The architecture of the reflex arc.

The identification of local detectors, command neurons, and modulator neurons has opened up the possibility of the structural identification of individual synaptic contacts supporting the functioning of the reflex arc. Nonassociative plasticity (habituation and sensitization) are [sic] realized at the level of the receptors and potential-dependent calcium channels through dephosphorylation-phosphorylation of receptor and channel proteins. Associative plasticity (the development and extinction of the conditioned reflex) includes two levels of regulation: short-term (through dephosphorylation-phosphorylation of receptor and channel proteins) and long-term (through the expression of genes coding structural and translocational genes). Its selectivity is an extremely important characteristic of associative plasticity. The mechanism of associative plasticity is based on the principles of the Hebb plastic synapse, supplemented by indication of the role of nonspecific (modulating) influences.