scholarly journals Plasticity based on compensatory effector use in the association but not primary sensorimotor cortex of people born without hands

2018 ◽  
Vol 115 (30) ◽  
pp. 7801-7806 ◽  
Author(s):  
Ella Striem-Amit ◽  
Gilles Vannuscorps ◽  
Alfonso Caramazza
Keyword(s):  
Sensorimotor Cortex ◽  
Brain Regions ◽  
Association Cortex ◽  
Body Parts ◽  
Brain Organization ◽  
Neural Organization ◽  
Functional Development ◽  
Primary Sensorimotor Cortex ◽  
Hand Region ◽  
High Level

What forces direct brain organization and its plasticity? When brain regions are deprived of their input, which regions reorganize based on compensation for the disability and experience, and which regions show topographically constrained plasticity? People born without hands activate their primary sensorimotor hand region while moving body parts used to compensate for this disability (e.g., their feet). This was taken to suggest a neural organization based on functions, such as performing manual-like dexterous actions, rather than on body parts, in primary sensorimotor cortex. We tested the selectivity for the compensatory body parts in the primary and association sensorimotor cortex of people born without hands (dysplasic individuals). Despite clear compensatory foot use, the primary sensorimotor hand area in the dysplasic subjects showed preference for adjacent body parts that are not compensatorily used as effectors. This suggests that function-based organization, proposed for congenital blindness and deafness, does not apply to the primary sensorimotor cortex deprivation in dysplasia. These findings stress the roles of neuroanatomical constraints like topographical proximity and connectivity in determining the functional development of primary cortex even in extreme, congenital deprivation. In contrast, increased and selective foot movement preference was found in dysplasics’ association cortex in the inferior parietal lobule. This suggests that the typical motor selectivity of this region for manual actions may correspond to high-level action representations that are effector-invariant. These findings reveal limitations to compensatory plasticity and experience in modifying brain organization of early topographical cortex compared with association cortices driven by function-based organization.

scholarly journals Limitations of compensatory plasticity: the organization of the primary sensorimotor cortex in foot-using bilateral upper limb dysplasics

2017 ◽  
Author(s):  
Ella Striem-Amit ◽  
Gilles Vannuscorps ◽  
Alfonso Caramazza
Keyword(s):  
Sensorimotor Cortex ◽  
Functional Organization ◽  
Brain Regions ◽  
Association Cortex ◽  
Body Parts ◽  
Brain Organization ◽  
Primary Sensorimotor Cortex ◽  
Hand Area ◽  
Compensatory Plasticity

SummaryWhat forces direct brain organization and its plasticity? When a brain region is deprived of its input would this region reorganize based on compensation for the disability and experience, or would strong limitations of brain structure limit its plasticity? People born without hands activate their sensorimotor hand region while moving body parts used to compensate for this ability (e.g. their feet). This has been taken to suggest a neural organization based on functions, such as performing manual-like dexterous actions, rather than on body parts. Here we test the selectivity for functionally-compensatory body parts in the sensorimotor cortex of people born without hands. Despite clear compensatory foot use, the sensorimotor hand area in the dysplasic subjects showed preference for body parts whose cortical territory is close to the hand area, but which are not compensatorily used as effectors. This suggests that function-based organization, originally proposed for congenital blindness and deafness, does not apply to cases of the primary sensorimotor cortex deprivation in dysplasia. This is consistent with the idea that experience-independent functional specialization occurs at relatively high levels of representation. Indeed, increased and selective foot movement preference in the dysplasics was found in the association cortex, in the inferior parietal lobule. Furthermore, it stresses the roles of neuroanatomical constraints such as topographical proximity and connectivity in determining the functional development of brain regions. These findings reveal limitations to brain plasticity and to the role of experience in shaping the functional organization of the brain.Significance StatementWhat determines the role of brain regions, and their plasticity when typical inputs or experience is not provided? To what extent can extreme compensatory use affect brain organization? We tested the functional reorganization of the primary sensorimotor cortex hand area in people born without hands, who use their feet for every-day tasks. We found that it is preferentially activated by close-by body-parts which cannot serve as effectors, and not by the feet. In contrast, foot-selective compensatory plasticity was found in the association cortex, in an area involved in tool use. This shows limitations of compensatory plasticity and experience in modifying brain organization of early topographical cortex, as compared to association cortices where function-based organization is the driving factor.ClassificationBiological Sciences\Neuroscience

scholarly journals Hand, foot and lip representations in primary sensorimotor cortex: a high-density electroencephalography study

