scholarly journals The Cortical Motor System in the Domestic Pig: Origin and Termination of the Corticospinal Tract and Cortico-Brainstem Projections

2021 ◽  
Vol 15 ◽  
Author(s):  
Patricia del Cerro ◽  
Ángel Rodríguez-De-Lope ◽  
Jorge E. Collazos-Castro
Keyword(s):  
Spinal Cord ◽  
Motor System ◽  
Primary Motor Cortex ◽  
Corticospinal Tract ◽  
Premotor Cortex ◽  
Mesencephalic Reticular Formation ◽  
Reticular Nucleus ◽  
Descending Pathways ◽  
Spinal Segment ◽  
Cortical Motor

The anatomy of the cortical motor system and its relationship to motor repertoire in artiodactyls is for the most part unknown. We studied the origin and termination of the corticospinal tract (CST) and cortico-brainstem projections in domestic pigs. Pyramidal neurons were retrogradely labeled by injecting aminostilbamidine in the spinal segment C1. After identifying the dual origin of the porcine CST in the primary motor cortex (M1) and premotor cortex (PM), the axons descending from those regions to the spinal cord and brainstem were anterogradely labeled by unilateral injections of dextran alexa-594 in M1 and dextran alexa-488 in PM. Numerous corticospinal projections from M1 and PM were detected up to T6 spinal segment and showed a similar pattern of decussation and distribution in the white matter funiculi and the gray matter laminae. They terminated mostly on dendrites of the lateral intermediate laminae and the internal basilar nucleus, and some innervated the ventromedial laminae, but were essentially absent in lateral laminae IX. Corticofugal axons terminated predominantly ipsilaterally in the midbrain and bilaterally in the medulla oblongata. Most corticorubral projections arose from M1, whereas the mesencephalic reticular formation, superior colliculus, lateral reticular nucleus, gigantocellular reticular nucleus, and raphe received abundant axonal contacts from both M1 and PM. Our data suggest that the porcine cortical motor system has some common features with that of primates and humans and may control posture and movement through parallel motor descending pathways. However, less cortical regions project to the spinal cord in pigs, and the CST neither seems to reach the lumbar enlargement nor to have a significant direct innervation of cervical, foreleg motoneurons.

The effect of continuous theta burst stimulation over premotor cortex on circuits in primary motor cortex and spinal cord

2009 ◽  
Vol 120 (4) ◽  
pp. 796-801 ◽  
Author(s):  
Ying-Zu Huang ◽  
John C. Rothwell ◽  
Chin-Song Lu ◽  
JiunJie Wang ◽  
Yi-Hsin Weng ◽  
...  
Keyword(s):  
Spinal Cord ◽  
Motor Cortex ◽  
Primary Motor Cortex ◽  
Premotor Cortex ◽  
Theta Burst Stimulation ◽  
Burst Stimulation ◽  
Theta Burst ◽  
Continuous Theta Burst Stimulation

Effects of a Body-oriented Response Measure on the Neural Substrate of Imagined Perspective Rotations

2010 ◽  
Vol 22 (8) ◽  
pp. 1782-1793 ◽  
Author(s):  
Maryjane Wraga ◽  
Catherine M. Flynn ◽  
Holly K. Boyle ◽  
Gretchen C. Evans
Keyword(s):  
Primary Motor Cortex ◽  
Premotor Cortex ◽  
The Body ◽  
Neural Activation ◽  
Low Level ◽  
Cortical Motor ◽  
Behavioral Studies ◽  
Object Part ◽  
Response Measures ◽  
Motor Areas

Previous behavioral studies suggest that response measures related to the body, such as pointing, serve to anchor participants to their physical body during mental rotation tasks in which their perspective must be shifted elsewhere. This study investigated whether such measures engage spatial and low-level cortical motor areas of the brain more readily than non-body-related measures. We directly compared activation found in two imagined perspective rotation tasks, using responses that varied in the degree to which they emphasized the human body. In the body minimize condition, participants imagined rotating themselves around an object and judged whether a prescribed part of the object would be visible from the imagined viewpoint. In the body maximize condition, participants imagined rotating around the object and then located the prescribed object part with respect to their bodies. A direct comparison of neural activation in both conditions revealed distinct yet overlapping neural regions. The body maximize condition yielded activation in low-level cortical motor areas such as premotor cortex and primary motor cortex, as well as bilateral spatial processing areas. The body minimize condition yielded activation in nonmotoric egocentric processing regions. However, both conditions showed activation in the parietal–occipital region that is thought to be involved in egocentric transformations. These findings are discussed in the context of recent hypotheses regarding the role of the body percept in imagined egocentric transformations.

