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This study investigated how emotional valence of a perceived emotional state impacted performance on the Reading the Mind in the Eyes task (RMET) in adolescents with autism spectrum disorder (ASD) and typically developing (TD) controls. Valence of items on the RMET, Adult (RMET-A) and Child (RMET-C) versions, was first classified in a survey of 113 medical students. Adolescents with ASD (N = 33) and TD adolescents (N = 30) were administered both RMET versions. Individuals with ASD made more errors than TD controls on positive and negative, but not neutral, valence items. The difference in performance was accentuated on the RMET-A compared to the RMET-C. Both emotional valence and complexity of language contribute to RMET performance in individuals with ASD.

There has been a recent major upsurge in the concerns about reproducibility in many areas of science. Within the neuroimaging domain, one approach is to promote reproducibility is to target the re-executability of the publication. The information supporting such re-executability can enable the detailed examination of how an initial finding generalizes across changes in the processing approach, and sampled population, in a controlled scientific fashion. ReproNim: A Center for Reproducible Neuroimaging Computation is a recently funded initiative that seeks to facilitate the "last mile" implementations of core re-executability tools in order to reduce the accessibility barrier and increase adoption of standards and best practices at the neuroimaging research laboratory level. In this report, we summarize the overall approach and tools we have developed in this domain.

There has been a recent major upsurge in the concerns about reproducibility in many areas of science. Within the neuroimaging domain, one approach is to promote reproducibility is to target the re-executability of the publication. The information supporting such re-executability can enable the detailed examination of how an initial finding generalizes across changes in the processing approach, and sampled population, in a controlled scientific fashion. ReproNim: A Center for Reproducible Neuroimaging Computation is a recently funded initiative that seeks to facilitate the ‘last mile’ implementations of core re-executability tools in order to reduce the accessibility barrier and increase adoption of standards and best practices at the neuroimaging research laboratory level. In this report, we summarize the overall approach and tools we have developed in this domain.

This study was to examine cortical thickness in drug naive, first episode schizophrenia patients, and to explore its relationship with serum levels of brain-derived neurotrophic factor (BDNF). Forty-five drug naive schizophrenia patients and 28 healthy controls were enrolled in the study. Freesurfer was used to parcellate cortical regions, and vertex-wise group analysis was used for whole brain cortical thickness. The clusters for the brain regions that demonstrated group differences were extracted, and the mean values of thickness were calculated. Serum levels of BDNF were measured using enzyme-linked immunosorbent assay (ELISA). After controlling for age and gender, significantly thinner cortical thickness was found in left insula and superior temporal gyrus in the patient group compared with the healthy control group (HC group) (p's < 0.001). Lower serum levels of BDNF were also found in the patient group compared with the HC group (p = 0.001). Correlation analysis showed a significant positive relationship between thickness of left insula and serum levels of BDNF within the HC group (r = 0.396, p = 0.037) but there was no such relationship within the patient group (r = 0.035, p = 0.819). Cortical thinning is present in drug naive, first episode schizophrenia patients, indicating neurodevelopmental abnormalities at the onset of schizophrenia. Left insula might be an imaging biomarker in detecting the impaired protective role of neurotrophic factor for the brain development in schizophrenia.

We examine the similarity of outputs from Freesurfer version 5.1, Freesurfer version 5.3 and ANTS for the ABIDEI dataset.

