title: Neural Substrates for Head Movements in Humans: A Functional Magnetic Resonance Imaging Study.
abstract: The neural systems controlling head movements are not well delineated in humans. It is not clear whether the ipsilateral or contralateral primary motor cortex is involved in turning the head right or left. Furthermore, the exact location of the neck motor area in the somatotopic organization of the motor homunculus is still debated and evidence for contributions from other brain regions in humans is scarce. Because currently available neuroimaging methods are not generally suitable for mapping brain activation patterns during head movements, we conducted fMRI scans during isometric tasks of the head. During isometric tasks, muscle contractions occur without an actual movement and they have been used to delineate patterns of brain activity related to movements of other body parts such as the hands. Healthy individuals were scanned during isometric head rotation or wrist extension. Isometric wrist extension was examined as a positive control and to establish the relative locations of head and hand regions in the motor cortex. Electromyographic recordings of neck and hand muscles during scanning ensured compliance with the tasks. Increased brain activity during isometric head rotation was observed bilaterally in the precentral gyrus, both medial and lateral to the hand area, as well the supplementary motor area, insula, putamen, and cerebellum. These findings clarify the location of the neck region in the motor homunculus and help to reconcile some of the conflicting results obtained in earlier studies.
authors.affiliation: Department of Neurology.
authors.forename: Cecilia N
authors.initials: CN
authors.lastname: Prudente
authors.affiliation: Department of Neurology.
authors.forename: Randall
authors.initials: R
authors.lastname: Stilla
authors.affiliation: Departments of Neurology and Rehabilitation Medicine, Emory University, Atlanta, Georgia 30309.
authors.forename: Cathrin M
authors.initials: CM
authors.lastname: Buetefisch
authors.affiliation: Department of Neurology.
authors.forename: Shivangi
authors.initials: S
authors.lastname: Singh
authors.affiliation: Departments of Pharmacology and Neurology.
authors.forename: Ellen J
authors.identifier: http://orcid.org/0000-0002-8546-8184
authors.initials: EJ
authors.lastname: Hess
authors.affiliation: Coulter Department of Biomedical Engineering, Emory University and Georgia Institute of Technology, Atlanta, Georgia 30322, and.
authors.forename: Xiaoping
authors.initials: X
authors.lastname: Hu
authors.affiliation: Departments of Neurology, Rehabilitation Medicine, and Psychology, and Rehabilitation R&D Center of Excellence, Atlanta VA Medical Center, Decatur, Georgia 30033.
authors.forename: Krish
authors.initials: K
authors.lastname: Sathian
authors.affiliation: Departments of Neurology, Human Genetics, and Pediatrics, Emory University, Atlanta, Georgia, 30332, hjinnah@emory.edu.
authors.forename: H A
authors.initials: HA
authors.lastname: Jinnah
mesh_terms: D000328:Adult; D000368:Aged; D001921:Brain / Q000502:physiology*; D001931:Brain Mapping / Q000379:methods*; D004576:Electromyography / Q000379:methods; D005260:Female; D019416:Head Movements / Q000502:physiology*; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D009044:Motor Cortex / Q000502:physiology; D009415:Nerve Net / Q000502:physiology*; D010865:Pilot Projects; D011597:Psychomotor Performance / Q000502:physiology*
keywords: fMRI; head movements; isometric; motor control; neck; somatotopic