Ventral Tegmental Area Neurons in Learned Appetitive Behavior and Positive Reinforcement

Abstract

Ventral tegmental area (VTA) neuron firing precedes behaviors elicited by reward-predictive sensory cues and scales with the magnitude and unpredictability of received rewards. These patterns are consistent with roles in the performance of learned appetitive behaviors and in positive reinforcement, respectively. The VTA includes subpopulations of neurons with different afferent connections, neurotransmitter content, and projection targets. Because the VTA and substantia nigra pars compacta are the sole sources of striatal and limbic forebrain dopamine, measurements of dopamine release and manipulations of dopamine function have provided critical evidence supporting a VTA contribution to these functions. However, the VTA also sends GABAergic and glutamatergic projections to the nucleus accumbens and prefrontal cortex. Furthermore, VTA-mediated but dopamine-independent positive reinforcement has been demonstrated. Consequently, identifying the neurotransmitter content and projection target of VTA neurons recorded in vivo will be critical for determining their contribution to learned appetitive behaviors.

Affective neuroscience of pleasure: reward in humans and animals

“…Cellular and molecular studies of long-term potentiation (LTP) and long-term depression (LTD) of neurotransmission onto neuronal targets of dopamine add ostensible mechanisms for prediction and learning about rewards that give pleasure (Berke 2003;Fields et al 2007;Hyman et al 2006;Kelley 2004;Malenka and Bear 2004). Similarly, studies of learning consolidation, and of striatum-accumbens interactions with associative brain structures such as amygdala, hippocampus, prefrontal cortex, and anterior cingulate cortex, have been conducted in support of this hypothesis (Balleine 2005;Balleine and Killcross 2006;Cardinal and Everitt 2004;Cohen et al 2005;Everitt and Robbins 2005;Feldman Barrett and Wager 2006;Schultz 2006).…”

Influence of reward motivation on human declarative memory

“…Dopamine neurons are found mainly in the VTA and the neighboring substantia nigra pars compacta (SNpc) (D'Ardenne et Fields et al, 2007;Luo et al, 2011). The dopaminergic signal in the VTA reflects the valence of the feedback received (rewarding or punishing), and the degree to which the feedback was expected, referred to as "prediction error" (Bromberg-Martin et al, 2010b, 2010cSchultz, 2010).…”

Computational models of reinforcement learning: the role of dopamine as a reward signal

“…How is this phasic change in firing activity translated into DA release at target structures? Experimental data has shown that a single-pulse stimulation applied to the VTA or the median forebrain bundle leads to a DA release lasting a few seconds (Kilpatrick et al 2000;Fields et al 2007;Phillips et al 2003;Robinson et al 2002;Roitman et al 2004;Yavich and MacDonald 2000). The probability of release of DA is however lower than that of glutamate and is varies greatly among DA synapses (Daniel et al 2009).…”