There are numerous psychiatric disorders that can plague the development of children. Each of these disorders manifests as a distinct pattern of clinical, behavioral, etiological, neuroanatomic and neurofunctional characteristics that challenge the management of the individual patient, as well as the development of successful intervention and prevention strategies. In the area of neuroimaging, a substantial number of studies have been performed to date; and while much has been learned from this investment, this represents only the tip-of-the-iceberg of the information that can be gleaned from the data. Unfortunately, most of this additional, untapped information resource is lost due to ineffective sharing of the data that is possible by application of current technologies. The Child and Adolescent NeuroDevelopment Initiative (CANDI) at University of Massachusetts Medical School is making available a series of structural brain images, as well as their anatomic segmentations and demographic data, as a coordinated set of related morphometric resources. The initial data set is a release of 103 subjects (T1-weighted MRI scans and anatomic segmentation) that comprised the neuroanatomic data published in 2008 in an article by Frazier, et al.1 The subjects include 57 males and 46 females, aged 4–17, and come from four diagnostic groups: Healthy Controls (N=29), Schizophrenia Spectrum (N=20), Bipolar Disorder with Psychosis (N=19), and Bipolar Disorder without Psychosis (N=35). Both the McLean Hospital and Cambridge Health Alliance Institutional Review Boards approved the original data acquisition research protocols. All subjects signed assent forms, and their parents/legal guardians signed informed consent forms. The University of Massachusetts Medical School Institutional Review Board approved the data sharing protocol. Images were acquired from 1996–2006 at the McLean Hospital Brain Imaging Center on a 1.5 Tesla General Electric Signa Scanner. Structural imaging was performed using a three-dimensional inversion recovery-prepared spoiled gradient recalled echo in the coronal plane with 124 1.5 mm thick slices, repetition time 10 ms, TE 3, flip angle 25°, field of view 24 cm, acquisition matrix 256×192 and 2 excitations.2 All scans were reviewed by a clinical neuroradiologist to rule out gross pathology. The MR images released have undergone analysis at the Center for Morphometric Analysis (CMA) at the Massachusetts General Hospital which includes: preprocessing (‘positional normalization’ to put the image into the standard orientation of the Talairach coordinate space,3 and bias field correction4) and ‘general segmentation’ following the CMA segmentation protocol.5 Segmented regions include: Cerebral Cortex and White Matter, Cerebellum Cortex and White Matter, Lateral Ventricle, Thalamus, Ventral Diencephalon, Caudate, Putamen, Pallidum, Accumbens, Hippocampus and Amygdala, bilaterally; as well as Brain Stem, 3rd and 4th ventricles. Basic demographic details for each subject include diagnosis, age, gender, and handedness (Fig. 1). Fig. 1 The figure shows the data and resource relationships accessible from the CANDIShare data release. From the CANDIShare NITRC download page, both version V1.0 and V1.1 can be accessed. Accessing V1.1 for the healthy control group (HC) gains the user access ... The release is provided under the Creative Commons: Attribute license,6 and is structured as four bundles (tar) of imaging data, one for each diagnostic group. Within each bundle, there are separate directories for each subject that includes the data. Release version V1.0 includes only the imaging data and basic demographics and is accessible with no limitations. Version V1.1 adds the segmentation data as an indexed label file in register with the MR image for each subject, and requires provision of a contact email address (via the NITRC registration process) and requires a ‘clickthrough’ acceptance of the licensing terms. We do not perceive these extra access ‘hoops’ as burdensome, but they are necessary. While we hope that the data provided are perfect and free of any errors, experience has taught that some unforeseen errors may be present. If found, we will correct any error, and re-release a new version of the data and are obligated to inform all prior users of the data of any errors and corrections that were necessitated in order to limit the impact of any errors. In addition to the image releases, the CANDIShare portal begins to establish a more richly interconnected set of related informatics resources. The first example of this is the inclusion of linkages between each data release and their representation in the Internet Brain Volume Database (IBVD).7 The IBVD is a web-based database of published brain neuroanatomic volumetric observations. As the images and segmentation in this data release supports the volumetric observations in a specific publication, this linkage completes the connection between the high-level, group volumetric observation and the detailed individualized data that supports it. As the IBVD is also interoperable with PubMed via the ‘Link-Out’ function, a PubMed user can get from the publication listing at PubMed, to the summary volumetric observations reported in IBVD, to the raw data that supports the observation in the CANDIShare data release. Each of the diagnostic group bundles are linked to their respective group pages in the IBVD via the link exposed at the download page of the NITRC project. This image and segmentation data release for a specific publication represents the first in a series of data representing the pediatric brain in health and disease from data collected in our lab over the past 15 years. Additional publications will be added, and more resource interconnectivity will be included to maximize the utility of the released data with other classes of available data. This release of information is designed to be dramatically greater than merely ‘making the images available’: each image is associated with substantial analytic results, many of which have been utilized in the preparation of various publications and comparisons. Moreover, these data will be most effectively shared with the research community when shared in a way that preserves the linkages between the images, the resultant analytic data and meta-data, and its relationships to other public sources of related information. The utility of this shared data includes potentially expanding the numbers of subjects available for other studies (when the imaging protocols are comparable), facilitating additional research findings in this specific data set through reuse by other laboratories, and additional community access to accurate, manually-labeled datasets to promote development and testing of data analysis software. Access to data of this sort has already been valuable in development of numerous analysis techniques.8 In short, this represents a ‘Knowledge Management’ environment that will facilitate traversal of these data and linkages.

Every month, numerous publications appear that include neuroanatomic volumetric observations. The current and past literature that includes volumetric measurements is vast, but variable with respect to specific species, structures, and subject characteristics (such as gender, age, pathology, etc.). In this report we introduce the Internet Brain Volume Database (IBVD), www.nitrc.org/projects/ibvd , a site devoted to facilitating access to and utilization of neuroanatomic volumetric observations as published in the literature. We review the design and functionality of the site. The IBVD is the first database dedicated to integrating, exposing and sharing brain volumetric observations across species and disease. It offers valuable functionality for quality assurance assessment of results as well as support for meta-analysis across large segments of the published literature that are obscured from traditional text-based search engines.

