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1.
Neuroreport ; 35(5): 283-290, 2024 03 20.
Artigo em Inglês | MEDLINE | ID: mdl-38407836

RESUMO

OBJECTIVE: This study aimed to comprehensively investigate the functional connectivity of key brain regions involved in motor and sensory functions, namely the precentral gyrus, postcentral gyrus and supplementary motor area (SMA). Using advanced MRI, the objective was to understand the neurophysiological integrative characterizations of these regions by examining their connectivity with eight distinct functional brain networks. The goal was to uncover their roles beyond conventional motor and sensory functions, contributing to a more holistic understanding of brain functioning. METHODS: The study involved 198 healthy volunteers, with the primary methodology being functional connectivity analysis using advanced MRI techniques. The bilateral precentral gyrus, postcentral gyrus and SMA served as seed regions, and their connectivity with eight distinct brain regional functional networks was investigated. This approach allowed for the exploration of synchronized activity between these critical brain areas, shedding light on their integrated functioning and relationships with other brain networks. RESULTS: The study revealed a nuanced landscape of functional connectivity for the precentral gyrus, postcentral gyrus and SMA with the main functional brain networks. Despite their high functional connectedness, these regions displayed diverse functional integrations with other networks, particularly in the salience, visual, cerebellar and language networks. Specific data and statistical significance were not provided in the abstract, but the results suggested unique and distinct roles for each brain area in sophisticated cognitive tasks beyond their conventional motor and sensory functions. CONCLUSION: The study emphasized the multifaceted roles of the precentral gyrus, postcentral gyrus and SMA. Beyond their crucial involvement in motor and sensory functions, these regions exhibited varied functional integrations with different brain networks. The observed disparities, especially in the salience, visual, cerebellar and language networks, indicated a nuanced and specialized involvement of these regions in diverse cognitive functions. The study underscores the importance of considering the broader neurophysiological landscape to comprehend the intricate roles of these brain areas, contributing to ongoing efforts in unraveling the complexities of brain function.


Assuntos
Córtex Motor , Humanos , Córtex Motor/diagnóstico por imagem , Córtex Somatossensorial , Encéfalo/diagnóstico por imagem , Mapeamento Encefálico/métodos , Cognição , Imageamento por Ressonância Magnética/métodos
2.
Curr Med Imaging ; 20: 1-9, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38389361

RESUMO

OBJECTIVE: Cytoarchitectonic mapping has revealed distinct subregions within Broadmann area 4 (BA 4) - BA 4a and BA 4p - with varying functional roles across tasks. We investigate their functional connectivity using resting-state functional magnetic resonance imaging (rsfMRI) to explore bilateral differences and the impact of handedness on connectivity within major brain networks. METHODS: This retrospective study involved 54 left- and right-handed subjects. We employed regions-to-regions-network rsfMRI analysis to examine the Cytoarchitectonic mapping of BA 4a and BA 4p functional connectivity with eight major brain networks. RESULTS: Our findings reveal differential connectivity patterns in both right-handed and left-handed subjects: Both right-handed subjects' BA 4a and BA 4p subregions exhibit connections to sensorimotor, dorsal attention, frontoparietal, and anterior cerebellar networks. Notably, BA 4a shows unique connectivity to the posterior cerebellum, lateral visual networks, and select salience regions. Similar connectivity patterns are observed in left-handed subjects, with BA 4a linked to sensorimotor, dorsal attention, frontoparietal, and anterior cerebellar networks. However, BA 4a in left-handed subjects shows distinct connectivity only to the posterior cerebellum. In both groups, the right portion of BA 4 demonstrates heightened connectivity compared to the left portion within each subregion. CONCLUSION: Our study uncovers complex patterns of functional connectivity within BA 4a and BA 4p, influenced by handedness. These findings emphasize the importance of considering hemisphere-specific and handedness-related factors in functional connectivity analyses, with potential implications for understanding brain organization in health and neurodegenerative diseases.


