This finding in normal male subjects indicated that the serotonin system may serve as a biological basis for spiritual experiences. The authors speculated that the several-fold variability in 5-HT(1A) receptor density may explain why people vary greatly in spiritual zeal.

Neurodevelopmental disorders affect a substantial minority of the general population. Their origins are still largely unknown, but a complex interplay of genetic and environmental factors causing disturbances of the central nervous system's maturation and a variety of higher cognitive skills is presumed. Only limited research of rather small sample size and narrow scope has been conducted in neurodevelopmental disorders using a twin-differences design. The Roots of Autism and ADHD Twin Study in Sweden (RATSS) is an ongoing project targeting monozygotic twins discordant for categorical or dimensional autistic and inattentive/hyperactive-impulsive phenotypes as well as other neurodevelopmental disorders, and typically developing twin controls. Included pairs are 9 years of age or older, and comprehensively assessed for psychopathology, medical history, neuropsychology, and dysmorphology, as well as structural, functional, and molecular brain imaging. Specimens are collected for induced pluripotent (iPS) and neuroepithelial stem cells, genetic, gut bacteria, protein-/monoamine, and electron microscopy analyses. RATSS's objective is to generate a launch pad for novel surveys to understand the complexity of genotype-environment-phenotype interactions in autism spectrum disorder and attention-deficit hyperactivity disorder (ADHD). By October 2013, RATSS had collected data from 55 twin pairs, among them 10 monozygotic pairs discordant for autism spectrum disorder, seven for ADHD, and four for other neurodevelopmental disorders. This article describes the design, recruitment, data collection, measures, collected pairs’ characteristics, as well as ongoing and planned analyses in RATSS. Potential gains of the study comprise the identification of environmentally mediated biomarkers, the emergence of candidates for drug development, translational modeling, and new leads for prevention of incapacitating outcomes.

The human serotonin transporter (5-HTT) gene is one of the most extensively studied in psychiatry. A functional polymorphism in the promoter region of the 5-HTT gene (5-HTTLPR) has been associated with several psychiatric disorders as well as anxiety-related personality traits. In search of a mechanistic understanding of the functional implications of 5-HTTLPR, the influence of this polymorphism on regional 5-HT1A receptor density has previously been examined in two positron emission tomography (PET) studies in humans, yielding, however, contradictory results. In the present study, 54 control subjects were examined with [11C]WAY 100635 PET and a battery of cognitive tests. Regional binding potential (BP) of [11C]WAY 100635 to 5-HT1A receptor was calculated for the dorsal raphe nuclei, the hippocampus, the anterior cingulate, the insula, the temporal cortex and the frontal cortex. The influence of 5-HTTLPR genotype on regional 5-HT1A BP and cognitive performance was investigated. No differences in 5-HT1A receptor density between carriers and non-carriers of the S allele were found. Thus, we could not replicate any of the previously reported associations between 5-HTTLPR and 5-HT1A density. There was, however, a highly significant association between 5-HTTLPR genotype and performance in Wisconsin Card Sorting Test; carriers of the S allele had a superior performance compared to the LL carriers. These observations suggest that functional implications of the 5-HTTLPR polymorphism are not likely to be mediated by differences in 5-HT1A expression levels and that other biomarkers must be considered for future investigations at phenotype level.

Objective: Surgery launches a systemic inflammatory reaction that reaches the brain and associates with immune activation and cognitive decline. Although preclinical studies have in part described this systemic-to-brain signaling pathway, we lack information on how these changes appear in humans. This study examines the short-and longterm impact of abdominal surgery on the human brain immune system by positron emission tomography (PET) in relation to blood immune reactivity, plasma inflammatory biomarkers, and cognitive function. Methods: Eight males undergoing prostatectomy under general anesthesia were included. Prior to surgery (baseline), at postoperative days 3 to 4, and after 3 months, patients were examined using [ 11 C]PBR28 brain PET imaging to assess brain immune cell activation. Concurrently, systemic inflammatory biomarkers, ex vivo blood tests on immunoreactivity to lipopolysaccharide (LPS) stimulation, and cognitive function were assessed. Results: Patients showed a global downregulation of gray matter [ 11 C]PBR28 binding of 26 6 26% (mean 6 standard deviation) at 3 to 4 days postoperatively compared to baseline (p 5 0.023), recovering or even increasing after 3 months. LPS-induced release of the proinflammatory marker tumor necrosis factor-a in blood displayed a reduction (41 6 39%) on the 3rd to 4th postoperative day, corresponding to changes in [ 11 C]PBR28 distribution volume. Change in Stroop Color-Word Test performance between postoperative days 3 to 4 and 3 months correlated to change in [ 11 C]PBR28 binding (p 5 0.027). Interpretation: This study translates preclinical data on changes in the brain immune system after surgery to humans, and suggests an interplay between the human brain and the inflammatory response of the peripheral innate immune system. These findings may be related to postsurgical impairments of cognitive function. ANN NEUROL 2017;81:572-582 A growing body of evidence suggests that surgical trauma launches a systemic inflammatory response that ultimately reaches and activates the intrinsic immune system of the brain. [1][2][3][4] Triggered by surgery-induced damage-associated molecular patterns (DAMPs), an array of proinflammatory mediators and activated blood-borne immune cells orchestrate a rapid spread of this systemic response to the central nervous system (CNS), with inflammatory markers detectable in human cerebrospinal fluid (CSF) within 12 hours. [4][5][6][7] In surgical rodent models, this periphery-to-brain pathway seems critically dependent on NF-jB and proinflammatory cytokine signaling (eg, tumor necrosis factor-a [TNF-a]) associated with a shortlasting disruption of blood-brain barrier integrity, 2,3,8 migration of peripheral macrophages into the CNS, and subsequent hippocampal neuronal dysfunction and cognitive impairment. 8 In addition to an acute and transient response, often referred to as a syndrome of sickness behavior including fatigue, anorexia, and fever, surgery-induced immune activation may be associated with prolonged impairments in learning,...

Motor response inhibition is mediated by neural circuits involving dopaminergic transmission

This study suggests that TSPO imaging with [(18)F]FEDAA1106 does not enable the detection of microglial activation in AD.

Preliminary studies have suggested that γ-aminobutyric acid type A (GABAA) receptors, and potentially the GABAAα5 subtype, are deficient in autism spectrum disorder (ASD). However, prior studies have been confounded by the effects of medications, and these studies did not compare findings across different species. We measured both total GABAAand GABAAα5 receptor availability in two positron emission tomography imaging studies. We used the tracer [11C]flumazenil in 15 adults with ASD and in 15 control individuals without ASD and the tracer [11C]Ro15-4513 in 12 adults with ASD and in 16 control individuals without ASD. All participants were free of medications. We also performed autoradiography, using the same tracers, in three mouse models of ASD: theCntnap2knockout mouse, theShank3knockout mouse, and mice carrying a 16p11.2 deletion. We found no differences in GABAAreceptor or GABAAα5 subunit availability in any brain region of adults with ASD compared to those without ASD. There were no differences in GABAAreceptor or GABAAα5 subunit availability in any of the three mouse models. However, adults with ASD did display altered performance on a GABA-sensitive perceptual task. Our data suggest that GABAAreceptor availability may be normal in adults with ASD, although GABA signaling may be functionally impaired.

No abstract