An examination of maternal prenatal BMI and human fetal brain development.

BACKGROUND: Prenatal development is a time when the brain is acutely vulnerable to insult and alteration by environmental factors (e.g., toxins, maternal health). One important risk factor is maternal obesity (Body Mass Index > 30). Recent research indicates that high maternal BMI during pregnancy is associated with increased risk for numerous physical health, cognitive, and mental health problems in offspring across the lifespan. It is possible that heightened maternal prenatal BMI influences the developing brain even before birth. METHODS: The present study examines this possibility at the level of macrocircuitry in the human fetal brain. Using a data-driven strategy for parcellating the brain into subnetworks, we test whether MRI functional connectivity within or between fetal neural subnetworks varies with maternal prenatal BMI in 109 fetuses between the ages of 26 and 39weeks. RESULTS: We discovered that strength of connectivity between two subnetworks, left anterior insula/inferior frontal gyrus (aIN/IFG) and bilateral prefrontal cortex (PFC), varied with maternal BMI. At the level of individual aIN/IFG-PFC connections, we observed both increased and decreased between-network connectivity with a tendency for increased within-hemisphere connectivity and reduced cross-hemisphere connectivity in higher BMI pregnancies. Maternal BMI was not associated with global differences in network topography based on network-based statistical analyses. CONCLUSIONS: Overall effects were localized in regions that will later support behavioral regulation and integrative processes, regions commonly associated with obesity-related deficits. By establishing onset in neural differences prior to birth, this study supports a model in which maternal BMI-related risk is associated with fetal connectome-level brain organization with implications for offspring long-term cognitive development and mental health.

Neural Basis of Visual Attentional Orienting in Childhood Autism Spectrum Disorders.

We examined spontaneous attention orienting to visual salience in stimuli without social significance using a modified Dot-Probe task during functional magnetic resonance imaging in high-functioning preadolescent children with Autism Spectrum Disorder (ASD) and age- and IQ-matched control children. While the magnitude of attentional bias (faster response to probes in the location of solid color patch) to visually salient stimuli was similar in the groups, activation differences in frontal and temporoparietal regions suggested hyper-sensitivity to visual salience or to sameness in ASD children. Further, activation in a subset of those regions was associated with symptoms of restricted and repetitive behavior. Thus, atypicalities in response to visual properties of stimuli may drive attentional orienting problems associated with ASD.

Sensitivity of fNIRS to cognitive state and load.

Functional near-infrared spectroscopy (fNIRS) is an emerging low-cost noninvasive neuroimaging technique that measures cortical bloodflow. While fNIRS has gained interest as a potential alternative to fMRI for use with clinical and pediatric populations, it remains unclear whether fNIRS has the necessary sensitivity to serve as a replacement for fMRI. The present study set out to examine whether fNIRS has the sensitivity to detect linear changes in activation and functional connectivity in response to cognitive load, and functional connectivity changes when transitioning from a task-free resting state to a task. Sixteen young adult subjects were scanned with a continuous-wave fNIRS system during a 10-min resting-state scan followed by a letter n-back task with three load conditions. Five optical probes were placed over frontal and parietal cortices, covering bilateral dorsolateral PFC (dlPFC), bilateral ventrolateral PFC (vlPFC), frontopolar cortex (FP), and bilateral parietal cortex. Activation was found to scale linearly with working memory load in bilateral prefrontal cortex. Functional connectivity increased with increasing n-back loads for fronto-parietal, interhemispheric dlPFC, and local connections. Functional connectivity differed between the resting state scan and the n-back scan, with fronto-parietal connectivity greater during the n-back, and interhemispheric vlPFC connectivity greater during rest. These results demonstrate that fNIRS is sensitive to both cognitive load and state, suggesting that fNIRS is well-suited to explore the full complement of neuroimaging research questions and will serve as a viable alternative to fMRI.

Atypical modulation of distant functional connectivity by cognitive state in children with Autism Spectrum Disorders.

We examined whether modulation of functional connectivity by cognitive state differed between pre-adolescent children with Autism Spectrum Disorders (ASD) and age and IQ-matched control children. Children underwent functional magnetic resonance imaging (fMRI) during two states, a resting state followed by a sustained attention task. A voxel-wise method was used to characterize functional connectivity at two levels, local (within a voxel's 14 mm neighborhood) and distant (outside of the voxel's 14 mm neighborhood to the rest of the brain) and regions exhibiting Group × State interaction were identified for both types of connectivity maps. Distant functional connectivity of regions in the left frontal lobe (dorsolateral [BA 11, 10]; supplementary motor area extending into dorsal anterior cingulate [BA 32/8]; and premotor [BA 6, 8, 9]), right parietal lobe (paracentral lobule [BA 6]; angular gyrus [BA 39/40]), and left posterior middle temporal cortex (BA 19/39) showed a Group × State interaction such that relative to the resting state, connectivity reduced (i.e., became focal) in control children but increased (i.e., became diffuse) in ASD children during the task state. Higher state-related increase in distant connectivity of left frontal and right angular gyrus predicted worse inattention in ASD children. Two graph theory measures (global efficiency and modularity) were also sensitive to Group × State differences, with the magnitude of state-related change predicting inattention in the ASD children. Our results indicate that as ASD children transition from an unconstrained to a sustained attentional state, functional connectivity of frontal and parietal regions with the rest of the brain becomes more widespread in a manner that may be maladaptive as it was associated with attention problems in everyday life.

Seeing human: distinct and overlapping neural signatures associated with two forms of dehumanization.

The process of dehumanization, or thinking of others as less than human, is a phenomenon with significant societal implications. According to Haslam's (2006) model, two concepts of humanness derive from comparing humans with either animals or machines: individuals may be dehumanized by likening them to either animals or machines, or humanized by emphasizing differences from animals or machines. Recent work in cognitive neuroscience emphasizes understanding cognitive processes in terms of interactions between distributed cortical networks. It has been found that reasoning about internal mental states is associated with activation of the default mode network (DMN) and deactivation of the task positive network (TPN); whereas reasoning about mechanical processes produces the opposite pattern. We conducted two neuroimaging studies. The first examined the neural bases of dehumanization and its relation to these two brain networks, using images and voice-over social narratives which either implicitly contrasted or implicitly likened humans to either animals or machines. The second study addressed a discrepancy between findings from the first study and prior work on the neural correlates of dehumanization: using a design similar to prior work we examined neural responses to pictures of humans, animals and machines, presented without any social context. In both studies, human and humanizing conditions were associated with relatively high activity in the DMN and relatively low activity in the TPN. However, the non-human and dehumanizing conditions deviated in different ways: they demonstrated more marked changes either in the DMN or in the TPN. Notably, differences between the animal dehumanizing and humanizing conditions were most evident in regions associated with mechanistic reasoning, not in the mentalizing network. Conjunction analysis of contrasts from both paradigms revealed that only one region was consistently more active when participants saw human, a medial parietal region regarded as the central hub of the DMN. These findings provide a neural basis for Haslam's distinction between two types of dehumanization, and suggest that the DMN and TPN play opposing roles in creating a sense of moral concern.