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26,799 result(s) for "Reaction Time - genetics"
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Visual-spatial neglect after right-hemisphere stroke
Visual-spatial neglect (VSN) is a neuropsychological syndrome, and right-hemisphere stroke is the most common cause. The pathogenetic mechanism of VSN remains unclear. This study aimed to investigate the behavioral and event-related potential (ERP) changes in patients with or without VSN after right-hemisphere stroke. Eleven patients with VSN with right-hemisphere stroke (VSN group) and 11 patients with non-VSN with right-hemisphere stroke (non-VSN group) were recruited along with one control group of 11 age- and gender-matched healthy participants. The visual-spatial function was evaluated using behavioral tests, and ERP examinations were performed. The response times in the VSN and non-VSN groups were both prolonged compared with those of normal controls (P < 0.001). In response to either valid or invalid cues in the left side, the accuracy in the VSN group was lower than that in the non-VSN group (P < 0.001), and the accuracy in the non-VSN group was lower than that in controls (P < 0.05). The P1 latency in the VSN group was significantly longer than that in the control group (F[2, 30] = 5.494, P = 0.009), and the N1 amplitude in the VSN group was significantly lower than that in the control group (F[2, 30] = 4.343, P = 0.022). When responding to right targets, the left-hemisphere P300 amplitude in the VSN group was significantly lower than that in the control group (F[2, 30] = 4.255, P = 0.025). With either left or right stimuli, the bilateral-hemisphere P300 latencies in the VSN and non-VSN groups were both significantly prolonged (all P < 0.05), while the P300 latency did not differ significantly between the VSN and non-VSN groups (all P > 0.05). Visual-spatial attention function is impaired after right-hemisphere stroke, and clinicians should be aware of the subclinical VSN. Our findings provide neuroelectrophysiological evidence for the lateralization of VSN.
Study of 300,486 individuals identifies 148 independent genetic loci influencing general cognitive function
General cognitive function is a prominent and relatively stable human trait that is associated with many important life outcomes. We combine cognitive and genetic data from the CHARGE and COGENT consortia, and UK Biobank (total N  = 300,486; age 16–102) and find 148 genome-wide significant independent loci ( P  < 5 × 10 −8 ) associated with general cognitive function. Within the novel genetic loci are variants associated with neurodegenerative and neurodevelopmental disorders, physical and psychiatric illnesses, and brain structure. Gene-based analyses find 709 genes associated with general cognitive function. Expression levels across the cortex are associated with general cognitive function. Using polygenic scores, up to 4.3% of variance in general cognitive function is predicted in independent samples. We detect significant genetic overlap between general cognitive function, reaction time, and many health variables including eyesight, hypertension, and longevity. In conclusion we identify novel genetic loci and pathways contributing to the heritability of general cognitive function. Cognitive function is associated with health and important life outcomes. Here, the authors perform a genome-wide association study for general cognitive function in 300,486 individuals and identify genetic loci that implicate neural and cell developmental pathways in this trait.
TDP-43 gains function due to perturbed autoregulation in a Tardbp knock-in mouse model of ALS-FTD
Amyotrophic lateral sclerosis–frontotemporal dementia (ALS-FTD) constitutes a devastating disease spectrum characterized by 43-kDa TAR DNA-binding protein (TDP-43) pathology. Understanding how TDP-43 contributes to neurodegeneration will help direct therapeutic efforts. Here we have created a TDP-43 knock-in mouse with a human-equivalent mutation in the endogenous mouse Tardbp gene. TDP-43Q331K mice demonstrate cognitive dysfunction and a paucity of parvalbumin interneurons. Critically, TDP-43 autoregulation is perturbed, leading to a gain of TDP-43 function and altered splicing of Mapt, another pivotal dementia-associated gene. Furthermore, a new approach to stratify transcriptomic data by phenotype in differentially affected mutant mice revealed 471 changes linked with improved behavior. These changes included downregulation of two known modifiers of neurodegeneration, Atxn2 and Arid4a, and upregulation of myelination and translation genes. With one base change in murine Tardbp, this study identifies TDP-43 misregulation as a pathogenic mechanism that may underpin ALS-FTD and exploits phenotypic heterogeneity to yield candidate suppressors of neurodegenerative disease.
