Posts Tagged Corticospinal tract

[ARTICLE] Recovery of hand function after stroke: separable systems for finger strength and control – Full Text PDF

Abstract

Loss of hand function after stroke is a major cause of long-term disability. Hand function can be partitioned into strength and independent control of fingers (individuation).

Here we developed a novel paradigm, which independently quantifies these two aspects of hand function, to track hand recovery in 54 patients with hemiparesis over the first year after their stroke. Most recovery of both strength and individuation occurred in the first three months after stroke. Improvement in strength and individuation were tightly correlated up to a strength level of approximately 60% of the unaffected side. Beyond this threshold, further gains in strength were not accompanied by improvements in individuation. Any observed improvements in individuation beyond the 60% threshold were attributable instead to a second independent stable factor.

Lesion analysis revealed that damage to the hand area in motor cortex and the corticospinal tract (CST) correlated more with individuation than with strength. CST involvement correlated with individuation even after factoring out the strength-individuation correlation. The most parsimonious explanation for these behavioral and lesion-based findings is that most strength recovery, along with some individuation, can be attributed to descending systems other than the CST, whereas further recovery of individuation is CST dependent. (Note: Jing Xu and Naveed Ejaz contributed equally to this work.)

Preview PDF

Source: Recovery of hand function after stroke: separable systems for finger strength and control | bioRxiv

, , , , , , , , ,

Leave a comment

[Abstract] Neural network remodeling underlying motor map reorganization induced by rehabilitative training after ischemic stroke

Highlights

RFA plays a critical role in task-specific recovery induced by rehabilitative training after CFA stroke.

Rehabilitative training elevates responsiveness of the forelimb area and expands the RFA.

Rehabilitative training increases the corticospinal fibers from the RFA in the lower cervical cord.

Neurons projecting to the upper cervical cord provide new connections to the denervated forelimb area of the spinal cord.

Abstract

Motor map reorganization is believed to be one mechanism underlying rehabilitation-induced functional recovery. Although the ipsilesional secondary motor area has been known to reorganize motor maps and contribute to rehabilitation-induced functional recovery, it is unknown how the secondary motor area is reorganized by rehabilitative training. In the present study, using skilled forelimb reaching tasks, we investigated neural network remodeling in the rat rostral forelimb area (RFA) of the secondary motor area during 4 weeks of rehabilitative training. Following photothrombotic stroke in the caudal forelimb area (CFA), rehabilitative training led to task-specific recovery and motor map reorganization in the RFA. A second injury to the RFA resulted in reappearance of motor deficits. Further, when both the CFA and RFA were destroyed simultaneously, rehabilitative training no longer improved task-specific recovery. In neural tracer studies, although rehabilitative training did not alter neural projection to the RFA from other brain areas, rehabilitative training increased neural projection from the RFA to the lower spinal cord, which innervates the muscles in the forelimb. Double retrograde tracer studies revealed that rehabilitative training increased the neurons projecting from the RFA to both the upper cervical cord, which innervates the muscles in the neck, trunk, and part of the proximal forelimb, and the lower cervical cord. These results suggest that neurons projecting to the upper cervical cord provide new connections to the denervated forelimb area of the spinal cord, and these new connections may contribute to rehabilitation-induced task-specific recovery and motor map reorganization in the secondary motor area.

Source: Neural network remodeling underlying motor map reorganization induced by rehabilitative training after ischemic stroke

, , , , ,

Leave a comment

[Abstract] Brain–machine interfaces for rehabilitation of poststroke hemiplegia

Abstract

Noninvasive brain–machine interfaces (BMIs) are typically associated with neuroprosthetic applications or communication aids developed to assist in daily life after loss of motor function, eg, in severe paralysis.

However, BMI technology has recently been found to be a powerful tool to promote neural plasticity facilitating motor recovery after brain damage, eg, due to stroke or trauma.

In such BMI paradigms, motor cortical output and input are simultaneously activated, for instance by translating motor cortical activity associated with the attempt to move the paralyzed fingers into actual exoskeleton-driven finger movements, resulting in contingent visual and somatosensory feedback.

Here, we describe the rationale and basic principles underlying such BMI motor rehabilitation paradigms and review recent studies that provide new insights into BMI-related neural plasticity and reorganization.

Current challenges in clinical implementation and the broader use of BMI technology in stroke neurorehabilitation are discussed.

 

Source: Brain–machine interfaces for rehabilitation of poststroke hemiplegia

, , , , , , , ,

Leave a comment

[Abstract] Brain–machine interfaces for rehabilitation of poststroke hemiplegia

Abstract

Noninvasive brain–machine interfaces (BMIs) are typically associated with neuroprosthetic applications or communication aids developed to assist in daily life after loss of motor function, eg, in severe paralysis. However, BMI technology has recently been found to be a powerful tool to promote neural plasticity facilitating motor recovery after brain damage, eg, due to stroke or trauma. In such BMI paradigms, motor cortical output and input are simultaneously activated, for instance by translating motor cortical activity associated with the attempt to move the paralyzed fingers into actual exoskeleton-driven finger movements, resulting in contingent visual and somatosensory feedback. Here, we describe the rationale and basic principles underlying such BMI motor rehabilitation paradigms and review recent studies that provide new insights into BMI-related neural plasticity and reorganization. Current challenges in clinical implementation and the broader use of BMI technology in stroke neurorehabilitation are discussed.

 

Source: Brain–machine interfaces for rehabilitation of poststroke hemiplegia

, , , , , , , , ,

Leave a comment

[Abstract] Brain–machine interfaces for rehabilitation of poststroke hemiplegia

Abstract

Noninvasive brain–machine interfaces (BMIs) are typically associated with neuroprosthetic applications or communication aids developed to assist in daily life after loss of motor function, eg, in severe paralysis. However, BMI technology has recently been found to be a powerful tool to promote neural plasticity facilitating motor recovery after brain damage, eg, due to stroke or trauma. In such BMI paradigms, motor cortical output and input are simultaneously activated, for instance by translating motor cortical activity associated with the attempt to move the paralyzed fingers into actual exoskeleton-driven finger movements, resulting in contingent visual and somatosensory feedback. Here, we describe the rationale and basic principles underlying such BMI motor rehabilitation paradigms and review recent studies that provide new insights into BMI-related neural plasticity and reorganization. Current challenges in clinical implementation and the broader use of BMI technology in stroke neurorehabilitation are discussed.

Keywords

 

Source: Brain–machine interfaces for rehabilitation of poststroke hemiplegia

, , , , , , , ,

Leave a comment

%d bloggers like this: