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. Author manuscript; available in PMC: 2011 Jul 6.
Published in final edited form as: Nature. 2010 Dec 8;469(7328):53–57. doi: 10.1038/nature09588

Figure 2. Phasic dopamine signaling in response to CS and US presentation during the acquisition of Pavlovian conditioned approach behavior in bHR and bLR rats.

Figure 2

Phasic dopamine release was recorded in the core of the nucleus accumbens using FSCV across six days of training. (a, d) Representative surface plots depict trial-by-trial fluctuations in dopamine concentration during the twenty-second period around CS and US presentation in individual animals throughout training. (b, e) Mean + SEM change in dopamine concentration in response to CS and US presentation for each session of conditioning. (c, f) Mean + SEM change in peak amplitude of the dopamine signal observed in response to CS and US presentation for each session of conditioning (n=5/group; Bonferroni post-hoc comparison between CS- and US-evoked dopamine release: *P<0.05; **P<0.01). Panels a-c demonstrate that bHR animals, which developed a sign-tracking CR, show increasing phasic dopamine responses to CS presentation and decreasing responses to US presentation across the six sessions of training. In contrast, panels d-f demonstrate that bLR rats, which developed a goal-tracking CR, maintain phasic responses to US presentation throughout training.