Sagittal view of C-shaped nuclei and fiber tracts surrounding the lateral ventricle. The caudate nucleus is a prominent C-shaped nucleus that forms, throughout its entire extent, part of the wall of the corresponding C-shaped lateral ventricle. The head of the caudate is especially prominent and bulges conspicuously into the ventrolateral floor of the anterior horn of the lateral ventricle.  The tail of the caudate nucleus tapers progressively in size and runs forward within the roof of the inferior horn of the lateral ventricle to terminate immediately posterior to the amygdala.  The stria terminalis is a major output pathway of the amygdala and courses forward in the floor of the body of the lateral ventricle (in a shallow groove lateral to the thalamus and medial to the body of the caudate) and terminates mainly in the septal region and hypothalamus. The anterior commissure crosses the midline immediately anterior to the columns of the fornix.   The medial forebrain bundle interconnects the hypothalamus and the septal region/prefrontal cortices and is a part of the brain’s reward and pleasure circuitry. The extracapsular thalamic peduncle describes fibers originating from the medial thalamus, on the edge of the third ventricle, passing to the amygdala and temporal cortex. (Image courtesy of AL Rhoton, Jr.)