Function
The function of the dopamine neurons in the substantia nigra pars compacta is complex. Contrary to what was thought initially it is not directly linked to movements. "Dopamine neurons are activated by novel, unexpected stimuli, by primary rewards in the absence of predictive stimuli and during learning". Dopamine neurons are thought to be involved in learning to predict which behaviours will lead to a reward (for example food or sex). In particular, it is suggested that dopamine neurons fire when a reward is greater than that previously expected; a key component of many reinforcement learning models. This signal can then be used to update the expected value of that action. Many drugs of abuse, such as cocaine, mimic this reward response—providing an explanation for their addictive nature.
Read more about this topic: Pars Compacta
Famous quotes containing the word function:
“The function of literature, through all its mutations, has been to make us aware of the particularity of selves, and the high authority of the self in its quarrel with its society and its culture. Literature is in that sense subversive.”
—Lionel Trilling (1905–1975)
“If the children and youth of a nation are afforded opportunity to develop their capacities to the fullest, if they are given the knowledge to understand the world and the wisdom to change it, then the prospects for the future are bright. In contrast, a society which neglects its children, however well it may function in other respects, risks eventual disorganization and demise.”
—Urie Bronfenbrenner (b. 1917)
“The information links are like nerves that pervade and help to animate the human organism. The sensors and monitors are analogous to the human senses that put us in touch with the world. Data bases correspond to memory; the information processors perform the function of human reasoning and comprehension. Once the postmodern infrastructure is reasonably integrated, it will greatly exceed human intelligence in reach, acuity, capacity, and precision.”
—Albert Borgman, U.S. educator, author. Crossing the Postmodern Divide, ch. 4, University of Chicago Press (1992)