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Brain and Behavior Nov 2023Humans use discriminative touch to perceive texture through dynamic interactions with surfaces, activating low-threshold mechanoreceptors in the skin. It was largely... (Meta-Analysis)
Meta-Analysis
INTRODUCTION
Humans use discriminative touch to perceive texture through dynamic interactions with surfaces, activating low-threshold mechanoreceptors in the skin. It was largely assumed that texture was processed in primary somatosensory regions in the brain; however, imaging studies indicate heterogeneous patterns of brain activity associated with texture processing.
METHODS
To address this, we conducted a coordinate-based activation likelihood estimation meta-analysis of 13 functional magnetic resonance imaging studies (comprising 15 experiments contributing 228 participants and 275 foci) selected by a systematic review.
RESULTS
Concordant activations for texture perception occurred in the left primary somatosensory and motor regions, with bilateral activations in the secondary somatosensory, posterior insula, and premotor and supplementary motor cortices. We also evaluated differences between studies that compared touch processing to non-haptic control (e.g., rest or visual control) or those that used haptic control (e.g., shape or orientation perception) to specifically investigate texture encoding. Studies employing a haptic control revealed concordance for texture processing only in the left secondary somatosensory cortex. Contrast analyses demonstrated greater concordance of activations in the left primary somatosensory regions and inferior parietal cortex for studies with a non-haptic control, compared to experiments accounting for other haptic aspects.
CONCLUSION
These findings suggest that texture processing may recruit higher order integrative structures, and the secondary somatosensory cortex may play a key role in encoding textural properties. The present study provides unique insight into the neural correlates of texture-related processing by assessing the influence of non-textural haptic elements and identifies opportunities for a future research design to understand the neural processing of texture.
Topics: Humans; Brain Mapping; Likelihood Functions; Magnetic Resonance Imaging; Touch Perception
PubMed: 37749852
DOI: 10.1002/brb3.3264 -
Frontiers in Human Neuroscience 2023Motor evoked potentials (MEP) elicited by transcranial magnetic stimulation (TMS) over the primary motor cortex are used as a neurophysiological marker of cortical...
AIMS
Motor evoked potentials (MEP) elicited by transcranial magnetic stimulation (TMS) over the primary motor cortex are used as a neurophysiological marker of cortical excitability in clinical and scientific practice. Though, the reliability of this outcome parameter has not been clarified. Using a systematic approach, this work reviews and critically appraises studies on the reliability of MEP outcome parameters derived from hand muscles of healthy subjects and gives a proposal for most reliable TMS practice.
METHODS
A systematic literature research was performed in PubMed, according to the PRISMA guidelines. Articles published up to March 2023 that were written in English, conducted repeated measurements from hand muscles of healthy subjects and reliability analysis were included. The risk of publication bias was determined. Two authors conducted the literature search and rated the articles in terms of eligibility and methodological criteria with standardized instruments. Frequencies of the checklist criteria were calculated and inter-rater reliability of the rating procedure was determined. Reliability and stimulation parameters were extracted and summarized in a structured way to conclude best-practice recommendation for reliable measurements.
RESULTS
A total of 28 articles were included in the systematic review. Critical appraisal of the studies revealed methodological heterogeneity and partly contradictory results regarding the reliability of outcome parameters. Inter-rater reliability of the rating procedure was almost perfect nor was there indication of publication bias. Identified studies were grouped based on the parameter investigated: number of applied stimuli, stimulation intensity, reliability of input-output curve parameters, target muscle or hemisphere, inter-trial interval, coil type or navigation and waveform.
CONCLUSION
The methodology of studies on TMS is still subject to heterogeneity, which could contribute to the partly contradictory results. According to the current knowledge, reliability of the outcome parameters can be increased by adjusting the experimental setup. Reliability of single pulse MEP measurement could be optimized by using (1) at least five stimuli per session, (2) a minimum of 110% resting motor threshold as stimulation intensity, (3) a minimum of 4 s inter-trial interval and increasing the interval up to 20 s, (4) a figure-of-eight coil and (5) a monophasic waveform. MEPs can be reliably operationalized.
PubMed: 37719769
DOI: 10.3389/fnhum.2023.1237712 -
Journal of Alzheimer's Disease Reports 2023Cognitive impairment (CI) is an important extrapulmonary complication in patients with chronic obstructive pulmonary disease (COPD). Multimodal Neuroimaging Examination...
BACKGROUND
Cognitive impairment (CI) is an important extrapulmonary complication in patients with chronic obstructive pulmonary disease (COPD). Multimodal Neuroimaging Examination can display changes in brain structure and functions in patients with COPD.
OBJECTIVE
The purpose of this systematic review is to provide an overview of the variations in brain imaging in patients with COPD and their potential relationship with CI. Furthermore, we aim to provide new ideas and directions for future research.
