Changes In Motor Areas Research Articles

Somatosensory cortical excitability changes precede those in motor cortex during human motor learning.

Motor learning is associated with plasticity in both motor and somatosensory cortex. It is known from animal studies that tetanic stimulation to each of these areas individually induces long-term potentiation in its counterpart. In this context it is possible that changes in motor cortex contribute to somatosensory change and that changes in somatosensory cortex are involved in changes in motor areas of the brain. It is also possible that learning-related plasticity occurs in these areas independently. To better understand the relative contribution to human motor learning of motor cortical and somatosensory plasticity, we assessed the time course of changes in primary somatosensory and motor cortex excitability during motor skill learning. Learning was assessed using a force production task in which a target force profile varied from one trial to the next. The excitability of primary somatosensory cortex was measured using somatosensory evoked potentials in response to median nerve stimulation. The excitability of primary motor cortex was measured using motor evoked potentials elicited by single-pulse transcranial magnetic stimulation. These two measures were interleaved with blocks of motor learning trials. We found that the earliest changes in cortical excitability during learning occurred in somatosensory cortical responses, and these changes preceded changes in motor cortical excitability. Changes in somatosensory evoked potentials were correlated with behavioral measures of learning. Changes in motor evoked potentials were not. These findings indicate that plasticity in somatosensory cortex occurs as a part of the earliest stages of motor learning, before changes in motor cortex are observed.NEW & NOTEWORTHY We tracked somatosensory and motor cortical excitability during motor skill acquisition. Changes in both motor cortical and somatosensory excitability were observed during learning; however, the earliest changes were in somatosensory cortex, not motor cortex. Moreover, the earliest changes in somatosensory cortical excitability predict the extent of subsequent learning; those in motor cortex do not. This is consistent with the idea that plasticity in somatosensory cortex coincides with the earliest stages of human motor learning.

Neurochemical correlates of functional decline in amyotrophic lateral sclerosis

ObjectiveTo determine whether proton magnetic resonance spectroscopy (1H-MRS) can detect neurochemical changes in amyotrophic lateral sclerosis (ALS) associated with heterogeneous functional decline.MethodsNineteen participants with early-stage ALS and 18 age-matched and...

Different effects of the mirror illusion on motor and somatosensory processing

Mirror therapy can improve motor and sensory functions, but effects of the mirror illusion on primary motor and somatosensory cortex could not be established consistently. Fifteen right handed healthy volunteers performed or observed a finger-thumb opposition task. Cerebral activations during normal movement (NOR), mirrored movement (MIR) and movement observation (OBS) by means of a video chain were recorded with functional magnetic resonance imaging (fMRI). Activation sizes in movement > static conditions were identified using SPM8 (p < 0.001, unc.) and attributed to predefined areas employing the Anatomy toolbox 1.8. Laterality indices for the responsive areas were calculated on the basis of the number of activated voxels. Relevant bilateral BOLD responses were found in primary motor (M1) and somatosensory (S1 - BA 2, 3b and 3a) cortex, premotor and parietal areas and V5. When comparing MIR to NOR, no significant change of contralateral activation in M1 was found, but clearly at S1 with differences between hands. The mirror illusion does not elicit immediate changes in motor areas, yet there is a direct effect on somatosensory areas, especially for left hand movements. These results suggest different effects of mirror therapy on processing and rehabilitation of motor and sensory function.

