University of Washington, Department of Bioengineering, Seattle, Washington, United States.
J Biomed Opt. 2020 Sep;25(9). doi: 10.1117/1.JBO.25.9.096005.
Cerebral blood flow (CBF) regulation at neurovascular coupling (NVC) plays an important role in normal brain functioning to support oxygen delivery to activating neurons. Therefore, studying the mechanisms of CBF adjustment is crucial for the improved understanding of brain activity.
We investigated the temporal profile of hemodynamic signal change in mouse cortex caused by neural activation and its variation over cortical depth.
Following the cranial window surgery, intrinsic optical signal imaging (IOSI) was used to spatially locate the activated region in mouse cortex during whisker stimulation. Optical microangiography (OMAG), the functional extension of optical coherence tomography, was applied to image the activated and control regions identified by IOSI. Temporal profiles of hemodynamic response signals obtained by IOSI and OMAG were compared, and OMAG signal was analyzed over cortical layers.
Our results showed that the hemodynamic response to neural activity revealed by blood flow change signal signal through IOSI is slower than that observed by OMAG signal. OMAG also indicated the laminar variation of the response over cortical depth, showing the largest response in cortical layer IV.
Overall, we demonstrated the development and application of dual-modality imaging system composed of IOSI and OMAG, which may have potential to enable the future investigations of depth-resolved CBF and to provide the insights of hemodynamic events associated with the NVC.
神经血管耦合（NVC）时的脑血流（CBF）调节在正常大脑功能中起着重要作用，以支持向激活神经元供氧。因此，研究 CBF 调节的机制对于更好地理解大脑活动至关重要。
我们研究了由神经激活引起的小鼠皮层血流动力学信号变化的时间分布及其在皮层深度上的变化。
在颅窗手术后，使用固有光学信号成像（IOSI）在胡须刺激期间在小鼠皮层中空间定位激活区域。光学微血管造影（OMAG）是光相干断层扫描的功能扩展，用于对 IOSI 识别的激活和对照区域进行成像。比较了 IOSI 和 OMAG 获得的血流动力学响应信号的时间分布，并对皮层层进行了 OMAG 信号分析。
我们的结果表明，通过 IOSI 测量的血流变化信号揭示的神经活动引起的血液动力学反应比 OMAG 信号观察到的要慢。OMAG 还表明，响应在皮层深度上的分层变化，在皮层 IV 层中显示出最大的响应。
总体而言，我们展示了由 IOSI 和 OMAG 组成的双模成像系统的开发和应用，这可能为未来对深度分辨 CBF 的研究提供潜力，并提供与 NVC 相关的血液动力学事件的见解。