METHODS
Literature searches were performed using the electronic databases PubMed, Scopus, and ScienceDirect. All articles published between January 2000 and November 2021 that met the eligibility criteria were included.
RESULTS
Twenty of the 23 studies focused on changes in brain structure and function. Alterations in the brain's macrostructure are manifested in the bilateral frontal lobe, hippocampus, right temporal lobe, motor cortex, and supplementary motor area. The white matter microstructural changes initially appear in the bilateral frontal subcortical region. Regarding brain function, patients with COPD exhibited reduced frontal cerebral perfusion and abnormal alterations in intrinsic brain activity in the bilateral posterior cingulate cortex, precuneus, right lingual gyrus, and left anterior central gyrus. Currently, there is limited research related to brain networks.
CONCLUSION
CI in patients with COPD may present as a type of dementia different from Alzheimer's disease, which tends to manifest as frontal cognitive decline early in the disease. Further studies are required to clarify the neurobiological pathways of CI in patients with COPD from the perspective of brain connectomics based on the whole-brain system in the future.
PubMed: 37662615
DOI: 10.3233/ADR-220083 -
Clinical Neurophysiology : Official... Oct 2023Cortico-cortical paired associative stimulation (ccPAS) is a form of dual-site transcranial magnetic stimulation (TMS) entailing a series of single-TMS pulses paired at...
OBJECTIVE
Cortico-cortical paired associative stimulation (ccPAS) is a form of dual-site transcranial magnetic stimulation (TMS) entailing a series of single-TMS pulses paired at specific interstimulus intervals (ISI) delivered to distant cortical areas. The goal of this article is to systematically review its efficacy in inducing plasticity in humans focusing on stimulation parameters and hypotheses of underlying neurophysiology.
METHODS
A systematic review of the literature from 2009-2023 was undertaken to identify all articles utilizing ccPAS to study brain plasticity and connectivity. Six electronic databases were searched and included.
RESULTS
32 studies were identified. The studies targeted connections within the same hemisphere or between hemispheres. 28 ccPAS studies were in healthy participants, 1 study in schizophrenia, and 1 in Alzheimer's disease (AD) patients. 2 additional studies used cortico-cortical repetitive paired associative stimulation (cc-rPAS) in generalized anxiety disorder (GAD) patients. Outcome measures include electromyography (EMG), behavioral measures, electroencephalography (EEG), and functional magnetic resonance imaging (fMRI). ccPAS seems to be able to modulate brain connectivity depending on the ISI.
CONCLUSIONS
ccPAS can be used to modulate corticospinal excitability, brain activity, and behavior. Although the stimulation parameters used across studies reviewed in this paper are varied, ccPAS is a promising approach for basic research and potential clinical applications.
SIGNIFICANCE
Recent advances in neuroscience have caused a shift of interest from the study of single areas to a more complex approach focusing on networks of areas that orchestrate brain activity. Consequently, the TMS community is also witnessing a change, with a growing interest in targeting multiple brain areas rather than a single locus, as evidenced by an increasing number of papers using ccPAS. In light of this new enthusiasm for brain connectivity, this review summarizes existing literature and stimulation parameters that have proven effective in changing electrophysiological, behavioral, or neuroimaging-derived measures.
Topics: Humans; Motor Cortex; Evoked Potentials, Motor; Transcranial Magnetic Stimulation; Brain; Neuronal Plasticity
PubMed: 37634335
DOI: 10.1016/j.clinph.2023.06.016 -
Journal of Perinatal Medicine Nov 2023Dexamethasone administration can reduce bronchopulmonary dysplasia, our objective was to identify long term adverse effects. (Review)
Review
BACKGROUND
Dexamethasone administration can reduce bronchopulmonary dysplasia, our objective was to identify long term adverse effects.
CONTENT
A systematic review was performed to determine the childhood and adolescent cardiopulmonary and cognitive effects of dexamethasone systemically administered to preterm infants during neonatal intensive care. Relevant studies were identified by searching two electronic health databases and the grey literature. Spirometry assessments were used as respiratory outcomes, blood pressure and echocardiography assessments as cardiovascular outcomes and cognitive and motor function as cognitive outcomes. From 1,479 articles initially identified, 18 studies (overall 1,609 patients) were included (respiratory n=8, cardiovascular n=2, cognitive n=10); all were observational cohort studies. Dexamethasone exposure was associated with worse pulmonary outcomes in children and adolescents (more abnormal FVC and FEV1:FVC z scores). Dexamethasone exposure was associated in one study with lower IQ scores compared to preterm controls (mean 78.2 [SD 15.0] vs. 84.4 [12.6], [p=0.008]) and in two others was associated with lower total and performance IQ when compared to term controls (p<0.001).
