Background: The BOLD signal in functional MRI (fMRI) is closely related to neu ral activity. Objective: To investigate if this relationship is disrupted after ischemic stroke. Methods: BOLD activity during tactile exp...Background: The BOLD signal in functional MRI (fMRI) is closely related to neu ral activity. Objective: To investigate if this relationship is disrupted after ischemic stroke. Methods: BOLD activity during tactile exploration of objects wa s measured with fMRI at 1 week (subacute), 2 to 4 weeks (early chronic), and aft er 1 month (chronic) after the first completed brain infarction affecting the se nsorimotor 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 vi cinity related to finger movements of the affected hand. However, during the ear ly chronic stage there was a transient lack of this activation despite clinical improvement of hand function and preserved motor evoked potentials. The BOLD act ivity reappeared after further improvement in the chronic stage. Conclusions: Ou r findings suggest a transient hemodynamic electrical decoupling in the post i schemic cerebral cortex during the early phase of spontaneous clinical recovery.展开更多
文摘Background: The BOLD signal in functional MRI (fMRI) is closely related to neu ral activity. Objective: To investigate if this relationship is disrupted after ischemic stroke. Methods: BOLD activity during tactile exploration of objects wa s measured with fMRI at 1 week (subacute), 2 to 4 weeks (early chronic), and aft er 1 month (chronic) after the first completed brain infarction affecting the se nsorimotor 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 vi cinity related to finger movements of the affected hand. However, during the ear ly chronic stage there was a transient lack of this activation despite clinical improvement of hand function and preserved motor evoked potentials. The BOLD act ivity reappeared after further improvement in the chronic stage. Conclusions: Ou r findings suggest a transient hemodynamic electrical decoupling in the post i schemic cerebral cortex during the early phase of spontaneous clinical recovery.