Assuntos
Mapeamento Encefálico , Córtex Motor , Humanos , Mapeamento Encefálico/métodos , Córtex Motor/diagnóstico por imagem , Lateralidade Funcional , Estudos Retrospectivos , Imageamento por Ressonância Magnética/métodos
3.
Heliyon ; 9(10): e20389, 2023 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-37780771

RESUMO

Introduction: The hippocampus plays a significant role in learning, memory encoding, and spatial navigation. Typically, the hippocampus is investigated as a whole region of interest. However, recent work has developed fully detailed atlases based on cytoarchitecture properties of brain regions, and the hippocampus has been sub-divided into seven sub-areas that have structural differences in terms of distinct numbers of cells, neurons, and other structural and chemical properties. Moreover, gender differences are of increasing concern in neuroscience research. Several neuroscience studies have found structural and functional variations between the brain regions of females and males, and the hippocampus is one of these regions. Aim: The aim of this study to explore whether the cytoarchitecturally distinct sub-regions of the hippocampus have varying patterns of functional connectivity with different networks of the brain and how these functional connections differ in terms of gender differences. Method: This study investigated 200 healthy participants using seed-based resting-state functional magnetic resonance imaging (rsfMRI). The primary aim of this study was to explore the resting connectivity and gender distinctions associated with specific sub-regions of the hippocampus and their relationship with major functional brain networks. Results: The findings revealed that the majority of the seven hippocampal sub-regions displayed functional connections with key brain networks, and distinct patterns of functional connectivity were observed between the hippocampal sub-regions and various functional networks within the brain. Notably, the default and visual networks exhibited the most consistent functional connections. Additionally, gender-based analysis highlighted evident functional resemblances and disparities, particularly concerning the anterior section of the hippocampus. Conclusion: This study highlighted the functional connectivity patterns and involvement of the hippocampal sub-regions in major brain functional networks, indicating that the hippocampus should be investigated as a region of multiple distinct functions and should always be examined as sub-regions of interest. The results also revealed clear gender differences in functional connectivity.

4.
PLoS One ; 18(9): e0291450, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37703254

RESUMO

Carotid plaque features assessed using B-mode ultrasound can be useful for the prediction of cerebrovascular symptoms. Therefore, the aim of this retrospective study was to determine the ability of ultrasound B-mode imaging to differentiate between carotid plaques causing less than 50% stenosis in symptomatic and asymptomatic patients. A dataset of 1,593 patients with carotid disease who underwent carotid ultrasound between 2016 and 2021 was evaluated retrospectively between January and April of 2022. A total of 107 carotid plaques from 35 symptomatic and 52 asymptomatic patients causing low-grade stenosis on B-mode images were included in the analysis. Chi-square, independent t-test and Mann-Whitney U test were used to compare the variables. There was a significant association between hypertension and the presence of cerebrovascular symptoms (p = 0.01). Predominantly hypoechoic and hyperechoic carotid plaque were significantly associated with the presence and absence of cerebrovascular symptoms, respectively (predominantly hypoechoic: p = 0.01; predominantly hyperechoic: p = 0.02). Surface irregularity was significantly associated with the presence of cerebrovascular symptoms (p = 0.02). There is was a significant difference in the carotid plaque length and area between the symptomatic and asymptomatic patients (plaque length: symptomatic median 9 mm, interquartile range [IQR] 6 mm; asymptomatic median 6 mm, IQR 4.5 mm, p = 0.01; plaque area: symptomatic median 24 mm, IQR 30 mm; asymptomatic median 14 mm, IQR 17 mm, p = 0.01); however, this difference was not significant for plaque thickness (p = 0.55), or common carotid artery intima-media thickness (p = 0.7). Our findings indicate that hypertension patients with predominantly hypoechoic carotid plaques and plaques with an irregular surface are associated with the presence of cerebrovascular symptoms. In addition, the carotid plaques in symptomatic patients were longer and larger compared to asymptomatic patients.


