The lateral hypothalamus and motivated behavior: an old syndrome reassessed and a new perspective gained

For 40 years, thinking about the neurobiology of motivation has been dominated by the model of Eliot Stellar, who suggested that "the amount of motivated behaviour is a direct function of the amount of activity in certain excitatory centres of the hypothalamus," a proposal consistent with both physiological and psychological theories dominant in the 1950s. Physiologists argued that motivated behaviour was shaped by signals closely monitored by the brain, while some psychologists were adopting engineering control systems to describe cognitive processes. One can still describe the brain in term of centres, as Stellar did, because different regions of it, defined by morphology, connections, and neurochemistry, have different roles in controlling psychological and behavioural processes, but this kind of analysis is now considered superficial. Current models of brain function recognize that complex activities like eating and drinking depend on widespread neural activity. We no longer look for centres exclusively regulating complex psychological processes, but instead ask questions such as these: How are brain structures functionally grouped? What particular processing steps do different parts of the brain contribute in order the coordinated behaviour can occur?