scholarly journals Dynamics of brain connectivity after stroke

2019 ◽  
Vol 30 (6) ◽  
pp. 605-623 ◽  
Author(s):  
Adela Desowska ◽  
Duncan L. Turner
Keyword(s):  
Brain Connectivity ◽  
Effective Connectivity ◽  
Network Connectivity ◽  
Connectivity Pattern ◽  
Compensatory Mechanisms ◽  
Neural Structure ◽  
Motor Network ◽  
The Central Nervous System ◽  
Dynamic Time ◽  
The Impact

Abstract Recovery from a stroke is a dynamic time-dependent process, in which the central nervous system reorganises to accommodate for the impact of the injury. The purpose of this paper is to review recent longitudinal studies of changes in brain connectivity after stroke. A systematic review of research papers reporting functional or effective connectivity at two or more time points in stroke patients was conducted. Stroke leads to an early reduction of connectivity in the motor network. With recovery time, the connectivity increases and can reach the same levels as in healthy participants. The increase in connectivity is correlated with functional motor gains. A new, more randomised pattern of connectivity may then emerge in the longer term. In some instances, a pattern of increased connectivity even higher than in healthy controls can be observed, and is related either to a specific time point or to a specific neural structure. Rehabilitation interventions can help improve connectivity between specific regions. Moreover, motor network connectivity undergoes reorganisation during recovery from a stroke and can be related to behavioural recovery. A detailed analysis of changes in connectivity pattern may enable a better understanding of adaptation to a stroke and how compensatory mechanisms in the brain may be supported by rehabilitation.

scholarly journals Brain Connectivity Plasticity in the Motor Network after Ischemic Stroke

2013 ◽  
Vol 2013 ◽  
pp. 1-11 ◽  
Author(s):  
Lin Jiang ◽  
Huijuan Xu ◽  
Chunshui Yu
Keyword(s):  
Ischemic Stroke ◽  
Motor Function ◽  
Brain Connectivity ◽  
Effective Connectivity ◽  
Motor Impairment ◽  
Treatment Strategies ◽  
Motor Recovery ◽  
Therapeutic Interventions ◽  
Motor Network ◽  
Motor Areas

The motor function is controlled by the motor system that comprises a series of cortical and subcortical areas interacting via anatomical connections. The motor function will be disturbed when the stroke lesion impairs either any of these areas or their connections. More and more evidence indicates that the reorganization of the motor network including both areas and their anatomical and functional connectivity might contribute to the motor recovery after stroke. Here, we review recent studies employing models of anatomical, functional, and effective connectivity on neuroimaging data to investigate how ischemic stroke influences the connectivity of motor areas and how changes in connectivity relate to impaired function and functional recovery. We suggest that connectivity changes constitute an important pathophysiological aspect of motor impairment after stroke and important mechanisms of motor recovery. We also demonstrate that therapeutic interventions may facilitate motor recovery after stroke by modulating the connectivity among the motor areas. In conclusion, connectivity analyses improved our understanding of the mechanisms of motor recovery after stroke and may help to design hypothesis-driven treatment strategies and sensitive measures for outcome prediction in stroke patients.

scholarly journals Neuroplasticity Within and between Functional Brain Networks in Mental Training Based on Long-Term Meditation

2021 ◽  
Vol 11 (8) ◽  
pp. 1086
Author(s):  
Roberto Guidotti ◽  
Cosimo Del Gratta ◽  
Mauro Gianni Perrucci ◽  
Gian Luca Romani ◽  
Antonino Raffone
Keyword(s):  
Large Scale ◽  
Brain Connectivity ◽  
Brain Networks ◽  
Connectivity Pattern ◽  
Mental Training ◽  
Functional Brain ◽  
Connectivity Patterns ◽  
Open Monitoring ◽  
The Impact

(1) The effects of intensive mental training based on meditation on the functional and structural organization of the human brain have been addressed by several neuroscientific studies. However, how large-scale connectivity patterns are affected by long-term practice of the main forms of meditation, Focused Attention (FA) and Open Monitoring (OM), as well as by aging, has not yet been elucidated. (2) Using functional Magnetic Resonance Imaging (fMRI) and multivariate pattern analysis, we investigated the impact of meditation expertise and age on functional connectivity patterns in large-scale brain networks during different meditation styles in long-term meditators. (3) The results show that fMRI connectivity patterns in multiple key brain networks can differentially predict the meditation expertise and age of long-term meditators. Expertise-predictive patterns are differently affected by FA and OM, while age-predictive patterns are not influenced by the meditation form. The FA meditation connectivity pattern modulated by expertise included nodes and connections implicated in focusing, sustaining and monitoring attention, while OM patterns included nodes associated with cognitive control and emotion regulation. (4) The study highlights a long-term effect of meditation practice on multivariate patterns of functional brain connectivity and suggests that meditation expertise is associated with specific neuroplastic changes in connectivity patterns within and between multiple brain networks.

scholarly journals SARS-CoV-2 and the Nervous System: From Clinical Features to Molecular Mechanisms