Background: Regional prefrontal cortex gray matter reductions have been identified in schizophrenia, likely reflecting a combination of genetic vulnerability and disease effects. Few morphometric studies to date have examined regional prefrontal abnormalities in non-psychotic biological relatives who have not passed through the age range of peak risk for onset of psychosis. We conducted a region-of-interest morphometric study of prefrontal subregions in adolescent and young adult relatives of schizophrenia patients. Methods: Twenty-seven familial high-risk (FHR) first-degree relatives of schizophrenia patients and forty-eight control subjects without a family history of psychosis (ages 13–28) underwent high-resolution magnetic resonance imaging at 1.5 Tesla. The prefrontal cortex was parcellated into polar, dorsolateral, ventrolateral, ventromedial and orbital subregions. The Chapman scales measured subpsychotic symptoms. General linear models examined associations of prefrontal subregion volumes with familial risk and subpsychotic symptoms. Results: FHR subjects had significantly reduced bilateral ventromedial prefrontal and frontal pole gray matter volumes compared with controls. Ventromedial volume was significantly negatively correlated with magical ideation and anhedonia scores in FHR subjects. Conclusions: Selective, regional prefrontal gray matter reductions may differentially mark genetic vulnerability and early symptom processes among non-psychotic young adults at familial risk for schizophrenia.

Corpus callosum (CC) area abnormalities have been reported in magnetic resonance imaging (MRI) studies of adults and youths with bipolar disorder (BPD), suggesting interhemispheric communication may be abnormal in BPD and may be present early in the course of illness and affect normal neuromaturation of this structure throughout the lifecycle. Neuroimaging scans from 44 youths with DSM-IV BPD and 22 healthy controls (HC) were analyzed using cross-sectional area measurements and a novel method of volumetric parcellation. Univariate analyses of variance were conducted on CC subregions using both volume and traditional area measurements. Youths with BPD had smaller middle and posterior callosal regions, and reduced typical age-related increases in CC size. The cross-sectional area and novel volumetric methodologies resulted in similar findings. Future longitudinal assessments of CC development would track the evolution of callosal abnormalities in youths with BPD and allow exploration of the functional significance of these findings.

A significant number of children with bipolar disorder (BP) have co-morbid attention-deficit/hyperactivity disorder (ADHD). It is unknown if these children have neuroimaging findings unique to their co-morbid presentation, or if their brain findings are similar to children diagnosed with BP alone.Fifty three children with Diagnostic and Statistical Manual of Mental Disorders, 4(th) edition (DSM-IV) BP (23 with ADHD, 30 without), 29 healthy controls (HC), and 23 children with ADHD, similar in sex and age, had magnetic resonance imaging (MRI) scans on a 1.5T GE scanner. Volumetric assessments were performed for basal ganglia and limbic subcortical structures.Youths with ADHD had smaller caudate and putamen volumes compared to both BP groups and they had moderately smaller total amygdala volumes compared to the other three groups. Youths with BP + ADHD had moderately larger nucleus accumbens volumes than HC, and females in both BP groups had smaller hippocampal volumes compared to ADHD and HC. No differences were found between the BP and BP + ADHD groups.These data suggest that morphometric subcortical volumes in youths with BP + ADHD are more similar to those in youths with BP. They do not share subcortical neuroanatomic correlates with the ADHD group. These findings suggest that BP + ADHD is a subtype of pediatric BP rather than severe ADHD.

SummaryThe structural effects of cocaine on neural systems mediating cognition and motivation are not well known. By comparing the thickness of neocortical and paralimbic brain regions between cocaine-dependent and matched control subjects, we found that four of 18 a priori regions involved with executive regulation of reward and attention were significantly thinner in addicts. Correlations were significant between thinner prefrontal cortex and reduced keypresses during judgment and decision making of relative preference in addicts, suggesting one basis for restricted behavioral repertoires in drug dependence. Reduced effortful attention performance in addicts also correlated with thinner paralimbic cortices. Some thickness differences in addicts were correlated with cocaine use independent of nicotine and alcohol, but addicts also showed diminished thickness heterogeneity and altered hemispheric thickness asymmetry. These observations suggest that brain structure abnormalities in addicts are related in part to drug use and in part to predisposition toward addiction.