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Mingqi Zhao ◽  
Marco Marino ◽  
Jessica Samogin ◽  
Stephan P. Swinnen ◽  
Dante Mantini
Keyword(s):  
Sensorimotor Cortex ◽  
High Spatial Resolution ◽  
Movement Control ◽  
Contralateral Side ◽  
High Density ◽  
The Body ◽  
Body Parts ◽  
Gamma Frequency ◽  
Neural Processes ◽  
Primary Sensorimotor Cortex

AbstractThe primary sensorimotor cortex plays a major role in the execution of movements of the contralateral side of the body. The topographic representation of different body parts within this brain region is commonly investigated through functional magnetic resonance imaging (fMRI). However, fMRI does not provide direct information about neuronal activity. In this study, we used high-density electroencephalography (hdEEG) to map the representations of hand, foot, and lip movements in the primary sensorimotor cortex, and to study their neural signatures. Specifically, we assessed the event-related desynchronization (ERD) in the cortical space. We found that the performance of hand, foot, and lip movements elicited an ERD in beta and gamma frequency bands. The primary regions showing significant beta- and gamma-band ERD for hand and foot movements, respectively, were consistent with previously reported using fMRI. We observed relatively weaker ERD for lip movements, which may be explained by the fact that less fine movement control was required. Overall, our study demonstrated that ERD based on hdEEG data can support the study of motor-related neural processes, with relatively high spatial resolution. An interesting avenue may be the use of hdEEG for deeper investigations into the pathophysiology of neuromotor disorders.

scholarly journals Conservative and disruptive modes of adolescent change in brain functional connectivity

2019 ◽  
Author(s):  
František Váša ◽  
Rafael Romero-Garcia ◽  
Manfred G. Kitzbichler ◽  
Jakob Seidlitz ◽  
Kirstie J. Whitaker ◽  
...  
Keyword(s):  
Functional Connectivity ◽  
Human Brain ◽  
Developmental Change ◽  
Aerobic Glycolysis ◽  
Brain Regions ◽  
Association Cortex ◽  
Brain Organization ◽  
Healthy Human ◽  
Age Related ◽  
Strongly Connected

AbstractAdolescent changes in human brain function are not entirely understood. Here we used multi-echo functional magnetic resonance imaging (fMRI) to measure developmental change in functional connectivity (FC) of resting-state oscillations between pairs of 330 cortical regions and 16 subcortical regions in N=298 healthy adolescents. Participants were aged 14-26 years and were scanned on two or more occasions at least 6 months apart. We found two distinct modes of age-related change in FC: “conservative” and “disruptive”. Conservative development was characteristic of primary cortex, which was strongly connected at 14 years and became even more connected in the period 14-26 years. Disruptive development was characteristic of association cortex, hippocampus and amygdala, which were not strongly connected at 14 years but became more strongly connected during adolescence. We defined the maturational index (MI) as the signed coefficient of the linear relationship between baseline FC (at 14 years,FC14) and adolescent change in FC (∆FC14−26). Disruptive systems (with negative MI) were functionally specialised for social cognition and autobiographical memory and were significantly co-located with prior maps of aerobic glycolysis (AG), AG-related gene expression, post-natal expansion of cortical surface area, and adolescent shrinkage of cortical depth. We conclude that human brain organization is disrupted during adolescence by the emergence of strong functional connectivity of subcortical nuclei and association cortical areas, representing metabolically expensive re-modelling of synaptic connectivity between brain regions that were not strongly connected in childhood. We suggest that this re-modelling process may support emergence of social skills and self-awareness during healthy human adolescence.

scholarly journals A Distributed Network for Multimodal Experiential Representation of Concepts

2021 ◽  
Author(s):  
Jia-Qing Tong ◽  
Jeffrey R. Binder ◽  
Colin J. Humphries ◽  
Lisa L. Conant ◽  
Leonardo Fernandino
Keyword(s):  
Brain Regions ◽  
Association Cortex ◽  
Specific Information ◽  
Concept Representation ◽  
Sensory Motor ◽  
Similarity Structure ◽  
Convergence Zones ◽  
Cortical Regions ◽  
Cortical System ◽  
High Level

