abnormal nucleus accumbens morphology abnormal olfactory tubercle morphology abnormal islands of Calleja morphology 2010-02-16T02:00:17Z MA:0000977 MP:0010010 MPheno.ontology The islands of Calleja are located within the olfactory tubercle in most species; however, in primates these islands are located within the nucleus accumbens, since the olfactory tubercle is absent or extremely rudimentary in the brains of primates. We have currently placed this term as a child of both abnormal nucleus accumbens morphology and abnormal olfactory tubercle morphology but we may need to reconsider this placement. any structural anomaly of the seven small groups of granule cells in the polymorph layer of the olfactory tubercle and one large group, the insula magna, which lies along the border between septum, nucleus accumbens and nucleus of the diagonal band csmith