SUMMARY AND OUTLOOK
Postnatal dexamethasone exposure has a negative influence on pulmonary and cognitive outcomes in childhood and adolescence. Medications with a better benefit to risk profile need to be identified.
Topics: Adolescent; Child; Humans; Infant; Infant, Newborn; Adrenal Cortex Hormones; Anti-Inflammatory Agents; Bronchopulmonary Dysplasia; Chronic Disease; Dexamethasone; Glucocorticoids; Infant, Premature
PubMed: 37606507
DOI: 10.1515/jpm-2023-0297 -
Life (Basel, Switzerland) Jul 2023Although in 2017 a repetitive transcranial magnetic stimulation (rTMS) protocol received Food and Drug Administration approval for the first time for the treatment of... (Review)
Review
Will Transcranial Magnetic Stimulation Improve the Treatment of Obsessive-Compulsive Disorder? A Systematic Review and Meta-Analysis of Current Targets and Clinical Evidence.
BACKGROUND
Although in 2017 a repetitive transcranial magnetic stimulation (rTMS) protocol received Food and Drug Administration approval for the first time for the treatment of obsessive-compulsive disorder (OCD), which neural target and which protocol should be used for OCD are still debated. The aim of the present study was to perform a systematic review and meta-analysis of the available open and sham-controlled trials.
METHODS
The primary analysis included a pairwise meta-analysis (over 31 trials), and then subgroup analyses were performed for each targeted brain area. Meta-regression analyses explored the possible moderators of effect size.
RESULTS
The pairwise meta-analysis showed a significant reduction in OCD symptoms following active rTMS (g = -0.45 [95%CI: -0.62, -0.29]) with moderate heterogeneity (I = 34.9%). Subgroup analyses showed a significant effect of rTMS over the bilateral pre-SMA (supplementary motor area), the DLPFC (dorsolateral prefrontal cortex), the ACC/mPFC (anterior cingulate cortex and medial prefrontal cortex), and the OFC (orbitofrontal cortex). No moderators of the effect size emerged.
CONCLUSIONS
TMS of several brain targets represents a safe and effective treatment option for OCD patients. Further studies are needed to help clinicians to individualize TMS protocols and targets for each patient.
PubMed: 37511869
DOI: 10.3390/life13071494 -
Neuroscience and Biobehavioral Reviews Sep 2023Neural adaptations to resistance training (RT) and their correlation with muscle strength remain partially understood. We conducted a systematic review and multivariate... (Meta-Analysis)
Meta-Analysis Review
Neural adaptations to resistance training (RT) and their correlation with muscle strength remain partially understood. We conducted a systematic review and multivariate meta-analysis to examine the effects of metronome-paced (MP), self-paced (SP), and isometric (IM) training on M1 and corticospinal pathway activity. Following MP RT, a significant increase in corticospinal excitability was observed, correlating with increased strength. Conversely, no significant relationship was found after SP or IM training. RT also reduced the duration of the cortical silent period, but this change did not predict strength changes and was not specific to any training modality. No significant effects were found for short-interval intracortical inhibition. Our findings suggest that changes in corticospinal excitability may contribute to strength gains after RT. Furthermore, the relationship between these adaptations and strength appears dependent on the type of training performed.
Topics: Humans; Resistance Training; Pyramidal Tracts; Transcranial Magnetic Stimulation; Motor Cortex; Muscle Strength; Evoked Potentials, Motor; Muscle, Skeletal
PubMed: 37353049
DOI: 10.1016/j.neubiorev.2023.105289 -
Frontiers in Neuroscience 2023Transcranial magnetic stimulation (TMS) is widely used to investigate central nervous system mechanisms underlying motor control. Despite thousands of TMS studies on... (Review)
Review
INTRODUCTION
Transcranial magnetic stimulation (TMS) is widely used to investigate central nervous system mechanisms underlying motor control. Despite thousands of TMS studies on neurophysiological underpinnings of corticomotor control, a large majority of studies have focused on distal muscles, and little is known about axial muscles (e.g., low back muscles). Yet, differences between corticomotor control of low back and distal muscles (e.g., gross vs. fine motor control) suggest differences in the neural circuits involved. This systematic review of the literature aims at detailing the organisation and neural circuitry underlying corticomotor control of low back muscles tested with TMS in healthy humans.
METHODS
The literature search was performed in four databases (CINAHL, Embase, Medline (Ovid) and Web of science) up to May 2022. Included studies had to use TMS in combination with EMG recording of paraspinal muscles (between T12 and L5) in healthy participants. Weighted average was used to synthesise quantitative study results.