Activity Properties and Location of Neurons in the Motor Thalamus That Project to the Cortical Motor Areas in Monkeys

2005 ◽  
Vol 94 (1) ◽  
pp. 550-566 ◽  
Author(s):  
Kiyoshi Kurata
Keyword(s):  
Primary Motor Cortex ◽  
Movement Time ◽  
Premotor Cortex ◽  
Direction Selectivity ◽  
Related Activity ◽  
Cortical Motor ◽  
Somatosensory Stimulus ◽  
Preparation Period ◽  
Sustained Change ◽  
Motor Areas

The activity of neurons in the motor nuclei of the thalamus that project to the cortical motor areas (the primary motor cortex, the ventral and dorsal premotor cortex, and the supplementary motor area) was investigated in monkeys that were performing a task in which wrist extension and flexion movements were instructed by visuospatial cues before the onset of movement. Movement was triggered by a visual, auditory, or somatosensory stimulus. Thalamocortical neurons were identified by a spike collision, and exhibited 2 distinct types of task-related activity: 1) a sustained change in activity during the instructed preparation period in response to the instruction cues (set-related activity); and 2) phasic changes in activity during the reaction and movement time periods (movement-related activity). A number of set- and moment-related neurons exhibited direction selectivity. Most movement-related neurons were similarly active, irrespective of the different sensory modalities of the cue for movement. These properties of neuronal activity were similar, regardless of their target cortical motor areas. There were no significant differences in the antidromic latencies of neurons that projected to the primary and nonprimary motor areas. These results suggest that the thalamocortical neurons play an important role in the preparation for, and initiation and execution of, the movements, but are less important than neurons of the nonprimary cortical motor areas in modality-selective sensorimotor transformation. It is likely that such transformations take place within the nonprimary cortical motor areas, but not through thalamocortical information channels.

scholarly journals Plasticity of the Cortical Motor System

2008 ◽  
Vol 20 (1) ◽  
pp. 5-22 ◽  
Author(s):  
Bogdan Sadowski
Keyword(s):  
Motor Cortex ◽  
Motor System ◽  
Primary Motor Cortex ◽  
Pyramidal Neurons ◽  
Pyramidal Cells ◽  
Long Term Potentiation ◽  
Skill Learning ◽  
Dynamic Features ◽  
Cortical Motor

Plasticity of the Cortical Motor SystemThe involvement of brain plastic mechanisms in the control of motor functions under normal and pathological conditions is described. These mechanisms are based on a similar principle as the neuronal models of neuronal plasticity - long-term potentiation (LTP), and long-term depression (LTD). In the motor cortex, LTP-like phenomena play a role in strengthening synaptic connections between pyramidal neurons. LTD is important for the elimination of unnecessary inputs to the cortex. The dynamic features of the primary motor cortex activity depend on particular neuronal interconnectivity within this area. The pyramidal cells send horizontal collaterals to adjacent subregions of the primary motor cortex, and so can either excite or inhibit remote pyramidal cells. These connections can expand or shrink depending on actual physiological demands, and play a role in skill learning.

Laterality of Movement-Related Activity Reflects Transformation of Coordinates in Ventral Premotor Cortex and Primary Motor Cortex of Monkeys

2007 ◽  
Vol 98 (4) ◽  
pp. 2008-2021 ◽  
Author(s):  
Kiyoshi Kurata
Keyword(s):  
Motor Cortex ◽  
Neuronal Activity ◽  
Primary Motor Cortex ◽  
Premotor Cortex ◽  
Visuomotor Transformation ◽  
Related Activity ◽  
Reaching Task ◽  
Ventral Premotor Cortex ◽  
Cortical Motor ◽  
Target Locations

The ventral premotor cortex (PMv) and the primary motor cortex (MI) of monkeys participate in various sensorimotor integrations, such as the transformation of coordinates from visual to motor space, because the areas contain movement-related neuronal activity reflecting either visual or motor space. In addition to relationship to visual and motor space, laterality of the activity could indicate stages in the visuomotor transformation. Thus we examined laterality and relationship to visual and motor space of movement-related neuronal activity in the PMv and MI of monkeys performing a fast-reaching task with the left or right arm, toward targets with visual and motor coordinates that had been dissociated by shift prisms. We determined laterality of each activity quantitatively and classified it into four types: activity that consistently depended on target locations in either head-centered visual coordinates (V-type) or motor coordinates (M-type) and those that had either differential or nondifferential activity for both coordinates (B- and N-types). A majority of M-type neurons in the areas had preferences for reaching movements with the arm contralateral to the hemisphere where neuronal activity was recorded. In contrast, most of the V-type neurons were recorded in the PMv and exhibited less laterality than the M-type. The B- and N-types were recorded in the PMv and MI and exhibited intermediate properties between the V- and M-types when laterality and correlations to visual and motor space of them were jointly examined. These results suggest that the cortical motor areas contribute to the transformation of coordinates to generate final motor commands.

