Cortical Reorganization Due to Impaired Cerebral Autoregulation in Individuals With Occlusive Processes of the Internal Carotid Artery

• Main Authors: Jonathan List, Susan Hertel-Zens, Jan Carl Kübke, Anne Lesemann, Stephan J. Schreiber, Agnes Flöel
• Format: Article
• Language: English
• Published: Elsevier 2014-05-01
• Series: Brain Stimulation
• Subjects: Carotid artery stenosis; Transcranial magnetic stimulation; LTP-like plasticity; Motor learning; GABA
• Online Access: http://www.sciencedirect.com/science/article/pii/S1935861X14001041

Background and purpose: To study the impact of impaired cerebral autoregulation on cortical neurophysiology, long term potentiation (LTP)-like plasticity, motor learning and brain structure. Methods: 12 patients with unilateral occlusion or severe stenosis of the internal carotid artery were included. Impairment of cerebral autoregulation was determined by vasomotor reactivity in transcranial Doppler sonography. Corticomotor excitability, cortical silent period and LTP-like plasticity were assessed with transcranial magnetic stimulation, motor learning with a force production task, and brain structure with high-resolution MRI of the brain. Results: In the affected hemisphere, corticomotor excitability was significantly higher, cortical silent period and LTP-like plasticity significantly lower, compared to the contralateral side. No significant difference emerged for motor learning, cortical thickness and white matter integrity between the hemispheres. Conclusion: Despite decreased LTP-like plasticity in the affected hemisphere, motor learning was comparable between hemispheres, possibly due to gamma-aminobutyric-acid (GABA)B-mediated corticomotor excitability changes within the affected hemisphere. Our results may help to develop interventions to beneficially modulate cortical physiology in the presence of cerebral hypoperfusion.