a Graduate School, Jinzhou Medical University , Jinzhou , China.
b Department of Medical Imaging , Jinan Military General Hospital , Jinan , China.
Int J Hyperthermia. 2018 Nov;34(7):1010-1019. doi: 10.1080/02656736.2017.1392046. Epub 2017 Nov 1.
To investigate the effect of head-cooling on resting-state spontaneous brain activity during passive hyperthermia.
An environmental heat exposure was simulated on 16 healthy men under a normal control condition (NC) at 25 °C and two hot conditions at 50 °C with hyperthermia with head-cooling condition (HHC) and without hyperthermia condition (HOT) keeping the head cool, respectively. Resting-state functional MRI (fMRI) data were acquired under each condition and the values of amplitude low frequency fluctuations (ALFF) and z functional connectivity (zFC) were computed to examine regional activity and functional integration, respectively. Pearson's correlation analysis between the ALFF value and subjective sensations scores were performed.
Brain regions with significant ALFF differences among the three conditions were found primarily in the right medial prefrontal cortex/anterior cingulate cortex (MPFC/ACC), bilateral posterior cingulate cortex/precuneus (PCC/PCu), and right fusiform gyrus. Compared to the NC or HOT condition, the HHC condition exhibited significantly increased ALFF in the bilateral PCC/PCu and decreased ALFF in the right fusiform gyrus. However, ALFF of the right MPFC/ACC showed no significant difference between the NC and HHC conditions. Positive FC between the right MPFC/ACC and bilateral PCC/PCu was significantly increased in HHC condition with respect to HOT condition. Negative FC between the right fusiform gyrus and the right MPFC/ACC, bilateral PCC/PCu was observed with a decreasing trend from the HHC condition to the HOT condition. Moreover, head-cooling also improved thermal comfort during passive hyperthermia.
Head-cooling could substantially reduce the negative effect of hyperthermia on human brain activity as well as thermal sensation.
研究头部冷却对被动性高温时静息状态自发脑活动的影响。
在正常控制条件（NC）下（25°C）和两个热条件下（50°C），分别模拟环境热暴露，分别保持头部凉爽的头部冷却条件（HHC）和无高温条件（HOT）。在每种条件下采集静息态功能磁共振成像（fMRI）数据，并计算幅度低频波动（ALFF）和 z 功能连接（zFC）的值，分别检查区域活动和功能整合。对 ALFF 值与主观感觉评分之间的 Pearson 相关性进行分析。
在三种条件之间，大脑区域的 ALFF 差异显著，主要位于右侧内侧前额叶/前扣带皮层（MPFC/ACC）、双侧后扣带皮层/楔前叶（PCC/PCu）和右侧梭状回。与 NC 或 HOT 条件相比，HHC 条件下双侧 PCC/PCu 的 ALFF 显著增加，右侧梭状回的 ALFF 显著降低。然而，NC 和 HHC 条件之间右侧 MPFC/ACC 的 ALFF 没有显著差异。与 HOT 条件相比，HHC 条件下右侧 MPFC/ACC 与双侧 PCC/PCu 之间的正功能连接显著增加。从 HHC 条件到 HOT 条件，右侧梭状回与右侧 MPFC/ACC、双侧 PCC/PCu 之间的负功能连接呈下降趋势。此外，头部冷却还改善了被动性高温时的热舒适度。
头部冷却可以显著减轻高温对人体大脑活动和热感觉的负面影响。
