Cerebral ischemia and hypoxia are generally associated with alterations in blood volume and/or oxygenation. Concurrent bioelectric potential measurements have been limited. We designed a system that allows the concurrent measurement of electroencephalogram (EEG) and brain stem evoked potentials (EP). Experiments were performed in white New Zealand rabbits. Brain stem auditory EP and EEG were obtained from scalp electrodes, together with near-infrared spectroscopy measured relative changes in blood volume and oxygenation. Auditory stimulus was 90 db contralateral with 40 db masking sound. Ischemia was obtained by unilateral and bi-lateral carotid artery occlusions. Hypoxia was induced by graded changes in N2O/O2 mixture. Ischemia induced smaller changes in EEG and/or EP than hypoxia for comparable durations. However, both ischemia and hypoxia induced decreases in blood volume and oxygenated hemoglobin and observable shifts in spectral power of the EEG and EP to lower frequencies. Thus, bioelectric potential morphology is closely related to perfusion and oxygenation of target organs, such as the brain.
|Original language||English (US)|
|State||Published - 1997|
All Science Journal Classification (ASJC) codes
- Molecular Biology