The architecture of the cortical system underlying concept representation is a topic of intense debate. Much evidence supports the claim that concept retrieval selectively engages sensory, motor, and other neural systems involved in the acquisition of the retrieved concept, yet there is also strong evidence for involvement of high-level, supramodal cortical regions. A fundamental question about the organization of this system is whether modality-specific information originating from sensory and motor areas is integrated across multiple ″convergence zones″ or in a single centralized ″hub″. We used representational similarity analysis (RSA) of fMRI data to map brain regions where the similarity structure of neural patterns elicited by large sets of concepts matched the similarity structure predicted by a high-dimensional model of concept representation based on sensory, motor, affective, and other modal aspects of experience. Across two studies involving different sets of concepts, different participants, and different tasks, searchlight RSA revealed a distributed, bihemispheric network engaged in multimodal experiential representation, composed of high-level association cortex in anterior, lateral, and ventral temporal lobe; inferior parietal lobule; posterior cingulate gyrus and precuneus; and medial, dorsal, ventrolateral, and orbital prefrontal cortex. These regions closely resemble networks previously implicated in general semantic and ″default mode″ processing and are known to be high-level hubs for convergence of multimodal processing streams. Supplemented by an exploratory cluster analysis, these results indicate that the concept representation system consists of multiple, hierarchically organized convergence zones supporting multimodal integration of experiential information.

scholarly journals Cerebral Reorganization in Subacute Stroke Survivors after Virtual Reality-Based Training: A Preliminary Study

2017 ◽  
Vol 2017 ◽  
pp. 1-8 ◽  
Author(s):  
Xiang Xiao ◽  
Qiang Lin ◽  
Wai-Leung Lo ◽  
Yu-Rong Mao ◽  
Xin-chong Shi ◽  
...  
Keyword(s):  
Virtual Reality ◽  
Sensorimotor Cortex ◽  
Brain Regions ◽  
Cortical Reorganization ◽  
Gait Velocity ◽  
Stroke Survivors ◽  
Subacute Stroke ◽  
Before And After ◽  
Primary Sensorimotor Cortex ◽  
Gait Function

Background. Functional magnetic resonance imaging (fMRI) is a promising method for quantifying brain recovery and investigating the intervention-induced changes in corticomotor excitability after stroke. This study aimed to evaluate cortical reorganization subsequent to virtual reality-enhanced treadmill (VRET) training in subacute stroke survivors.Methods. Eight participants with ischemic stroke underwent VRET for 5 sections per week and for 3 weeks. fMRI was conducted to quantify the activity of selected brain regions when the subject performed ankle dorsiflexion. Gait speed and clinical scales were also measured before and after intervention.Results. Increased activation in the primary sensorimotor cortex of the lesioned hemisphere and supplementary motor areas of both sides for the paretic foot (p<0.01) was observed postintervention. Statistically significant improvements were observed in gait velocity (p<0.05). The change in voxel counts in the primary sensorimotor cortex of the lesioned hemisphere is significantly correlated with improvement of 10 m walk time after VRET (r=−0.719).Conclusions. We observed improved walking and increased activation in cortical regions of stroke survivors after VRET training. Moreover, the cortical recruitment was associated with better walking function. Our study suggests that cortical networks could be a site of plasticity, and their recruitment may be one mechanism of training-induced recovery of gait function in stroke. This trial is registered with ChiCTR-IOC-15006064.

scholarly journals Parallel systems for social and spatial reasoning within the cortical apex

2021 ◽  
Author(s):  
Ben Deen ◽  
Winrich A Freiwald
Keyword(s):  
Spatial Reasoning ◽  
Brain Regions ◽  
Association Cortex ◽  
Temporal Lobes ◽  
Neural Architecture ◽  
Content Domain ◽  
Parallel Networks ◽  
High Level ◽  
Human Brains ◽  
Individual Human

What is the cognitive and neural architecture of systems for high-level reasoning and memory in humans? We ask this question using deep neuroimaging of individual human brains on various tasks involving reasoning and memory about familiar people, places, and objects. We find that thinking about people and places elicits responses in distinct but parallel networks within high-level association cortex, spanning the frontal, parietal, and temporal lobes. Person- and place-preferring brain regions were systematically yoked across multiple cortical zones. These regions were strongly category-selective, across visual, semantic, and episodic tasks, and were specifically functionally connected to other parts of association cortex with similar category preferences. These results demonstrate that selectivity for content domain is a widespread feature of high-level association cortex in humans. They support a theoretical model in which reasoning about people and places are supported by parallel cognitive and neural mechanisms.

