Department of Physiology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA.
J Neurophysiol. 2012 Dec;108(11):3138-46. doi: 10.1152/jn.00557.2012. Epub 2012 Sep 12.
Many neuroscientists access surface brain structures via a small cranial window, opened in the bone above the brain region of interest. Unfortunately this methodology has the potential to perturb the structure and function of the underlying brain tissue. One potential perturbation is heat loss from the brain surface, which may result in local dysregulation of brain temperature. Here, we demonstrate that heat loss is a significant problem in a cranial window preparation in common use for electrical recording and imaging studies in mice. In the absence of corrective measures, the exposed surface of the neocortex was at ∼28°C, ∼10°C below core body temperature, and a standing temperature gradient existed, with tissue below the core temperature even several millimeters into the brain. Cooling affected cellular and network function in neocortex and resulted principally from increased heat loss due to convection and radiation through the skull and cranial window. We demonstrate that constant perfusion of solution, warmed to 37°C, over the brain surface readily corrects the brain temperature, resulting in a stable temperature of 36-38°C at all depths. Our results indicate that temperature dysregulation may be common in cranial window preparations that are in widespread use in neuroscience, underlining the need to take measures to maintain the brain temperature in many physiology experiments.
许多神经科学家通过在感兴趣的脑区上方颅骨上开一个小的颅窗来访问脑表面结构。不幸的是，这种方法有可能干扰下面脑组织的结构和功能。潜在的干扰之一是脑表面的热量损失，这可能导致脑温度的局部失调。在这里，我们证明在一种常用的用于小鼠电记录和成像研究的颅窗制备中，热量损失是一个严重的问题。在没有纠正措施的情况下，暴露的新皮层表面温度约为 28°C，比核心体温低约 10°C，并且存在一个静止的温度梯度，组织温度比核心温度低甚至几毫米进入大脑。冷却会影响新皮层的细胞和网络功能，主要是由于通过颅骨和颅窗的对流和辐射导致的热量损失增加所致。我们证明，将加热至 37°C 的溶液持续灌注到脑表面上，可轻松纠正脑温，使所有深度的温度稳定在 36-38°C。我们的结果表明，温度失调可能在神经科学中广泛使用的颅窗制备中很常见，这凸显了在许多生理学实验中需要采取措施来维持脑温的必要性。
