Open Collections

Cutaneous modulation of the stretch reflex pathway during standing

University of British Columbia. Djavad Mowafaghian Centre for Brain Health; International Collaboration on Repair Discoveries; University of British Columbia. Institute for Computing, Information and Cognitive Systems

Cutaneous feedback from the foot sole provides balance relevant information and has the potential to interact with spinal reflex pathways. In this study, we examined how cutaneous feedback from the foot sole (heel and metatarsals) influenced the soleus response to proprioceptive stimuli during standing. We delivered noisy vibration (10-115 Hz) to the right Achilles tendon while we intermittently applied electrical pulse trains (five 1 ms pulses at 200 Hz, every 0.8-1.0 s) to the skin under the heel or metatarsals of the ipsilateral foot sole. We analyzed time-dependent (referenced to cutaneous stimuli) coherence and cross- correlations between the vibration acceleration and rectified soleus EMG. Vibration-EMG coherence was observed across a bandwidth of ~10-80 Hz, and coherence was suppressed by heel but enhanced by metatarsal cutaneous stimuli. Cross-correlations showed soleus EMG was correlated with the vibration (~40 ms lag) and cross-correlations were also suppressed by heel (from 104-155 ms) but enhanced by metatarsal (from 76-128 ms) stimuli. To examine the neural mechanisms mediating this reflex interaction, we conducted two experiments to probe potential contributions from 1) presynaptic inhibition, and 2) modulations at the ⍺- and 𝛾-motoneuron pools. Results suggest the cutaneous interactions with the stretch reflex pathway required a modulation at the ⍺-motoneuron pool and were likely not mediated by presynaptic inhibition. These findings demonstrate that foot sole cutaneous information functionally tunes the stretch reflex pathway during the control of upright posture and balance.

Preprint

eng

Vancouver : University of British Columbia Library

10.14288/1.0395129

Education, Faculty of; Alumni; Non UBC; Kinesiology, School of

Unreviewed

http://creativecommons.org/licenses/by-nc-nd/4.0/