Amygdala volume has been associated with drug craving in cocaine addicts, and amygdala volume reduction is observed in some alcohol-dependent subjects. This study sought an association in alcohol-dependent subjects between volumes of reward-related brain regions, alcohol craving, and the risk of relapse.Besides alcohol craving, the authors assessed amygdala, hippocampus, and ventral striatum volumes in 51 alcohol-dependent subjects and 52 age- and education-matched healthy comparison subjects after detoxification. After imaging and clinical assessment, patients were followed for 6 months and alcohol intake was recorded.Alcohol-dependent subjects showed reduced amygdala, hippocampus, and ventral striatum volumes and reported stronger craving in relation to healthy comparison subjects. However, only amygdala volume and craving differentiated between subsequent relapsers and abstainers. A significant decrease of amygdala volume in alcohol-dependent subjects was associated with increased alcohol craving before imaging and an increased alcohol intake during the 6-month follow-up period.These findings suggest a relationship between amygdala volume reduction, alcohol craving, and prospective relapse into alcohol consumption.

Objectives: Diffusion tensor magnetic resonance imaging (DT-MRI) assesses the integrity of white matter (WM) tracts in the brain. Children with bipolar disorder (BPD) may have WM abnormalities that precede illness onset. To more fully examine this possibility, we scanned children with DSM-IV BPD and compared them to healthy peers and children at risk for BPD (AR-BPD), defined as having a first-degree relative with the disorder. Methods: Ten children with BPD, eight healthy controls (HC), and seven AR-BPD, similar in age, had MRI scans on a 1.5 Tesla GE scanner, including a standard DT-MRI sequence (T2-EPI) with 25 axial slices. Fractional anisotropy (FA) values were compared between groups to determine regions of significant difference (p

Recent anatomical studies have found that cortical neurons are mainly preserved during the aging process while myelin damage and even axonal loss is prominent throughout the forebrain. We used diffusion tensor imaging (DT-MRI) to evaluate the hypothesis that during the process of normal aging, white matter changes preferentially affect the integrity of long corticocortical association fiber tracts, specifically the superior longitudinal fasciculus II and the cingulum bundle. This would disrupt communication between the frontal lobes and other forebrain regions leading to cognitive impairments. We analyzed DT-MRI datasets from seven young and seven elderly behaviorally characterized rhesus monkeys, creating fractional anisotropy (FA) maps of the brain. Significant age-related reductions in mean FA values were found for the superior longitudinal fasciculus II and the cingulum bundle, as well as the anterior corpus callosum. Comparison of these FA reductions with behavioral measures demonstrated a statistically significant linear relationship between regional FA and performance on a test of executive function. These findings support the hypothesis that alterations to the integrity of these long association pathways connecting the frontal lobe with other forebrain regions contribute to cognitive impairments in normal aging. To our knowledge this is the first investigation reporting such alterations in the aging monkey.

Autism spectrum disorder (ASD) affects 1 in 50 children between the ages of 6 and 17 years. The etiology of ASD is not precisely known. ASD is an umbrella term, which includes both low- (IQ70) and high-functioning (IQ70) individuals. A better understanding of the disorder and how it manifests in individual subjects can lead to more effective intervention plans to fulfill the individual's treatment needs.Magnetic resonance imaging (MRI) is a non-invasive investigational tool that can be used to study the ways in which the brain develops or deviates from the typical developmental trajectory. MRI offers insights into the structure, function, and metabolism of the brain. In this article, we review published studies on brain connectivity changes in ASD using either resting state functional MRI or diffusion tensor imaging.The general findings of decreases in white matter integrity and in long-range neural coherence are well known in the ASD literature. Nevertheless, the detailed localization of these findings remains uncertain, and few studies link these changes in connectivity with the behavioral phenotype of the disorder. With the help of data sharing and large-scale analytic efforts, however, the field is advancing toward several convergent themes, including the reduced functional coherence of long-range intra-hemispheric cortico-cortical default mode circuitry, impaired inter-hemispheric regulation, and an associated, perhaps compensatory, increase in local and short-range cortico-subcortical coherence.

An imbalance of excitatory and inhibitory neurotransmission in autism spectrum disorder (ASD) has been proposed. We compared glutamate (Glu), glutamine (Gln), and γ-aminobutyric acid (GABA) levels in the anterior cingulate cortex (ACC) of 13 males with ASD and 14 typically developing (TD) males (ages 13-17), and correlated these levels with intelligence quotient (IQ) and measures of social cognition.Social cognition was evaluated by administration of the Social Responsiveness Scale (SRS) and the Reading the Mind in the Eyes Test (RMET). We acquired proton magnetic resonance spectroscopy ((1)H-MRS) data from the bilateral ACC using the single voxel point resolved spectroscopy sequence (PRESS) to quantify Glu and Gln, and Mescher-Garwood point-resolved spectroscopy sequence (MEGA-PRESS) to quantify GABA levels referenced to creatine (Cr).There were higher Gln levels (p=0.04), and lower GABA/Cre levels (p=0.09) in the ASD group than in the TD group. There was no difference in Glu levels between groups. Gln was negatively correlated with RMET score (rho=-0.62, p=0.001) and IQ (rho=-0.56, p=0.003), and positively correlated with SRS scores (rho=0.53, p=0.007). GABA/Cre levels were positively correlated with RMET score (rho=0.34, p=0.09) and IQ (rho=0.36, p=0.07), and negatively correlated with SRS score (rho=-0.34, p=0.09).These data suggest an imbalance between glutamatergic neurotransmission and GABA-ergic neurotransmission in ASD. Higher Gln levels and lower GABA/Cre levels were associated with lower IQ and greater impairments in social cognition across groups.

