Sensory Biomarkers

Spinal reflex and cortical sensorimotor integration tasks

The proprioceptive/kinaesthetic signals that arrive from the periphery can be non-invasively recorded using focal vibration stimulation, EEG, and EMG. A new project firstly aims to assess the activity in the spinal myotatic pathway by evoking the Tonic Vibration Reflex (TVR). The TVR is an indirect measure of the action of the bulbospinal monoaminergic (Ca2+, Na) pathways acting on motor neuron responses to post-synaptic potentials generated by focal vibration of the tendon. This is a highly sensitive measure for assessing a major determinant of the excitability of motor neurones in spinal cord. Secondly, the project will assess how kinaesthetic information is integrated by the motor system at the cortical level, using EEG. Normal cortical processing of kinaesthetic feedback/feedforward processing likely undergoes changes in normal ageing and in disease. By eliciting cortical evoked potentials using vibration with different parameters than that for the TVR, we can examine the changes in cortical processing of afferent information that occur in disease. How the nervous system integrates afferent signals is crucial for motor adaptation and learning over the lifespan. Therefore, examining the state of this system in normal ageing and disease will be essential for improving clinical decision making in the treatment of neurodegenerative disease.

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