Tonic (physiology)

Neuroscience

Reward system

Dopaminergic

Psychology

Chemistry

Nucleus accumbens

Ventral tegmental area

Dopamine

Brain stimulation reward

Optogenetics

Dopamine release in the nucleus accumbens is involved in all types of reward-related behaviors, including reward learning, seeking and intake (Schultz et al., 1997; Hyland et al., 2002; Phillips et al., 2003b; Roitman et al., 2004; Wise, 2004; Stuber et al., 2005). This neurotransmitter can be released naturally with two main patterns: phasic and tonic (Grace, 1991, 2000; Schultz, 1998; Wightman and Robinson, 2002). Tonic dopamine firing occurs at a low frequency of ∼5Hz and results in steady-state dopamine concentrations that are lower than 50nM (Parsons and Justice, 1992; Justice, 1993).

Optogenetically-induced tonic dopamine release from VTA-nucleus accumbens projections inhibits reward consummatory behaviors