The insula is anatomically situated to be critically involved in many bio-behavioral functions impaired in schizophrenia. Furthermore, its total volume has been shown to be reduced in schizophrenia. In the present study, we tested the hypothesis that in schizophrenia it is the anterior insular lobule (aINS(lbl)) rather than the posterior insular lobule (pINS(lbl)) that is smaller, given that limbic system abnormalities are central in schizophrenia and that the affiliations of the limbic system are principally with the anterior insular lobule. We used T1-weighted high resolution magnetic resonance imaging (MRI) to measure the cortical volume of the left and right anterior and posterior insular subdivisions. The subjects included a sample of healthy community controls (N=40) and chronic patients with DSM-III-R schizophrenia (N=41). We correlated insula volumes with positive and negative symptoms. We found that the total aINS(lbl), and the left aINS(lbl) in particular, were significantly volumetrically smaller in schizophrenia compared to controls, and significantly correlated with bizarre behavior. Given that the anterior insular lobule offers anatomic features that allow for MRI-based morphometric analysis, namely its central and circular sulci, this brain structure provides a useful model to test hypotheses regarding genotype-phenotype relationships in schizophrenia using the anterior insular lobule as a candidate endophenotype.

Pediatric bipolar disorder (BPD) is a severe psychiatric illness with significant morbidity whose pathophysiology is largely still unknown. The morbidity associated with this disorder is driven, in part, by the child’s inability to modulate affect and cognition; those affected by the disorder have a diminished ability to control the intensity of a response to the environment and the ease of recovery from the response. For example, even in euthymic individuals with BPD, there are enduring impairments in attention, executive functioning, processing speed, and in working and verbal declarative memory that lead to difficulties in daily life (1). In addition, individuals who are genetically at risk for developing BPD have deficits in verbal declarative memory, selective and sustained attention, and in working memory, suggesting that these domains may serve as cognitive endophenotypic markers of the disorder that in turn could implicate areas of pathophysiology in the brain (1). For example, these domains of cognitive functioning are largely under the control of the cerebral cortex and are highly heritable (2–4). Therefore, in order to contribute to a deeper understanding of the neurobiological correlates that underlie the dysfunction associated with the disorder (5), it is critical to study the cerebral cortex, where brain operations occur that govern cognitive abilities (6). Taken collectively, published neuroimaging (functional, biochemical, and structural) studies indicate that there may be cortical abnormalities in adults and children with BPD (7–12). To understand more fully the differences in the cortex seen in children with BPD, it is critical to assess the lobes of cortical gray matter (GM) and the gyri of each lobe, as different regions of the cortex subserve different cognitive functions. For example, the frontal lobe (FL) is involved in cognition, memory, sensory processing, planning and initiation of voluntary movements, language production, and integration of cognition and affect. The temporal lobe (TL) is integral for auditory processing, language comprehension, semantic memory processing, visual perception, and sensory integration (13). The parietal lobe (PL) is involved in processing tactile and proprioceptive information, language comprehension, speech, writing, and aspects of spatial orientation and perception. The occipital lobe (OL) is involved in visual functions (13). To our knowledge a detailed anatomical assessment of the entire cerebral cortex, using structural magnetic resonance imaging (MRI), has not been carried out in studies in adults with BPD, nor has it been carried out in child studies. Of particular importance is the need to assess the cortex in children with BPD, given that their brains are relatively free from factors known to affect the brain, such as lengthy medication exposure, substance abuse, and electroconvulsive therapies (14). To our knowledge, this is the first structural neuroimaging study to fully assess the entire cortical GM and subsequently the gyri of the lobes of the cortex in pediatric BPD. Based on prior studies (neuroimaging and neuropsychological), we set out to assess expected alterations in cortical volumes, in pediatric BPD, to determine if these youth might show a specific pattern of cortical GM deficits. Given the data from the prior neuroimaging studies (in both children and adults), we hypothesized that children with BPD would show cortical GM deficits, particularly in sections of the FL, similar to adults with the disorder.

