Search

Objective: This study aimed at assessing the alterations in upper limb motor impairment and connectivity between motor areas following the post-stroke delivery of cathodal transcranial direct current stimulation sessions., Methods: Modifications in the Fugl-Meyer Assessment scores, connectivity between the primary motor cortex of the unaffected and affected hemispheres, and between the primary motor and premotor cortices of the unaffected hemisphere were compared prior to and following six sessions of cathodal transcranial direct current stimulation application in 13 patients (active = 6; sham = 7); this modality targets the primary motor cortex of the unaffected hemisphere early after a stroke., Results: Clinically relevant distinctions in Fugl-Meyer Assessment scores (≥9 points) were observed more frequently in the Sham Group than in the Active Group. Between-group differences in the alterations in Fugl-Meyer Assessment scores were not statistically significant (Mann-Whitney test, p=0.133). ROI-to-ROI correlations between the primary motor cortices of the affected and unaffected hemispheres post-therapeutically increased in 5/6 and 2/7 participants in the Active and Sham Groups, respectively. Between-group differences in modifications in connectivity between the aforementioned areas were not statistically significant. Motor performance enhancements were more frequent in the Sham Group compared to the Active Group., Conclusion: The results of this hypothesis-generating investigation suggest that heightened connectivity may not translate into early clinical benefits following a stroke and will be crucial in designing larger cohort studies to explore mechanisms underlying the impacts of this intervention. ClinicalTrials.gov Identifier: NCT02455427.

Specific brain activation patterns during fear conditioning and the recall of previously extinguished fear responses have been associated with obsessive-compulsive disorder (OCD). However, further replication studies are necessary. We measured skin-conductance response and blood oxygenation level-dependent responses in unmedicated adult patients with OCD (n = 27) and healthy participants (n = 22) submitted to a two-day fear-conditioning experiment comprising fear conditioning, extinction (day 1) and extinction recall (day 2). During conditioning, groups differed regarding the skin conductance reactivity to the aversive stimulus (shock) and regarding the activation of the right opercular cortex, insular cortex, putamen, and lingual gyrus in response to conditioned stimuli. During extinction recall, patients with OCD had higher responses to stimuli and smaller differences between responses to conditioned and neutral stimuli. For the entire sample, the higher the response delta between conditioned and neutral stimuli, the greater the dACC activation for the same contrast during early extinction recall. While activation of the dACC predicted the average difference between responses to stimuli for the entire sample, groups did not differ regarding the activation of the dACC during extinction recall. Larger unmedicated samples might be necessary to replicate the previous findings reported in patients with OCD., Competing Interests: Declaration of Competing Interest Dr Diniz has received speaker's fees from Lundbeck and Janssen Cilag for lectures that were unrelated to the contents of this work. Dr. RGS has received a consultancy fee from Lundbeck Remaining authors have no conflicts of interest to declare., (Copyright © 2023 Elsevier B.V. All rights reserved.)

The study of an Ischemic stroke infarction allows verifying how the lesion produces alterations in the neuronal networks resulting in cognitive deficits. It also allows the verification of adaptive and maladaptive cerebral reorganization related to the injury. In our previous fMRI study, we found that patients without ischemic vascular lesions in left inferior frontal gyrus showed an efficient compensation mechanism during the associative encoding of face name pairs, by the increased activation of ventrolateral and dorsolateral areas of contralesional hemisphere associated with better memory performance. While patients with ischemic vascular lesions on left inferior frontal gyrus (IFG) demonstrated worse memory performance and no signs of compensation mechanism. The present study explores more of these findings by analyzing perilesional and contralesional activations related to unfamiliar face name associative encoding in adults with chronic ischemic stroke, with or without left IFG lesion, compared to healthy controls. The main results showed that stroke survivors without lesions in IFG demonstrated increased activation in perilesional and contralesional prefrontal regions associated with better associative memory recognition, which are indicative of adaptive compensatory mechanisms. However, they also showed a negative correlation between the activation of right anterior prefrontal and inferior parietal regions and the associative memory performance, which may indicate the presence of maladaptive interhemispheric disinhibition. On the other hand, stroke survivors with IFG lesions demonstrated negative correlations in activations of the ipsilesional inferior parietal cortex and positive correlations in activations of the left middle frontal gyrus and left precentral cortex, which demonstrate the simultaneous occurrence of adaptive and maladaptive brain reorganization mechanisms in this group. However, the increase in perilesional prefrontal regions, associated with bilateral activation of the hippocampus and amygdala, was not enough to compensate for the inefficiency of associative memory performance. Finally, the differences in activation observed in stroke survivors reflect their clinical heterogeneity and demonstrate that adaptive or maladaptive compensatory mechanisms can coexist in the same group of patients. Furthermore, they reinforce the importance of the left IFG in the associative encoding of unfamiliar face name pairs and may suggest a deficit in associative memory related to injury in this region., (Copyright © 2023. Published by Elsevier Ltd.)

