Preparing to React: A Behavioral Study on the Interplay between Proactive and Reactive Action Inhibition

Abstract

Motor preparation, based on one's goals and expectations, allows for prompt reactions to stimulations from the environment. Proactive and reactive inhibitory mechanisms modulate this preparation and interact to allow a flexible control of responses. In this study, we investigate these two control mechanisms with an ad hoc cued Go/NoGo Simon paradigm in a within-subjects design, and by measuring subliminal motor activities through electromyographic recordings. Go cues instructed participants to prepare a response and wait for target onset to execute it (Go target) or inhibit it (NoGo target). Proactive inhibition keeps the prepared response in check, hence preventing false alarms. Preparing the cue-coherent effector in advance speeded up responses, even when it turned out to be the incorrect effector and reactive inhibition was needed to perform the action with the contralateral one. These results suggest that informative cues allow for the investigation of the interaction between proactive and reactive action inhibition. Partial errors' analysis suggests that their appearance in compatible conflict-free trials depends on cue type and prior preparatory motor activity. Motor preparation plays a key role in determining whether proactive inhibition is needed to flexibly control behavior, and it should be considered when investigating proactive/reactive inhibition.

Keywords: EMG; action inhibition; compatibility effect; inhibitory control; motor inhibition; motor preparation; partial error; proactive; reactive.

Figure 1

A visual representation of cue-target probabilities is displayed in (a). In this example, a squared central cue instructs participants to prepare a left-hand response. In 50% of the trials, a lateralized squared target was presented, requiring a left-hand button press. Such trials are termed valid cue Go trials. Conversely, a triangle target (presented in 25% of square cue trials, equiprobably on both side) required a contralateral (right-hand, in this example) button press, representing invalid cue Go trials. For both valid and invalid trials, the Go target can be presented ipsilaterally (compatible trials) or contralaterally (incompatible trials) to the required response. Finally, a NoGo circle target (presented in 25% of square cue trials, equiprobably on both side) requires for all participants to not respond. The central cue (empty square, triangle or circle) is presented for 300 ms, followed by a foreperiod of 600 ms. An example of invalid cue incompatible trial of the cued Go/NoGo Simon paradigm is shown in (b). In this example, the square instructs (half of the) participants to prepare a left-hand button press. Following a 600 ms-long foreperiod, a lateralized filled-shape target is displayed for 1000 ms, during which responses are collected. A stimulus’ location can be compatible or incompatible with the side of the required response (in this case, a triangle requires a right-hand response, but it is presented on the left side). Following a variable inter-trial-interval (ITI), a new trial starts. Colors are inverted for displaying purposes.

Figure 2

Average RTs (a) and percentage of correct responses (b) are displayed separately for compatible (filled line) and incompatible (dashed line) trials, and for each cueing condition. Error bars represent the standard error.

Figure 3

Cumulative distribution function of correct binned RTs (a). Delta plots calculated over correct trials (b). The compatibility effect (incompatible–compatible) is plotted as a function of RTs separately for each cue condition. Horizontal error bars (a) and shaded areas (b) represent the standard error.

Figure 4

Conditional accuracy function. The ratio of correct responses is plotted as a function of RTs, divided in quintiles separately for each cue and compatibility condition. Error bars represent the standard error.

Figure 5

The percentage of partial errors committed following valid (blue bars), invalid (red bars), and NoGo (green bars) cues is displayed separately for compatible (filled lines) and incompatible (dashed lines) trials. Error bars represent the standard error.

Figure 6

Conditional incorrect accuracy function. The ratio of correct responses is plotted as a function of RTs, divided in quintiles separately for each cue and compatibility condition. Error bars represent the standard error.

Figure 7

Average RTs for valid and invalid cue trials are plotted for pure correct (a) and partial errors (b). Error bars represent the standard error.