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Interlimb reflexes evoked in human arm muscles by ankle displacement
Electroencephalography and Clinical Neurophysiology
|July 1, 1981
Summary
Ankle movements trigger significant reflexes in arm muscles, particularly the triceps brachii (TB). Proprioceptive afferents from the ankle show stronger interlimb reflex connections than cutaneous ones.
Area of Science:
- Neuroscience
- Human Physiology
- Motor Control
Background:
- Interlimb reflexes coordinate movements between different body parts.
- Previous research has explored reflexes evoked by cutaneous stimulation.
Purpose of the Study:
- To investigate interlimb reflexes in arm muscles evoked by ankle displacements.
- To compare the strength and latency of proprioceptive versus cutaneous afferent-mediated reflexes.
Main Methods:
- Electromyography (EMG) recorded from leg (gastrocnemius, tibialis anterior) and arm (biceps brachii, triceps brachii) muscles.
- Ankle displacements (dorsiflexion, plantarflexion) were used to evoke reflexes.
- Signal averaging and Wiener filtering analyzed tonic EMG activity changes.
Main Results:
- Consistent reflex patterns observed in all subjects.
- Ankle dorsiflexion evoked decreased triceps brachii (TB) activity; plantarflexion evoked excitation then inhibition in TB.
- Similar, though smaller, responses observed in biceps brachii (BB).
- Ankle-evoked reflexes were larger and faster than those from cutaneous stimulation.
Conclusions:
- Ankle proprioceptive afferents mediate stronger, more direct interlimb reflex connections than cutaneous afferents.
- These reflexes play a crucial role in coordinating movements between the limbs.