Ventral frontal contribution to self-regulation: Convergence of episodic memory and inhibition

Ventral frontal brain damage is associated with impaired self-regulation of behaviour in unstructured situations (self-regulatory disorder; SRD). This report attempts to integrate this brain-behaviour correlation with earlier animal literature on disinhibition and recent cognitive neuroscience literature on the frontal lobes and episodic memory. Data are presented from patient ML (Levine etal., Brain 1998; 121: 1951-73), who has isolated retrograde amnesia, ventral frontal dysfunction and SRD. Impaired strategic self-regulation of behaviour was documented with psychosocial outcome questionnaires and two laboratory analogues of real-life unstructured situations: a strategy application task and a gambling task. Previous findings of deficits in anterograde episodic memory (i.e. re-experiencing) using the remember/ know distinction were replicated and extended. The role of disinhibition as a mechanism for SRD was supported by MCs severely impaired performance on object alternation, a task with documented sensitivity to disinhibition following ventral frontal dysfunction in non-human primates and humans. It is argued that autonoetic awareness (i.e. awareness of the self as a continuous entity across time) supports self-regulation of behaviour in unstructured situations by providing access to a network of accumulated episodic information. This information is held on-line to facilitate inhibition of inappropriate actions arising from prepotent environmental or internal stimuli. In patients with SRD, these on-line maintenance and inhibition mechanisms are inoperative, resulting in inappropriate behaviour in unstructured situations. Therefore, patients with SRD should be impaired on both tests of episodic re-experiencing and inhibition.