Moderate cortical cooling is known to suppress slow oscillations and to evoke persistent cortical activity. However, the cooling-induced changes in electrical activity across cortical layers remain largely unknown. Here, we performed multi-channel local field potential (LFP) and multi-unit activity (MUA) recordings with linear silicone probes through the layers of single cortical barrel columns in urethane-anesthetized rats under normothermia (38°C) and during local cortical surface cooling (30°C). During cortically generated slow oscillations, moderate cortical cooling decreased delta wave amplitude, delta-wave occurrence, the duration of silent states, and delta wave-locked MUA synchronization. Moderate cortical cooling increased total time spent in the active state and decreased total time spent in the silent state. Cooling-evoked changes in the MUA firing rate in cortical layer 5 (L5) varied from increase to decrease across animals, and the polarity of changes in L5 MUA correlated with changes in total time spent in the active state. The decrease in temperature reduced MUA firing rates in all other cortical layers. Sensory-evoked MUA responses also decreased during cooling through all cortical layers. The cooling-dependent slowdown was detected at the fast time-scale with a decreased frequency of sensory-evoked high-frequency oscillations (HFO). Thus, moderate cortical cooling suppresses slow oscillations and desynchronizes neuronal activity through all cortical layers, and is associated with reduced firing across all cortical layers except L5, where cooling induces variable and non-consistent changes in neuronal firing, which are common features of the transition from slow-wave synchronization to desynchronized activity in the barrel cortex.

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皮质冷却对大鼠桶状皮质各层活动的影响

众所周知，适度的皮质冷却可以抑制缓慢的振荡并引起持续的皮质活动。然而，冷却引起的皮层电活动的变化在很大程度上仍然未知。在这里，我们在常温 (38°C) 和局部皮层期间通过聚氨酯麻醉大鼠的单皮层桶柱层使用线性硅胶探针进行多通道局部场电位 (LFP) 和多单位活动 (MUA) 记录。表面冷却 (30°C)。在皮质产生的缓慢振荡期间，适度的皮质冷却降低了 delta 波振幅、delta 波发生、沉默状态的持续时间和 delta 波锁定 MUA 同步。适度的皮质冷却增加了活跃状态的总时间，减少了沉默状态的总时间。皮质层 5 (L5) 中 MUA 放电率的冷却引起的变化在动物中从增加到减少变化，并且 L5 MUA 变化的极性与活动状态总时间的变化相关。温度的降低降低了所有其他皮质层的 MUA 发射率。在通过所有皮质层冷却期间，感官诱发的 MUA 反应也降低。在快速时间尺度上检测到冷却相关的减速，感觉诱发的高频振荡 (HFO) 的频率降低。因此，适度的皮质冷却抑制了所有皮质层的缓慢振荡并使神经元活动不同步，并且与除 L5 之外的所有皮质层的放电减少有关，其中冷却引起神经元放电的可变和不一致变化，