2020 ◽  
Vol 21 (15) ◽  
pp. 5475 ◽  
Author(s):  
Manuela Pennisi ◽  
Giuseppe Lanza ◽  
Luca Falzone ◽  
Francesco Fisicaro ◽  
Raffaele Ferri ◽  
...  
Keyword(s):  
Nervous System ◽  
Molecular Mechanisms ◽  
Neuronal Damage ◽  
Neurological Complications ◽  
Neurological Manifestations ◽  
Wide Range ◽  
Inflammatory State ◽  
Acute Polyneuropathy ◽  
The Central Nervous System ◽  
The Impact

Increasing evidence suggests that Severe Acute Respiratory Syndrome-coronavirus-2 (SARS-CoV-2) can also invade the central nervous system (CNS). However, findings available on its neurological manifestations and their pathogenic mechanisms have not yet been systematically addressed. A literature search on neurological complications reported in patients with COVID-19 until June 2020 produced a total of 23 studies. Overall, these papers report that patients may exhibit a wide range of neurological manifestations, including encephalopathy, encephalitis, seizures, cerebrovascular events, acute polyneuropathy, headache, hypogeusia, and hyposmia, as well as some non-specific symptoms. Whether these features can be an indirect and unspecific consequence of the pulmonary disease or a generalized inflammatory state on the CNS remains to be determined; also, they may rather reflect direct SARS-CoV-2-related neuronal damage. Hematogenous versus transsynaptic propagation, the role of the angiotensin II converting enzyme receptor-2, the spread across the blood-brain barrier, the impact of the hyperimmune response (the so-called “cytokine storm”), and the possibility of virus persistence within some CNS resident cells are still debated. The different levels and severity of neurotropism and neurovirulence in patients with COVID-19 might be explained by a combination of viral and host factors and by their interaction.

scholarly journals Lasting effects of prenatal exposure to Cannabis in the retina of the offspring: an experimental study in mice

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Paulo Roberto Arruda Zantut ◽  
Mariana Matera Veras ◽  
Sarah Gomes Menezes Benevenutto ◽  
Angélica Mendonça Vaz Safatle ◽  
Ricardo Augusto Pecora ◽  
...  
Keyword(s):  
Young Adult ◽  
Light Microscopy ◽  
Prenatal Exposure ◽  
Structural Changes ◽  
Volume Fraction ◽  
Clinical Care ◽  
Retinal Layer ◽  
Exposed Population ◽  
The Central Nervous System ◽  
The Impact

Abstract Background Prenatal exposure to Cannabis is a worldwide growing problem. Although retina is part of the central nervous system, the impact of maternal Cannabis use on the retinal development and its postnatal consequences remains unknown. As the prenatal period is potentially sensitive in the normal development of the retina, we hypothesized that recreational use of Cannabis during pregnancy may alter retina structure in the offspring. To test this, we developed a murine model that mimics human exposure in terms of dose and use. Methods Pregnant BalbC mice were exposed daily for 5 min to Cannabis smoke (0.2 g of Cannabis) or filtered air, from gestational day 5 to 18 (N = 10/group). After weaning period, pups were separated and examined weekly. On days 60, 120, 200, and 360 after birth, 10 pups from each group were randomly selected for Spectral Domain Optical Coherence Tomography (SD-OCT) analysis of the retina. All retina layers were measured and inner, outer, and total retina thickness were calculated. Other 37 mice from both groups were sacrificed on days 20, 60, and 360 for retinal stereology (total volume of the retina and volume fraction of each retinal layer) and light microscopy. Means and standard deviations were calculated and MANOVA was performed. Results The retina of animals which mother was exposed to Cannabis during gestation was 17% thinner on day 120 (young adult) than controls (P = 0.003) due to 21% thinning of the outer retina (P = 0.001). The offspring of mice from the exposed group presented thickening of the IS/OS in comparison to controls on day 200 (P < 0.001). In the volumetric analyzes by retinal stereology, the exposed mice presented transitory increase of the IS/OS total volume and volume fraction on day 60 (young adult) compared to controls (P = 0.008 and P = 0.035, respectively). On light microscopy, exposed mice presented thickening of the IS/OS on day 360 (adult) compared to controls (P = 0.03). Conclusion Gestational exposure to Cannabis smoke may cause structural changes in the retina of the offspring that return to normal on mice adulthood. These experimental evidences suggest that children and young adults whose mothers smoked Cannabis during pregnancy may require earlier and more frequent clinical care than the non-exposed population.

scholarly journals Hypoxia and Hypoxia-Inducible Factor Signaling in Muscular Dystrophies: Cause and Consequences

2021 ◽  
Vol 22 (13) ◽  
pp. 7220
Author(s):  
Thuy-Hang Nguyen ◽  
Stephanie Conotte ◽  
Alexandra Belayew ◽  
Anne-Emilie Declèves ◽  
Alexandre Legrand ◽  
...  
Keyword(s):  
Cell Function ◽  
Current Knowledge ◽  
Genetic Defect ◽  
Hypoxia Inducible Factor ◽  
Muscular Dystrophies ◽  
Compensatory Mechanisms ◽  
Hypoxia Response ◽  
Muscle Disorders ◽  
Almost All ◽  
The Impact

