[Show abstract][Hide abstract] ABSTRACT: Novelty Seeking (NS) and Harm Avoidance (HA) temperamental traits are related to approaching or avoiding motivational circuits relying on the integrity and functionality of distributed brain areas implicated in arousal and action. The present study verified whether and how macro- and micro-structural variations of basal ganglia are correlated with scores obtained in the NS and HA temperamental scales of the Temperament and Character Inventory by Cloninger. To this aim, 125 healthy adults aged 18-67 years of both sexes completed the Temperament and Character Inventory and underwent a high-resolution T1-weighted magnetic resonance imaging and a diffusion tensor imaging using a 3T scanner. The scores obtained in the temperamental scales were associated with volumes, mean diffusivity and fractional anisotropy measures of basal ganglia of both hemispheres separately, by using linear regression analyses. We found increased bilateral caudate and pallidum volumes associated with higher NS scores, as well as increased mean diffusivity in the bilateral putamen associated with higher HA scores. Macro- and micro-structural variations of basal ganglia regions contribute to explain the biological variance associated with NS or HA personality phenotype. The present findings evidencing some brain-temperament relationships highlight the importance of obtaining macro- and micro-structural measures in relation to individual differences.
Brain Structure and Function 03/2013; 219(3). DOI:10.1007/s00429-013-0535-5 · 4.57 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Insight has been mostly studied from a clinical perspective. Recently, attention moved to cognitive insight or the ability to monitor and correct one's erroneous convictions. Here, we investigated the neuroanatomical correlates of cognitive insight. We administered the Beck cognitive insight scale to 45 outpatients with a schizophrenia diagnosis and 45 age- and gender-matched healthy control subjects who underwent a MRI investigation, including high-resolution volumetric and diffusion tensor imaging sequences. Gray and white matter volume, mean diffusivity and fractional anisotropy were used as dependent variables and were analyzed on a voxel-by-voxel basis with reference to the cognitive insight indexes. Self-reflectiveness was positively related to gray matter volume of the right ventro-lateral prefrontal cortex (VLPFC). No statistically significant results emerged from the DTI analyses, and no significant relationships were found for self-certainty and global cognitive insight. Reduced self-reflectiveness is related to a reduced volume of the VLPFC, an area involved in generating and maintaining in working memory different hypotheses about the self. This line of research focusing on the metacognitive features of insight in schizophrenia can provide relevant information to identify patients who are most vulnerable to lack of insight and develop effective cognitive therapeutic strategies.
Social Cognitive and Affective Neuroscience 01/2012; 8(4). DOI:10.1093/scan/nss016 · 5.88 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Right brain damaged patients with left spatial neglect typically bisect long horizontal lines to the right of their midpoint. However, bisections of very short lines can favour the emergence of a paradoxical "cross-over" effect in which lines are bisected to the left of the true midpoint. It has been suggested that in healthy participants similar variations in the position of the subjective line midpoint can be observed in the bisections of long and short Oppel-Kundt (O-K) illusory gradients (Savazzi et al., 2007). This analogy was taken as proof that patients with neglect suffer a distorted representation of horizontal space that is equivalent to illusory distortions that O-K gradients induce in the intact brain (Savazzi et al., 2007). In contrast to this proposal, however, it has been noted that reversal of O-K illusion with short gradients was never described in literature (Doricchi et al., 2008). To resolve this incongruence, it was argued that such a reversal can be observed in healthy participants showing strong conventional illusory effects with long gradients (Savazzi, 2008). This proposal suggests that the greater the shift in the conventional direction of the illusion for long gradients, the greater the shift in the opposite direction with equivalent short gradients (i.e., negative correlation). Here we tested this hypothesis in a sample of 100 healthy participants who bisected horizontal O-K illusory gradients of different lengths (2, 4, 8 and 16cm). We found no reversal of O-K illusion with short gradients and a positive, rather than negative, correlation between bisection of long and short gradients. Participants showing strong illusory effects in the bisection of long gradients showed analogous effects in the bisection of very short ones. These findings do not support the space anisometry interpretation of line bisection performance and the cross-over effect in patients with neglect.
[Show abstract][Hide abstract] ABSTRACT: Voluntary orienting of visual attention is conventionally measured in tasks with predictive central cues followed by frequent valid targets at the cued location and by infrequent invalid targets at the uncued location. This implies that invalid targets entail both spatial reorienting of attention and breaching of the expected spatial congruency between cues and targets. Here, we used event-related functional magnetic resonance imaging (fMRI) to separate the neural correlates of the spatial and expectancy components of both endogenous orienting and stimulus-driven reorienting of attention. We found that during endogenous orienting with predictive cues, there was a significant deactivation of the right Temporal-Parietal Junction (TPJ). We also discovered that the lack of an equivalent deactivation with nonpredictive cues was matched to drop in attentional costs and preservation of attentional benefits. The right TPJ showed equivalent responses to invalid targets following predictive and nonpredictive cues. On the contrary, infrequent-unexpected invalid targets following predictive cues specifically activated the right Middle and Inferior Frontal Gyrus (MFG-IFG). Additional comparisons with spatially neutral trials demonstrated that, independently of cue predictiveness, valid targets activate the left TPJ, whereas invalid targets activate both the left and right TPJs. These findings show that the selective right TPJ activation that is found in the comparison between invalid and valid trials results from the reciprocal cancelling of the different activations that in the left TPJ are related to the processing of valid and invalid targets. We propose that left and right TPJs provide "matching and mismatching to attentional template" signals. These signals enable reorienting of attention and play a crucial role in the updating of the statistical contingency between cues and targets.