Assuntos
Besouros , Hipertensão , Humanos , Animais , Estudos Retrospectivos , Espessura Intima-Media Carotídea , Constrição Patológica , Artéria Carótida Primitiva , Hipertensão/complicações , Hipertensão/diagnóstico por imagem , Placa Amiloide
5.
Tomography ; 9(2): 883-893, 2023 04 21.
Artigo em Inglês | MEDLINE | ID: mdl-37104143

RESUMO

The cerebellum, a crucial brain region, significantly contributes to various brain functions. Although it occupies a small portion of the brain, it houses nearly half of the neurons in the nervous system. Previously thought to be solely involved in motor activities, the cerebellum has since been found to play a role in cognitive, sensory, and associative functions. To further elucidate the intricate neurophysiological characteristics of the cerebellum, we investigated the functional connectivity of cerebellar lobules and deep nuclei with 8 major functional brain networks in 198 healthy subjects. Our findings revealed both similarities and differences in the functional connectivity of key cerebellar lobules and nuclei. Despite robust functional connectivity among these lobules, our results demonstrated that they exhibit heterogeneous functional integration with different functional networks. For instance, lobules 4, 5, 6, and 8 were linked to sensorimotor networks, while lobules 1, 2, and 7 were associated with higher-order, non-motor, and complex functional networks. Notably, our study uncovered a lack of functional connectivity in lobule 3, strong connections between lobules 4 and 5 with the default mode networks, and connections between lobules 6 and 8 with the salience, dorsal attention, and visual networks. Additionally, we found that cerebellar nuclei, particularly the dentate cerebellar nuclei, were connected to sensorimotor, salience, language, and default-mode networks. This study provides valuable insights into the diverse functional roles of the cerebellum in cognitive processing.


Assuntos
Mapeamento Encefálico , Imageamento por Ressonância Magnética , Humanos , Vias Neurais/diagnóstico por imagem , Vias Neurais/fisiologia , Imageamento por Ressonância Magnética/métodos , Encéfalo/diagnóstico por imagem , Cerebelo/diagnóstico por imagem
6.
Neuroreport ; 34(4): 214-219, 2023 03 01.
Artigo em Inglês | MEDLINE | ID: mdl-36789843

RESUMO

Sub-cortical grey matter structures, such as the putamen, pallidum, caudate, thalamus, amygdala and hippocampus, play substantial roles in both simple and complex brain functions, including regulation of pleasure and emotions; control of movements; learning; decision-making; language development; and sensory, cognitive, social and other higher-order functions. Most of these regions act as information hubs for the nervous system, relaying and controlling the flow of information to various portions of the brain. To further understand the complex neurophysiological characteristics of sub-cortical areas, the aim of this study was to investigate the functional integrations of six sub-cortical areas to different major functional brain networks. One hundred ninety-eight healthy individuals were examined using resting-state functional MRI. The seeds identified in this study were six sub-cortical deep grey matter regions, namely putamen, pallidum, caudate, thalamus, amygdala and hippocampus. The analysis indicated that the link between the sub-cortical regions and some functional brain networks was similar in some aspects, but there were disparities in the mechanism underlying such a link and in the existence of functional connections between these regions and networks. Despite the substantial functional connectivity linkages between the sub-cortical regions, discrepancies were still noted. On the basis of the connections to the majority of the major brain networks, this study demonstrated the essential functional roles and involvements of the sub-cortical regions. This finding is consistent with an earlier report that revealed a substantial role of the sub-cortical regions in several brain functions.


