White matter predicts functional connectivity in premanifest Huntington's disease.

OBJECTIVES: The distribution of pathology in neurodegenerative disease can be predicted by the organizational characteristics of white matter in healthy brains. However, we have very little evidence for the impact these pathological changes have on brain function. Understanding any such link between structure and function is critical for understanding how underlying brain pathology influences the progressive behavioral changes associated with neurodegeneration. Here, we demonstrate such a link between structure and function in individuals with premanifest Huntington's. METHODS: Using diffusion tractography and resting state functional magnetic resonance imaging to characterize white matter organization and functional connectivity, we investigate whether characteristic patterns of white matter organization in the healthy human brain shape the changes in functional coupling between brain regions in premanifest Huntington's disease. RESULTS: We find changes in functional connectivity in premanifest Huntington's disease that link directly to underlying patterns of white matter organization in healthy brains. Specifically, brain areas with strong structural connectivity show decreases in functional connectivity in premanifest Huntington's disease relative to controls, while regions with weak structural connectivity show increases in functional connectivity. Furthermore, we identify a pattern of dissociation in the strongest functional connections between anterior and posterior brain regions such that anterior functional connectivity increases in strength in premanifest Huntington's disease, while posterior functional connectivity decreases. INTERPRETATION: Our findings demonstrate that organizational principles of white matter underlie changes in functional connectivity in premanifest Huntington's disease. Furthermore, we demonstrate functional antero-posterior dissociation that is in keeping with the caudo-rostral gradient of striatal pathology in HD.

The use of prebiotics and probiotics in Infant Formula

Gastrointestinal flora influences health; but the composition of flora can be changed with prebiotics or probiotics. The addition of probiotics to powdered infant formula has not been demonstrated to be harmful to healthy term infants. However; evidence of clinical efficacy regarding their addition is insufficient to recommend the routine use of such formula. The administration of probiotic (single or in combination) supplementation in infant or follow-on formula; and given beyond early infancy; may be associated with some clinical benefits; such as a reduction in the risk of nonspecific gastrointestinal infections; a reduced risk of antibiotic use and a lower frequency of colic and irritability. Confirmatory well-designed clinical research studies are necessary

Executive function in body dysmorphic disorder.

BACKGROUND: Body dysmorphic disorder (BDD) is a poorly understood disorder that involves a preoccupation with imagined or minor bodily defects. Only a few studies of neuropsychological function have been conducted. Two previous studies have indicated executive dysfunction in BDD. The current study sought to further define these executive deficits. METHOD: Fourteen DSM-IV BDD patients and 14 age- and sex-matched control participants took part. Because of the high incidence of co-morbidity in BDD, patients with co-morbid Axis I disorders were not excluded. Control participants had no history of psychiatric illness. All participants completed the following executive function (EF) tests: Spatial Span (SS), Spatial Working Memory (SWM) and the Stockings of Cambridge (SOC) task. They also completed the Pattern Recognition (PR) test, a test of visual memory (VM). RESULTS: BDD participants made significantly more between-search errors on the SWM task, an effect that increased with task difficulty. Between-search errors are an example of poor maintenance and manipulation of information. SOC results indicated slower subsequent thinking times (i.e. the time taken to plan) in BDD participants. There were no group differences in SS or PR scores. The severity of BDD, depressive or anxiety symptoms was not correlated with performance on any of the cognitive tasks. CONCLUSIONS: The results of this study indicate that BDD patients have EF deficits in on-line manipulation, planning and organization of information. By contrast, spatial memory capacity, motor speed and visual memory were intact. Considered with evidence from lesion and neuroimaging studies, these results suggest frontal lobe dysfunction in BDD.

Augmenting serotonin neurotransmission with citalopram modulates emotional expression decoding but not structural encoding of moderate intensity sad facial emotional stimuli: an event-related potential (ERP) investigation.

Antidepressants targeting the serotonergic system have been shown to modulate biases in emotional processing. The effects of serotonergic modulation on the temporal course of emotional processing (accruing within milliseconds) are unknown. Furthermore, it is unknown how serotonin affects different stages of facial emotional processing. The current study investigated the effects of acute serotonin augmentation on event-related potential (ERP) measures associated with 'structural encoding' (N170) and emotion 'expression decoding' (N250 and a late slow-wave positive potential [LPP]) of happy and sad facial stimuli, relative to neutral facial stimuli. The study was a double-blind, placebo-controlled, cross-over design, in which 14 healthy male participants completed a facial recognition task under two acute treatment conditions: 1) placebo (PLB) and 2) 20 mg citalopram (CIT). ERP recording were conducted while subjects viewed neutral, happy and sad facial stimuli. Findings indicated that under PLB, the N170 was not modulated by valence (happy or sad versus neutral), but the N250 and LPP were enhanced for processing happy (relative to neutral) faces. Citalopram had no effect on the N170, but it enhanced the LPP for processing sad (relative to neutral) faces. These findings suggest that serotonin enhancement has selective and temporal effects on emotional face processing, with evidence for modulating processes associated with 'expression decoding' but not 'structural encoding'. The enhanced cortical response to perception of moderately intense sad facial expressions following citalopram administration may relate to the cognitive processing of the social relevance or significance of such ambiguous stimuli.