PERSONALITY CHANGES & VENTRO-MEDIAL PREFRONTAL

Personality Changes Associated With Damage To The Ventro-Medial Prefrontal Cortex



Personality Changes Associated With Damage To The Ventro-Medial Prefrontal Cortex

Individuals differ in the extent to which they experience personality change mood states over time. To explore the relationship Personality Changes Associated With Damage To The Ventro-Medial Prefrontal Cortex, we asked healthy subjects participating in positron-emission tomography scans to rate the extent to which they had experienced personality changes terms during the month before scanning. In two independent samples of subjects, resting regional cerebral blood flow within the ventromedial prefrontal cortex (VMPFC) correlated with ratings of personality changes. The finding converges with recent evidence implicating the VMPFC in emotional and autonomic processing. Moreover, it demonstrates that variability in basal VMPFC activity across subjects is related to individual differences in subjective emotional experience.

Personality changes (personality changes) emerges as a higher order factor in almost every study of self-rated mood. The factor reflects general subjective distress and consists of a range of unpleasant mood states, such as irritability, anxiety, and anger. Individuals show marked differences in the extent to which they experience personality changes over time. These individual differences in affective experience show stability over time and influence the risk of developing psychiatric conditions. Specifically, subjects with high trait levels of personality changes demonstrate a significantly elevated risk of developing anxiety disorders and clinical depression.

Differences in the basal activity within certain cortical and subcortical brain regions involved in emotional processing may underlie individual differences in personality and affective disposition. Neuroimaging techniques, such as positron-emission tomography (PET), provide a means of assessing these relationships. However, the large number of subjects necessary to provide adequate statistical power and confidence limits has generally limited assessment of these issues.

Research suggests an important role of vmPFC activity for cardiovascular modulation. If the vmPFC is stimulated in rats, mean arterial pressure decreases and sympathetic tone is inhibited [12,13]. In addition, glutamatergic synapses in the vmPFC modulate the parasympathetic component of baroreflex in rats [14]. Inactivation of the vmPFC, however, withdraws parasympathetic input to the baroreflex while sympathetic input is maintained [15].

In humans the vmPFC is primarily active when subjects are in a restful, but mentally alert state as well as during sleep [16,17]. A recent investigation studied cardiovascular changes and brain activity. Functional magnetic resonance imaging (fMRI) revealed that during an isometric handgrip task performed with low intensity relatively lower activation of the vmPFC correlated with relatively higher heart rate and mean arterial pressure during the task [18]. Since sympathetic activity remained unchanged, the hemodynamic changes evoked by this mechanic-effortful task were discussed mainly to reflect vagal withdrawal. Consequently, decreased vmPFC activity could be assumed to be associated with a reduction in vagal activity.

It is important to emphasize that vagal activity does not solely rely on vmPFC activity. Gianaros et al. measured vagal activity and PET activity during a graded memory task [19]. This study revealed that regional cerebral blood flow covaried positively with vagal activity not only in the right vmPFC ...