Assuntos
Encéfalo , Imageamento por Ressonância Magnética , Humanos , Encéfalo/diagnóstico por imagem , Mapeamento Encefálico , Substância Cinzenta , Tálamo/diagnóstico por imagem , Vias Neurais/fisiologia
7.
J Radiol Nurs ; 42(2): 236-240, 2023 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-36742419

RESUMO

Purpose: In response to the coronavirus (COVID-19) pandemic, most educational institutions transitioned to online delivery because of the urgent need to avoid spreading the virus. For this study, the emergency transformation to 100% online education in a diagnostic radiology department was evaluated based on student experience and performance. Methods: One hundred and thirty four radiology students participated in this study. Reflecting on the department's shift to online education, students rated their experience: their general opinions about courses, preferences for online education, their evaluation of the procedures of the implemented plans, and their evaluation of academic components such as exams, lectures, assignments, teamwork, interaction, and compensating for the loss of practical learning. Results: The results indicate that the students appreciated the online emergency plan. Overall, they preferred online education compared to traditional classes, especially with regard to lectures, exams, teamwork, and interaction. Students agreed that some courses can be delivered online effectively, such as physics and research courses, while others should not. In general, this study demonstrates that radiology courses can be effectively delivered using online distance methods, and this should be a compulsory part of instruction in the future. Conclusion: This study describes the effects of moving to online education in the field of radiology on both practical and theoretical learning outcomes.

8.
Polymers (Basel) ; 13(10)2021 May 17.
Artigo em Inglês | MEDLINE | ID: mdl-34067569

RESUMO

The global transplantation market size was valued at USD 8.4 billion in 2020 and is expected to grow at a compound annual growth rate of 11.5% over the forecast period. The increasing demand for tissue transplantation has inspired researchers to find alternative approaches for making artificial tissues and organs function. The unique physicochemical and biological properties of biopolymers and the attractive structural characteristics of aerogels such as extremely high porosity, ultra low-density, and high surface area make combining these materials of great interest in tissue scaffolding and regenerative medicine applications. Numerous biopolymer aerogel scaffolds have been used to regenerate skin, cartilage, bone, and even heart valves and blood vessels by growing desired cells together with the growth factor in tissue engineering scaffolds. This review focuses on the principle of tissue engineering and regenerative medicine and the role of biopolymer aerogel scaffolds in this field, going through the properties and the desirable characteristics of biopolymers and biopolymer tissue scaffolds in tissue engineering applications. The recent advances of using biopolymer aerogel scaffolds in the regeneration of skin, cartilage, bone, and heart valves are also discussed in the present review. Finally, we highlight the main challenges of biopolymer-based scaffolds and the prospects of using these materials in regenerative medicine.

9.
Front Cell Neurosci ; 15: 616028, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33981201

RESUMO

This study highlights the importance of looking beyond the main effect of movement to study alterations in functional response in the presence of central nervous system pathologies such as multiple sclerosis (MS). Data show that MS selectively affects regional BOLD (blood oxygenation level dependent) responses to variable grip forces (GF). It is known that the anterior and posterior BA 4 areas (BA 4a and BA 4p) are anatomically and functionally distinct. It has also been shown in healthy volunteers that there are linear (first order, typical of BA 4a) and nonlinear (second to fourth order, typical of BA 4p) BOLD responses to different levels of GF applied during a dynamic motor paradigm. After modeling the BOLD response with a polynomial expansion of the applied GFs, the particular case of BA 4a and BA 4p were investigated in healthy volunteers (HV) and MS subjects. The main effect of movement (zeroth order) analysis showed that the BOLD signal is greater in MS compared with healthy volunteers within both BA 4 subregions. At higher order, BOLD-GF responses were similar in BA 4a but showed a marked alteration in BA 4p of MS subjects, with those with greatest disability showing the greatest deviations from the healthy response profile. Therefore, the different behaviors in HV and MS could only be uncovered through a polynomial analysis looking beyond the main effect of movement into the two BA 4 subregions. Future studies will investigate the source of this pathophysiology, combining the present fMRI paradigm with blood perfusion and nonlinear neuronal response analysis.

