The neurochemistry of learning and memory.

The neurochemical basis of memory has been approached experimentally in four different ways: the bioassay; the interventive approach; the interventive-correlative approach; and the correlative approach. These approaches are fundamentally similar to those used for the study of the chemistry of any behavior. Each of these approaches has serious limitations, and significant progress has only been made by combinations of more than one. I shall discuss each of these approaches in turn.