Planning on Autopilot? Associative Contributions to Proactive Control.

Proactive cognitive control is thought to rely on the active maintenance of goals or contextual information in working memory. It is often measured using the AX-CPT, in which antecedent cues (A/B) are used to proactively prepare a response to a subsequently-presented probe (X/Y). Although control in this task purportedly requires active maintenance of information in working memory, it also provides conditions in which learning the contingencies between relevant events could influence performance via associative learning. We tested this hypothesis using a dot-pattern expectancy version of the AX-CPT whereby a set of new rules (test phase) for responding changed the control operations required for some previously trained cues, while keeping the operations the same for others, allowing us to measure associative interference. We also tested the relationship between associative interference and working memory capacity (operation span; Experiments 1-3) and tested the effect of applying working memory load during the initial acquisition period (Experiment 2) and during the test phase (Experiment 3). We found robust evidence of interference after the rule change based on previously learnt contingencies, suggesting that learnt contingencies come to influence proactive planning, even when they are task-irrelevant. This associative effect had no relationship with working memory capacity or load, based on a load manipulation commonly used in executive control tasks. The findings suggest that proactive control does not always require active maintenance of current goals and environmental cues in working memory. Instead, proactive control may run on autopilot if the individual can rely upon stable relationships in the environment to trigger planning and preparation. SIGNIFICANCE: Navigating daily life requires us to anticipate future events and plan our thoughts and actions accordingly to achieve our goals. This forward planning, or proactive control, is thought to be a resource-intensive and metabolically costly process that recruits higher-order cognitive functions, such as working memory, where relevant thoughts and actions have to be maintained online. The current study challenged this notion by finding that proactive control can be incrementally relegated to simpler processes based on one's learning of stable relationships in the environment, thereby reducing the need to actively maintain information online. Individuals can come to rely on underlying contingencies in stimuli associated with proactive control, even when it is detrimental to their goals.

TMS reveals distinct patterns of proactive and reactive inhibition in motor system activity.

Response inhibition is our ability to suppress or cancel actions when required. Deficits in response inhibition are linked with a range of psychopathological disorders including addiction and OCD. Studies on response inhibition have largely focused on reactive inhibition-stopping an action when explicitly cued. Less work has examined proactive inhibition-preparation to stop ahead of time. In the current experiment, we studied both reactive and proactive inhibition by adopting a two-step continuous performance task (e.g., "AX"-CPT) often used to study cognitive control. By combining a dot pattern expectancy (DPX) version of this task with transcranial magnetic stimulation (TMS), we mapped changes in reactive and proactive inhibition within the motor system. Measured using motor-evoked potentials, we found modulation of corticospinal excitability at critical timepoints during the DPX when participants were preparing in advance to inhibit a response (at step 1: during the cue) and while inhibiting a response (at step 2: during the probe). Notably, motor system activity during early timepoints was predicted by a behavioural index of proactive capacity and could predict whether participants would later successfully inhibit their response. Our findings demonstrate that combining TMS with a two-step CPT such as the DPX can be useful for studying reactive and proactive inhibition, and reveal that successful inhibition is determined earlier than previously thought.