Research Report White matter connectivity of human hypothalamus Jean-Jacques Lemaire a, b, ⁎ , Andrew J. Frew b, e , David McArthur b , Alessandra A. Gorgulho b , Jeffry R. Alger c , e , Noriko Salomon d , Clive Chen b , Eric J. Behnke b , Antonio A.F. De Salles b a Univ Clermont 1, UFR Médecine, EA3295, Equipe de Recherche en signal et Imagerie Médicale, Clermont-Ferrand, F-63001, France b Department of Neurosurgery, University of California, Los Angeles, USA c Department of Neurology, University of California, Los Angeles, USA d Department of Radiology, University of California, Los Angeles, USA e Human Brain Mapping Center, University of California, Los Angeles, USA ARTICLE INFO ABSTRACT Article history: Accepted 19 November 2010 Available online 29 November 2010 The macroscopic extrinsic white matter connectivity and the internal structure of the hypothalamus are still incompletely defined in humans. We investigated whether in-vivo diffusion tensor imaging tractography provides evidence of systematization according to hypothalamic compartmentalization. Six defined hypothalamic macroscopic compartments, preoptic, supraoptic, anteroventral, anterodorsal, lateral and posterior, were probed, within the right and left hemispheres of 14 subjects. Important new insights into the macroscopic structure of hypothalamus and white matter connections were found; the preoptic, anteroventral, lateral and posterior compartments are strongly connected to the cortex. The anteroventral connects particularly to the prefrontal cortex while the preoptic compartment connects mainly to the deep anterior brain. The anterodorsal connects mainly to the medial thalamus and the midline gray matter. There is a rightward frontal trend of hemispheric connectivity for the preoptic, anteroventral and lateral compartments. These findings may aid new neuromodulation applications and understanding in brain connectomics. Published by Elsevier B.V. Keywords: Hypothalamus DTI Fiber tracking Fascicle Connectivity Glossary The human hypothalamus is a multi-nuclear anatomic structure located below and anteriorly to the thalamus and crossed by the basal forebrain bundle. It is placed medially to the basal ganglia and the anterior limb of the internal capsule. The macroscopic boundaries are: rostrally the lamina terminalis and the preoptic region (confounded with hypothalamus); caudally the mamillary region and the posterior or dorsal hypothalamic nucleus (this latter being contiguous with the central gray matter); laterally the internal capsule and the substantia innominata of Reichert; and medially the wall of the third ventricle (Haymaker et al., 1969). The ventral and anterior part of the third ventricle, or infundibulum, is also named as the median eminence viewed from the base of the brain. The posterior hypothal- amus is a topographic region poorly defined in humans (Fontaine et al., 2010) where Schaltenbrand and Wahren, 1977 identified a small region named the post mamillary hypothalamus. It is likely that this confined region belongs to BRAIN RESEARCH 1371 (2011) 43 – 64 ⁎ Corresponding author. Service de Neurochirurgie A, Hôpital Gabriel Montpied, B.P. 69, 63003 Clermont-Ferrand cedex 1, France. Fax: +33 4 73 75 21 66. E-mail address: jjlemaire@chu-clermontferrand.fr (J.-J. Lemaire). 0006-8993/$ – see front matter. Published by Elsevier B.V. doi:10.1016/j.brainres.2010.11.072 available at www.sciencedirect.com www.elsevier.com/locate/brainres