Abstract
Cortical reorganization in response to peripheral nervous system damage is only poorly understood. In patients with complete brachial plexus avulsion and subsequent reconnection of the end of the musculocutaneous nerve to the side of a phrenic nerve, reorganization leads to a doubled arm representation in the primary motor cortex. Despite, homuncular organization being one of the most fundamental principles of the human brain, movements of the affected arm now activate 2 loci: the completely denervated arm representation and the diaphragm representation. Here, we investigate the details behind this peripherally triggered reorganization, which happens in healthy brains. fMRI effective connectivity changes within the motor network were compared between a group of patients and age matched healthy controls at 7 Tesla (6 patients and 12 healthy controls). Results show the establishment of a driving input of the denervated arm area to the diaphragm area which is now responsible for arm movements. The findings extend current knowledge about neuroplasticity in primary motor cortex: a denervated motor area may drive an auxilliary area to reroute its motor output.
Highlights
A disturbance of arm functions can occur as a result of various lesions within the central and/or peripheral nervous system
Such cortical reorganization even occurs in the case of extreme central nervous system damage such as hemispherectomy [3]
Only few neuroimaging studies exist on cortical reorganization in response to peripheral nervous system damage
Summary
A disturbance of arm functions can occur as a result of various lesions within the central and/or peripheral nervous system. Typical mechanisms include an overactivation of secondary brain areas or of homologous (contralateral to the damaged side) brain areas, and a changed pattern of driving/inhibiting interactions within the somatosensory network [for review [1]] or the motor network [for review [2]]. Such cortical reorganization even occurs in the case of extreme central nervous system damage such as hemispherectomy [3]. The primary motor cortex is an essential cortex—its function is not recoverable after destruction
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have