Journal of Neuroscience, Vol 6, 3152-3160, Copyright © 1986 by Society for Neuroscience
Competition regulates the efficacy of an identified synapse in crickets
D Shepherd and RK Murphey
The efficacy of the synaptic contact between an identified sensory neuron
and an identified interneuron in crickets is increased when neighboring
afferent synapses are removed early in postembryonic life. The
physiological changes are correlated with changes in the structure of the
presynaptic neuron's axonal arborizations: When neighboring axons are
destroyed, there is a shift of the remaining axonal arbors into
deafferented regions and an increase in the number of putative contacts
with the postsynaptic neuron. Changes in the structure of the presynaptic
neuron also directly affect the probability of formation of this synaptic
connection. The connection was found in 67% of the control specimens, but
it was present in 100% of the partially deafferented specimens. The results
demonstrate that interactions between growing sensory neurons can influence
both the probability of synapse formation and the strength of those
connections. This is the first case in which the effects of competition on
the structure of a single, identified, presynaptic neuron can be directly
related to its synaptic efficacy.