Recovery from deafferentation by cricket interneurons after reinnervation by their peripheral field

The physiological and morphological recovery of cricket (Acheta domesticus) abdominal giant interneurons following varying periods of deafferentation and subsequent regeneration was examined. The principal afferent input to two identified interneurons was removed by surgically ablating an abdominal sensory appendage, the cercus. Deafferentation restricts the growth of the dendrites of the medial giant interneuron. Reinnervation by the peripheral sensory field leads to recovery of the dendrite length which is dependent on the time allowed for recovery. The response properties of the reinnervated neurons never completely recovers irregardless of how short the period of deafferentation. Reinnervated neurons respond more weakly to standard tones than do control neurons. This is due in part to faciliation of an inhibitory synaptic input which is activated by the control cercus. The results suggest that the balance between the excitatory and the inhibitory synaptic inputs to these interneurons is irrevocably altered by brief periods of deafferentation early in life.