White matter connections of the supplementary motor area in humans
J Neurol Neurosurg Psychiatry. 2014-04-16; 85(12): 1377-1385
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1. J Neurol Neurosurg Psychiatry. 2014 Dec;85(12):1377-85. doi:
10.1136/jnnp-2013-307492. Epub 2014 Apr 16.
White matter connections of the supplementary motor area in humans.
Vergani F(1), Lacerda L(2), Martino J(3), Attems J(4), Morris C(5), Mitchell
P(1), Thiebaut de Schotten M(6), Dell’Acqua F(7).
(1)Department of Neurosurgery, Royal Victoria Infirmary, Newcastle upon Tyne, UK
Institute of Neuroscience, Newcastle University, Newcastle upon Tyne, UK.
(2)Natbrainlab, Department of Neuroimaging, Institute of Psychiatry, King’s
College London, London, UK.
(3)Department of Neurological Surgery, Hospital Universitario Marqués de
Valdecilla and Instituto de Formación e Investigación Marqués de Valdecilla
(IFIMAV), Santander, Cantabria, Spain.
(4)Institute for Ageing and Health, Newcastle University, Newcastle upon Tyne,
(5)Institute of Neuroscience, Newcastle University, Newcastle upon Tyne, UK
Medical Toxicology Centre, Newcastle University, Newcastle upon Tyne, UK.
(6)Natbrainlab, Department of Forensic and Neurodevelopmental Sciences, Institute
of Psychiatry, King’s College London, London, UK Université Pierre et Marie
Curie-Paris 6, Centre de Recherche de l’Institut du Cerveau et de la Moelle
épinière (CRICM), UMRS 975, INSERM U 975, CNRS UMR, Paris, France.
(7)Natbrainlab, Department of Neuroimaging, Institute of Psychiatry, King’s
College London, London, UK NIHR Biomedical Research Centre for Mental Health at
South London and Maudsley NHS Foundation Trust and King’s College London,
Institute of Psychiatry, London, UK.
INTRODUCTION: The supplementary motor area (SMA) is frequently involved by brain
tumours (particularly WHO grade II gliomas). Surgery in this area can be followed
by the ‘SMA syndrome’, characterised by contralateral akinesia and mutism.
Knowledge of the connections of the SMA can provide new insights on the genesis
of the SMA syndrome, and a better understanding of the challenges related to
operating in this region.
METHODS: White matter connections of the SMA were studied with both postmortem
dissection and advance diffusion imaging tractography. Postmortem dissections
were performed according to the Klingler technique. 12 specimens were fixed in
10% formalin and frozen at -15°C for 2 weeks. After thawing, dissection was
performed with blunt dissectors. For diffusion tractography, high-resolution
diffusion imaging datasets from 10 adult healthy controls from the Human
Connectome Project database were used. Whole brain tractography was performed
using a spherical deconvolution approach.
RESULTS: Five main connections were identified in both postmortem dissections and
tractography reconstructions: (1) U-fibres running in the precentral sulcus,
connecting the precentral gyrus and the SMA; (2) U-fibres running in the
cingulate sulcus, connecting the SMA with the cingulate gyrus; (3) frontal
‘aslant’ fascicle, directly connecting the SMA with the pars opercularis of the
inferior frontal gyrus; (4) medial fibres connecting the SMA with the striatum;
and (5) SMA callosal fibres. Good concordance was observed between postmortem
dissections and diffusion tractography.
CONCLUSIONS: The SMA shows a wide range of white matter connections with motor,
language and lymbic areas. Features of the SMA syndrome (akinesia and mutism) can
be better understood on the basis of these findings.
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PMID: 24741063 [Indexed for MEDLINE]