Electrophysiological and Optical Assessment of Neurovascular Coupling in Rat with Cerebral Ischemia

• Main Authors: Ying-chi Lien, 連英淇
• Other Authors: Jia-jin Chen
• Format: Others
• Language: en_US
• Published: 2009
• Online Access: http://ndltd.ncl.edu.tw/handle/60450599999264869364

碩士 === 國立成功大學 === 醫學工程研究所碩博士班 === 97 === For systemic study of cerebral dysfunction under ischemic stroke, continuous and instant measurement is crucial to provide the information about the eventual fate of brain tissue in the acute stage. This study combined electrophysiological measurement and optical imaging system for assessment of neurovascular responses to forepaw stimulation in rat model before and after experimental cerebral ischemia. The instrumentation contains an electrical stimulator to evoke somatosensory cortex, a biopotential amplifier to measure electrophysiological change, a near infrared spectroscopy to measure hemodynamic change. We designed a custom-made cranial probe which aligned electrodes and optic fibers for concurrent electrical and optical signal acquisition. At the stage of system validation, robust in-vivo experiments had been performed to verify the availability of somatosensory evoked potentials (SEP) and event related optical signals (EROS). We have conducted a pilot animal experiment to investigate the temporal evolution of neural response and hemodynamic response to iterative stimulations. The pattern of neurovascular coupling in normal was compared with the altered pattern after transient carotid artery occlusion. Both neuronal and vascular response showed 20-50% decay and delay in time-to-peak response due to ischemic insult. In conclusion, the utilization of neurovascular coupling assessment could help to investigate the noninvasive monitoring of cerebral reactivity and functional recovery after experimental focal ischemia.