1,288 research outputs found
Reduced grey matter in the posterior insula as a structural vulnerability or diathesis to addiction.
No full textA number of neuroimaging studies have shown that drug addiction is associated with morphological differences in several brain areas, including orbito-frontal and limbic structures. Most of these studies have investigated patients with addiction to cocaine. The neurobiological mechanisms which play a role in drug addiction are not fully understood, however, and the causal factors remain under investigation. The present study investigated morphological differences between patients with history of cocaine (N=14) and heroin (N=24) abuse and healthy matched controls (N=24). A 3D T1W MRI scan was acquired for all participants and the grey matter images of each patient group compared with those of controls. A direct comparison of the two addiction groups was also carried out. When compared with controls cocaine dependent patients had lower grey matter values in the left middle occipital gyrus, right putamen and insula, whereas heroin abusers had lower grey matter values in the right insula. The direct comparison between the two addiction groups showed that cocaine abusers had less grey matter in the right posterior cingulate, medio-temporal and cerebellar regions, whereas heroin abusers showed less grey matter in parietal regions on both sides, including postcentral gyrus and inferior parietal lobule. Reduced right posterior insular cortex was commonly found in both cocaine and heroin dependent patients. This morphological difference might represent a structural marker of addiction, which is independent of the discrete regional effects of each psychotropic substance of abuse, and might constitute a possible neurobiological vulnerability or diathesis to addiction. Equally, the discrete structural differences emerging from the direct comparison of cocaine and heroin abusers might reflect the effects of differential drug binding in the brain and/or express a form of neurobiological vulnerability which might explain individual drug choice
Individual differences in personality traits reflect structural variance in specific brain regions.
No full textPersonality dimensions such as novelty seeking (NS), harm avoidance (HA), reward dependence (RD) and persistence (PER) are said to be heritable, stable across time and dependent on genetic and neurobiological factors. Recently a better understanding of the relationship between personality traits and brain structures/systems has become possible due to advances in neuroimaging techniques. This Magnetic Resonance Imaging (MRI) study investigated if individual differences in these personality traits reflected structural variance in specific brain regions. A large sample of eighty five young adult participants completed the Three-dimensional Personality Questionnaire (TPQ) and had their brain imaged with MRI. A voxel-based correlation analysis was carried out between individuals' personality trait scores and grey matter volume values extracted from 3D brain scans. NS correlated positively with grey matter volume in frontal and posterior cingulate regions. HA showed a negative correlation with grey matter volume in orbito-frontal, occipital and parietal structures. RD was negatively correlated with grey matter volume in the caudate nucleus and in the rectal frontal gyrus. PER showed a positive correlation with grey matter volume in the precuneus, paracentral lobule and parahippocampal gyrus. These results indicate that individual differences in the main personality dimensions of NS, HA, RD and PER, may reflect structural variance in specific brain areas
Can we have an image of a concept? The generation process of general and specific mental images
No full textThe role of mental rotation and age in spatial perspective-taking tasks: when age does not impair perspective taking performance
No full text
Decreased drug-cue induced attentional bias in individuals with treated and untread drug dependence
No full textThe generation and maintenance of visual images: Evidences from image type and aging.
No full textImagery is a multi-componential process involving diVerent mental operations. This paper addresses whether separate processes
underlie the generation, maintenance and transformation of mental images or whether these cognitive processes rely on the same mental
functions. We also examine the inXuence of age on these mental operations for independence of components. In Experiment 1, younger
(22 years) and older (69 years) adults generated and maintained general, speciWc, contextual and autobiographical visual mental images
evoked in response to concrete nouns. The older adults had longer generation times, but there was no diVerence between the two groups
on maintenance. Both groups had shortest generation and maintenance times for general images, whereas only the older adults took longest
in generating autobiographical images. In Experiment 2, the total maintenance time and number of transformations for each type of
image were compared in another group of younger and older adults. General images were less transformed and more subject to decay for
both groups. The older people maintained the autobiographical mental images for longest compared to other image types. In conclusion,
image generation, maintenance and transformation seem to be diVerently aVected by type of image and aging, supporting a model of their
cognitive segregatio
- …
