Abstract
Odor-preferences are usually influenced by life experiences. However, the neural circuit mechanisms remain unclear. The medial olfactory tubercle (mOT) is involved in both reward and olfaction, whereas the ventral tegmental area (VTA) dopaminergic (DAergic) neurons are considered to be engaged in reward and motivation. Here, we found that the VTA (DAergic)-mOT pathway could be activated by different types of naturalistic rewards as well as odors in DAT-cre mice. Optogenetic activation of the VTA-mOT DAergic fibers was able to elicit preferences for space, location and neutral odor, while pharmacological blockade of the dopamine receptors in the mOT fully prevented the odor-preference formation. Furthermore, inactivation of the mOT-projecting VTA DAergic neurons eliminated the previously formed odor-preference and strongly affected the Go-no go learning efficiency. In summary, our results revealed that the VTA (DAergic)-mOT pathway mediates a variety of naturalistic reward processes and different types of preferences including odor-preference in mice.
Highlights
Sensory perceptions are influenced by life experiences
We first showed that various types of odors and diverse naturalistic reward stimulations can activate the medial olfactory tubercle (mOT) and the ventral tegmental area (VTA)-mOT DAergic projection, respectively
We found that activation of the VTA (DAergic)-mOT pathway can generate preference for a neutral odor or abolish the avoidance for an aversive odor; inhibition of the projection downstream in the mOT through specific dopamine receptor antagonists prevented odor-preference formation completely; and inactivation of the mOT-projecting VTA DAergic neurons fully blocked the formed odor-preference, and strongly attenuated the Go-no go learning performance which leads to the odor-preference established through naturalistic reward odor-preference
Summary
Sensory perceptions are influenced by life experiences. For us, it’s a pleasure to unexpectedly smell the odor of grandmother’s cookies that we loved in our childhood, and people of different cultures may have different odor-preferences, such as blue cheese to European and stinky bean-curd to Chinese. The olfactory tubercle (OT) is a long and narrow tubular brain structure located at the ventral part of striatum. It belongs to the olfactory system and receives dense direct inputs from the main olfactory bulb (OB) and other olfactory cortexes such as the anterior olfactory nucleus (AON) and piriform cortex (PCX) (Wesson and Wilson, 2011). As a part of the ventral striatum reward circuitry, the OT is heavily innervated by dopaminergic (DAergic) neurons from the ventral tegmental area (VTA, [Voorn et al, 1986]). Belonging to both the olfactory and reward circuits
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