Abstract 12: Effect of Corticospinal Tract Injury on Motor Cortex Function and Connectivity After Stroke

Stroke ◽  
2017 ◽  
Vol 48 (suppl_1) ◽  
Author(s):  
Steven C Cramer ◽  
Jessica M Cassidy ◽  
Morgan Ingemanson ◽  
Ramesh Srinivasan
Keyword(s):  
Motor Cortex ◽  
Frequency Band ◽  
Primary Motor Cortex ◽  
Corticospinal Tract ◽  
Premotor Cortex ◽  
Structural Mri ◽  
Network Activity ◽  
Neural Function ◽  
Lead System ◽  
Hemiparetic Stroke

Background and Purpose: Behavioral outcome after stroke is the product of both neural injury and neural function. Little is known about how injury to the corticospinal tract (CST) affects the function of motor cortex. The purpose of this study was to understand how subcortical injury to the CST affects function and connectivity of motor cortex. Methods: Patients with chronic hemiparetic stroke completed (1) a 3-minute resting-state EEG recording using a dense-array (256-lead) system, (2) a structural MRI scan, and (3) behavioral testing. Motor cortex activity was defined as EEG power within the high beta (20-30 Hz) frequency band commonly associated with motor network activity. Motor cortex connectivity was defined as coherence in the same frequency band. CST injury was defined as % lesion overlap with CST. Results: Of the 39 subjects (56 ± 14 years, 10 females, 15 ± 25 months post-stroke), none had injury to ipsilesional primary motor cortex (M1). Spearman correlation analyses revealed that increased CST injury was significantly related to reduced cortical activity in EEG leads overlying M1 (r= -0.48, p <0.002), dorsal premotor cortex (r= -0.41, p= 0.01), and supplementary motor area (r= -0.41, p= 0.01), but not in any other brain region, bilaterally. However, increased CST injury was not associated with any changes in M1 connectivity. Arm motor status (Fugl-Meyer score) tended to be associated with increased CST injury (r= -0.28, p= 0.08) but had no relationship with M1 connectivity. Conclusions: Increased CST injury after stroke is associated with decreased activity in those motor areas that issue descending fibers via this tract, a finding consistent with prior reports indicating that axonal injury modulates upstream function of surviving cortical elements. Increased CST injury was not associated with changes in M1 connectivity, suggesting a retained capacity for plasticity in support of behavioral recovery.

Mechanisms for Recovery of Hand and Arm Function after Stroke: A Review of Evidence from Studies Using Non-Invasive Investigative Techniques

1998 ◽  
Vol 61 (8) ◽  
pp. 359-364 ◽  
Author(s):  
Ailie Turton
Keyword(s):  
Corticospinal Tract ◽  
Hand Function ◽  
Emission Tomography ◽  
Descending Pathways ◽  
Non Invasive ◽  
Cortical Motor ◽  
Positron Emission ◽  
Investigative Techniques ◽  
Invasive Techniques ◽  
Recovery Of Motor Function

The mechanisms for recovery of motor function after stroke are largely unknown. New non-invasive techniques of Positron Emission Tomography (PET) and Transcranial Magnetic Stimulation (TMS) have provided evidence for changes within the cortical motor areas and descending pathways after stroke in adult subjects. Reorganisation of the corticospinal tract originating from the damaged hemisphere is important for recovery of hand function. Some implications for occupational therapy are discussed.

Dynamic Reorganization of Motor Networks During Recovery from Partial Spinal Cord Injury in Monkeys

2018 ◽  
Vol 29 (7) ◽  
pp. 3059-3073 ◽  
Author(s):  
Zenas C Chao ◽  
Masahiro Sawada ◽  
Tadashi Isa ◽  
Yukio Nishimura
Keyword(s):  
Spinal Cord ◽  
Spinal Cord Injury ◽  
Functional Recovery ◽  
Time Course ◽  
Primary Motor Cortex ◽  
Premotor Cortex ◽  
Motor Preparation ◽  
Compensatory Mechanism ◽  
Primate Model ◽  
Cord Injury