10.
Insights Imaging ; 12(1): 47, 2021 Apr 13.
Artigo em Inglês | MEDLINE | ID: mdl-33847819

RESUMO

OBJECTIVES: Traditionally, the superior parietal lobule (SPL) is usually investigated as one region of interest, particularly in functional magnetic resonance imaging (fMRI) studies. However, cytoarchitectonic analysis has shown that the SPL has a complex, heterogeneous topology that comprises more than seven sub-regions. Since previous studies have shown how the SPL is significantly involved in different neurological functions-such as visuomotor, cognitive, sensory, higher order, working memory and attention-this study aims to investigate whether these cytoarchitecturally different sub-regions have different functional connectivity to different functional brain networks. METHODS: This study examined 198 healthy subjects using resting-state fMRI and investigated the functional connectivity of seven sub-regions of the SPL to eight regional functional networks. RESULTS: The findings showed that most of the seven sub-regions were functionally connected to these targeted networks and that there are differences between these sub-regions and their functional connectivity patterns. The most consistent functional connectivity was observed with the visual and attention networks. There were also clear functional differences between Brodmann area (BA) 5 and BA7. BA5, with its three sub-regions, had strong functional connectivity to both the sensorimotor and salience networks. CONCLUSION: These findings have enhanced our understanding of the functional organisations of the complexity of the SPL and its varied topology and also provide clear evidence of the functional patterns and involvements of the SPL in major brain functions.

11.
Polymers (Basel) ; 13(4)2021 Feb 20.
Artigo em Inglês | MEDLINE | ID: mdl-33672526

RESUMO

Biopolymers have gained tremendous attention in many daily life applications, including medical applications, in the past few years. Obstetrics and gynecology are two fields dealing with sensitive parts of the woman's body and her newborn baby, which are normally associated with many issues such as toxicity, infections, and even gene alterations. Medical professions that use screening, examination, pre, and post-operation materials should benefit from a better understanding of each type of material's characteristics, health, and even environmental effects. The underlying principles of biopolymer-based materials for different obstetric and gynecologic applications may discover various advantages and benefits of using such materials. This review presents the health impact of conventional polymer-based materials on pregnant women's health and highlights the potential use of biopolymers as a safer option. The recent works on utilizing different biopolymer-based materials in obstetric and gynecologic are presented in this review, which includes suture materials in obstetric and gynecologic surgeries, cosmetic and personal care products, vaginal health, and drug delivery; as well as a wound dressing and healing materials. This review highlights the main issues and challenges of biopolymers in obstetric and gynecologic applications.

12.
Nat Rev Neurol ; 17(3): 173-184, 2021 03.
Artigo em Inglês | MEDLINE | ID: mdl-33437067

RESUMO

MRI studies have provided valuable insights into the structure and function of neural networks, particularly in health and in classical neurodegenerative conditions such as Alzheimer disease. However, such work is also highly relevant in other diseases of the CNS, including multiple sclerosis (MS). In this Review, we consider the effects of MS pathology on brain networks, as assessed using MRI, and how these changes to brain networks translate into clinical impairments. We also discuss how this knowledge can inform the targeting of MS treatments and the potential future directions for research in this area. Studying MS is challenging as its pathology involves neurodegenerative and focal inflammatory elements, both of which could disrupt neural networks. The disruption of white matter tracts in MS is reflected in changes in network efficiency, an increasingly random grey matter network topology, relative cortical disconnection, and both increases and decreases in connectivity centred around hubs such as the thalamus and the default mode network. The results of initial longitudinal studies suggest that these changes evolve rather than simply increase over time and are linked with clinical features. Studies have also identified a potential role for treatments that functionally modify neural networks as opposed to altering their structure.


Assuntos
Encéfalo/fisiopatologia , Esclerose Múltipla/fisiopatologia , Esclerose Múltipla/terapia , Rede Nervosa/fisiopatologia , Neurônios/fisiologia , Doença de Alzheimer/fisiopatologia , Doença de Alzheimer/terapia , Humanos , Inflamação/fisiopatologia
13.
Neuroradiology ; 63(1): 99-109, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-32840683

