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2,286
result(s) for
"Prefrontal Cortex - pathology"
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Impairment of Neuroplasticity in the Dorsolateral Prefrontal Cortex by Alcohol
by
Le Foll, Bernard
,
Zomorrodi, Reza
,
Loheswaran, Genane
in
631/378/2591/2592
,
631/443/376
,
Adult
2017
Previous studies have demonstrated that alcohol consumption impairs neuroplasticity in the motor cortex. However, it is unknown whether alcohol produces a similar impairment of neuroplasticity in the dorsolateral prefrontal cortex (DLPFC), a brain region that plays an important role in cognitive functioning. The aim of the current study was to evaluate the effect of alcohol intoxication on neuroplasticity in the DLPFC. Paired associative stimulation (PAS) combined with electroencephalography (EEG) was used for the induction and measurement of associative LTP-like neuroplasticity in the DLPFC. Fifteen healthy subjects were administered PAS to the DLPFC following consumption of an alcohol (1.5 g/l of body water) or placebo beverage in a within-subject cross-over design. PAS induced neuroplasticity was indexed up to 60 minutes following PAS. Additionally, the effect of alcohol on PAS-induced potentiation of theta-gamma coupling (an index associated with learning and memory) was examined prior to and following PAS. Alcohol consumption resulted in a significant impairment of mean (t = 2.456, df = 13, p = 0.029) and maximum potentiation (t = −2.945, df = 13, p = 0.011) compared to the placebo beverage in the DLPFC and globally. Alcohol also suppressed the potentiation of theta-gamma coupling by PAS. Findings from the present study provide a potential neurophysiological mechanism for impairment of cognitive functioning by alcohol.
Journal Article
Neurofunctional correlates of attention rehabilitation in Parkinson’s disease: an explorative study
by
Chiriaco, Carmelina
,
Gioia, Maria Cecilia
,
Realmuto, Sabrina
in
Attention - physiology
,
Cognition Disorders - etiology
,
Cognition Disorders - rehabilitation
2014
The effectiveness of cognitive rehabilitation (CR) in Parkinson’s disease (PD) is in its relative infancy, and nowadays there is insufficient information to support evidence-based clinical protocols. This study is aimed at testing a validated therapeutic strategy characterized by intensive computer-based attention-training program tailored to attention deficits. We further investigated the presence of synaptic plasticity by means of functional magnetic resonance imaging (fMRI). Using a randomized controlled study, we enrolled eight PD patients who underwent a CR program (Experimental group) and seven clinically/demographically-matched PD patients who underwent a placebo intervention (Control group). Brain activity was assessed using an 8-min resting state (RS) fMRI acquisition. Independent component analysis and statistical parametric mapping were used to assess the effect of CR on brain function. Significant effects were detected both at a phenotypic and at an intermediate phenotypic level. After CR, the Experimental group, in comparison with the Control group, showed a specific enhanced performance in cognitive performance as assessed by the SDMT and digit span forward. RS fMRI analysis for all networks revealed two significant groups (Experimental vs Control) × time (T0 vs T1) interaction effects on the analysis of the attention (superior parietal cortex) and central executive neural networks (dorsolateral prefrontal cortex). We demonstrated that intensive CR tailored for the impaired abilities impacts neural plasticity and improves some aspects of cognitive deficits of PD patients. The reported neurophysiological and behavioural effects corroborate the benefits of our therapeutic approach, which might have a reliable application in clinical management of cognitive deficits.
Journal Article
Differential effects of DRD4 and DAT1 genotype on fronto-striatal gray matter volumes in a sample of subjects with attention deficit hyperactivity disorder, their unaffected siblings, and controls
by
Steenhuis, M P
,
Durston, S
,
Kahn, R S
in
Adolescent
,
Analysis of Variance
,
Attention Deficit Disorder with Hyperactivity - genetics
2005
Genetic influences on behavior are complex and, as such, the effect of any single gene is likely to be modest. Neuroimaging measures may serve as a biological intermediate phenotype to investigate the effect of genes on human behavior. In particular, it is possible to constrain investigations by prior knowledge of gene characteristics and by including samples of subjects where the distribution of phenotypic variance is both wide and under heritable influences. Here, we use this approach to show a dissociation between the effects of two dopamine genes that are differentially expressed in the brain. We show that the
DAT1
gene, a gene expressed predominantly in the basal ganglia, preferentially influences caudate volume, whereas the
DRD4
gene, a gene expressed predominantly in the prefrontal cortex, preferentially influences prefrontal gray matter volume in a sample of subjects including subjects with ADHD, their unaffected siblings, and healthy controls. This demonstrates that, by constraining our investigations by prior knowledge of gene expression, including samples in which the distribution of phenotypic variance is wide and under heritable influences, and by using intermediate phenotypes, such as neuroimaging, we may begin to map out the pathways by which genes influence behavior.
