LTP as a Cellular Basis for Learning and Memory.

Long term potentiation (LTP) of synaptic transmission has been considered a cellular mechanism for learning and memory. Pharmacological blockade of synaptic receptors or recent gene-targeting approaches gave evidence to support the hypothesis. However, modifiable synapses are generally embedded deep in complex circuits and many neurons participate in a learning behavior. We first demonstrated a link between LTP and behavioral learning by using a simple circuit for goldfish escape behavior: a single spike of one of the paired Mauthner cells in hindbrain initiates the fast escape response. Repeated sound stimuli to the fish induce LTP of the feedforward inhibition of the M-cell from the auditory nerve and long-lasting desensitization of the escape behavior.