A NETWORK MODEL OF CATECHOLAMINE EFFECTS - GAIN, SIGNAL-TO-NOISE RATIO, AND BEHAVIOR

At the level of individual neurons, catecholamine release increases the responsivity of cells to excitatory and inhibitory inputs. A model ofcatecholamine effects in a network of neural-like elements is presented, which shows that (i) changes in the responsivity of individual elements do not affect their ability to detect a signal and ignore noise but (ii) the same changes in cell responsivity in a network of such elements do improve the signal detection performance of the network as a whole. The second result is used in a computer simulation based on principles of parallel distributed processing to account for the effect of central nervous system stimulants on the signal detection performance of human subjects.