Is there a proactive and a reactive mechanism of inhibition? Towards an executive account of the attentional inhibitory control model.

In cognitive neuroscience, an extensive debate concerns the mechanisms of inhibition and the relationship between inhibitory and behavioural control. Since the proactive mode of inhibition was first described, several studies have aimed to distinguish this form of inhibitory control from the reactive one. In fact, according to the dualistic models of cognitive control, the two forms of inhibition regulate the action control. However, most of the studies in this field neglected the role of attention in response inhibition, as well as the role of inhibition as an executive function. In the present article, emerging evidence in favour of a unitary mechanism of inhibition is reviewed: recent observations suggest that inhibition represents a default mode of the human brain, and that inhibitory control should not be dissociated from attentional control. Accordingly, the so-called proactive and reactive inhibition might reflect the contribution of the sustained and selective attention in the implementation of the default inhibitory control, which might be more properly termed as attentional inhibitory control (AIC). Evidence of the integrated perspective of the AIC model is reviewed from the neural, cognitive and neuropsychological point of view. Theoretical and clinical implications are discussed.