Abstract:
Brain arterioles are active, multicellular complexes whose diameters oscillate at ∼ 0.1 Hz. We assess the physiological impact and spatiotemporal dynamics of vaso-oscillations in the awake mouse. First, vaso-oscillations in penetrating arterioles, which source blood from pial arterioles to the capillary bed, profoundly impact perfusion throughout neocortex. The modulation in flux during resting-state activity exceeds that of stimulus-induced activity. Second, the change in perfusion through arterioles relative to the change in their diameter is weak. This implies that the capillary bed dominates the hydrodynamic resistance of brain vasculature. Lastly, the phase of vaso-oscillations evolves slowly along arterioles, with a wavelength that exceeds the span of the cortical mantle and sufficient variability to establish functional cortical areas as parcels of uniform phase. The phase-gradient supports traveling waves in either direction along both pial and penetrating arterioles. This implies that waves along penetrating arterioles can mix, but not directionally transport, interstitial fluids.
摘要:
脑小动脉很活跃,直径在0.1Hz振荡的多细胞复合物。我们评估了清醒小鼠中血管振荡的生理影响和时空动力学。首先,穿透性小动脉的血管振荡,将血液从软动脉输送到毛细血管床,深刻影响整个新皮层的灌注。静息状态活动期间的通量调节超过刺激诱导的活动。第二,通过小动脉的灌注变化相对于其直径的变化是微弱的。这意味着毛细血管床主导了脑血管系统的流体动力学阻力。最后,血管振荡的相位沿着小动脉缓慢演变,波长超过皮质地幔的跨度,并且具有足够的变异性,可以将功能皮质区域建立为均匀的相位。相位梯度支持沿动脉和穿透小动脉的任一方向的行波。这意味着沿着穿透小动脉的波浪可以混合,但不是定向运输,间质液。