The influence of uncertainty on action preparation

When people have more certainty about what action must be made in response to a future event their actions are faster and more accurate. It is unknown which brain processes are modulated by uncertainty leading to these altered behavioural outcomes. Some research has found that differing uncertainty about required responses predominately modulates central premotor brain processes, while contrasting evidence suggests that the effect is at a peripheral motor stage of processing. Electroencephalography (EEG) gives insight into these different brain processes during preparation for action, with the contingent negative variation (CNV) reflecting central premotor planning, and the lateralized readiness potential (LRP) indicating response-specific preparation. EEG was recorded from 24 healthy adult participants while they performed a response-precuing task. Uncertainty about the upcoming response was manipulated by changing the reliability with which the precue accurately predicted the response cue between blocks of trials. Participants responded faster and more accurately when they had less uncertainty about which response would be required. The CNV was unchanged between experimental conditions, while a foreperiod LRP developed only during the low uncertainty condition. This suggests that people integrate information about the likelihood of required future actions to complete response-specific motor processes earlier.