Lateral Perspective of Hemispheric White Matter Dissection. At the center of this dissection are visualized the external capsule and claustrum. The claustrum is a thin sheet of gray matter that has connections with the pre-frontal cortex and the thalamus. It is located between the insula laterally and the putamen medially. The external capsule intervenes between the putamen and the claustrum. (Image courtesy of M Nunez)