Plasticity in the cricket central nervous system

Abstract

The auditory system of the cricket shows a remarkable level of anatomical plasticity in response to injury. Removal of the auditory organ deafferents several types of auditory neurons of the central nervous system. These neurons respond to the loss of input by sending dendrites across the midline, a boundary they typically respect, and forming synapses with the auditory afferents of the contralateral ear. This compensatory growth and synapse formation reinstates neuron-specific frequency tuning curves. Growth and branching after deafferentation are sexually dimorphic, with male growth rates being linear and female growth rates being nonlinear. Female dendrites stop growing and branching after only a few days, while male dendrites continue to grow steadily, becoming twice as long as females by 20 days after deafferentation. Exploration of the molecular basis of this compensatory plasticity has revealed a number of possible candidates, including semaphorins and a VAMP family member, neuronal synaptobrevin.