Journal Article
Does rTMS Alter Neurocognitive Functioning in Patients with Panic Disorder/Agoraphobia? An fNIRS-Based Investigation of Prefrontal Activation during a Cognitive Task and Its Modulation via Sham-Controlled rTMS
2014
Objectives. Neurobiologically, panic disorder (PD) is supposed to be characterised by cerebral hypofrontality. Via functional near-infrared spectroscopy (fNIRS), we investigated whether prefrontal hypoactivity during cognitive tasks in PD-patients compared to healthy controls (HC) could be replicated. As intermittent theta burst stimulation (iTBS) modulates cortical activity, we furthermore investigated its ability to normalise prefrontal activation. Methods. Forty-four PD-patients, randomised to sham or verum group, received 15 iTBS-sessions above the left dorsolateral prefrontal cortex (DLPFC) in addition to psychoeducation. Before first and after last iTBS-treatment, cortical activity during a verbal fluency task was assessed via fNIRS and compared to the results of 23 HC. Results. At baseline, PD-patients showed hypofrontality including the DLPFC, which differed significantly from activation patterns of HC. However, verum iTBS did not augment prefrontal fNIRS activation. Solely after sham iTBS, a significant increase of measured fNIRS activation in the left inferior frontal gyrus (IFG) during the phonological task was found. Conclusion. Our results support findings that PD is characterised by prefrontal hypoactivation during cognitive performance. However, verum iTBS as an “add-on” to psychoeducation did not augment prefrontal activity. Instead we only found increased fNIRS activation in the left IFG after sham iTBS application. Possible reasons including task-related psychophysiological arousal are discussed.
Journal Article
Symptom provocation and reduction in patients suffering from spider phobia
2007
Neurofunctional mechanisms underlying cognitive behavior therapy (CBT) are still not clearly understood. This functional magnetic resonance imaging (fMRI) study focused on changes in brain activation as a result of one-session CBT in patients suffering from spider phobia. Twenty-six female spider phobics and 25 non-phobic subjects were presented with spider pictures, generally disgust-inducing, generally fear-inducing and affectively neutral scenes in an initial fMRI session. Afterwards, the patients were randomly assigned to either a therapy group (TG) or a waiting list group (WG). The scans were repeated one week after the treatment or after a one-week waiting period. Relative to the non-phobic participants, the patients displayed increased activation in the amygdala and the fusiform gyrus as well as decreased activation in the medial orbitofrontal cortex (OFC) during the first exposure. The therapy effect consisted of increased medial OFC activity in the TG relative to the WG. Further, therapy-related reductions in experienced somatic anxiety symptoms were positively correlated with activation decreases in the amygdala and the insula. We conclude that successful treatment of spider phobia is primarily accompanied by functional changes of the medial OFC. This brain region is crucial for the self-regulation of emotions and the relearning of stimulus-reinforcement associations.
Journal Article
Single-cell transcriptomic analysis of Alzheimer’s disease
2019
Alzheimer’s disease is a pervasive neurodegenerative disorder, the molecular complexity of which remains poorly understood. Here, we analysed 80,660 single-nucleus transcriptomes from the prefrontal cortex of 48 individuals with varying degrees of Alzheimer’s disease pathology. Across six major brain cell types, we identified transcriptionally distinct subpopulations, including those associated with pathology and characterized by regulators of myelination, inflammation, and neuron survival. The strongest disease-associated changes appeared early in pathological progression and were highly cell-type specific, whereas genes upregulated at late stages were common across cell types and primarily involved in the global stress response. Notably, we found that female cells were overrepresented in disease-associated subpopulations, and that transcriptional responses were substantially different between sexes in several cell types, including oligodendrocytes. Overall, myelination-related processes were recurrently perturbed in multiple cell types, suggesting that myelination has a key role in Alzheimer’s disease pathophysiology. Our single-cell transcriptomic resource provides a blueprint for interrogating the molecular and cellular basis of Alzheimer’s disease.
Single-cell transcriptomics from 48 individuals with varying degrees of Alzheimer’s disease pathology demonstrates that gene-expression changes in Alzheimer’s disease are both cell-type specific and shared, and that transcriptional responses show sexual dimorphism.
Journal Article
Cellular communities reveal trajectories of brain ageing and Alzheimer’s disease
2024
Alzheimer’s disease (AD) has recently been associated with diverse cell states
1
–
11
, yet when and how these states affect the onset of AD remains unclear. Here we used a data-driven approach to reconstruct the dynamics of the brain’s cellular environment and identified a trajectory leading to AD that is distinct from other ageing-related effects. First, we built a comprehensive cell atlas of the aged prefrontal cortex from 1.65 million single-nucleus RNA-sequencing profiles sampled from 437 older individuals, and identified specific glial and neuronal subpopulations associated with AD-related traits. Causal modelling then prioritized two distinct lipid-associated microglial subpopulations—one drives amyloid-β proteinopathy while the other mediates the effect of amyloid-β on tau proteinopathy—as well as an astrocyte subpopulation that mediates the effect of tau on cognitive decline. To model the dynamics of cellular environments, we devised the BEYOND methodology, which identified two distinct trajectories of brain ageing, each defined by coordinated progressive changes in certain cellular communities that lead to (1) AD dementia or (2) alternative brain ageing. Thus, we provide a cellular foundation for a new perspective on AD pathophysiology that informs personalized therapeutic development, targeting different cellular communities for individuals on the path to AD or to alternative brain ageing.
