nucleus accumbens morphology trait Any measurable or observable characteristic related to the shape, structure, color, or pattern of the group of neurons located at the head of the caudate nucleus and anterior to the putamen; these neurons normally are involved in sensations of pleasure and reactions to addictive substances. EFO:0006931 Nacc morphology trait Trait.ontology VT:0004080 accumbens nucleus morphology trait ventral striatum morphology trait limbic system morphology trait