Institut d'Investigacions Biomèdiques August Pi i Sunyer, Barcelona, Spain.
J Neurophysiol. 2010 Mar;103(3):1253-61. doi: 10.1152/jn.00890.2009. Epub 2009 Dec 23.
In the local cortical network, spontaneous emergent activity self-organizes in rhythmic patterns. These rhythms include a slow one (<1 Hz), consisting in alternation of up and down states, and also faster rhythms (10-80 Hz) generated during up states. Varying the temperature in the bath between 26 and 41 degrees C resulted in a strong modulation of the emergent network activity. Up states became shorter for warmer temperatures and longer with cooling, whereas down states were shortest at physiological (36-37 degrees C) temperature. The firing rate during up states was robustly modulated by temperature, increasing with higher temperatures. The sparse firing rate during down states hardly varied with temperature, thus resulting in a progressive merging of up and down states for temperatures around 30 degrees C. Below 30 degrees C and down to 26 degrees C the firing lost rhythmicity, becoming progressively continuous. The slope of the down-to-up transitions, which reflects the speed of recruitment of the local network, was progressively steeper for higher temperatures, whereas wave-propagation speed exhibited only a moderate increase. Fast rhythms were particularly sensitive to temperature. Broadband high-frequency fluctuations in the local field potential were maximal for recordings at 36-38 degrees C. Overall, we found that maintaining cortical slices at physiological temperature is critical for the generated activity to be analogous to that in vivo. We also demonstrate that changes in activity with temperature were not secondary to oxygenation changes. Temperature variation sets the in vitro cortical network at different functional regimes, allowing the exploration of network activity generation and control mechanisms.
在局部皮质网络中，自发涌现的活动会自行组织成有节奏的模式。这些节律包括一个较慢的节律（<1 Hz），由上下状态的交替组成，以及在上升状态期间产生的更快的节律（10-80 Hz）。在浴温在 26 到 41 摄氏度之间变化时，会对涌现的网络活动产生强烈的调制。对于较暖的温度，上升状态会变短，而对于冷却，下降状态会最短，而生理温度（36-37 摄氏度）下的下降状态最短。上升状态期间的发射率受温度的强烈调制，随温度升高而增加。下降状态期间稀疏的发射率几乎不受温度变化的影响，因此在接近 30 摄氏度的温度下，上升和下降状态逐渐融合。在 30 摄氏度以下，降至 26 摄氏度，发射率失去节律性，逐渐变得连续。反映局部网络招募速度的下至上转换斜率随温度升高而逐渐变陡，而波传播速度仅略有增加。快节律对温度特别敏感。局部场电位中的宽带高频波动在 36-38 摄氏度的记录中达到最大值。总的来说，我们发现将皮质切片保持在生理温度对于产生类似于体内的活动至关重要。我们还证明，活动随温度的变化不是氧合变化的次要原因。温度变化使体外皮质网络处于不同的功能状态，允许探索网络活动的产生和控制机制。