Background: Obesity is a disease that may involve disrupted connectivity of brain networks. Bariatric surgery is an effective treatment for obesity, and the positive effects on obesity-related conditions may be enhanced by exercise. Herein, we aimed to investigate the possible synergistic effects of Roux-en-Y Gastric Bypass (RYGB) and exercise training on brain functional networks., Methods: Thirty women eligible for bariatric surgery were randomly assigned to a Roux-en-Y gastric bypass (RYGB: n = 15, age = 41.0 ± 7.3 years) or RYGB plus Exercise Training (RYGB + ET: n = 15, age = 41.9 ± 7.2 years). Clinical, laboratory, and brain functional connectivity parameters were assessed at baseline, and 3 (POST3) and 9 months (POST9) after surgery. The 6-month, three-times-a-week, exercise intervention (resistance plus aerobic exercise) was initiated 3 months post-surgery (for RYGB + ET)., Results: Exercise superimposed on bariatric surgery (RYGB + ET) increased connectivity between hypothalamus and sensorial regions (seed-to-voxel analyses of hypothalamic connectivity), and decreased default mode network (DMN) and posterior salience (pSAL) network connectivity (ROI-to-ROI analyses of brain networks connectivity) when compared to RYGB alone (all p-FDR < 0.05). Increases in basal ganglia (BG) network connectivity were only observed in the exercised training group (within-group analyses)., Conclusion: Exercise training is an important component in the management of post-bariatric patients and may improve the hypothalamic connectivity and brain functional networks that are involved in controlling food intake., Trial Registration: Clinicaltrial.gov: NCT02441361., (© 2022. The Author(s), under exclusive licence to Springer Nature Limited.)

Introduction: Considering the relevance of the emotional state, it is necessary to understand how daily stimuli can modulate the emotions. Animated short films are common stimuli, but it is unknown how they can modulate the emotional state. The study aimed to evaluate: how participants' emotional state changed after watching animated short films with positive or negative emotional valence in an online experiment; the relationship between participants' baseline score on an Emotional Intensity Scale and their potential change in the main emotion after watching the films; and the association between the initial main emotion valence and the potential change in this emotion with participants' sociodemographic information., Methods: A sample of 2,269 participants recruited during COVID-19 pandemic were randomly assigned to either watch a negative or positive animated short film., Results: The results showed that, after watching a film with negative valence, participants were in a more negative emotional state than at baseline and compared with those who watched the film with positive valence. Also, individuals who had a negative baseline emotion and maintained the same emotion after the film had presented higher baseline emotional state scores (more negative emotion) than those who changed their emotions. In addition, the individuals who kept the baseline emotion had an association with age, marital status, level of education and psychiatric disorders, use of medication, and emotional awareness, while the individuals who changed the baseline emotion had an association with age, gender, and following or not social distancing recommendations., Conclusion: Baseline emotional state may influence the response to animated short films and sociodemographic characteristics are associated with the initial main emotion valence and its potential change in this emotion., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Negrão, Bazán, de Azevedo Neto, Lacerda, Ekman and Kozasa.)

Functional near-infrared spectroscopy (fNIRS) is a noninvasive method particularly suitable for measuring cerebral cortex activation in multiple subjects, which is relevant for studying group interpersonal interactions in ecological settings. Although many fNIRS systems technically offer the possibility to monitor more than two individuals simultaneously, establishing easy-to-implement setup procedures and reliable paradigms to track hemodynamic and behavioral responses in group interaction is still required. The present protocol combines fNIRS and video-based observation to measure interpersonal synchronization in quartets during a cooperative task.This protocol provides practical recommendations for data acquisition and paradigm design, as well as guiding principles for an illustrative data analysis example. The procedure is designed to assess differences in brain and behavior interpersonal responses between social and non-social conditions inspired by a well-known ice-breaker activity, the Collaborative Face Drawing Task. The described procedures can guide future studies to adapt group naturalistic social interaction activities to the fNIRS environment.