Associations between prepulse inhibition and executive visual attention in children with the 22q11 deletion syndrome
The 22q11 deletion syndrome (DS) results in the loss of approximately 30 gene copies and is associated with possible physical anomalies, varied learning disabilities, and a specific cluster of neurocognitive deficits, including primary impairment in working memory, executive visual attention, and sensorimotor processing. Retrospective studies have suggested that children with 22q11DS are at 25 times greater risk of developing schizophrenia, thus specification of early brain network vulnerabilities among children with 22q11DS is critical. Previously, we reported that children with 22q11DS as compared with sibling controls had selective deficits in visual executive attention, and subsequently found lowered prepulse inhibition (PPI) in these same children. Visual executive attention and PPI recruit the same brain pathways linking prefrontal cortex to basal ganglia structures. To test the specificity of brain pathway vulnerability among children with 22q11DS, we examined visual executive attention and PPI paradigm data collected during the same test session from 21 children with 22q11DS and 25 sibling controls. We predicted lower %PPI and less efficient executive attention scores, and a significant inverse correlation between measures. %PPI in children with 22q11DS as compared with sibling controls was 20% lower, and visual executive attention efficiency scores 40% worse. As predicted, %PPI was inversely correlated only with executive attention efficiency scores. The implications of these findings with regard to brain pathway vulnerability in children with 22q11DS are considered. These results suggest that children with 22q11DS have early functional abnormality in pathways linking the prefrontal cortex and basal ganglia.
Synaptic scaffold evolution generated components of vertebrate cognitive complexity
In this paper, the authors show that mice lacking Dlg genes each show distinct deficits in various learning paradigms. In addition, they find that humans with DLG2 mutations show similar cognitive deficits to their murine counterparts, suggesting an evolutionary conservation of function. The origins and evolution of higher cognitive functions, including complex forms of learning, attention and executive functions, are unknown. A potential mechanism driving the evolution of vertebrate cognition early in the vertebrate lineage (550 million years ago) was genome duplication and subsequent diversification of postsynaptic genes. Here we report, to our knowledge, the first genetic analysis of a vertebrate gene family in cognitive functions measured using computerized touchscreens. Comparison of mice carrying mutations in each of the four Dlg paralogs showed that simple associative learning required Dlg4 , whereas Dlg2 and Dlg3 diversified to have opposing functions in complex cognitive processes. Exploiting the translational utility of touchscreens in humans and mice, testing Dlg2 mutations in both species showed that Dlg2 's role in complex learning, cognitive flexibility and attention has been highly conserved over 100 million years. Dlg -family mutations underlie psychiatric disorders, suggesting that genome evolution expanded the complexity of vertebrate cognition at the cost of susceptibility to mental illness.
Perceptual discrimination of complex objects: Apolipoprotein E e4 gene‐dose effects in mid‐life
INTRODUCTION Complex perceptual discrimination is supported by tau‐vulnerable regions of the medial temporal lobe (MTL); notably the perirhinal cortex. This research tests whether there is a gene‐dose effect of apolipoprotein E (APOE) e4 on perceptual discrimination in mid‐life. METHODS Three hundred and thirteen adults (45–65 years; grouped by APOE e4 gene‐dose (142 APOE33, 135 APOE34, 36 APOE44)) completed a Greebles “odd‐one‐out” task. RESULTS APOE44 carriers were significantly less accurate in their perceptual judgments than APOE33 and APOE34 individuals. There was a significant Age x APOE e4 gene‐dose interaction in response speed, with the slope of age‐related slowing increasing stepwise with the number of e4 alleles carried. Estimates suggest high‐risk individuals are quicker than the APOE33 control group until age 54, but slower thereafter. DISCUSSION Perceptual disadvantages specific to APOE44 individuals suggest this high‐risk group show compromised MTL function by mid‐life, potentially through accelerated tau‐aggregation. Task performance in APOE34 carriers is relatively preserved in mid‐life. Highlights APOE44 carriers show impaired perceptual discrimination in mid‐age. APOE34 carriers show preserved perceptual discrimination in mid‐age. Age‐related slowing of perceptual judgments increases with APOE e4 gene‐dose. Perceptual discrimination tasks may be a valuable early marker of AD risk.