Abstract After spinal cord injury (SCI), the motor-related cortical areas can be a potential substrate for functional recovery in addition to the spinal cord. However, a dynamic description of how motor cortical circuits reorganize after SCI is lacking. Here, we captured the comprehensive dynamics of motor networks across SCI in a nonhuman primate model. Using electrocorticography over the sensorimotor areas in monkeys, we collected broadband neuronal signals during a reaching-and-grasping task at different stages of recovery of dexterous finger movements after a partial SCI at the cervical levels. We identified two distinct network dynamics: grasping-related intrahemispheric interactions from the contralesional premotor cortex (PM) to the contralesional primary motor cortex (M1) in the high-γ band (>70 Hz), and motor-preparation-related interhemispheric interactions from the contralesional to ipsilesional PM in the α and low-β bands (10–15 Hz). The strengths of these networks correlated to the time course of behavioral recovery. The grasping-related network showed enhanced activation immediately after the injury, but gradually returned to normal while the strength of the motor-preparation-related network gradually increased. Our findings suggest a cortical compensatory mechanism after SCI, where two interdependent motor networks redirect activity from the contralesional hemisphere to the other hemisphere to facilitate functional recovery.

Changes in motor cortex activation after recovery from spinal cord inflammation

2001 ◽  
Vol 7 (6) ◽  
pp. 364-370 ◽  
Author(s):  
S C Cramer ◽  
E Fray ◽  
A Tievsky ◽  
R A Parker ◽  
P N Riskind ◽  
...  
Keyword(s):  
Spinal Cord ◽  
Motor Cortex ◽  
Activation Volume ◽  
Cervical Spinal Cord ◽  
Premotor Cortex ◽  
Left Index Finger ◽  
Control Group ◽  
Cortical Motor ◽  
Motor Improvement ◽  
Contralateral Motor

Diseases of the spinal cord are associated with reactive changes in cerebral cortex organization. Many studies in this area have examined spinal cord conditions not associated with recovery, making it difficult to consider the value of these cortical events in the restoration of neurological function. We studied patients with myelitis, a syndrome of transient spinal cord inflammation, in order to probe cortical changes that might contribute to recovery after disease of the spinal cord. Seven patients, each of whom showed improvement in hand motor function after a diagnosis of myelitis involving cervical spinal cord, were clinically evaluated then studied with functional MRI. During right and left index finger tapping, activation volumes were assessed in three cortical motor regions within each hemisphere. Results were compared with findings in nine control subjects. Compared to the control group, myelitis patients had larger activation volumes within contralateral sensorimotor as well as contralateral premotor cortex. The degree of daily hand use showed a significant correlation with the volume of activation in contralateral sensorimotor cortex. Recovery from myelitis is associated with an enlarged activation volume in contralateral motor cortices. This change in motor cortex function is related to behavioral experience, and thus may contribute to motor improvement. The expanded activation in motor cortex, seen with several forms of spinal cord insult, may have maximal utility when corticospinal tract axons are preserved.

scholarly journals Refinement of corticospinal neuron activity during skilled motor learning

2021 ◽  
Author(s):  
Najet Serradj ◽  
Francesca Marino ◽  
Yunuen Moreno-López ◽  
Sydney Agger ◽  
Andrew Sloan ◽  
...  
Keyword(s):  
Large Scale ◽  
Primary Motor Cortex ◽  
Corticospinal Tract ◽  
Activity Patterns ◽  
Critical Role ◽  
Network Activity ◽  
Neuron Activity ◽  
Cortical Motor ◽  
Dependent Behavior

AbstractThe learning of motor skills relies on plasticity of the primary motor cortex as task acquisition drives the remodeling of cortical motor networks1,2. Large scale cortical remodeling of evoked motor outputs occurs in response to the learning of skilled, corticospinal-dependent behavior, but not simple, unskilled tasks1. Here we determine the response of corticospinal neurons to both skilled and unskilled motor training and assess the role of corticospinal neuron activity in the execution of the trained behaviors. Using in vivo calcium imaging, we found that refinement of corticospinal activity correlated with the development of skilled, but not unskilled, motor expertise. Animals that failed to learn our skilled task exhibited a limited repertoire of dynamic movements and a corresponding absence of network modulation. Transection of the corticospinal tract and aberrant activation of corticospinal neurons show the necessity for corticospinal network activity patterns in the execution of skilled, but not unskilled, movement. We reveal a critical role for corticospinal network modulation in the learning and execution of skilled motor movements. The integrity of the corticospinal tract is essential to the recovery of voluntary movement after central nervous system injuries and these findings should help to shape translational approaches to motor recovery.

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