Brain ischemia affects the integrity of local white matter and regions that are distant to the primary lesion location. In this study, we analyzed the patterns of white matter microstructural damage and the cognitive performance of 22 patients with left hemisphere stroke. Patients were divided in two groups: one with target lesion affecting the left inferior frontal gyrus (left inferior frontal gyrus, LIFG, n = 11) and the other without ischemic lesion in this region (non-left inferior frontal gyrus, NLIFG, n = 11). Each group was compared with 11 matched healthy controls. Tract-Based Spatial Statistics was used to assess differences in diffusion tensor indices between the groups and for the association of white matter structure with cognitive performance. When compared to Controls, the LIFG showed extensive intra- and interhemispheric disconnection, with surrogate markers for tissue loss with demyelination in the corpus callosum, and microstructural changes that are independent of gross tissue loss in the contralateral hemisphere. The NLIFG group presented discrete alterations in white matter from the ipsilateral hemisphere, with surrogate markers for tissue loss with axonal injury. When LIFG is compared to NLIFG, white matter abnormalities with no gross tissue loss were observed in the corpus callosum and in the contralateral hemisphere. In addition LIFG had worse performance on cognitive functions. In conclusion, our results identify different diffusion profiles for LIFG and NLIFG groups, suggesting more extensive and pronounced white matter damage in the commissural and interhemispheric connections in the LIFG group, in addition to more pronounced cognitive impairment., (Copyright © 2022. Published by Elsevier B.V.)

Background: Previous studies of hippocampal function and volume related to episodic memory deficits in patients with amnestic mild cognitive impairment (aMCI) have produced mixed results including increased or decreased activity and volume. However, most of them have not included biomarkers, such as amyloid-β (Aβ) deposition which is the hallmark for early identification of the Alzheimer's disease continuum., Objective: We investigated the role of Aβ deposition, functional hippocampal activity and structural volume in aMCI patients and healthy elderly controls (HC) using a new functional MRI (fMRI) ecological episodic memory task., Methods: Forty-six older adults were included, among them Aβ PET PIB positive (PIB+) aMCI (N = 17), Aβ PET PIB negative (PIB-) aMCI (N = 15), and HC (N = 14). Hippocampal volume and function were analyzed using Freesurfer v6.0 and FSL for news headlines episodic memory fMRI task, and logistic regression for group classification in conjunction with episodic memory task and traditional neuropsychological tests., Results: The aMCI PIB+ and PIB-patients showed significantly worse performance in relation to HC in most traditional neuropsychological tests and within group difference only on story recall and the ecological episodic memory fMRI task delayed recall. The classification model reached a significant accuracy (78%) and the classification pattern characterizing the PIB+ included decreased left hippocampal function and volume, increased right hippocampal function and volume, and worse episodic memory performance differing from PIB-which showed increased left hippocampus volume., Conclusion: The main findings showed differential neural correlates, hippocampal volume and function during episodic memory in aMCI patients with the presence of Aβ deposition.

In individuals with Parkinson's disease (PD), the medication induces different and inconsistent results in the spatiotemporal parameters of gait, making it difficult to understand its effects on gait. As spatiotemporal gait parameters have been reported to be affected by gait speed, it is essential to consider the gait speed when studying walking biomechanics to interpret the results better when comparing the gait pattern of different conditions. Since the medication alters the self-selected gait speed of individuals with PD, this study analysed whether the change in gait speed can explain the selective effects of l-DOPA on the spatiotemporal parameters of gait in individuals with PD. We analysed the spatiotemporal gait parameters at the self-selected speed of 22 individuals with PD under ON and OFF states of l-DOPA medication. Bayesian mediation analysis evaluated which gait variables were affected by the medication state and checked if those effects were mediated by speed changes induced by medication. The gait speed was significantly higher among ON compared with OFF medication. All the spatiotemporal parameters of the gait were mediated by speed, with proportions of mediation close to 1 (effect entirely explained by speed changes). Our results show that a change in gait speed better explains the changes in the spatiotemporal gait parameters than the ON-OFF phenomenon. As an implication for rehabilitation, our results suggest that it is possible to assess the effect of l-DOPA on improving motor symptoms related to gait disorders by measuring gait speed., (© 2021 Federation of European Neuroscience Societies and John Wiley & Sons Ltd.)