title: Do we need to revise the tripartite subdivision hypothesis of the human subthalamic nucleus (STN)? Response to Alkemade and Forstmann.
abstract: Recently in this journal, Alkemade and Forstmann again challenged the evidence for a tripartite organisation to the subthalamic nucleus (STN) (Alkemade & Forstmann 2014). Additionally, they raised specific issues with the earlier published results using 3T MRI to perform in vivo diffusion weighted imaging (DWI) based segmentation of the STN (Lambert et al. 2012). Their comments reveal a common misconception related to the underlying methodologies used, which we clarify in this reply, in addition to highlighting how their current conclusions are synonymous with our original paper. The ongoing debate, instigated by the controversies surrounding STN parcellation, raises important implications for the assumptions and methodologies employed in mapping functional brain anatomy, both in vivo and ex vivo, and reveals a fundamental emergent problem with the current techniques. These issues are reviewed, and potential strategies that could be developed to manage them in the future are discussed further.
authors.affiliation: Clinical Neuroscience, St George's University of London, London, UK. Electronic address: clambert112358@gmail.com.
authors.forename: Christian
authors.initials: C
authors.lastname: Lambert
authors.affiliation: Unit of Functional Neurosurgery, University College London Institute of Neurology, Queen Square, London, UK.
authors.forename: Ludvic
authors.initials: L
authors.lastname: Zrinzo
authors.affiliation: Laboratory for Social and Neural Systems Research (SNS Lab), University Hospital Zürich, P.O. Box 146, Rämistrasse 100, CH-8091 Zürich, Switzerland; Wellcome Trust Centre for Neuroimaging, UCL Institute of Neurology, University College London, 12 Queen Square, London WC1N 3BG, UK.
authors.forename: Zoltan
authors.initials: Z
authors.lastname: Nagy
authors.affiliation: LREN, Département des Neurosciences Cliniques, CHUV, Université de Lausanne, Lausanne, Switzerland.
authors.forename: Antoine
authors.initials: A
authors.lastname: Lutti
authors.affiliation: Unit of Functional Neurosurgery, University College London Institute of Neurology, Queen Square, London, UK.
authors.forename: Marwan
authors.initials: M
authors.lastname: Hariz
authors.affiliation: Unit of Functional Neurosurgery, University College London Institute of Neurology, Queen Square, London, UK.
authors.forename: Thomas
authors.initials: T
authors.lastname: Foltynie
authors.affiliation: LREN, Département des Neurosciences Cliniques, CHUV, Université de Lausanne, Lausanne, Switzerland.
authors.forename: Bogdan
authors.initials: B
authors.lastname: Draganski
authors.affiliation: Wellcome Trust Centre for Neuroimaging, UCL Institute of Neurology, University College London, 12 Queen Square, London WC1N 3BG, UK.
authors.forename: John
authors.initials: J
authors.lastname: Ashburner
authors.affiliation: LREN, Département des Neurosciences Cliniques, CHUV, Université de Lausanne, Lausanne, Switzerland.
authors.forename: Richard
authors.initials: R
authors.lastname: Frackowiak
mesh_terms: D001931:Brain Mapping; D046690:Deep Brain Stimulation; D006801:Humans; D008279:Magnetic Resonance Imaging; D020531:Subthalamic Nucleus / Q000033:anatomy & histology* / Q000502:physiology*
keywords: Basal ganglia; Deep brain stimulation; Parcellation; Segmentation; Subthalamic nucleus