Reorganization Of Motor Cortex Research Articles

Functional reorganization of the rat motor cortex following motor skill learning.

Functional reorganization of the rat motor cortex following motor skill learning. J. Neurophysiol. 80: 3321-3325, 1998. Adult rats were allocated to either a skilled or unskilled reaching condition (SRC and URC, respectively). SRC animals were trained for 10 days on a skilled reaching task while URC animals were trained on a simple bar pressing task. After training, microelectrode stimulation was used to derive high resolution maps of the forelimb and hindlimb representations within the motor cortex. In comparison with URC animals, SRC animals exhibited a significant increase in mean area of the wrist and digit representations but a decrease in elbow/shoulder representation within the caudal forelimb area. No between-group differences in areal representation were found in either the hindlimb or rostral forelimb areas. These results demonstrate that motor skill learning is associated with a reorganization of movement representations within the rodent motor cortex.

Recovery of swallowing after dysphagic stroke relates to functional reorganization in the intact motor cortex

Background & Aims: The aim of this study was to determine the mechanism for recovery of swallowing after dysphagic stroke. Methods: Twenty-eight patients who had a unilateral hemispheric stroke were studied 1 week and 1 and 3 months after the stroke by videofluoroscopy. Pharyngeal and thenar electromyographic responses to magnetic stimulation of multiple sites over both hemispheres were recorded, and motor representations were correlated with swallowing recovery. Results: Dysphagia was initially present in 71% of patients and in 46% and 41% of the patients at 1 and 3 months, respectively. Cortical representation of the pharynx was smaller in the affected hemisphere (5 ± 1 sites) than the unaffected hemisphere (13 ± 1 sites; P ≤ 0.001). Nondysphagic and persistently dysphagic patients showed little change in pharyngeal representation in either hemisphere at 1 and 3 months compared with presentation, but dysphagic patients who recovered had an increased pharyngeal representation in the unaffected hemisphere at 1 and 3 months (15 ± 2 and 17 ± 3 vs. 9 ± 2 sites; P ≤ 0.02) without change in the affected hemisphere. In contrast, thenar representation increased in the affected hemisphere but not the unaffected hemisphere at 1 and 3 months ( P ≤ 0.01). Conclusions: Return of swallowing after dysphagic stroke is associated with increased pharyngeal representation in the unaffected hemisphere, suggesting a role for intact hemisphere reorganization in recovery. GASTROENTEROLOGY 1998;115:1104-1112

Gut feelings about recovery after stroke: the organization and reorganization of human swallowing motor cortex

Swallowing problems can affect as many as one in three patients in the period immediately after a stroke. In some cases this can lead to serious morbidity, in particular malnutrition and pulmonary aspiration. Despite this, swallowing usually recovers completely in the vast majority of patients within weeks. This impressive propensity for recovery is likely to relate to how the area of the motor cortex concerned with swallowing is organized and then reorganized after cerebral injury. Recent studies have indicated that swallowing has a bilateral but asymmetric inter-hemisphere representation within motor and premotor cortex. Damage to the hemisphere that has the greater swallowing output appears to predispose that individual to swallowing problems. However, because there is additional substrate for swallowing in the undamaged hemisphere, the capacity for compensatory reorganization in the contralateral motor cortex might be increased, leading to a greater likelihood of recovery. Swallowing might be an excellent system for studying cortical plasticity, and might prove useful in the development of new therapies aimed at accelerating reorganization in the undamaged hemisphere after unilateral cerebral injury.

Receptor organ damage causes loss of cortical surround inhibition without topographic map plasticity.

Following restricted peripheral damage, reorganization of adult sensory or motor cortex is believed to depend on loss of surround inhibition, which unmasks latent inputs to the deprived cortex. Here I demonstrate that limited damage to auditory receptors causes loss of functional surround inhibition in the cortex, unmasking of latent inputs and significantly altered neural coding. However, these changes do not lead to plasticity of the cortical map, defined by the most sensitive input from the receptor surface to each cortical location. Thus, in sensory cortex, loss of surround inhibition as a consequence of receptor organ damage does not necessarily result in cortical map plasticity.

Long-term reorganization of human motor cortex driven by short-term sensory stimulation.

Removal of sensory input can induce changes in cortical motor representation that reverse when sensation is restored. Here we ask whether manipulation of sensory input can induce long-term reorganization in human motor cortex that outlasts the initial conditioning. We report that for at least 30 minutes after pharyngeal stimulation, motor cortex excitability and area of representation for the pharynx increased, while esophagus representation decreased, without parallel changes in the excitability of brainstem-mediated reflexes. Therefore increased sensory input can drive long-term cross-system changes in motor areas of the cerebral cortex, which suggests that sensory stimulation might rehabilitate dysphagia, a frequent consequence of cerebral injury.