RESUMO

PURPOSE: Spatial smoothing is an essential pre-processing step in the process of analysing functional magnetic resonance imaging (fMRI) data, both during an experimental task or during resting-state fMRI (rsfMRI). The main benefit of this spatial smoothing step is to artificially increase the signal-to-noise ratio of the fMRI signal. Previous fMRI studies have investigated the impact of spatial smoothing on task fMRI data, while rsfMRI studies usually apply the same analytical process used for the task data. However, this study investigates changes in different rsfMRI analyses, such as ROI-to-ROI, seed-to-voxels and ICA analyses. METHODS: Nineteen healthy volunteers were scanned using rsfMRI with three applied smoothing kernels: 0 mm, 4 mm and 8 mm. Appropriate statistical comparisons were made. RESULTS: The findings showed that spatial smoothing has a greater effect on rsfMRI data when analysed using seed-to-voxel-based analysis. The effect was less pronounced when analysing data using ROI-ROI or ICA analyses. The results demonstrated that even when analysing the data without the application of spatial smoothing, the results were significant compared with data analysed using a typical smoothing kernel. However, data analysed with lower-smoothing kernels produced greater negative correlations, particularly with the ICA analysis. CONCLUSION: The results suggest that a medium smoothing kernel (around 4 mm) may be preferable, as it is comparable with the 8 mm kernel in all of the analyses performed. It is also recommended that the researchers consider analysing the data using two different smoothing kernels, as this will help to confirm the significance of the results and avoid overestimating the findings.


Assuntos
Encéfalo , Descanso , Encéfalo/diagnóstico por imagem , Mapeamento Encefálico , Voluntários Saudáveis , Humanos , Imageamento por Ressonância Magnética , Razão Sinal-Ruído
14.
Antibiotics (Basel) ; 9(10)2020 Sep 28.
Artigo em Inglês | MEDLINE | ID: mdl-32998197

RESUMO

A biopolymer-based aerogel has been developed to become one of the most potentially utilized materials in different biomedical applications. The biopolymer-based aerogel has unique physical, chemical, and mechanical properties and these properties are used in tissue engineering, biosensing, diagnostic, medical implant and drug delivery applications. Biocompatible and non-toxic biopolymers such as chitosan, cellulose and alginates have been used to deliver antibiotics, plants extract, essential oils and metallic nanoparticles. Antibacterial aerogels have been used in superficial and chronic wound healing as dressing sheets. This review critically analyses the utilization of biopolymer-based aerogels in antibacterial delivery. The analysis shows the relationship between their properties and their applications in the wound healing process. Furthermore, highlights of the potentials, challenges and proposition of the application of biopolymer-based aerogels is explored.

15.
Polymers (Basel) ; 12(9)2020 Sep 08.
Artigo em Inglês | MEDLINE | ID: mdl-32911705

RESUMO

Biopolymers have been used as a replacement material for synthetic polymers in scaffold forming due to its biocompatibility and nontoxic properties. Production of scaffold for tissue repair is a major part of tissue engineering. Tissue engineering techniques for scaffold forming with cellulose-based material is at the forefront of present-day research. Micro- and nanocellulose-based materials are at the forefront of scientific development in the areas of biomedical engineering. Cellulose in scaffold forming has attracted a lot of attention because of its availability and toxicity properties. The discovery of nanocellulose has further improved the usability of cellulose as a reinforcement in biopolymers intended for scaffold fabrication. Its unique physical, chemical, mechanical, and biological properties offer some important advantages over synthetic polymer materials. This review presents a critical overview of micro- and nanoscale cellulose-based materials used for scaffold preparation. It also analyses the relationship between the method of fabrication and properties of the fabricated scaffold. The review concludes with future potential research on cellulose micro- and nano-based scaffolds. The review provides an up-to-date summary of the status and future prospective applications of micro- and nanocellulose-based scaffolds for tissue engineering.

