The Anterior Globus Pallidus Externus of Basal Ganglia as Primarily a Limbic and Associative Territory

There have been an increasing number of functions attributed to the basal ganglia, such as cognitive, emotional, and motor functions. As a result, there is a growing interest to localize these functions to different subregions of the basal ganglia. Most research on localization has been conducted on animals. The experiments subdivide the basal ganglia regions into motor, limbic, and associative functioning areas. There are sparse reports on the localization of functions in humans. This paper attempts to provide such localization of function with a focus on the globus pallidus externus of the basal ganglia. We present the case of a young man who had impairment in mixed cognitive, perceptual, and mood disturbances. No significant motor symptoms were noted in the patient. Brain imaging demonstrated dense bilateral calcifications in the basal ganglia, bilaterally localizing to the anterior region of the globus pallidus externus. We discuss our findings in light of recent studies that imply that isolated pathology in the anterior region of the globus pallidus externus may be associated with behavioral, mood, and cognitive disturbance without motor symptoms.