Personality factors correlate with regional cerebral perfusion.
ABSTRACT There is an increasing body of evidence pointing to a neurobiological basis of personality. The purpose of this study was to investigate the biological bases of the major dimensions of Eysenck's and Cloninger's models of personality using a noninvasive magnetic resonance perfusion imaging technique in 30 young, healthy subjects. An unbiased voxel-based analysis was used to identify regions where the regional perfusion demonstrated significant correlation with any of the personality dimensions. Highly significant positive correlations emerged between extraversion and perfusion in the basal ganglia, thalamus, inferior frontal gyrus and cerebellum and between novelty seeking and perfusion in the cerebellum, cuneus and thalamus. Strong negative correlations emerged between psychoticism and perfusion in the basal ganglia and thalamus and between harm avoidance and perfusion in the cerebellar vermis, cuneus and inferior frontal gyrus. These observations suggest that personality traits are strongly associated with resting cerebral perfusion in a variety of cortical and subcortical regions and provide further evidence for the hypothesized neurobiological basis of personality. These results may also have important implications for functional neuroimaging studies, which typically rely on the modulation of cerebral hemodynamics for detection of task-induced activation since personality effects may influence the intersubject variability for both task-related activity and resting cerebral perfusion. This technique also offers a novel approach for the exploration of the neurobiological correlates of human personality.
Article: Differences in spontaneously avoiding or approaching mice reflect differences in CB1-mediated signaling of dorsal striatal transmission.[show abstract] [hide abstract]
ABSTRACT: Approach or avoidance behaviors are accompanied by perceptual vigilance for, affective reactivity to and behavioral predisposition towards rewarding or punitive stimuli, respectively. We detected three subpopulations of C57BL/6J mice that responded with avoiding, balancing or approaching behaviors not induced by any experimental manipulation but spontaneously displayed in an approach/avoidance conflict task. Although the detailed neuronal mechanisms underlying the balancing between approach and avoidance are not fully clarified, there is growing evidence that endocannabinoid system (ECS) plays a critical role in the control of these balancing actions. The sensitivity of dorsal striatal synapses to the activation of cannabinoid CB1 receptors was investigated in the subpopulations of spontaneously avoiding, balancing or approaching mice. Avoiding animals displayed decreased control of CB1 receptors on GABAergic striatal transmission and in parallel increase of behavioral inhibition. Conversely, approaching animals exhibited increased control of CB1 receptors and in parallel increase of explorative behavior. Balancing animals reacted with balanced responses between approach and avoidance patterns. Treating avoiding animals with URB597 (fatty acid amide hydrolase inhibitor) or approaching animals with AM251 (CB1 receptor inverse agonist) reverted their respective behavioral and electrophysiological patterns. Therefore, enhanced or reduced CB1-mediated control on dorsal striatal transmission represents the synaptic hallmark of the approach or avoidance behavior, respectively. Thus, the opposite spontaneous responses to conflicting stimuli are modulated by a different involvement of endocannabinoid signaling of dorsal striatal neurons in the range of temperamental traits related to individual differences.PLoS ONE 01/2012; 7(3):e33260. · 4.09 Impact Factor
Chapter: Addiction: Frontal Personality Change but not Personality Disorder Comorbidity. Implications for Treatment of Addictive Disorders[show abstract] [hide abstract]
ABSTRACT: A high prevalence of co-occurrence among addictive disorders and personality disorders has been documented. Studies have usually found between a 50 and 75 percent of addicted individuals with Axis II concurrent diagnosis. However, such diagnoses often do not take account of several changes related to the course of addiction that affect functioning of the frontal lobe and, consequently, the overall programming of behaviour. Simple diagnosis based on the ICD or DSM classifications, without regard to etiological factors, is just a still photograph reflecting a fractal of a long development process altered by addiction. Impairment of frontal cortical function due to direct effects of the substance or to mediators as stress factors, are the basis of most of the symptoms justifying the diagnosis of personality disorders. Miller's proposals on stable and induced-by-stress disorders, as well as new findings on executive dysfunction linked to addiction must be taken into consideration. Personality disorders, so understood, should be treated differently from the present, including cognitive stimulation techniques and attending to stress and coping, preventing symptomatic prescribing of drugs with dubious benefits and multiple side effects. New neurological and neuropsychological perspectives of addiction do not support concepts such as comorbidity as a priority intervention guide.01/2011: pages 1-36; , ISBN: 978-1-61728-934-7
Article: Sex-dependent correlations between the personality dimension of harm avoidance and the resting-state functional connectivity of amygdala subregions.[show abstract] [hide abstract]
ABSTRACT: Harm avoidance (HA) is a personality dimension involving the tendency to respond intensely to signals of aversive stimuli. Many previous neuroimaging studies have associated HA scores with the structural and functional organization of the amygdala, but none of these studies have evaluated the correlation between HA score and amygdala resting-state functional connectivity (rsFC). Moreover, the amygdala is not a homogeneous structure, and it has been divided into several structurally and functionally distinct subregions. Investigating the associations between HA score and properties of subregions of the amygdala could greatly improve our understanding of HA. In the present study, using a large sample of 291 healthy young adults, we aimed to uncover correlations between HA scores and the rsFCs of each amygdala subregion and to uncover possible sex-based differences in these correlations. We found that subregions of the amygdala showed different rsFC patterns, which contributed differently to individual HA scores. More specifically, HA scores were correlated with rsFCs between the laterobasal amygdala subregion and temporal and occipital cortices related to emotional information input, between the centromedial subregion and the frontal cortices associated with emotional output control, and between the superficial subregion and the frontal and temporal areas involved in both functions. Moreover, significant gender-based differences were uncovered in these correlations. Our findings provide a more detailed model of association between HA scores and amygdala rsFC, extend our understanding of the connectivity of subregions of the amygdala, and confirm sex-based differences in HA associations.PLoS ONE 01/2012; 7(4):e35925. · 4.09 Impact Factor