Topic
Nonprimary motor cortex
About: Nonprimary motor cortex is a research topic. Over the lifetime, 5 publications have been published within this topic receiving 317 citations.
Papers
Book•
1 Dec 2003
TL;DR: The question whether a motor task engages only the "motor domain" of the supplementary motor/premotor cortex or in addition the "cognitive domain of the prefrontal cortex can only be answered by superimposing the functional activation map with the microstructural population map of area 6.
Abstract: When we voluntarily interact with our environment, the agranular frontal cortex (Brodmann's areas 4 and 6) plays a pivotal role in cortical motor control. The primary motor cortex (area 4) influences kinematic and dynamic parameters of movements, whereas the rostrally adjoining nonprimary motor cortex (area 6) uses external (e.g., sensory) or internal cues to trigger and guide movements. Once thought to be homogeneous, data from nonhuman primates have shown that area 6 is a mosaic of areas, each with distinct structural and functional properties: the supplementary motor areas "SMA proper" and "pre-SMA" on the mesial cortical surface, and the dorso- and ventrolateral premotor cortex on the cortical convexity. Dorso- and ventrolateral premotor areas are specifically connected with posterior parietal areas. These parieto-frontal circuits work in parallel and tranform different aspects of sensory information into appropriate motor commands. The rostral border of area 6 is very important for functional neuroimaging studies in humans since it separates the "motor domain" of the supplementary motor/premotor cortex from the "cognitive domain" of the prefrontal cortex. Can the topography of this border be inferred from the gyral pattern of the frontal lobe? To answer this, ten postmorterm brains were scanned with a T1-weighted magnetic resonance sequence. The brains were serially sectioned at 20 micro M and area 6 was defined by subjective and objective cytoarchitectonic analysis. Each brain's histological volume (with the representation of area 6) was reconstructed in 3-D and spatially normalized to the reference brain of a computerized atlas. The ten normalized volumes were superimposed and a population map was generated that describes, for each voxel, how many brains have a representation of area 6. On the mesial coetical surface, the rostral border of area 6 lies rostral to the anterior commissure-- though the distance varies across different brains. On the lateral convexity, the border recedes in a caudal direction-- again to a varying degree in different brains-- and lies on the precentral gyrus close to the sylvian fissure. No macroanatomical landmark indicates the border between area 6 and the prefrontal cortex. The question whether a motor task engages only the "motor domain" of the supplementary motor/premotor cortex or in addition the "cognitive domain" of the prefrontal cortex can only be answered by superimposing the functional activation map with the microstructural population map of area 6.
199 citations
Journal Article•
TL;DR: No particular type of reorganization pattern could be predicted fMRI could be localized reorganized cortex and was found to be a useful tool to assess the lesion-to-activation distance for predicting risk of new motor deficit after surgery.
Abstract: Objective: Test the hypothesis about the potential role of functional MRI (fMRI) to evaluate the plasticity of the cortical motor areas in patients with brains tumors and brain arteriovenous malformations (AVMs) and measurement of the lesion-to-fMRI activation distance for predicting risk of new motor deficit after surgery. Material and Method: This was a retrospective study. The present study population enrolled eight patients with motor cortex lesions. Cortical motor representations were mapped in these patients harboring tumor or AVMs occupying the region of primary motor cortex (M1). Five patients had known diagnosis of primary brain tumor including glioblastoma multiforme, (n = 1), diffuse astrocytoma (n = 2), dysembryoplastic neuroepithelial tumor (DNET) (n = 1) and unknown pathology (n = 1). Three patients had known diagnosis of brain AVMs. Three patients showed hemiparesis at the time of presentation. Focal/generalized seizure or headache was present in the remaining patients. Simple movements of both hands were performed. Localization of the activation in the affected hemisphere was compared with that in the unaffected hemisphere and evaluated with respect to the normal M1 somatotopic organization. Distance between the location of the fMRI activation (M1) and margin of the lesion was recorded. Results: Cortical activation was found in two patterns: 1) functional displacement within affected M1 independent of the structural distortion induced by the tumor or AVMs (n = 7) and 2) presence of activation within the non-primary motor cortex without activation in the affected or unaffected M1 (n = 1). Conclusion: Brain tumor or AVMs led to reorganization within the somatotopic affected M1 and can expand into nonprimary motor cortex area. Distortion of the anatomy alone by the space-taking lesion did not influence the location of the reorganized cortex. No particular type of reorganization pattern could be predicted. fMRI could be localized reorganized cortex and was found to be a useful tool to assess the lesion-to-activation distance for predicting risk of new motor deficit after surgery. The present study thus emphasizes the importance of considering additional fMRI with structural MRI to evaluate individual differences in cortical plasticity for treatment planning, particularly in the neurosurgical procedure. Keywords: Plasticity, Motor cortex, Brain tumors, Arteriovenous malformations, Functional MR
17 citations
TL;DR: In this paper, mirror movements (MMs; involuntary movements occurring in 1 hand when performing unilateral movements with the contralateral hand) in the paretic hand rarely occur.
