Ability to Maintain Internal Arousal and Motivation Modulates Brain Responses to Emotions

<div><p>Persistence (PS) is defined as the ability to generate and maintain arousal and motivation internally in the absence of immediate external reward. Low PS individuals tend to become discouraged when expectations are not rapidly fulfilled. The goal of this study was to investigate whether individual differences in PS influence the recruitment of brain regions involved in emotional processing and regulation. In a functional MRI study, 35 subjects judged the emotional intensity of displayed pictures. When processing <i>negative</i> pictures, low PS (vs. high PS) subjects showed higher amygdala and right orbito-frontal cortex (OFC) activity but lower left OFC activity. This dissociation in OFC activity suggests greater prefrontal cortical asymmetry for approach/avoidance motivation, suggesting an avoidance response to aversive stimuli in low PS. For <i>positive</i> or <i>neutral</i> stimuli, low PS subjects showed lower activity in the amygdala, striatum, and hippocampus. These results suggest that low PS may involve an imbalance in processing distinct emotional inputs, with greater reactivity to aversive information in regions involved in avoidance behaviour (amygdala, OFC) and dampened response to positive and neutral stimuli across circuits subserving motivated behaviour (striatum, hippocampus, amygdala). Low PS affective style was associated with depression vulnerability. These findings in non-depressed subjects point to a neural mechanism whereby some individuals are more likely to show systematic negative emotional biases, as frequently observed in depression. The assessment of these individual differences, including those that may cause vulnerability to depressive disorders, would therefore constitute a promising approach to risk assessment for depression.</p></div

Functional MRI responses to negative vs. neutral pictures.

<p>Functional MRI responses to negative vs. neutral pictures.</p

Functional MRI responses to low vs. high PS (regardless of picture valence).

<p>Brain regions significantly less activated in low PS subjects compared to high PS subjects: The locus coeruleus, insula, and amygdala. Functional results are displayed on the mean structural MR image of subjects normalized to the MNI stereotactic space (display at p, 0.001, uncorrected). Parameter estimates are calculated for neutral (Neu) items for both subject groups. Arbitrary units, error bars: SEM.</p

Functional MRI responses to positive vs. negative pictures.

<p>Functional MRI responses to positive vs. negative pictures.</p

Functional MRI responses to neutral, positive, and negative pictures.

<p>Functional MRI responses to neutral, positive, and negative pictures.</p

Functional MRI responses to neutral pictures (exclusively masked by negative and positive pictures).

<p>Brain regions significantly less activated in low PS subjects compared to high PS subjects: the caudate nucleus. Functional results are displayed on the mean structural MR image of subjects normalized to the MNI stereotactic space (display at p, 0.001, uncorrected). Parameter estimates are calculated for neutral (Neu) items for both subject groups. Arbitrary units, error bars: SEM.</p

Functional MRI responses to positive vs. negative pictures.

<p>Brain regions significantly deactivated in low PS subjects compared to high PS subjects: the right amygdala and right hippocampus. Functional results are displayed on the mean structural MR image of subjects normalized to the MNI stereotactic space (display at p, 0.001, uncorrected). Parameter estimates are calculated for positive (Pos) and negative (Neg) items. Arbitrary units, error bars: SEM.</p

Functional MRI responses to neutral pictures (exclusively masked by negative and positive pictures).

<p>Functional MRI responses to neutral pictures (exclusively masked by negative and positive pictures).</p

Multiple regression analyses predicting craving scores (T2) as a function of depression T2, SC T2, and their interaction.

*<p><i>p</i><0.05,</p>**<p><i>p</i><0.01,</p>***<p><i>p</i><0.001,</p>†<p><i>p</i><0.1.</p

Correlation matrix between variables at T1&T2 with each variables overall Mean and SD at T1&T2.

†<p>.05<<i>p</i><.10,</p>*<p>p<.05,</p>**<p>p<.01,</p>***<p>p<.001.</p><p>Abbreviations: T1 = Time 1, T2 = Time 2, BDI = Beck Depression Inventory, Ob = Obsessive factor, Co = Compulsive factor, Tot = Total craving, PrSC = Private Self-Consciousness; PuSC = Public Self-Consciousness; SA = Social Anxiety, SC = Self-Consciousness.</p><p>Values in the tables represent the Pearson-moment correlation coefficient (r).</p><p>Values in the tables represent the Pearson-moment correlation coefficient (r).</p