How the brain codes, stores and retrieves memories is one of the most important questions in neuroscience today. The answer lies in the application of techniques contributed by many disciplines, from animal behavior to neurochemistry, anatomy and physiology. Most learning theorists agree that memory occurs in several sequentially-linked "stages" or time periods, frequently referred to as short-, intermediate- and long-term memory. The importance of this distinction is that each stage has a relatively discrete duration, and, as Drs. Rosenzweig and Bennett have reported, each appears to be influenced primarily by a different neurochemical transmitter system. They are now pursuing a subcellular neurochemical analysis of these different memory stages. These outstanding investigators (Dr. Rosenzweig is a member of the National Academy of Sciences) are examining the temporal and neurochemical bases of single trial taste discrimination in the chick. In this paradigm, young cockerels are presented with a bitter tasting bead to peck: After a single taste they will avoid pecking at similar beads. One of several drugs is then administered, each capable of interfering with the normal processes of memory. At different times following different drug treatment, the chicks will "forget" the bitter taste, and will again peck at the bead. Since many of the mechanisms of action of these drugs are currently known, these studies will provide valuable information regarding which neurotransmitters, and which subcellular events, influence each stage of memory. Drs. Rosenzweig and Bennett are now proceeding with an even more molecular analysis of events leading to memory, examining the roles of calcium influx, protein synthesis and phosphorylation, and glucose utilization. Answers to these questions could reorient much research on the neuroscience of memory, and will be relevant to several applied fields such as age-related memory deficits, mental retardation, and rehabilitation from brain injuries and disease.