Dysbindin-1 modulates prefrontal cortical activity and schizophrenia-like behaviors via dopamine/D2 pathways
Dysbindin-1 regulates D2-receptor trafficking and is implicated in schizophrenia and related cognitive abnormalities, but whether this molecular effect mediates the clinical manifestations of the disorder is unknown. We explored in dysbindin-1-deficient mice (dys−/−) (1) schizophrenia-related behaviors, (2) molecular and electrophysiological changes in medial prefrontal cortex (mPFC) and (3) the dependence of these on D2-receptor stimulation. Dysbindin-1 disruption altered dopamine-related behaviors and impaired working memory under challenging/stressful conditions. Dys−/− pyramidal neurons in mPFC layers II/III were hyperexcitable at baseline but hypoexcitable following D2 stimulation. Dys−/− were also respectively more and less sensitive to D2 agonist- and antagonist-induced behavioral effects. Dys−/− had reduced expression of Ca 2+ /calmodulin-dependent protein kinase II (CaMKII) and CaMKKβ in mPFC. Chronic D2 agonist treatment reproduced these changes in protein expression, and some of the dys−/− behavioral effects. These results elucidate dysbindin's modulation of D2-related behavior, cortical activity and mPFC CaMK components, implicating cellular and molecular mechanisms of the association of dysbindin with psychosis.
Amygdala NRG1–ErbB4 Is Critical for the Modulation of Anxiety-Like Behaviors
Anxiety disorder is related to the pathophysiology of psychiatric diseases, including major depression, substance abuse, and schizophrenia. The amygdala is important for manifestation and modulation of anxiety. However, relatively little is known regarding the mechanisms that control the amygdala inhibitory activity that is involved in anxiety. We found that almost all ErbB4, which is the only autonomous receptor of neuregulin 1 (NRG1) in the basolateral amygdala (BLA), was expressed in GABAergic neurons. Endogenous NRG1-ErbB4 signaling pathway in the BLA could modulate anxiety-like behaviors and GABA release, whereas it had no effect on glutamatergic transmission. The administration of NRG1 into the BLA of high-anxiety mice alleviated their anxiety and enhanced GABAergic neurotransmission. Moreover, exogenous NRG1 also produced an anxiolytic effect in the stressed mice. Together, these observations indicated that NRG1-ErbB4 signaling is critical to maintaining GABAergic activity in the amygdala and thus to modulating anxiety-like behaviors. Because NRG1 and ErbB4 are susceptibility genes of schizophrenia, our findings might also help to explain the potential mechanism of emotional abnormality in schizophrenia.
FoxP influences the speed and accuracy of a perceptual decision in Drosophila
Decisions take time if information gradually accumulates to a response threshold, but the neural mechanisms of integration and thresholding are unknown. We characterized a decision process in Drosophila that bears the behavioral signature of evidence accumulation. As stimulus contrast in trained odor discriminations decreased, reaction times increased and perceptual accuracy declined, in quantitative agreement with a drift-diffusion model. FoxP mutants took longer than wild-type flies to form decisions of similar or reduced accuracy, especially in difficult, low-contrast tasks. RNA interference with FoxP expression in αβ core Kenyon cells, or the overexpression of a potassium conductance in these neurons, recapitulated the FoxP mutant phenotype. A mushroom body subdomain whose development or function require the transcription factor FoxP thus supports the progression of a decision toward commitment.
Zinc alleviates pain through high-affinity binding to the NMDA receptor NR2A subunit
The authors use transgenic mice to show that zinc modulates NMDA receptors containing the NR2A subunit, and that this interaction influences pain control in vivo . Zinc is abundant in the central nervous system and regulates pain, but the underlying mechanisms are unknown. In vitro studies have shown that extracellular zinc modulates a plethora of signaling membrane proteins, including NMDA receptors containing the NR2A subunit, which display exquisite zinc sensitivity. We created NR2A-H128S knock-in mice to investigate whether Zn 2+ –NR2A interaction influences pain control. In these mice, high-affinity (nanomolar) zinc inhibition of NMDA currents was lost in the hippocampus and spinal cord. Knock-in mice showed hypersensitivity to radiant heat and capsaicin, and developed enhanced allodynia in inflammatory and neuropathic pain models. Furthermore, zinc-induced analgesia was completely abolished under both acute and chronic pain conditions. Our data establish that zinc is an endogenous modulator of excitatory neurotransmission in vivo and identify a new mechanism in pain processing that relies on NR2A NMDA receptors. The study also potentially provides a molecular basis for the pain-relieving effects of dietary zinc supplementation.