Brain Genomics Superstruct Project initial data release with structural, functional, and behavioral measures.

The goal of the Brain Genomics Superstruct Project (GSP) is to enable large-scale exploration of the links between brain function, behavior, and ultimately genetic variation. To provide the broader scientific community data to probe these associations, a repository of structural and functional magnetic resonance imaging (MRI) scans linked to genetic information was constructed from a sample of healthy individuals. The initial release, detailed in the present manuscript, encompasses quality screened cross-sectional data from 1,570 participants ages 18 to 35 years who were scanned with MRI and completed demographic and health questionnaires. Personality and cognitive measures were obtained on a subset of participants. Each dataset contains a T1-weighted structural MRI scan and either one (n=1,570) or two (n=1,139) resting state functional MRI scans. Test-retest reliability datasets are included from 69 participants scanned within six months of their initial visit. For the majority of participants self-report behavioral and cognitive measures are included (n=926 and n=892 respectively). Analyses of data quality, structure, function, personality, and cognition are presented to demonstrate the dataset's utility.

High-field magnetic resonance imaging of brain iron in Alzheimer disease.

OBJECTIVES: Increased iron deposition in the brain may occur in several neurodegenerative diseases, including Alzheimer disease (AD). Iron deposits shorten T2 relaxation times on T2-weighted magnetic resonance (MR) images. Iron-dependent contrast increases with magnetic field strength. We hypothesized that T2 mapping using 3 T MR imaging (MRI) can disclose differences between normal controls and AD subjects. METHODS: High-resolution brain imaging protocols were developed and applied to 24 AD patients and 20 age-matched controls using 3 T MRI. Eight anatomical regions of interest were manually segmented, and T2 histograms were computed. A visual analysis technique, the heat map, was modified and applied to the large image data sets generated by these protocols. RESULTS: A large number (163) of features from these histograms were examined, and 38 of these were significantly different (P < 0.05) between the groups. In the hippocampus, evidence was found for AD-related increases in iron deposition (shortened T2) and in the concentration of free tissue water (lengthened T2). Imaging of a section of postmortem brain before and after chemically extracting the iron established the presence of MRI-detectable iron in the hippocampus, cortex, and white matter in addition to brain regions traditionally viewed as containing high iron concentrations.

Dysfunctional action monitoring hyperactivates frontal-striatal circuits in obsessive-compulsive disorder: an event-related fMRI study.

Converging evidence suggests that hyperactivity in frontal-striatal circuits and in action-monitoring processes characterizes obsessive-compulsive disorder (OCD). It remains unclear, however, just how these abnormalities in brain function translate into the cognitive, affective, and behavioral manifestations of OCD. One possibility is that exaggerated or false error signals generated by the anterior cingulate (ACC) underlie compulsive behaviors by triggering the feeling that things are "not just right" even when no actual error has been made. Since recurrent compulsive behavior typically follows correct completion of a behavioral task (e.g., hand washing), ACC hyperactivity should be observed during correctly completed, high-conflict trials as well as during error trials. Frontal-striatal regions would also be expected to be activated during both trial types, as these regions are robustly associated with OCD across multiple neuroimaging paradigms. To test this hypothesis, 14 OCD patients and 14 matched controls completed a speeded reaction time task during functional magnetic resonance imaging (fMRI). Only correctly rejected, high-conflict trials produced excessive activation in both action monitoring (rostral and caudal ACC, LPFC) and frontal striatal regions (lateral orbitofrontal cortex (OFC), caudate, and thalamus) among OCD patients when compared to healthy controls. Portions of the posterior cingulate were also hyperactive among OCD patients. These results suggest that correctly rejected, high-conflict trials that require response inhibition may provide a better model than error trials of compulsive behaviors in OCD.