Youths with bipolar disorder are ideal for studying illness pathophysiology given their early presentation, lack of extended treatment, and high genetic loading. Adult bipolar disorder MRI studies have focused increasingly on limbic structures and the thalamus because of their role in mood and cognition. On the basis of adult studies, the authors hypothesized a priori that youths with bipolar disorder would have amygdalar, hippocampal, and thalamic volume abnormalities.Forty-three youths 6-16 years of age with DSM-IV bipolar disorder (23 male, 20 female) and 20 healthy comparison subjects (12 male, eight female) similar in age and sex underwent structured and clinical interviews, neurological examination, and cognitive testing. Differences in limbic and thalamic brain volumes, on the logarithmic scale, were tested using a two-way (diagnosis and sex) univariate analysis of variance, with total cerebral volume and age controlled.The subjects with bipolar disorder had smaller hippocampal volumes. Further analysis revealed that this effect was driven predominantly by the female bipolar disorder subjects. In addition, both male and female youths with bipolar disorder had significantly smaller cerebral volumes. No significant hemispheric effects were seen.These findings support the hypothesis that the limbic system, in particular the hippocampus, may be involved in the pathophysiology of pediatric bipolar disorder. While this report may represent the largest MRI study of pediatric bipolar disorder to date, more work is needed to confirm these findings and to determine if they are unique to pediatric bipolar disorder.

Language deficits are among the core impairments of autism. We previously reported asymmetry reversal of frontal language cortex in boys with autism. Specific language impairment (SLI) and autism share similar language deficits and may share genetic links. This study evaluated asymmetry of frontal language cortex in a new, independent sample of right-handed boys, including a new sample of boys with autism and a group of boys with SLI. The boys with autism were divided into those with language impairment (ALI) and those with normal language ability (ALN). Subjects (righthanded, aged 6.2–13.4 years) included 22 boys with autism (16 ALI and 6 ALN), 9 boys with a history of or present SLI, and 11 normal controls. MRI brain scans were segmented into grey and white matter; then the cerebral cortex was parcellated into 48 gyral-based divisions per hemisphere. Group differences in volumetric asymmetry were predicted a priori in language-related regions in inferior lateral frontal (Broca’s area) and posterior superior temporal cortex. Language impaired boys with autism and SLI both had significant reversal of asymmetry in frontal language-related cortex; larger on the right side in both groups of language impaired boys and larger on the left in both unimpaired language groups, strengthening a phenotypic link between ALI and SLI. Thus, we replicated the observation of reversed asymmetry in frontal language cortex reported previously in an independent autism sample, and observed similar reversal in boys with SLI, further strengthening a phenotypic link between SLI and a subgroup of autism. Linguistically unimpaired boys with autism had similar asymmetry compared with the control group, suggesting that Broca’s area asymmetry reversal is related more to language impairment than specifically to autism diagnosis. Ann Neurol 2004;56:757–766

This study examined activation levels in the left (L) supplementary motor area (SMA) and the right (R) SMA (separately), and activation in nine R perisylvian language homologues during overt, propositional speech in chronic nonfluent aphasia patients. Previous functional imaging studies with a variety of chronic aphasia patients have reported activation in these regions during different language tasks, however, overt propositional speech has not been examined. In the present research, four nonfluent aphasia patients were studied during overt elicited propositional speech at 4-9 years post-single L hemisphere stroke, which spared the SMA. The dynamic susceptibility contrast (DSC) method of functional MRI was used to calculate relative cerebral blood volume (relCBV) for cortical regions of interest (ROIs) during the first-pass bolus of gadolinium during two conditions: (1) pattern (silent viewing of checkerboard patterns) and (2) story (overt, elicited propositional speech describing sequential pictures, which formed a story). During the story condition, controls had significantly higher relCBV in L SMA than in R SMA; aphasics, however, had significantly higher relCBV in R SMA than in L SMA. During the pattern condition, no significant differences were observed between the L SMA and the R SMA for either controls or aphasics. In addition, aphasics had significantly higher relCBV in the R sensorimotor mouth during story than pattern. This R sensorimotor mouth relCBV was also significantly higher in aphasics than controls during story, and the two groups did not differ during pattern. The overall mean relCBV for the nine R perisylvian ROIs was significantly higher for aphasics than controls during both story and pattern. These results suggest that poor modulation, including possible over-activation of R sensorimotor mouth and other R perisylvian language homologues may underlie in part, the hesitant, poorly articulated, agrammatic speech associated with nonfluent aphasia.

