Neurochemical organization of the ventral striatum's olfactory tubercle

Abstract

The ventral striatum is a collection of brain structures, including the nucleus accumbens, ventral pallidum and the olfactory tubercle (OT). While much attention has been devoted to the nucleus accumbens, a comprehensive understanding of the ventral striatum and its contributions to neurological diseases requires an appreciation for the complex neurochemical makeup of the ventral striatum's other components. This review summarizes the rich neurochemical composition of the OT, including the neurotransmitters, neuromodulators and hormones present. We also address the receptors and transporters involved in each system as well as their putative functional roles. Finally, we end with briefly reviewing select literature regarding neurochemical changes in the OT in the context of neurological disorders, specifically neurodegenerative disorders. By overviewing the vast literature on the neurochemical composition of the OT, this review will serve to aid future research into the neurobiology of the ventral striatum.

Keywords: GABA; Parkinson's disesae; acetylcholine; behavior; dementia; dopamine; motivation; neurodegeneration; sensory; striatum.

Figure 1.. The localization of the olfactory tubercle in a rodent brain.

(Top) Diagram of a rat brain, including a coronal section indicating the nucleus accumbens, ventral pallidum, and olfactory tubercle (beige shaded region). (Bottom) Enlarged view of the olfactory tubercle, with layer 1 depicted in pink, layer 2 depicted in orange, and layer 3 depicted in yellow. An island of Calleja is depicted in red. Some examples of different cell types found in the olfactory tubercle are illustrated. Based in part upon (Xiong and Wesson 2016). M, medial; D, dorsal; MSN, medium spiny neuron; GC, granule cell; CIN, cholinergic interneuron.