FMRI of Cortical Reorganization in the Primary Motor and Sensory Cortex after Traumatic upper Limb Amputation

fMRI of Cortical Reorganization in the Primary Motor and Sensory Cortex after Traumatic upper Limb Amputation

Precentral glioma location determines the displacement of cortical hand representation.

Low-grade brain tumors may remain asymptomatic in contrast to malignant gliomas. The mechanisms underlying the preservation of cerebral function in such gliomas are not well understood. We used positron emission tomography and transcranial magnetic stimulation for presurgical monitoring of motor hand function in six patients with gliomas of the precentral gyrus. All patients were able to perform finger movements of the contralesional hand. Movement-related increases of the regional cerebral blood flow occurred only outside the tumor in surrounding brain tissue. Compared with the contralateral side, these activations were shifted by 20 +/- 13 mm (standard deviation) within the dorsoventral dimension of the precentral gyrus. This shift of cortical hand representation could not be explained by the deformation of the central sulcus as determined from the spatially aligned magnetic resonance images but was closely related to the location of the maximal tumor growth. Dorsal tumor growth resulted in ventral displacement of motor hand representation, leaving the motor cortical output system unaffected, whereas ventral tumor growth leading to dorsal displacement of motor hand representation compromised the motor cortical output, as evident from transcranial magnetic stimulation. In two patients, additional activation of the supplementary motor area was present. Our data provide evidence for the reorganization of the human motor cortex to allow for preserved hand function in Grade II astrocytomas.

Primary motor cortex reorganization in a long-term monkey amputee

The primary motor cortex (M1) was mapped with intracortical microstimulation (ICMS) in a 15 year-old macaque whose right upper extremity was amputated at the shoulder joint prior to 2 years of age. Movements of the right shoulder girdle and stump were evoked by ICMS throughout the left M1 upper extremity region. The size of the left M1 upper extremity region contralateral to the amputated arm was not appreciably different from the size of the right upper extremity region contralateral to the intact arm. Long stimulus trains and/or higher stimulus currents were needed to evoke detectable movements at significantly more loci in the left than in the right M1 upper extremity region. These observations would be consistent with unmasking of a high threshold representation of shoulder musculature that normally exists throughout the central core of the upper extremity region, where it underlies a lower threshold representation of the distal forelimb. Alternatively, invasion of the de-efferented distal forelimb core by surrounding shoulder representation may have occurred. Differences between the limited M1 reorganization observed in the present study and the more extensive reorganization of S1 observed in other studies may reflect fundamental differences between M1 and S1, and/or differences in the extent of de-efferentation versus deafferentation.

Neural substrates for the effects of rehabilitative training on motor recovery after ischemic infarct.

Substantial functional reorganization takes place in the motor cortex of adult primates after a focal ischemic infarct, as might occur in stroke. A subtotal lesion confined to a small portion of the representation of one hand was previously shown to result in a further loss of hand territory in the adjacent, undamaged cortex of adult squirrel monkeys. In the present study, retraining of skilled hand use after similar infarcts resulted in prevention of the loss of hand territory adjacent to the infarct. In some instances, the hand representations expanded into regions formerly occupied by representations of the elbow and shoulder. Functional reorganization in the undamaged motor cortex was accompanied by behavioral recovery of skilled hand function. These results suggest that, after local damage to the motor cortex, rehabilitative training can shape subsequent reorganization in the adjacent intact cortex, and that the undamaged motor cortex may play an important role in motor recovery.

Electron microscopical evidence of synaptic reorganization in the contralateral motor cortex of adult rats following facial nerve lesion.

Here we report on the rapid changes in the motor cortex of the rat following peripheral lesioning of a motor nerve. Facial nerve transection increases synaptic reorganization (autophagy, lysosomal degradation of synaptic components) already within 4 h after lesion. These changes occur in the motor cortex of both hemispheres, i.e. on the same and contralateral sides. An increase in the number of presynaptic lysosomes was transient and returned to below normal values within 24 h after facial nerve transection.

Spatial organization of precentral cortex in awake primates. III. Input-output coupling.