Time series of net and seasonal mass balances for three glaciers in western North America, one in the Pacific Northwest and two in Alaska, show various relationships to Pacific hemisphere climate indexes. During the winter season the two coastal, maritime-regime glaciers, over 2000 km apart, are affected almost identically, albeit inversely, by atmospheric and oceanic conditions in both the tropical and North Pacific. The two Alaska glaciers, only 350 km apart, have almost no coherence. Lag correlations show that in winter the maritime glaciers are influenced by concurrent conditions in the North Pacific, but by conditions in the tropical Pacific in August–September of the prior northern summer. The winter balance variations contain interannual El Nino–Southern Oscillation variability superimposed on North Pacific interdecadal variability; the interdecadal 1976–77 climate regime shift is clearly evident. The summer balances and the continental-regime glacier have a general lack of correlations, w...

Marine ice-sheet collapse can contribute to rapid sea-level rise1. Today, the West Antarctic Ice Sheet contains an amount of ice equivalent to approximately six metres of sea-level rise, but most of the ice is in the slowly moving interior reservoir. A relatively small fraction of the ice sheet comprises several rapidly flowing ice streams which drain the ice to the sea. The evolution of this drainage system almost certainly governs the process of ice-sheet collapse2,3,4,5. The thick and slow-moving interior ice reservoir is generally fixed to the underlying bedrock while the ice streams glide over lubricated beds at velocities of up to several hundred metres per year. The source of the basal lubricant — a water-saturated till6,7 overlain by a water system8 — may be linked to the underlying geology. The West Antarctic Ice Sheet rests over a geologically complex region characterized by thin crust, high heat flows, active volcanism and sedimentary basins9,10,11,12,13,14,15,16. Here we use aerogeophysical measurements to constrain the geological setting of the onset of an active West Antarctic ice stream. The onset coincides with a sediment-filled basin incised by a steep-sided valley. This observation supports the suggestion5,17 that ice-stream dynamics — and therefore the response of the West Antarctice Ice Sheet to changes in climate — are strongly modulated by the underlying geology.

Five overlapping Landsat multispectral scanner satellite images of the interior of the West Antarctic ice sheet were enhanced with principal component analysis, high-pass filtering, and linear contrast stretching and merged into a mosaic by aligning surface features in the overlap areas. The mosaic was registered to geodetic coordinates, to an accuracy of about 1 km, using the five scene centers as control points. The onset of streaming flow of two tributaries of ice stream C and one tributary of ice stream D is visible in the mosaic. The onset appears to occur within a relatively short distance, less than the width of the ice stream, typically at a subglacial topographic feature, such as a step or ridge. The ice streams extend farther up into the interior than previously mapped. Ice stream D starts about 150 km from the ice divide, at an altitude of about 1500 m, approximately halfway up the convex-upward dome shape of the interior ice sheet. Ice stream D is relatively much longer than ice stream C, possibly because ice stream D is currently active, whereas ice stream C is currently inactive. The grounded portion of the West Antarctic ice sheet is perhaps best conceptualized as an ice sheet in which ice streams are embedded over most of its area, with slow-moving ice converging into fast-moving ice streams in a widely distributed pattern, much like that of streams and rivers in a hydrologic basin. A relic margin appears to parallel most of the south margin of the tributary of ice stream D, separated from the active shear margin by about 10 km or less for a distance of over 200 km. This means there is now evidence for recent changes having occurred in three of the five major ice streams which drain most of West Antarctica (B, C, and D), two of which (B and D) are currently active.

Ice penetrating radar measurements made over the summit region of Greenland show returns from internal layers which can be used to augment the interpretation of climate information from the two deep cores recently recovered from this area. These reflecting surfaces, believed to represent isochrones, give information about the stress regime near the summit, and may aid in a better calibration of the age depth scale between the two cores — particularly in the lowest 10% of ice thickness where there is currently disagreement. The approximate depth at which internal echoes become discontinuous corresponds with the observations of steep inclinations and overturned folds on the scale of centimeters in the core samples. However the deepest internal layers which can be distinguished in the profiles place constraints on the scale and location of high angle or overturned folds.

IT is widely understood that the collapse of the West Antarctic ice sheet (WAIS) would cause a global sea level rise of 6 m, yet there continues to be considerable debate about the detailed response of this ice sheet to climate changel–3. Because its bed is grounded well below sea level, the stability of the WAIS may depend on geologically controlled conditions at the base which are independent of climate. In particular, heat supplied to the base of the ice sheet could increase basal melting and thereby trigger ice streaming, by providing the water for a lubricating basal layer of till on which ice streams are thought to slide4,5. Ice streams act to protect the reservoir of slowly moving inland ice from exposure to oceanic degradation, thus enhancing ice-sheet stability. Here we present aerogeophysical evidence for active volcanism and associated elevated heat flow beneath the WAIS near the critical region where ice streaming begins. If this heat flow is indeed controlling ice-stream formation, then penetration of ocean waters inland of the thin hot crust of the active portion of the West Antarctic rift system could lead to the disappearance of ice streams, and possibly trigger a collapse of the inland ice reservoir.

