in physiology, a change in the activity of individual excitable formations, including cells, nerve and muscle fibers, and neurons, or of an entire organism after the cessation of an immediate reaction to a stimulus.
Trace-conditioned responses are associated with intracellular molecular transformations and with the activity of various parts of the central nervous system in animals and humans. They are important in determining an organism’s behavior—its unconditioned and conditioned responses. There are both short and long trace responses. Short trace responses are based on the delay and cyclic character of the processes that develop in living systems in response to an applied stimulus. Thus, trace responses may be caused by the delay in changes in ionic permeability and by the cyclic character of the interrelationships between ionic currents, membrane potential, and ionic permeability. In neuron chains trace-conditioned responses are often caused by the circulation of nerve impulses. In a nerve or muscle cell (fiber) they develop after the action potential and are expressed as trace changes in excitability, metabolism, and potentials (trace depolarization or hyperpolarization).
Long trace responses are associated with insufficiently studied ultrastructural cellular changes, for example, synapses with specific molecular processes at the level of individual organelles of the brain’s nerve cells.