MULTIARCHITECTONIC AND STEREOTAXIC ATLAS OF THE HUMAN THALAMUS

To improve anatomical definition and stereotactic precision of thalami c targets in neurosurgical treatments of chronic functional disorders, a new atlas of the human thalamus has been developed. This atlas is b ased on multiarchitectonic parcellation in sections parallel or perpen dicular to the standard intercommissural reference plane. The calcium- binding proteins parvalbumin (PV), calbindin D-28K (CB), and calretini n (CR) were used as neurochemical markers to further characterize thal amic nuclei and delimit subterritories of functional significance for stereotactic explorations. Their overall distribution reveals a subcom partmentalization of thalamic nuclei into several groups. Predominant PV immunostaining characterizes primary somatosensory, visual and audi tory nuclei, the ventral lateral posterior nucleus, reticular nucleus (R), and to a lesser degree also, lateral part of the centre median nu cleus, and anterior, lateral, and inferior divisions of the pulvinar c omplex. In contrast, CB immunoreactivity is prevalent in medial thalam ic nuclei (intralaminar and midline), the posterior complex, ventral p osterior inferior nucleus, the ventral lateral anterior nucleus, ventr al anterior, and ventral medial nuclei. The complementary distribution s of PV and CB appear to correlate with distinct lemniscal and spinoth alamic somatosensory pathways and to cerebellar and pallidal motor ter ritories, respectively. Calretinin, while overlapping with CB in media l thalamic territories, is also expressed in R and limbic associated a nterior group nuclei that contain little or no CB. Preliminary analysi s indicates that interindividual nuclear variations cannot easily be t aken into account by standardization procedures. Nevertheless, some co rrections in anteroposterior coordinates in relation to different inte rcommissural distances are proposed. J. Comp. Neurol. 387:588-630, 199 7. (C) 1997 Wiley-Liss, Inc.