We performed cerebellum segmentation and parcellation on magnetic resonance images from right-handed boys, aged 6-13 years, including 22 boys with autism [16 with language impairment (ALI)], 9 boys with Specific Language Impairment (SLI), and 11 normal controls. Language-impaired groups had reversed asymmetry relative to unimpaired groups in posterior-lateral cerebellar lobule VIIIA (right side larger in unimpaired groups, left side larger in ALI and SLI), contralateral to previous findings in inferior frontal cortex language areas. Lobule VIIA Crus I was smaller in SLI than in ALI. Vermis volume, particularly anterior I-V, was decreased in language-impaired groups. Language performance test scores correlated with lobule VIIIA asymmetry and with anterior vermis volume. These findings suggest ALI and SLI subjects show abnormalities in neurodevelopment of fronto-corticocerebellar circuits that manage motor control and the processing of language, cognition, working memory, and attention.

Background: Alcoholism-related deficits in cognition and emotion point toward frontal and limbic dysfunction, particularly in the right hemisphere. Prefrontal and anterior cingulate cortices are involved in cognitive and emotional functions and play critical roles in the oversight of the limbic reward system. In the present study, we examined the integrity of white matter tracts that are critical to frontal and limbic connectivity. Methods: Diffusion tensor magnetic resonance imaging (DT-MRI) was used to assess functional anisotropy (FA), a measure of white matter integrity, in 15 abstinent long-term chronic alcoholic and 15 demographically equivalent control men. Voxel-based and region-based analyses of group FA differences were applied to these scans. Results: Alcoholic subjects had diminished frontal lobe FA in the right superior longitudinal fascicles II and III, orbitofrontal cortex white matter, and cingulum bundle, but not in corresponding left hemisphere regions. These right frontal and cingulum white matter regional FA measures provided 97% correct group discrimination. Working Memory scores positively correlated with superior longitudinal fascicle III FA measures in control subjects only. Conclusions: The findings demonstrate white matter microstructure deficits in abstinent alcoholic men in several right hemisphere tracts connecting prefrontal and limbic systems. These white matter deficits may contribute to underlying dysfunction in memory, emotion, and reward response in alcoholism.

The surface and bottom topography of the central Greenland ice sheet was determined from airborne ice-radar soundings over a 180 km by 180 km grid centered on the 1974 “Summit” site (lat. 72°18′N., long. 37°55′W.), using the Technical University of Denmark 60 MHz ice radar. Over 6100 km of high-quality radar data were obtained, covering over 99'% of the grid, along lines spaced 12.5 km apart in both north-south and east-west directions. Aircraft location was done with an inertial navigation system (INS) and a pressure altimeter, with control provided by periodically flying over a known point at the center of the grid. The ice radar was used to determine ice thickness; the surface topography was determined independently using height-above-terrain measurements from the aircraft’s radar altimeter. The calculated surface topography is accurate to about ±6 m, with this error arising mostly from radar-altimeter errors. The ice thickness and bottom topography are accurate to about ±50 m, with this error dominated by the horizontal navigation uncertainties due to INS drift; this error increases to about ±125 m in areas of rough bottom relief (about 12% of the grid).The highest point on Greenland is at lat. 72°34′ N., long. 37°38′W., at an altitude of 3233 ± 6 m a.s.l. The ice surface at this point divides into three sectors, one facing north, one east-south-east, and one west-south-west, with each having a roughly uniform slope. The ice divide between the last two sectors is a well-defined ridge running almost due south. The ice is about 3025 m thick at the summit. Excluding the mountainous north-east corner of the grid, where the ice locally reaches a thickness of about 3470 m and the bed dips to about 370 m below sea-level, the maximum ice thickness, approximately 3375 m, occurs about 97 km south-south-west of the summit. The average bed altitude over the entire grid is 180 m and the average ice thickness is 2975 ± 235 m. The ice in most of the south-west quadrant of the grid is over 3200 m thick, and overlies a relatively smooth, flat basin with altitudes mostly below sea-level. There is no predominant direction to the basal topography over most of the grid; it appears to be undulating, rolling terrain with no obvious ridge/valley structure. The summit of the ice sheet is above the eastern end of a relatively large, smooth, flat plateau, about 10–15 km wide and extending about 50 km to the west. If the basal topography were the sole criterion, then a site somewhere on this plateau or in the south-west basin would be suitable for the drilling of a new deep ice core.