Stimulation system for rat whisker and functional recovery after infraorbital nerve transection
Date Issued
2016
Date
2016
Author(s)
Chen, Ji-Lin
Abstract
Functional loss of peripheral nerve, such as cutting injury, blunt injury, laceration injury and nerve transplantation, is a common clinical condition. For example, the sensation of the finger will take a long time to recover following a nerve reconstruction surgery for some patients with nerve injury. Therefore, the neuroplasticity mechanisms in the primary somatosensory cortex by a nerve reconstruction surgery were investigated. The whisker-to-barrel model was used to evaluate the change of neuronal tuning following neurotomy and neurorrhaphy surgery, an approach that simulates a clinical nerve reconstruction surgery. We first developed a whisker stimulator that can present precise whisker bending at various directions and speeds. The whiskers were bended by the piezoelectric actuator that has two degrees of freedom, each of which was driven by amplified voltage signals controlled by the software. We designed the whisker holder and completed the software calibration to provide whisker movement with precise amplitude and phase control. Furthermore, we developed a measuring device to monitor the amplitude movement of stimulator in real time. Multi-unit neuronal activities were recorded before and after the neurotomy and neurorrhaphy surgery, and the follow-up period reached 4-6 weeks post-surgery. The results showed that all units lost their sensory responses immediately after the surgery. Surprisingly, the sensory responses could recover as early as 7 days. In the long-term follow-up, one third of the unit regained whisker tuning that was analogous to that before the surgery. Also, their tuning strength to stimulus speed was weakened in the early recovery period and then gradually increased in the late recovery period. Similarly, the onset latency of a cortical response to whisker stimulation also prolonged in the early recovery period and gradually decreased in the late recovery period. In conclusion, the present study reveals the neuronal mechanisms that account for the functional recovery following nerve reconstruction in the whisker-to-barrel model.
Subjects
whisker stimulator
functional recovery
tuning function
receptive field
Type
thesis
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