Neural processing of the reward value of pleasantodorants


Pleasant odorants are represented in the posterior olfactory bulb (pOB) in mice. How does this hedonic in-formation generate odor-motivated behaviors? Using optogenetics, we report here that stimulating the rep-resentation of pleasant odorants in a sensory structure, the pOB, can be rewarding, self-motivating, and isaccompanied by ventral tegmental area activation. To explore the underlying neural circuitry downstreamof the olfactory bulb (OB), we use 3D high-resolution imaging and optogenetics and determine that thepOB preferentially projects to the olfactory tubercle, whose increased activity is related to odorant attraction.We further show that attractive odorants act as reinforcers in dopamine-dependent place preferencelearning. Finally, we extend those findings to humans, who exhibit place preference learning and an increaseBOLD signal in the olfactory tubercle in response to attractive odorants. Thus, strong and persistent attrac-tion induced by some odorants is due to a direct gateway from the pOB to the reward system.


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