Hemodynamic Impairment as a Stimulus for Functional Brain Reorganization
Open Access
- 18 January 2006
- journal article
- Published by SAGE Publications in Journal of Cerebral Blood Flow & Metabolism
- Vol. 26 (10), 1256-1262
- https://doi.org/10.1038/sj.jcbfm.9600274
Abstract
We used functional magnetic resonance imaging to investigate whether hemispheral hemodynamic impairment can play an independent role in the functional reorganization of motor-related activity in the brain. Fourteen patients with large vessel occlusion but no infarct performed a simple motor task with the hand contralateral to the occluded vessel. Statistical parametric maps of regional activity were generated to compare the distribution of motor-related activity among patients with that of control subjects. Patients were classified into normal or abnormal cerebral hemodynamics on the basis of intracerebral vasomotor reactivity using transcranial Doppler and carbon dioxide inhalation. Controls and patients with normal vasomotor reactivity showed typical motor activity in contralateral motor areas. When the 9 patients with abnormal vasomotor reactivity were compared with the 14 control subjects in a single analysis, unique motor activation was identified in ipsilateral motor regions in the nonhypoperfused hemisphere. In a confirmatory analysis, blood oxygen level-dependent (BOLD) signal intensity was averaged in prespecified motor regions of interest. A significant group by hemisphere interaction was identified, driven by higher ipsilateral and lower contralateral hemisphere BOLD signal in patients with abnormal vasomotor reactivity compared with controls (F = 12.40, P=0.002). The average ipsilateral motor region signal intensity was also significantly higher in the subgroup of patients with abnormal vasoreactivity and no TIA compared with controls (P =0.04). Our results suggest that hemodynamic impairment in one hemisphere, even in the absence of any focal lesion or any symptoms can be associated with a functional reorganization to the opposite hemisphere.Keywords
This publication has 40 references indexed in Scilit:
- Hypoperfusion without stroke alters motor activation in the opposite hemisphereAnnals of Neurology, 2004
- Brain Function Early after Stroke in Relation to Subsequent RecoveryJournal of Cerebral Blood Flow & Metabolism, 2004
- Monitoring of Cerebral Vasodilatory Capacity With Transcranial Doppler Carbon Dioxide Inhalation in Patients With Severe Carotid Artery DiseaseStroke, 2003
- Cerebral Hemodynamics and Metabolism in Patients With Symptomatic Occlusion of the Internal Carotid ArteryStroke, 2003
- Middle Cerebral Artery Function After StrokeStroke, 2002
- fMRI of the auditory cortex in patients with unilateral carotid artery steno‐occlusive diseaseJournal of Magnetic Resonance Imaging, 2002
- Sequential activation brain mapping after subcortical stroke: changes in hemispheric balance and recoveryNeuroReport, 2001
- Magnetic resonance markers of ischaemia: their correlation with vasodilatory reserve in patients with carotid artery stenosis and occlusionJournal of Neurology, Neurosurgery & Psychiatry, 2001
- Intraoperative validation of functional magnetic resonance imaging and cortical reorganization patterns in patients with brain tumors involving the primary motor cortexJournal of Neurosurgery, 1999
- Course of cerebrovascular reactivity in patients with carotid artery occlusions.Stroke, 1994