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 et al., Brain 1998; 121: 1951-73), who had isolated retrograde amnesia, ventral frontal dysfunction and SRD. Impaired strategic self-regulatory 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 ML's 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.
Levine B., Freedman M., Dawson D., Black S. & Stuss D.T.