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Tone burst-evoked myogenic potentials in human neck flexor and extensor
C H Wu1, Y H Young, T Murofushi
1Department of Otolaryngology, National Taiwan University Hospital, Taipei.
Acta Oto-Laryngologica
|February 25, 2000
Summary
Vestibular evoked myogenic potential (VEMP) reflects the sacculocollic reflex. This study found VEMP in human neck muscles mirrors feline responses, showing inhibitory activity in flexors and excitatory activity in extensors.
Area of Science:
- Neuroscience
- Vestibular System Research
- Otolithic Reflex Studies
Background:
- The sacculocollic reflex, crucial for head stability, has been studied in animals.
- Vestibular evoked myogenic potential (VEMP) is a proposed non-invasive measure of this reflex.
- Previous research in cats elucidated the neuronal pathways of the sacculocollic reflex.
Purpose of the Study:
- To investigate the sacculocollic reflexes in humans using VEMP.
- To compare human VEMP responses with known feline sacculocollic reflex pathways.
- To determine the neural activity (excitatory/inhibitory) in human neck muscles during the sacculocollic reflex.
Main Methods:
- Bilateral recordings of sternocleidomastoid (SCM) and splenius capitis (SC) muscles in 16 adults.
- Stimulation using 500 Hz short tone bursts.
- Analysis of VEMP wave polarity in relation to muscle activity.
Main Results:
- VEMP polarity in the splenius capitis (SC) was the reverse of that in the sternocleidomastoid (SCM).
- VEMP from ipsilateral SCM indicated inhibitory neural activity.
- VEMP from ipsilateral SC indicated excitatory neural activity, consistent with feline studies.
Conclusions:
- VEMP is a valid non-invasive method to study human sacculocollic reflexes.
- Human sacculocollic reflexes involve inhibitory connections to neck flexors (SCM) and excitatory connections to neck extensors (SC).
- Findings in humans align with previous animal model research, confirming conserved neural pathways.