Silencing normal input permits regenerating foreign afferents to innervate an identified crayfish sensory interneuron.

Interneuron A, an identified first-order sensory interneuron that is innervated by mechanoreceptors on one side of the crayfish tailfan, normally resists extra innervation by regenerating contralateral mechanoreceptor axons. However, if its normal innervation is silenced by covering mechanosensory hairs with a surgical glue, it accepts contralateral innervation. This finding on an arthropod provides evidence for the generality and antiquity of the principle, critical in development of the vertebrate nervous system, that activity of one set of afferents can control whether other afferents form synapses on a target.