The
islands of Calleja (IC, ISC, or IClj) are a group of neural
granule cells located within the
ventral striatum in the brains of most animals. This region of the brain is part of the
limbic system, where it aids in the reinforcing effects of reward-like activities. Within most species, the islands are specifically located within the
olfactory tubercle; however, in primates, these islands are located within the
nucleus accumbens, the reward center of the brain, since the olfactory tubercle has practically disappeared in the brains of primates. Both of these structures have been implicated in the processing of incentives as well as addictions to drugs. Projections to and from the islands supplement this knowledge with their involvement in the reward pathways for both cocaine and amphetamines.