Ferdinand Binkofski1, Rüdiger J Seitz. 1. Department of Neurology, University Hospital Schleswig-Holstein, Campus Lübeck, Ratzeburger Allee 160, 23539 Lübeck, Germany. binkofski.f@neuro.mu-luebeck.de
Abstract
BACKGROUND: The BOLD signal in functional MRI (fMRI) is closely related to neural activity. OBJECTIVE: To investigate if this relationship is disrupted after ischemic stroke. METHODS: BOLD activity during tactile exploration of objects was measured with fMRI at 1 week (subacute), 2 to 4 weeks (early chronic), and after 1 month (chronic) after the first completed brain infarction affecting the sensorimotor cortex in eight patients. Functional integrity of the motor cortical output system was assessed with transcranial magnetic stimulation (TMS). RESULTS: Early after infarction the BOLD-response occurred in the adjacent cortical vicinity related to finger movements of the affected hand. However, during the early chronic stage there was a transient lack of this activation despite clinical improvement of hand function and preserved motor evoked potentials. The BOLD activity reappeared after further improvement in the chronic stage. CONCLUSIONS: Our findings suggest a transient hemodynamic-electrical decoupling in the post-ischemic cerebral cortex during the early phase of spontaneous clinical recovery.
BACKGROUND: The BOLD signal in functional MRI (fMRI) is closely related to neural activity. OBJECTIVE: To investigate if this relationship is disrupted after ischemic stroke. METHODS: BOLD activity during tactile exploration of objects was measured with fMRI at 1 week (subacute), 2 to 4 weeks (early chronic), and after 1 month (chronic) after the first completed brain infarction affecting the sensorimotor cortex in eight patients. Functional integrity of the motor cortical output system was assessed with transcranial magnetic stimulation (TMS). RESULTS: Early after infarction the BOLD-response occurred in the adjacent cortical vicinity related to finger movements of the affected hand. However, during the early chronic stage there was a transient lack of this activation despite clinical improvement of hand function and preserved motor evoked potentials. The BOLD activity reappeared after further improvement in the chronic stage. CONCLUSIONS: Our findings suggest a transient hemodynamic-electrical decoupling in the post-ischemic cerebral cortex during the early phase of spontaneous clinical recovery.
Authors: Christian Enzinger; Stefan Ropele; Franz Fazekas; Marisa Loitfelder; Faton Gorani; Thomas Seifert; Gudrun Reiter; Christa Neuper; Gert Pfurtscheller; Gernot Müller-Putz Journal: Exp Brain Res Date: 2008-07-01 Impact factor: 1.972