16.
Polymers (Basel) ; 12(8)2020 Aug 06.
Artigo em Inglês | MEDLINE | ID: mdl-32781602

RESUMO

Cellulose nanomaterials from plant fibre provide various potential applications (i.e., biomedical, automotive, packaging, etc.). The biomedical application of nanocellulose isolated from plant fibre, which is a carbohydrate-based source, is very viable in the 21st century. The essential characteristics of plant fibre-based nanocellulose, which include its molecular, tensile and mechanical properties, as well as its biodegradability potential, have been widely explored for functional materials in the preparation of aerogel. Plant cellulose nano fibre (CNF)-based aerogels are novel functional materials that have attracted remarkable interest. In recent years, CNF aerogel has been extensively used in the biomedical field due to its biocompatibility, renewability and biodegradability. The effective surface area of CNFs influences broad applications in biological and medical studies such as sustainable antibiotic delivery for wound healing, the preparation of scaffolds for tissue cultures, the development of drug delivery systems, biosensing and an antimicrobial film for wound healing. Many researchers have a growing interest in using CNF-based aerogels in the mentioned applications. The application of cellulose-based materials is widely reported in the literature. However, only a few studies discuss the potential of cellulose nanofibre aerogel in detail. The potential applications of CNF aerogel include composites, organic-inorganic hybrids, gels, foams, aerogels/xerogels, coatings and nano-paper, bioactive and wound dressing materials and bioconversion. The potential applications of CNF have rarely been a subject of extensive review. Thus, extensive studies to develop materials with cheaper and better properties, high prospects and effectiveness for many applications are the focus of the present work. The present review focuses on the evolution of aerogels via characterisation studies on the isolation of CNF-based aerogels. The study concludes with a description of the potential and challenges of developing sustainable materials for biomedical applications.

17.
Neuroreport ; 31(9): 691-695, 2020 06 07.
Artigo em Inglês | MEDLINE | ID: mdl-32427715

RESUMO

The cytoarchitectonic properties of the primary motor cortex have shown two distinct sub-regions: Anterior Broadmann area 4 (BA4a) and Posterior Broadmann area 4 (BA4p). Some previous studies have suggested that these two sub-regions are functionally different and showed that in few fMRI experiments, these sub-regions may have different roles in brain functions. Resting-state fMRI (rsfMRI) is advanced technique that allows investigating in detail the functional connectivity and provides a greater understanding of the physiological behavior of different brain regions. In this study, 198 healthy subjects were examined using a region-based rsfMRI analysis to investigate whether BA4a and BA4p have similar or different connections to other brain networks. The finding shows that indeed these two sub-regions have distinct connectivity to different brain networks. BA4a has a greater connection to motor-related areas while BA4p has connections to nonmotor-related areas (such as sensory, attentional, and higher order regions), suggesting that these two sub-regions should be considered as two separate regions of interests.


Assuntos
Córtex Motor/fisiologia , Adolescente , Adulto , Mapeamento Encefálico/métodos , Feminino , Humanos , Imageamento por Ressonância Magnética , Masculino , Vias Neurais/fisiologia , Adulto Jovem
18.
Cereb Cortex ; 29(3): 1351-1368, 2019 03 01.
Artigo em Inglês | MEDLINE | ID: mdl-30615116

RESUMO

Action observation (AO) is crucial for motor planning, imitation learning, and social interaction, but it is not clear whether and how an action execution-observation network (AEON) processes the effort of others engaged in performing actions. In this functional magnetic resonance imaging (fMRI) study, we used a "squeeze ball" task involving different grip forces to investigate whether AEON activation showed similar patterns when executing the task or observing others performing it. Both in action execution, AE (subjects performed the visuomotor task) and action observation, AO (subjects watched a video of the task being performed by someone else), the fMRI signal was detected in cerebral and cerebellar regions. These responses showed various relationships with force mapping onto specific areas of the sensorimotor and cognitive systems. Conjunction analysis of AE and AO was repeated for the "0th" order and linear and nonlinear responses, and revealed multiple AEON nodes remapping the detection of actions, and also effort, of another person onto the observer's own cerebrocerebellar system. This result implies that the AEON exploits the cerebellum, which is known to process sensorimotor predictions and simulations, performing an internal assessment of forces and integrating information into high-level schemes, providing a crucial substrate for action imitation.


