Molecular Cellular and Integrative Bioscience program, The Pennsylvania State University, University Park, PA, 16802, USA.
Department of Biomedical Engineering, The Pennsylvania State University, University Park, PA, 16802, USA.
Commun Biol. 2023 Jul 17;6(1):738. doi: 10.1038/s42003-023-05121-5.
In the adult sensory cortex, increases in neural activity elicited by sensory stimulation usually drive vasodilation mediated by neurovascular coupling. However, whether neurovascular coupling is the same in neonatal animals as adults is controversial, as both canonical and inverted responses have been observed. We investigated the nature of neurovascular coupling in unanesthetized neonatal mice using optical imaging, electrophysiology, and BOLD fMRI. We find in neonatal (postnatal day 15, P15) mice, sensory stimulation induces a small increase in blood volume/BOLD signal, often followed by a large decrease in blood volume. An examination of arousal state of the mice revealed that neonatal mice were asleep a substantial fraction of the time, and that stimulation caused the animal to awaken. As cortical blood volume is much higher during REM and NREM sleep than the awake state, awakening occludes any sensory-evoked neurovascular coupling. When neonatal mice are stimulated during an awake period, they showed relatively normal (but slowed) neurovascular coupling, showing that that the typically observed constriction is due to arousal state changes. These result show that sleep-related vascular changes dominate over any sensory-evoked changes, and hemodynamic measures need to be considered in the context of arousal state changes.
在成人感觉皮层中，感觉刺激引起的神经活动增加通常会驱动神经血管耦合介导的血管舒张。然而，神经血管耦合在新生儿动物和成人中是否相同存在争议，因为已经观察到了经典和反转反应。我们使用光学成像、电生理学和 BOLD fMRI 研究了未麻醉的新生小鼠的神经血管耦合的性质。我们发现在新生（出生后 15 天，P15）小鼠中，感觉刺激会引起小的血容量/ BOLD 信号增加，通常随后会出现大的血容量减少。对小鼠觉醒状态的检查表明，新生小鼠在相当一部分时间处于睡眠状态，刺激会导致动物觉醒。由于皮质血容量在 REM 和 NREM 睡眠期间比清醒状态高得多，因此唤醒会阻断任何感觉诱发的神经血管耦合。当新生儿小鼠在清醒期受到刺激时，它们表现出相对正常（但较慢）的神经血管耦合，表明通常观察到的收缩是由于觉醒状态的变化。这些结果表明，与感觉诱发的变化相比，与睡眠相关的血管变化占主导地位，并且需要在觉醒状态变化的背景下考虑血液动力学测量。
