated that the stopping-interference effect could not be attributed entirely to attentional capture. A stimulus-nonselective increase in frontocentral {beta}-bursts occurred during stop and ignore trials, whilst sensorimotor response inhibition was reflected in maintenance of {beta}-bursts and SICI relative to disinhibition observed during go trials. Signatures of response inhibition in the sensorimotor cortex contralateral to the responding hand were not associated with the magnitude of stopping-interference. Therefore, nonselective response inhibition during selective stopping results primarily from a nonselective pause process but does not entirely account for the stopping-interference effect. 2 Significance statementSelective stopping is a complex form of response inhibition where a person must execute and cancel part of an action at the same time. A stopping-interference effect exemplifies the complexity of selective stopping. The present study examined whether nonselective response inhibition during selective stopping results from a global pause during attentional capture or is specific to a deliberate cancel process. Behaviourally, the interference effect was larger during selective stop stimuli than selective ignore stimuli. However, neurophysiological signatures of nonselective response inhibition were elicited in response to both stop and ignore stimuli. These findings indicate that nonselective response inhibition during selective stopping results primarily from a nonselective pause process but does not entirely account for the stopping-interference effect.

neuroscience↗

bioRxiv2022

Proactive interhemispheric disinhibition supports response preparation during selective stopping

Response inhibition is essential for terminating inappropriate actions. A substantial delay may occur in the response of the non-stopped effector when only part of a multi-effector action is terminated. This stopping-interference effect has been attributed to nonselective response inhibition processes and can be reduced with proactive cueing. This study aimed to elucidate the role of interhemispheric primary motor cortex (M1-M1) influences during selective stopping with proactive cueing. We hypothesized that stopping-interference would be reduced as stopping certainty increased, owing to proactive recruitment of interhemispheric facilitation or interhemispheric inhibition when cued to respond or stop, respectively. Twenty-three healthy human participants performed a bimanual anticipatory response inhibition paradigm with cues signaling the likelihood of a stop-signal occurring. Dual-coil transcranial magnetic stimulation was used to determine corticomotor excitability (CME), interhemispheric inhibition (IHI), and interhemispheric facilitation (IHF) in the left hand at rest and during response preparation. Response times slowed and stopping-interference decreased with cues signaling increased stopping certainty. Proactive response inhibition was marked by a reduced rate of rise and faster cancel time in electromyographical bursts during stopping. There was a nonselective release of IHI but not CME from rest to in-task response preparation, while IHF was not observed in either context. An effector-specific CME but not IHF or IHI reduction was observed when the left hand was cued to stop. These findings indicate that the stopping-interference effect can be reduced through proactive suppression. Interhemispheric M1-M1 channels modulate inhibitory tone that supports responding, but not selective stopping, in a proactive response inhibition context. Significance statementResponse inhibition is essential for terminating inappropriate actions and, in some cases, may be required for only part of a multi-effector action. The present study examined interhemispheric influences between the primary motor cortices during selective stopping with proactive cueing. Stopping selectivity was greater with increased stopping certainty and marked by proactive response inhibition of the hand cued to stop. Inhibitory interhemispheric influences were released during response preparation but were not affected by proactive cueing. These findings indicate that between-hand stopping can be selective with proactive cueing, but cue-related improvements are unlikely to reflect advance engagement of interhemispheric influences between primary motor cortices.

neuroscience↗