Combined pedunculopontine-subthalamic stimulation in Parkinson disease

To assess the effect of deep brain stimulation (DBS) in the pedunculopontine nucleus (PPN) and caudal zona incerta (cZi)-both separately and in combination-on motor symptoms and regional cerebral blood flow (rCBF) in patients with Parkinson disease (PD). Four patients with bilateral cZi and PPN DBS electrodes were rated with the Unified Parkinson's Disease Rating Scale motor subscale (UPDRS-III) when taking and withdrawn from medication. A block of 16 [(15)O]-H(2)O PET resting measurements of rCBF were performed in 4 different states with patients withdrawn from medication: 1) no stimulation, 2) cZi stimulation alone, 3) PPN stimulation alone, 4) combined PPN/cZi stimulation. When patients were medicated, combined PPN/cZi stimulation produced a statistically significant improvement in UPDRS-III score compared to cZi stimulation alone. In the "off" medication state, the clinical effect of combined stimulation was not significantly different from that induced by cZi stimulation alone. Concomitant PPN/cZi stimulation had a cumulative effect on levels of rCBF, effectively combining subcortical and cortical changes induced by stimulation of either target in isolation. These findings suggest that concomitant low frequency stimulation of PPN and cZi regions induces additive brain activation changes and provides improved control of PD symptoms when medicated. This study provides Class IV evidence that concomitant low frequency stimulation of PPN and cZI improves motor symptoms in patients with PD on dopamine replacement. It provides Class III evidence that concomitant low frequency stimulation of PPN and cZi induces additive rCBF changes in motor areas of brain.

Posterior medial frontal cortex signals the need for adaptations in visual and motor areas

Event Abstract Back to Event Posterior medial frontal cortex signals the need for adaptations in visual and motor areas Claudia Danielmeier1* 1 Donders Institute for Brain, Cognition and Behavior, Netherlands When errors are committed, it is important that adaptive processes take effect immediately to generate adequate behavioral and neuronal adjustments and to prevent further errors. The posterior medial frontal cortex (pMFC) has been associated with performance monitoring processes. Although the pMFC has also been hypothesized to be involved in signaling the need for these adjustments, to date there is only scarce evidence to support this. Here, I will present data showing that activity in the pMFC predicts post-error adaptations in visual and motor areas. Following errors, post-error slowing (PES) can be observed in a variety of tasks, which is thought to reflect adaptive processes and might be helpful to avoid further premature responses. Functional magnetic resonance and diffusion-weighted imaging results will be presented showing that a) pMFC activity predicts changes in motor areas that covary with PES and b) PES is structurally linked to white matter tracts that have been discussed in the context of motor inhibition. Furthermore, there are also attentional adaptations following errors. These changes seem to be task-specific and can be observed in task-related extrastriate visual areas. While activity in those visual areas encoding the relevant stimulus feature increases after errors, activity in visual areas, encoding the distracting stimulus feature, decreases. The strength of both effects is predicted by preceding error-related pMFC activity. Thus, pMFC activity predicts both attentional changes in visual areas and decreases in motor activity that are associated with PES. Keywords: goal-directed behavior, pMFC Conference: XI International Conference on Cognitive Neuroscience (ICON XI), Palma, Mallorca, Spain, 25 Sep - 29 Sep, 2011. Presentation Type: Symposium: Oral Presentation Topic: Symposium 24: Adaptive, goal-directed behavior: prefrontal cortex and beyond Citation: Danielmeier C (2011). Posterior medial frontal cortex signals the need for adaptations in visual and motor areas. Conference Abstract: XI International Conference on Cognitive Neuroscience (ICON XI). doi: 10.3389/conf.fnhum.2011.207.00601 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 14 Nov 2011; Published Online: 28 Nov 2011. * Correspondence: Dr. Claudia Danielmeier, Donders Institute for Brain, Cognition and Behavior, Nijmegen, Netherlands, c.danielmeier@donders.ru.nl Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Claudia Danielmeier Google Claudia Danielmeier Google Scholar Claudia Danielmeier PubMed Claudia Danielmeier Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.

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.

Relation of pyramidal tract activity to force exerted during voluntary movement.

in a series P of studies of the relation of discharge 01 pyramlda1 tract neurons (PTNs) to voluntary movement. The first of the previous studies (5) showed that PTN activity both at rest and during movement is related to axonal conduction velocity. PTNs with the highest axonal conduction velocities tend to be silent during motor quiescence and to show phasic activity in association with movement. PTNs with lower axonal conduction velocities are for the most part active even in the absence of movement; with movement they show both upward and downward modulation of their resting discharge frequency. A second study (6) was carried out to obtain information as to the point in the interval between stimulus and response at which PTN discharge takes place in association with a conditioned hand movement. It was found that for many PTNs, responses to the conditioned stimulus (the onset of a light) preceded the first peripheral electromyographic correlates of the conditioned response (wrist extension). The fact that these PTN responses preceded the electromyographic response showed that they were not consequent upon feedback resulting from the movement. 1