Muscular dystrophies (MDs) are a group of inherited degenerative muscle disorders characterized by a progressive skeletal muscle wasting. Respiratory impairments and subsequent hypoxemia are encountered in a significant subgroup of patients in almost all MD forms. In response to hypoxic stress, compensatory mechanisms are activated especially through Hypoxia-Inducible Factor 1 α (HIF-1α). In healthy muscle, hypoxia and HIF-1α activation are known to affect oxidative stress balance and metabolism. Recent evidence has also highlighted HIF-1α as a regulator of myogenesis and satellite cell function. However, the impact of HIF-1α pathway modifications in MDs remains to be investigated. Multifactorial pathological mechanisms could lead to HIF-1α activation in patient skeletal muscles. In addition to the genetic defect per se, respiratory failure or blood vessel alterations could modify hypoxia response pathways. Here, we will discuss the current knowledge about the hypoxia response pathway alterations in MDs and address whether such changes could influence MD pathophysiology.

scholarly journals Validation and cross-cultural adaptation of sexual dysfunction modified scale in multiple sclerosis for Brazilian population

2015 ◽  
Vol 73 (8) ◽  
pp. 681-687 ◽  
Author(s):  
Raquel Ataíde Peres da Silva ◽  
Guilherme Sciascia do Olival ◽  
Lívia Palma Stievano ◽  
Vania Balardin Toller ◽  
Sergio Semeraro Jordy ◽  
...  
Keyword(s):  
Multiple Sclerosis ◽  
Sexual Dysfunction ◽  
Cultural Adaptation ◽  
Chronic Inflammatory Disease ◽  
Cross Cultural ◽  
Brazilian Population ◽  
Control Group ◽  
Cross Cultural Adaptation ◽  
The Central Nervous System ◽  
The Impact

Multiple sclerosis (MS) is a chronic inflammatory disease of the central nervous system (CNS). These patients suffer from various comorbidities, including sexual dysfunction (SD). The lesions of MS may affect regions of the CNS along the pathway of sexual response. The Multiple Sclerosis Intimacy and Sexuality Questionnaire-19 (MSISQ-19) is a scale that assesses sexual dysfunction. Adapt and validate the MSISQ-19 to Brazilian patients with MS. 204 individuals were evaluated, 134 patients with MS and 70 healthy persons for the control group. It was determined reproducibility, validity, internal consistency and sensitivity of the MSISQ-19-BR. Among patients with MS, 54.3% of male and 71.7% of female presented some kind of SD. In the control group the results were 12.5% and 19.5%, respectively. The MSISQ-19-BR is reproducible, reliable and valid for the Brazilian population and may be used as a tool for assessing the impact of sexual dysfunction in patients with MS.

scholarly journals Cognitive functions in young adults with generalized anxiety disorder

2018 ◽  
Vol 56 (1) ◽  
pp. 1-7 ◽  
Author(s):  
Kiara Leonard ◽  
Amitai Abramovitch
Keyword(s):  
Anxiety Disorder ◽  
Cognitive Load ◽  
Generalized Anxiety Disorder ◽  
Cognitive Functions ◽  
Theoretical Models ◽  
Generalized Anxiety ◽  
Neuropsychological Battery ◽  
Compensatory Mechanisms ◽  
Neuropsychological Profile ◽  
The Impact

AbstractBackground:Anxiety and worry are central symptoms of Generalized Anxiety Disorder (GAD) that have been theorized to negatively impact cognitive functions. However, most of the research has focused on threat-related or emotionally-charged stimuli, and a surprisingly small number of investigations examined ‘cold’ cognitive functions using classic neuropsychological tests. Such investigations are particularly important given that some theoretical models suggest compensatory mechanisms associated with anxiety that in certain circumstances may result in intact performance. The aim of the present study is to assess the neuropsychological profile associated with GAD, using a comprehensive neuropsychological battery.Methods:A sample of 23 college students meeting criteria for DSM-5 GAD and 20 control participants completed a psychometrically valid comprehensive computerized neuropsychological battery and clinical questionnaires.Results:The GAD sample presented with significantly elevated symptomatic rates of anxiety, worry, depression and stress. However, no significant differences were found on any neuropsychological outcome measures or domain indexes. Effect sizes were small, some of which favored the GAD sample.Conclusion:Despite substantial psychopathological burden, GAD exhibited intact cognitive functioning. These results support the Cognitive Control Theory of Anxiety, suggesting that elevated primary anxiety may not impact ‘cold’ cognitive functions in the absence of threat or substantial cognitive load. Given that this is one of the only studies employing a comprehensive neuropsychological battery in GAD, more research is needed in this population to replicate these results and to examine the impact of anxiety on cognitive functions at varying degrees of cognitive load in this population.

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