title: Lower limb sensorimotor network: issues of somatotopy and overlap.
abstract: Functional magnetic resonance imaging (fMRI) was used (1) to describe the pattern of whole brain activity during motion of isolated joints of the lower limb, (2) to examine the somatotopic organization of lower limb joint representations in the primary sensorimotor cortex and the anterior lobe of the cerebellum and 3) to quantify the degree of overlap between these lower limb joint activations. Eighteen healthy, right leg dominant volunteers participated in a motor block-design study, performing repetitive knee, ankle and toes flexion/extension movements. In order to relate lower limb joints activation to the well-described patterns of finger movement, serial finger-to-thumb opposition was also assessed. All movements were auditory paced at 72 beats/min (1.2 Hz). Isolated lower limb joints movement activated a distributed sensorimotor network, including primary and non-primary sensorimotor areas. Although a large overlap was evident in primary sensorimotor cortex (SM1) and cerebellum representations of the three lower limb joints, a somatotopic arrangement was recognizable with reference to center of mass coordinates of each individual joint in the above areas. Detection of active brain regions during movement of the lower limb joints is feasible with fMRI although a carefully optimized methodology protocol is required.
authors.affiliation: Department of Sports Medicine and Biology of Exercise, National and Kapodistrian University of Athens, Athens, Greece. ekapreli@teilam.gr
authors.forename: Eleni
authors.initials: E
authors.lastname: Kapreli
authors.forename: Spyros
authors.initials: S
authors.lastname: Athanasopoulos
authors.forename: Matilda
authors.initials: M
authors.lastname: Papathanasiou
authors.forename: Paul
authors.initials: P
authors.lastname: Van Hecke
authors.forename: Dimitrios
authors.initials: D
authors.lastname: Keleki
authors.forename: Ronald
authors.initials: R
authors.lastname: Peeters
authors.forename: Nikolaos
authors.initials: N
authors.lastname: Strimpakos
authors.forename: Stefan
authors.initials: S
authors.lastname: Sunaert
mesh_terms: D000328:Adult; D001931:Brain Mapping; D002531:Cerebellum / Q000502:physiology*; D005073:Evoked Potentials, Somatosensory / Q000502:physiology*; D006801:Humans; D007596:Joints / Q000502:physiology; D035002:Lower Extremity / Q000502:physiology*; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D009068:Movement / Q000502:physiology*; D011434:Proprioception / Q000502:physiology; D013003:Somatosensory Cortex / Q000502:physiology*