How different brain structures react to rewards?
Abstract (Via Wolfram Schultz @ Cal Tech)
The fundamental biological importance of rewards has created an increasing interest in the neuronal processing of reward information. The suggestion that the mechanisms underlying drug addiction might involve natural reward systems has also stimulated interest. This article focuses on recent neurophysiological studies in primates that have revealed that neurons in a limited number of brain structures carry specific signals about past and future rewards. This research provides the first step towards an understanding of how rewards influence behaviour before they are received and how the brain might use reward information to control learning and goal-directed behaviour.
Additional Paper Excerpt (Via Wolfram Schultz @ Cal Tech)
The fundamental role of reward in the survival and well- being of biological agents ranges from the control of vegetative functions to the organization of voluntary, GOAL-DIRECTED BEHAVIOUR. The control of behaviour requires the extraction of reward information from a large variety of stimuli and events. This information concerns the presence and values of rewards, their predictability and accessibility, and the numerous methods and costs associated with attaining them. Various experimental approaches including brain lesions, psychopharmacology, electrical self-stimulation and the administration of addictive drugs, have helped to determine the crucial structures involved in reward processing1–4 .
Conclusion Excerpt (Via Wolfram Schultz @ Cal Tech)
A limited number of brain structures process reward information in several different ways. Neurons detect reward prediction errors and produce a global reinforcement signal that might underlie the learning of appropriate behaviours. Future work will investigate how such signals lead to synaptic modifications96–99.
Other neurons detect and discriminate between different rewards and might be involved in assessing the nature and identity of individual rewards, and might thus underlie the perception of rewards. However, the brain not only detects and analyses past events; it also constructs and dynamically modifies predictions about future events on the basis of previous experience29,31 .Neurons respond to learned stimuli that predict rewards and show sustained activities during periods in which expectations of rewards are evoked. They even estimate future rewards and adapt their activity according to ongoing experience72,73.