Aberrant Neuronal Activity in a Model of Work-Related Upper Limb Pain and Dysfunction.

Area of Science:

• Neuroscience
• Musculoskeletal Health
• Occupational Health

Background:

• Work-related musculoskeletal disorders (WMSDs) are common, often linked to repetitive tasks.
• Neuropathy is a potential cause of pain in these conditions.

Purpose of the Study:

• To investigate neuronal changes in the median nerve following a repetitive task in a rat model.
• To characterize the development of neuropathy and its impact on neuronal activity.

Main Methods:

• Rats performed an operant repetitive task for 12 weeks.
• Neuronal discharge from the median nerve was recorded.
• Pain behaviors and grip strength were assessed.

Main Results:

• After 3 weeks, rats showed pain behaviors and reduced grip strength, with ongoing neuronal activity observed.
• By 12 weeks, irregular high-frequency discharge was prevalent in most neurons.
• A significant percentage of neurons exhibited bursting discharge, and fast-conducting neurons showed reduced receptive fields, indicating neuropathology.

Conclusions:

• Operant repetitive tasks induce progressive neuropathy with significant neuropathology, primarily affecting fast-conducting neurons.
• Aberrant neuronal activity observed in this model may underlie pain in WMSDs.
• Neuronal firing patterns could aid in stratifying patients with neuropathic pain.