cortical maps
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2021 ◽  
Author(s):  
David M Cole ◽  
Philipp Stämpfli ◽  
Robert Gandia ◽  
Louis Schibli ◽  
Sandro Gantner ◽  
...  

Persistent pain alters brain-body representations, highlighting their potential pathological significance. In chronic low back pain (LBP), sparse evidence points towards a shift of the cortical representation of sensory afferents of the back. However, systematic investigations of the cortical representation of tactile and proprioceptive paraspinal afferents along the thoracolumbar axis are lacking. Detailed cortical maps of paraspinal afferent input might be crucial to further explore potential relationships between brain changes and the development and maintenance of chronic LBP. We therefore validated a novel and functional magnetic resonance imaging- (fMRI-)compatible method of mapping cortical representations of tactile and proprioceptive afferents of the back, using pneumatic vibrotactile stimulation ("pneuVID") at varying frequencies and paraspinal locations, in conjunction with high-resolution fMRI. We hypothesised that: (i) high (80 Hz) frequency stimulation would lead to increased postural sway compared to low (20 Hz) stimulation, due to differential evoked mechanoreceptor contributions to postural control (proprioceptive vs tactile); and (ii) that high (80 Hz) versus low (20 Hz) frequency stimulation would be associated with neuronal activity in distinct primary somatosensory (S1) and motor (M1) cortical targets of tactile and proprioceptive afferents (N=15, healthy volunteers). Additionally, we expected neural representations to vary spatially along the thoracolumbar axis. We found significant differences between neural representations of low and high frequency stimulation and between representations of thoracic and lumbar paraspinal locations, in several bilateral sensorimotor cortical regions. Proprioceptive (80 Hz) stimulation preferentially activated sub-regions S1 3a and M1 4p, while tactile (20 Hz) stimulation was more encoded in S1 3b and M1 4a. Moreover, in S1, lower back proprioceptive stimulation activated dorsal-posterior representations, compared to ventral-anterior representations activated by upper back stimulation. As per our hypotheses, we found distinct sensorimotor cortical tactile and proprioceptive representations, with the latter displaying clear topographic differences between the upper and lower back. This thus represents the first behavioural and neurobiological validation of the novel pneuVID method for stimulating muscle spindles and mapping cortical representations of paraspinal afferents. Future investigations of detailed cortical maps will be of major importance in elucidating the role of cortical reorganization in the pathophysiology of chronic LBP.


2021 ◽  
Vol 13 (1) ◽  
Author(s):  
Minseok Lee ◽  
Sangwon Lee ◽  
Jejung Kim ◽  
Jeongsik Lim ◽  
Jinho Lee ◽  
...  

AbstractCortical maps, which are indicative of cognitive status, are shaped by the organism’s experience. Previous mapping tools, such as penetrating electrodes and imaging techniques, are limited in their ability to be used to assess high-resolution brain maps largely owing to their invasiveness and poor spatiotemporal resolution, respectively. In this study, we developed a flexible graphene-based multichannel electrode array for electrocorticography (ECoG) recording, which enabled us to assess cortical maps in a time- and labor-efficient manner. The flexible electrode array, formed by chemical vapor deposition (CVD)-grown graphene, provided low impedance and electrical noise because a good interface between the graphene and brain tissue was created, which improved the detectability of neural signals. Furthermore, cortical map remodeling was induced upon electrical stimulation at the cortical surface through a subset of graphene spots. This result demonstrated the macroscale plasticity of cortical maps, suggesting perceptual enhancement via electrical rehabilitation at the cortical surface.


2021 ◽  
pp. 102119
Author(s):  
Justine Facchini ◽  
Guillaume Rastoldo ◽  
Christian Xerri ◽  
David Péricat ◽  
Abdessadek El Ahmadi ◽  
...  

Science ◽  
2020 ◽  
Vol 369 (6506) ◽  
pp. 988-992
Author(s):  
Katrin Amunts ◽  
Hartmut Mohlberg ◽  
Sebastian Bludau ◽  
Karl Zilles

Cytoarchitecture is a basic principle of microstructural brain parcellation. We introduce Julich-Brain, a three-dimensional atlas containing cytoarchitectonic maps of cortical areas and subcortical nuclei. The atlas is probabilistic, which enables it to account for variations between individual brains. Building such an atlas was highly data- and labor-intensive and required the development of nested, interdependent workflows for detecting borders between brain areas, data processing, provenance tracking, and flexible execution of processing chains to handle large amounts of data at different spatial scales. Full cortical coverage was achieved by the inclusion of gap maps to complement cortical maps. The atlas is dynamic and will be adapted as mapping progresses; it is openly available to support neuroimaging studies as well as modeling and simulation; and it is interoperable, enabling connection to other atlases and resources.


2020 ◽  
Author(s):  
Ankur Gupta ◽  
Abdulraheem Nashef ◽  
Sharon Israely ◽  
Michal Segal ◽  
Ran Harel ◽  
...  

SummaryCortical maps often undergo plastic changes during learning or in response to injury. In sensory areas, these changes are thought to be triggered by alterations in the pattern of converging inputs and a functional reassignment of the deprived cortical region. In the motor cortex, training on a task that engages distal effectors was shown to increase their cortical representation (as measured by response to intracortical microstimulation). However, this expansion could be a specific outcome of using a demanding dexterous task. We addressed this question by measuring the long-term changes in cortical maps of monkeys that were sequentially trained on two different tasks involving either proximal or distal joints. We found that motor cortical remodeling in adult monkeys was symmetric such that both distal and proximal movements can comparably alter motor maps in a fully reversible manner according to task demands. Further, we found that the change in mapping often included a switch between remote joints (e.g., a finger site switched to a shoulder site) and reflected a usage-consistent reorganization of the map rather than the local expansion of one representation into nearby sites. Finally, although cortical maps were considerably affected by the performed task, motor cortical neurons throughout the motor cortex were equally likely to fire in a task-related manner independent of the task and/or the recording site. These results may imply that in the motor system, enhanced motor efficiency is achieved through a dynamical allocation of larger cortical areas and not by specific recruitment of task-relevant cells.


2019 ◽  
Author(s):  
Tomer Fekete ◽  
David B. Omer ◽  
Amiram Grinvald ◽  
Cees van Leeuwen

ABSTRACTSpontaneously emerging cortical maps related to the functional architecture of visual cortex have been observed initially in anesthetized cats and, subsequently, in monkey, albeit only under certain anesthetic regimes, and not in the awake state. Here we propose a network model that can accommodate these diverse findings. The model identifies two crucial determinants for the emergence of spontaneous map-like activity – local balance between excitatory and inhibitory activity, and the strength of feature-specific synaptic connections (e.g. orientation, ocularity). Our model further shows that dynamically, map-like activity patterns could be triggered either by standing or travelling waves, a mode of operation which is determined by the spatial extent of lateral connections within a given network. Our results suggest that careful pharmacological intervention can unveil the prevalence of maps – recurring spatial patterns of inhomogeneous lateral connectivity - in cortex without the need to explicitly identify area specific optimal features.


Epilepsia ◽  
2019 ◽  
Vol 60 (2) ◽  
pp. 255-267 ◽  
Author(s):  
Yasuo Nakai ◽  
Ayaka Sugiura ◽  
Erik C. Brown ◽  
Masaki Sonoda ◽  
Jeong‐Won Jeong ◽  
...  

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