ELIMINATION OF SENSORY INPUTS INDUCES GROWTH AND SYNAPTIC CHANGES IN CRAYFISH MOTOR AXONS

Damage to motor neurons induces regeneration processes including axona l growth and change of synaptic properties. Sensory axons that run alo ng the motor axons are also damaged, but their possible role in the mo tor neuron's regeneration is generally ignored. Here, the effect of el iminating some sensory inputs from intact motor axons on the motor axo n's properties was studied. Micro-dissecting one of the segmental, bil ateral, sensory stretch receptor pairs of the crayfish abdomen induced the deep extensor abdominal motor axons to grow and changed their syn aptic properties. The results demonstrate directly probably for the fi rst time, that change in sensory neuron activity can induce motor axon s to grow, form new synapses, and change their synaptic properties.