A comprehensive cell atlas of the aged prefrontal cortex identifies two distinct cellular trajectories of ageing driven by specific glial and neuronal subpopulations, some of which are associated with clinicopathologic traits that define Alzheimer’s disease.
Journal Article
Vascular and blood-brain barrier-related changes underlie stress responses and resilience in female mice and depression in human tissue
2022
Prevalence, symptoms, and treatment of depression suggest that major depressive disorders (MDD) present sex differences. Social stress-induced neurovascular pathology is associated with depressive symptoms in male mice; however, this association is unclear in females. Here, we report that chronic social and subchronic variable stress promotes blood-brain barrier (BBB) alterations in mood-related brain regions of female mice. Targeted disruption of the BBB in the female prefrontal cortex (PFC) induces anxiety- and depression-like behaviours. By comparing the endothelium cell-specific transcriptomic profiling of the mouse male and female PFC, we identify several pathways and genes involved in maladaptive stress responses and resilience to stress. Furthermore, we confirm that the BBB in the PFC of stressed female mice is leaky. Then, we identify circulating vascular biomarkers of chronic stress, such as soluble E-selectin. Similar changes in circulating soluble E-selectin, BBB gene expression and morphology can be found in blood serum and
postmortem
brain samples from women diagnosed with MDD. Altogether, we propose that BBB dysfunction plays an important role in modulating stress responses in female mice and possibly MDD.
The vascular, cellular and molecular changes underlying sex differences in mood disorders are unclear. Here, the authors show that blood-brain barrier dysfunction modulates anxiety- and depressive-like behaviors in female mice and endothelium-specific changes associated with maladaptive responses compared to resilience to stress.
Journal Article
Sustained rescue of prefrontal circuit dysfunction by antidepressant-induced spine formation
2019
A better understanding of the mechanisms underlying the action of antidepressants is urgently needed. Moda-Sava et al. explored a possible mode of action for the drug ketamine, which has recently been shown to help patients recover from depression (see the Perspective by Beyeler). Ketamine rescued behavior in mice that was associated with depression-like phenotypes by selectively reversing stress-induced spine loss and restoring coordinated multicellular ensemble activity in prefrontal microcircuits. The initial induction of ketamine's antidepressant effect on mouse behavior occurred independently of effects on spine formation. Instead, synaptogenesis in the prefrontal region played a critical role in nourishing these effects over time. Interventions aimed at enhancing the survival of restored synapses may thus be useful for sustaining the behavioral effects of fast-acting antidepressants. Science , this issue p. eaat8078 ; see also p. 129 Spine formation in the prefrontal cortex is central to the long-term antidepressant effects of ketamine. The neurobiological mechanisms underlying the induction and remission of depressive episodes over time are not well understood. Through repeated longitudinal imaging of medial prefrontal microcircuits in the living brain, we found that prefrontal spinogenesis plays a critical role in sustaining specific antidepressant behavioral effects and maintaining long-term behavioral remission. Depression-related behavior was associated with targeted, branch-specific elimination of postsynaptic dendritic spines on prefrontal projection neurons. Antidepressant-dose ketamine reversed these effects by selectively rescuing eliminated spines and restoring coordinated activity in multicellular ensembles that predict motivated escape behavior. Prefrontal spinogenesis was required for the long-term maintenance of antidepressant effects on motivated escape behavior but not for their initial induction.
Journal Article
Altered structural brain asymmetry in autism spectrum disorder in a study of 54 datasets
by
Murphy, Declan, G
,
Donders Center for Cognitive Neuroimaging ; Donders Centre for Cognitive Neuroimaging ; Radboud University [Nijmegen]-Radboud University [Nijmegen]
,
Oregon Health and Science University [Portland] (OHSU)
in
59/57
,
631/378
,
692/699/476/1373
2019
Altered structural brain asymmetry in autism spectrum disorder (ASD) has been reported. However, findings have been inconsistent, likely due to limited sample sizes. Here we investigated 1,774 individuals with ASD and 1,809 controls, from 54 independent data sets of the ENIGMA consortium. ASD was significantly associated with alterations of cortical thickness asymmetry in mostly medial frontal, orbitofrontal, cingulate and inferior temporal areas, and also with asymmetry of orbitofrontal surface area. These differences generally involved reduced asymmetry in individuals with ASD compared to controls. Furthermore, putamen volume asymmetry was significantly increased in ASD. The largest case-control effect size was Cohen's d = −0.13, for asymmetry of superior frontal cortical thickness. Most effects did not depend on age, sex, IQ, severity or medication use. Altered lateralized neurodevelopment may therefore be a feature of ASD, affecting widespread brain regions with diverse functions. Large-scale analysis was necessary to quantify subtle alterations of brain structural asymmetry in ASD.
Journal Article