scholarly journals Remapping in cerebral and cerebellar cortices is not restricted by somatotopy

2018 ◽  
Author(s):  
Avital Hahamy ◽  
Tamar R. Makin
Keyword(s):  
Cerebral Cortex ◽  
Brain Region ◽  
Body Part ◽  
Brain Regions ◽  
Body Parts ◽  
Sensorimotor Network ◽  
Arm Amputation ◽  
Sensorimotor Systems ◽  
Body Map ◽  
Hand Region

AbstractA fundamental organizing principle in the somatosensory and motor systems is somatotopy, where specific body parts are represented separately and adjacently to other body parts, resulting in a body map. Different terminals of the sensorimotor network show varied somatotopic layouts, in which the relative position, distance and overlap between body-part representations differ. Since somatotopy is best characterized in the primary somatosensory (S1) and motor (M1) cortices, these terminals have been the main focus of research on somatotopic remapping following loss of sensory input (e.g. arm amputation). Cortical remapping is generally considered to be driven by the layout of the underlying somatotopy, such that neighboring body-part representations tend to activate the deprived brain region. Here, we challenge the assumption that somatotopic layout restricts remapping, by comparing patterns of remapping in humans born without one hand (hereafter, one-handers, n=26) across multiple terminals of the sensorimotor pathway. We first report that in the cerebellum of one-handers, the deprived hand region represents multiple body parts. Importantly, the representations of some of these body parts do not neighbor the deprived hand region. We further replicate our previous finding, showing a similar pattern of remapping in the deprived hand region of the cerebral cortex in one-handers. Finally, we report preliminary results of a similar remapping pattern in the putamen of one-handers. Since these three sensorimotor terminals (cerebellum, cerebrum, putamen) contain different somatotopic layouts, the parallel remapping they undergo demonstrates that the mere spatial layout of body-part representations may not exclusively dictate remapping in the sensorimotor systems.Significance StatementWhen a hand is missing, the brain region that typically processes information from that hand may instead process information from other body-parts, a phenomenon termed remapping. It is commonly thought that only body-parts whose information is processed in regions neighboring the hand region could “take up” the resources of this now deprived region. Here we demonstrate that information from multiple body-parts is processed in the hand regions of both the cerebral cortex and cerebellum. The native brain regions of these body-parts have varying levels of overlap with the hand region across multiple terminals in the sensorimotor hierarchy, and do not necessarily neighbor the hand region. We therefore propose that proximity between brain regions does not limit brain remapping.

scholarly journals The gradient model of brain organization in decisions involving 'empathy for pain'

2021 ◽  
Author(s):  
Karin Labek ◽  
Elisa Sittenberger ◽  
Valerie Kienhoefer ◽  
Luna Rabl ◽  
Irene Messina ◽  
...  
Keyword(s):  
Default Mode Network ◽  
Functional Characterization ◽  
Visual Stimuli ◽  
Body Parts ◽  
Brain Organization ◽  
Default Mode ◽  
Cortical Areas ◽  
Gradient Model ◽  
Empathy For Pain ◽  
High Level

Recent meta-analytic studies of social cognition and the functional imaging of empathy have exposed the overlap between their neural substrates and heteromodal association areas. The 'gradient model' of cortical organization proposes a close relationship between these areas and highly connected hubs in the default mode network, a set of cortical areas deactivated by demanding tasks. Here, we used a decision-making task and representational similarity analysis with classic 'empathy for pain' visual stimuli to probe the relationship between high-level representations of imminent pain in others and the high end of the gradient of this model. High-level representations were found to co-localize with task deactivations or the transitions from activations to deactivations. These loci belonged to two groups: those that loaded on the high end of the principal cortical gradient and were associated by meta-analytic decoding with the default mode network, and those that appeared to accompany functional repurposing of somatosensory cortex in the presence of visual stimuli. In contrast to the nonspecific meta-analytic decoding of these loci, low-level representations, such as those of body parts involved in pain or of pain itself, were decoded with matching topics terms. These findings suggest that that task deactivations may set out cortical areas that host high-level representations, but whose functional characterization in terms of simple mappings is unlikely. We anticipate that an increased understanding of the cortical correlates of high-level representations may improve neurobiological models of social interactions and psychopathology.

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