Cerebral magnetic fields preceding self-paced plantar flexions of the foot

Antervo, A.; Hari, Riitta; Katila, T.; Poutanen, T.; Seppänen, Marko; Tuomisto, Timo

doi:10.1111/j.1600-0404.1983.tb04829.x

Cited by 7 publications

(1 citation statement)

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“…Previous MEG recordings for foot movements, however, have only been performed to confirm the somatotopic organization of the MI (Antervo et al, 1983;Deecke et al, 1983;Cheyne et al, 1991;Kristeva-Feige et al, 1994). In these reports, bilateral activation was not considered an estimator of the primary sensorimotor region of the foot in the longitudinal fissure, because of difficulties separating closely located central sources due to magnetic field cancellation and the spatial resolution of MEG.…”

Section: Introductionmentioning

confidence: 88%

Bilateral cerebral activity for unilateral foot movement revealed by whole-head magnetoencephalography

et al. 2004

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The primary motor cortices controlling foot movement are located on opposite sides of the longitudinal fissure. As a separation of closely located activity sources is not successful, the possibility of bilateral activation for lower limb movement remains undetermined. We therefore examined cerebral activity during unilateral foot movement to investigate the possibility of bilateral activation of primary foot motor cortices. Self-paced foot movement and finger movement (for comparison) were performed on ten subjects. Brain magnetic fields were recorded using a 64-channel whole-cortex magnetoencephalography (MEG) system. Brain activities were identified using 1- to 3-dipole models. Results evaluating finger movement were similar to previous reports. Equivalent current dipoles (ECDs) for foot movements were estimated in the primary foot motor and sensory regions. Sensory activity was always localized to the contralateral hemisphere. Motor activity was estimated by one ECD, but the laterality differed between subjects. Additional activity was discovered together with the primary motor activity, localized around the precentral sulcus. In contrast to consistent results of primary sensory activity, the variation of laterality of the foot primary motor ECD can be explained with a cancellation model, in which the magnetic fields generated from two closely spaced ECDs overlap to cancel each other out. Consequently, activation of the primary foot motor cortices was determined to be bilateral. Furthermore, it was estimated that additional activity may occur in the premotor area. This work suggests not only the bilateral activation of the primary foot motor cortices but also the possibility of a contribution of the premotor area.

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Section: Introductionmentioning

confidence: 88%