Assuntos
Encéfalo/fisiologia , Cerebelo/fisiologia , Desempenho Psicomotor/fisiologia , Percepção Visual/fisiologia , Adulto , Mapeamento Encefálico , Feminino , Humanos , Imageamento por Ressonância Magnética , Masculino , Vias Neurais/fisiologia , Adulto Jovem
19.
Hum Brain Mapp ; 38(5): 2566-2579, 2017 05.
Artigo em Inglês | MEDLINE | ID: mdl-28240422

RESUMO

The relationship between the BOLD response and an applied force was quantified in the cerebellum using a power grip task. To investigate whether the cerebellum responds in an on/off way to motor demands or contributes to motor responses in a parametric fashion, similarly to the cortex, five grip force levels were investigated under visual feedback. Functional MRI data were acquired in 13 healthy volunteers and their responses were analyzed using a cerebellum-optimized pipeline. This allowed us to evaluate, within the cerebellum, voxelwise linear and non-linear associations between cerebellar activations and forces. We showed extensive non-linear activations (with a parametric design), covering the anterior and posterior lobes of the cerebellum with a BOLD-force relationship that is region-dependent. Linear responses were mainly located in the anterior lobe, similarly to the cortex, where linear responses are localized in M1. Complex responses were localized in the posterior lobe, reflecting its key role in attention and executive processing, required during visually guided movement. Given the highly organized responses in the cerebellar cortex, a key question is whether deep cerebellar nuclei show similar parametric effects. We found positive correlations with force in the ipsilateral dentate nucleus and negative correlations on the contralateral side, suggesting a somatotopic organization of the dentate nucleus in line with cerebellar and cortical areas. Our results confirm that there is cerebellar organization involving all grey matter structures that reflect functional segregation in the cortex, where cerebellar lobules and dentate nuclei contribute to complex motor tasks with different BOLD response profiles in relation to the forces. Hum Brain Mapp 38:2566-2579, 2017. © 2017 Wiley Periodicals, Inc.


Assuntos
Mapeamento Encefálico , Núcleos Cerebelares/irrigação sanguínea , Cerebelo/irrigação sanguínea , Oxigênio/sangue , Adulto , Núcleos Cerebelares/diagnóstico por imagem , Cerebelo/diagnóstico por imagem , Feminino , Lateralidade Funcional , Humanos , Processamento de Imagem Assistida por Computador , Imageamento por Ressonância Magnética , Masculino , Análise e Desempenho de Tarefas
20.
JNMA J Nepal Med Assoc ; 54(202): 85-87, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-27935930

RESUMO

Ischemic stroke is due to either local thrombus formation or emboli that occlude a cerebral artery, together with chronic kidney disease represent major mortality and morbidity.Here we present a case of 53 years old Malay man, admitted to a hospital in Malaysia complaining of sudden on set of weakness on right sided upper and lower limb associated with slurred speech. Patient was also suffering from uncontrolled hypertension, hyperlipidemia, chronic kidney disease stage 4, and diabetes mellitus (uncontrolled). He was diagnosed with acute ischemic stroke with cranial nerve 7 palsy (with right hemiparesis), acute on chronic kidney disease precipitated by dehydration and ACE inhibitor, and hyperkalemia. Patients with ischemic disease and chronic kidney disaese require constant monitering and careful selected pharmacotherapy. Patient was placed under observation and was prescribed multiple pharamacotherpay to stabalise detoriating condition.


Assuntos
Insuficiência Renal Crônica/diagnóstico , Acidente Vascular Cerebral/diagnóstico , Doença Aguda , Inibidores da Enzima Conversora de Angiotensina/efeitos adversos , Paralisia de Bell/diagnóstico , Isquemia Encefálica/diagnóstico , Desidratação/complicações , Diabetes Mellitus/diagnóstico , Humanos , Hiperpotassemia/complicações , Hipertensão/diagnóstico , Masculino , Pessoa de Meia-Idade , Insuficiência Renal Crônica/etiologia
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