RESULTS
Forty-four articles met the selection criteria. TMS studies of low back muscles provided consistent evidence of contralateral and ipsilateral motor evoked potentials (with longer ipsilateral latencies) as well as of short intracortical inhibition/facilitation. However, few or no studies using other paired pulse protocols were found (e.g., long intracortical inhibition, interhemispheric inhibition). In addition, no study explored the interaction between different cortical areas using dual TMS coil protocol (e.g., between primary motor cortex and supplementary motor area).
DISCUSSION
Corticomotor control of low back muscles are distinct from hand muscles. Our main findings suggest: (i) bilateral projections from each single primary motor cortex, for which contralateral and ipsilateral tracts are probably of different nature (contra: monosynaptic; ipsi: oligo/polysynaptic) and (ii) the presence of intracortical inhibitory and excitatory circuits in M1 influencing the excitability of the contralateral corticospinal cells projecting to low back muscles. Understanding of these mechanisms are important for improving the understanding of neuromuscular function of low back muscles and to improve the management of clinical populations (e.g., low back pain, stroke).
PubMed: 37304019
DOI: 10.3389/fnins.2023.1180816 -
Brain and Behavior Jun 2023Primary generalized dystonia due to the DYT1 gene is an autosomal dominant disorder caused by a GAG deletion on chromosome 9q34. It is a well-defined, genetically... (Review)
Review
BACKGROUND
Primary generalized dystonia due to the DYT1 gene is an autosomal dominant disorder caused by a GAG deletion on chromosome 9q34. It is a well-defined, genetically proven, isolated dystonia syndrome. However, its pathophysiology remains unclear.
OBJECTIVES
This study was aimed at profiling the functional neuroimaging findings in DYT1 dystonia and harmonizing the pathophysiological implications for DYT1 dystonia from the standpoint of different neuroimaging techniques.
METHODS
A systematic review was conducted using identified studies published in English from Medline, PsycINFO, Embase, CINAHL, and the Cochrane Database of Systematic Reviews (CDSR), between 1985 and December 2019 (PROSPERO protocol CRD42018111211).
RESULTS
All DYT1 gene carriers irrespective of clinical penetrance have reduced striatal GABA, dopamine receptors and increased metabolic activity in the lentiform nucleus, supplementary motor area, and cerebellum in addition to an abnormal cerebellothalamocortical pathway. Nonmanifesting carriers on the other hand have a disruption of the distal (thalamocortical) segment and have larger putaminal volumes than manifesting carriers and healthy controls. Activation of the midbrain, thalamus, and sensorimotor cortex was only found in the manifesting carriers.
CONCLUSIONS
Therefore, we propose that DYT1 dystonia is a cerebellostriatothalamocortical network disorder affecting either the structure or function of the different structures or nodes in the network.
Topics: Humans; Dystonia; Dystonic Disorders; Molecular Chaperones; Neuroimaging
PubMed: 37165749
DOI: 10.1002/brb3.3023 -
Asian Journal of Surgery Jan 2024The comparative effect of commonly used conservative treatments for carpal tunnel syndrome remained controversial. The purpose of this study was to compare the clinical... (Comparative Study)
Comparative Study Meta-Analysis Review
The comparative effect of commonly used conservative treatments for carpal tunnel syndrome remained controversial. The purpose of this study was to compare the clinical effect of local corticosteroid injection and physical therapy for the treatment of carpal tunnel syndrome. A systematic literature search of PubMed, EMBASE, and Cochrane library was conducted to identify relevant randomized clinical trials published before 21st Mar 2023. Two independent reviewers assayed quality of included studies using the Cochrane collaboration risk of bias tool. Relevant data were extracted and pooled analyses were conducted. Outcome measurements included Boston Carpal Tunnel Syndrome Questionnaire, visual analogue scale and some electrophysiology tests, while the former two were set as the primary outcomes. Subgroup analysis and sensitive analysis were performed and publication bias was evaluated. Heterogeneity among the included studies was examined using the I statistic. After selection, 12 studies were identified eligibility for inclusion. Only one study was found to have a high risk of bias. Pooled data of primary outcomes did not show any differences between treatments, and subgroup analysis supported the results. However, patients treated with local corticosteroid injection showed better improvement in distal motor latency (p = 0.002) and compound muscle action potential (p = 0.04). Some studies failed to pass the sensitive analysis, indicating the related analysis might be not so stable. A slight publication bias was observed in subgroup analysis of function scales, among three publication bias test. In conclusion, compared to physical therapy, local corticosteroid injection might have better treatment effects on carpal tunnel syndrome.
Topics: Humans; Adrenal Cortex Hormones; Carpal Tunnel Syndrome; Conservative Treatment; Physical Therapy Modalities; Randomized Controlled Trials as Topic; Treatment Outcome
PubMed: 37147265
DOI: 10.1016/j.asjsur.2023.04.104