Abstract: When stroke occurs in adulthood, mirror movements (MMs; involuntary movements occurring in 1 hand when performing unilateral movements with the contralateral hand) in the paretic hand rarely occur. We present a case of an apparently healthy 54-year-old man presenting with MMs in his left (nondominant) hand. Further evaluation revealed diminished strength and dexterity in left hand, increased spinal excitability, decreased corticospinal excitability, occurrence of ipsilateral motor responses, enlarged cortical motor representation, and imaging findings consistent with a previously undiagnosed right-subcortical stroke. MMs and ipsilateral motor responses may reflect the increased spinal motor neurons' excitability sustained by the spared nonprimary ipsilesional motor areas.
3 citations
1 Jan 2015
TL;DR: A case of an apparently healthy 54‐year‐old man presenting with MMs in his left (nondominant) hand revealed diminished strength and dexterity in left hand, increased spinal excitability, decreased corticospinal excitable, occurrence of ipsilateral motor responses, enlarged cortical motor representation, and imaging findings consistent with a previously undiagnosed right‐subcortical stroke.
Abstract: When stroke occurs in adulthood, mirror movements (MMs; involuntary movements occurring in 1 hand when performing unilateral movements with the contralateral hand) in the paretic hand rarely occur. We present a case of an apparently healthy 54-year-old man presenting with MMs in his left (nondominant) hand. Further evaluation revealed diminished strength and dexterity in left hand, increased spinal excitability, decreased corticospinal excitability, occurrence of ipsilateral motor responses, enlarged cortical motor representation, and imaging findings consistent with a previously undiagnosed right-subcortical stroke. MMs and ipsilateral motor responses may reflect the increased spinal motor neurons’ excitability sustained by the spared nonprimary ipsilesional motor areas.
2 citations
TL;DR: This result indicates that the nonprimary motor cortex is involved in higher-order coding of the laterality of the motor response, implying that it exerts its motor control function at a higher hierarchical level3 than its counterpart in the primary motor cortex.
Abstract: In the primate cerebral cortex there are at least two somatotopically organized, nonprimary motor fields rostral to the primary motor area. To understand the functions of these multiple motor representations we have compared the neuronal activity in each of these fields while monkeys performed a trained motor task, using right, left or both hands. In the nonprimary motor cortex, activity in a number of neurons was related to the movement the animal chose and performed, whereas in the primary motor cortex, changes in the firing of most neurons were simply related to activity in the contralateral muscles. This result indicates that the nonprimary motor cortex is involved in higher-order coding of the laterality of the motor response, implying that it exerts its motor control function at a higher hierarchical level than its counterpart in the primary motor cortex.
Related Topics (5)
Performance Metrics
| Year | Papers |
|---|---|
| 2016 | 1 |
| 2015 | 1 |
| 2011 | 1 |
| 2003 | 1 |
| 1987 | 1 |