The Islands of Calleja refers to a specific anatomical structure located within the brain, more precisely in the area known as the gray matter. These islands are named after Juan Calleja, a Spanish neuroanatomist who first described them. The Islands of Calleja are clusters or small islands of neurons that are densely packed and form tight groups within the basal ganglia region.
These islands have a distinct appearance and are characterized by their isolated arrangement, surrounded by white matter tracts. They are mainly found in two specific regions of the brain: the septal region, which is located in the medial part of the frontal lobes, and the ventral striatum, which is situated within the basal forebrain.
The Islands of Calleja are mainly composed of medium-sized spiny neurons, with distinct axonal and dendritic connections. They receive input from various brain regions, including the olfactory system, hippocampus, amygdala, and other cortical areas. The output connections of these islands typically project to areas involved in reward processing and motivation, such as the nucleus accumbens.
While the exact function of the Islands of Calleja is still a subject of ongoing research, current evidence suggests their involvement in regulating emotional and motivational behaviors. Furthermore, abnormalities or dysfunction in these islands have been implicated in various neuropsychiatric disorders, including addiction, depression, and schizophrenia.
In conclusion, the Islands of Calleja are specialized clusters of neurons located within the basal ganglia region of the brain, playing a crucial role in emotional and reward-related processes.