Spatial organization of precentral cortex in awake primates. III. Input-output coupling.J T Murphy, H C Kwan, W A MacKay, and Y C WongJ T Murphy, H C Kwan, W A MacKay, and Y C WongPublished Online:01 Sep 1978https://doi.org/10.1152/jn.1978.41.5.1132MoreSectionsPDF (1 MB)Download PDF ToolsExport citationAdd to favoritesGet permissionsTrack citations ShareShare onFacebookTwitterLinkedInWeChat Previous Back to Top Next Download PDF FiguresReferencesRelatedInformationCited ByCortical Mechanisms Underlying the Organization of Goal-Directed Actions and Mirror Neuron-Based Action UnderstandingGiacomo Rizzolatti, Luigi Cattaneo, Maddalena Fabbri-Destro, and Stefano Rozzi1 April 2014 | Physiological Reviews, Vol. 94, No. 2Somatosensory responses in a human motor cortexAmmar Shaikhouni, John P. Donoghue, and Leigh R. 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Ostry1 February 2013 | Journal of Neurophysiology, Vol. 109, No. 3Sequential Activation of Motor Cortical Neurons Contributes to Intralimb Coordination During Reaching in the Cat by Modulating Muscle SynergiesSergiy Yakovenko, Nedialko Krouchev, and Trevor Drew1 January 2011 | Journal of Neurophysiology, Vol. 105, No. 1Encoding of Reach and Grasp by Single Neurons in Premotor Cortex Is Independent of Recording SiteEran Stark, Itay Asher, and Moshe Abeles1 May 2007 | Journal of Neurophysiology, Vol. 97, No. 5Fonctions motricesEMC - Neurologie, Vol. 1, No. 3Sensing Limb Movements in The Motor Cortex: How Humans Sense Limb Movement29 June 2016 | The Neuroscientist, Vol. 10, No. 1Roles of primate spinal interneurons in preparation and execution of voluntary hand movementBrain Research Reviews, Vol. 40, No. 1-3Constraints on Somatotopic Organization in the Primary Motor CortexMarc H. Schieber1 November 2001 | Journal of Neurophysiology, Vol. 86, No. 5Masticatory Force and Function in Patients with Hemispheric Brain Infarction and Hemiplegia8 November 2016 | Journal of Dental Research, Vol. 78, No. 12Motor Subcircuits Mediating the Control of Movement Velocity: A PET StudyRobert S. Turner, Scott T. Grafton, John R. Votaw, Mahlon R. Delong, and John M. Hoffman1 October 1998 | Journal of Neurophysiology, Vol. 80, No. 4Primary motor cortex reorganization in a long-term monkey amputee10 July 2009 | Somatosensory & Motor Research, Vol. 14, No. 3Control of remembered reaching sequences in monkeyExperimental Brain Research, Vol. 112, No. 3A mechanical analysis of force distribution between redundant, multiple degree-of-freedom actuators in the human: Implications for the central nervous systemHuman Movement Science, Vol. 13, No. 5Input-output relationships in the jaw and orofacial motor zones of the cat cerebral cortexBrain Research, Vol. 507, No. 2Topology-conserving maps for learning visuo-motor-coordinationNeural Networks, Vol. 2, No. 3S-adenosyl-l-methionine facilitates recovery from deficits in delayed response and hand movement tasks following brain lesions in monkeysExperimental Neurology, Vol. 98, No. 3Interaction between neurons in precentral cortical zones controlling different jointsBrain Research, Vol. 400, No. 2A chronic unit study of the sensory properties of neurons in the forelimb areas of rat sensorimotor cortexBrain Research, Vol. 381, No. 1Evoked potentials from passive elbow movements. II. Modification by motor intentElectroencephalography and Clinical Neurophysiology, Vol. 64, No. 2Redistributive function of the motor cortexTrends in Neurosciences, Vol. 9Nervous propagation along ‘central’ motor pathways in intact man: Characteristics of motor responses to ‘bifocal’ and ‘unifocal’ spine and scalp non-invasive stimulationElectroencephalography and Clinical Neurophysiology, Vol. 61, No. 4Focal and diffuse metabolic changes in the spinal cord of the monkey elicited by microstimulation of differing motor cortical fociBrain Research, Vol. 310, No. 1Functional muscle partitioning during voluntary movement: Facial muscle activity for speechExperimental Neurology, Vol. 85, No. 3Participation of precentral neurons in somatically and visually triggered movements in primatesBrain Research, Vol. 247, No. 1Activity of primate precentral neurons during voluntary movements triggered by visual signalsBrain Research, Vol. 236, No. 2Interaction between forced grasping and a learned precision grip after ablation of the supplementary motor areaBrain Research, Vol. 222, No. 2Distribution of responses to visual cues for movement in precentral cortex of awake primatesNeuroscience Letters, Vol. 24, No. 2Functional role of sensory inputs to the motor cortexProgress in Neurobiology, Vol. 16, No. 3-4Precentral cortical zones related to flexion and extension in two hindlimb movements in the monkeyBrain Research, Vol. 198, No. 2What is area 3a?Brain Research Reviews, Vol. 2, No. 1-3Function of caudate neurons during limb movements in awake primatesBrain Research, Vol. 173, No. 3Differential effects of reciprocal wrist torques on responses of somatotopically identified neurons of precentral cortex in awake primatesBrain Research, Vol. 172, No. 2Cerebellar modulation of reflex gainProgress in Neurobiology, Vol. 13, No. 4 More from this issue > Volume 41Issue 5September 1978Pages 1132-9 https://doi.org/10.1152/jn.1978.41.5.1132PubMed100585History Published online 1 September 1978 Published in print 1 September 1978 Metrics

Cerebrocerebellar communication systems.

Cerebrocerebellar communication systems.

Slow and fast groups of pyramidal tract cells and their respective membrane properties.

Slow and fast groups of pyramidal tract cells and their respective membrane properties.