Positive feedback to a muscle receptor stabilized by concurrent self-inhibition.
The two non-spiking afferent neurones (T and S fibres) of the crab's thoracic-coxal muscle receptor organ mediate antagonistic reflex controls upon the specific receptor motoneurone (Rm1). Depolarization of the 'in-series' T fibre, by receptor muscle stretch or intracellular current injection, reflexly excites Rm1, whereas length- or current-induced S fibre depolarization inhibits Rm1. The latter, autogenetic negative feedback stabilizes the concurrent positive feedback over the physiological range of receptor muscle lengths.
D000344:Afferent Pathways / Q000502:physiology; D000818:Animals; D003386:Brachyura; D006614:Hindlimb / Q000294:innervation; D008564:Membrane Potentials; D009046:Motor Neurons / Q000502:physiology*; D009119:Muscle Contraction; D009132:Muscles / Q000294:innervation*; D009412:Nerve Fibers / Q000502:physiology*; D009433:Neural Inhibition; D012026:Reflex, Stretch