These results suggest that fetal alcohol exposure should be considered a possible factor in the pathogenesis of childhood psychiatric disorders. These data provide clinically relevant information about the mental health problems that children with fetal alcohol exposure are likely to face.
BACKGROUND At least 60% of those treated for an alcohol use disorder will relapse. Empirical study of the integrity of the brain reward system (BRS) is critical to understanding the mechanisms of relapse as this collection of circuits is implicated in the development and maintenance of all forms of addictive disorders. This study compared thickness, surface area and volume in neocortical components of the BRS among non-smoking light drinking controls (Controls), individuals who remained abstinent and those who relapsed after treatment. METHODS Seventy-five treatment-seeking alcohol dependent individuals (abstinent for 7 ± 3 days) and 43 Controls completed 1.5T proton magnetic resonance imaging studies. Parcellated morphological data was obtained for following bilateral components of the BRS: rostral and caudal anterior cingulate cortex, insula, medial and lateral orbitofrontal cortex, rostral and caudal middle and superior frontal gyri, amygdala and hippocampus as well as for 26 other bilateral neocortical regions. Alcohol dependent participants were followed over 12-months after baseline study and were classified as Abstainers (no alcohol consumption; n=24) and Relapsers (any alcohol consumption; n=51) at follow-up. RESULTS Relapsers and Abstainers demonstrated lower cortical thickness in the vast majority of BRS regions as well as lower global thickness compared to Controls. Relapsers had lower total BRS surface area than both Controls and Abstainers, but Abstainers were not significantly different from Controls on any surface area measure. Relapsers demonstrated lower volumes than Controls in the majority of regions, while Abstainers showed lower volumes than Controls in the superior frontal gyrus, insula, amygdala and hippocampus, bilaterally. Relapsers exhibited smaller volumes than Abstainers in the right rostral middle and caudal middle frontal gyri and the lateral orbitofrontal cortex, bilaterally. In Relapsers, lower baseline volumes and surface areas in multiple regions were associated with a greater magnitude of post-treatment alcohol consumption. CONCLUSIONS Results suggest Relapsers demonstrated morphological abnormalities in regions involved in the “top down” regulation/modulation of internal drive states, emotions, reward processing and behavior, which may impart increased risk for the relapse/remit cycle that afflicts many with an AUD. Results also highlight the importance of examining both cortical thickness and surface area to better understand the nature of regional volume loss frequently observed in AUD. Results from this report are consistent with previous research implicating plastic neurobiological changes the brain reward system in the maintenance of addictive disorders.
These data provide an account of response inhibition-related brain functioning in youth with FASD. Furthermore, results suggest that the frontal-striatal circuitry thought to mediate inhibitory control is sensitive to alcohol teratogenesis.
Lack of replication between previous autism MRI studies could be due to intersite differences in MRI systems and subjects' age and IQ. Cerebral gray tissue findings suggest that ASP is on the mild end of the autism spectrum. However, exploratory assessments of brain-IQ relationships reveal differences between HFA and ASP, indicating that these conditions may be neurodevelopmentally different when patterns of multiple measures are examined. Further investigations of brain-behavior relationships are indicated to confirm these findings.
Individuals at clinical high-risk (CHR) for psychosis are characterized by attenuated psychotic symptoms. Only a minority of CHR individuals convert to full-blown psychosis. Therefore, there is a strong interest in identifying neurobiological abnormalities underlying the psychosis risk syndrome. Dynamic functional connectivity (DFC) captures time-varying connectivity over short time scales, and has the potential to reveal complex brain functional organization. Based on resting-state functional magnetic resonance imaging (fMRI) data from 70 healthy controls (HCs), 53 CHR individuals, and 58 early illness schizophrenia (ESZ) patients, we applied a novel group information guided ICA (GIG-ICA) to estimate inherent connectivity states from DFC, and then investigated group differences. We found that ESZ patients showed more aberrant connectivities and greater alterations than CHR individuals. Results also suggested that disease-related connectivity states occurred in CHR and ESZ groups. Regarding the dominant state with the highest contribution to dynamic connectivity, ESZ patients exhibited greater impairments than CHR individuals primarily in the cerebellum, frontal cortex, thalamus and temporal cortex, while CHR and ESZ populations shared common aberrances mainly in the supplementary motor area, parahippocampal gyrus and postcentral cortex. CHR-specific changes were also found in the connections between the superior frontal gyrus and calcarine cortex in the dominant state. Our findings suggest that CHR individuals generally show an intermediate functional connectivity pattern between HCs and SZ patients but also have unique connectivity alterations.
Background Exposure to alcohol during gestation is associated with CNS alterations, cognitive deficits, and behavior problems. This study investigated microstructural aspects of putative white matter abnormalities following prenatal alcohol exposure. Methods Diffusion tensor imaging was used to assess white matter microstructure in 27 youth (age range: 8 to 18 years) with (n = 15) and without (n = 12) histories of heavy prenatal alcohol exposure. Voxelwise analyses, corrected for multiple comparisons, compared fractional anisotropy (FA) and mean diffusivity (MD) between groups, throughout the cerebrum. Results Prenatal alcohol exposure was associated with low FA in multiple cerebral areas, including the body of the corpus callosum and white matter innervating bilateral medial frontal and occipital lobes. Fewer between-group differences in MD were observed. Conclusions These data provide an account of cerebral white matter microstructural integrity in fetal alcohol spectrum disorders and support extant literature showing that white matter is a target of alcohol teratogenesis. The white matter anomalies characterized in this study may relate to the neurobehavioral sequelae associated with gestational alcohol exposure, especially in areas of executive dysfunction and visual processing deficits.
Heavy prenatal alcohol exposure causes permanent structural alterations to the brain and can lead to numerous cognitive and behavioral outcomes. Consistent with many of the neuropsychological and behavioral deficits that have been reported, neuroimaging studies reveal a pattern of structural abnormalities associated with prenatal alcohol exposure. This chapter systematically reviews structural anomalies by brain region, identifying cognitive and behavioral correlates when relevant. The consensus shows that in addition to the overall reduction of brain size, prominent brain shape abnormalities have been observed, with narrowing in the parietal region and reduced brain growth in portions of the frontal lobe. Commensurate with these anomalies, volumetric and tissue density findings cite disproportionate reductions in the parietal lobe, cerebellar vermis, corpus callosum, and the caudate nucleus, suggesting that certain areas of the brain may be especially vulnerable to prenatal alcohol exposure. In sum, neuroimaging techniques have greatly advanced our understanding of brain-behavior relationships in fetal alcohol spectrum disorders (FASD), and hopefully will lead to improved diagnosis and treatment options for those affected by prenatal exposure to alcohol.
Background-Diffusion tensor imaging (DTI) has revealed microstructural aspects of adolescent brain development, the cognitive correlates of which remain relatively uncharacterized.
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