Nakata Hiroki, Oshiro Misaki, Namba Mari, Shibasaki Manabu
Department of Health Sciences, Faculty of Human Life and Environment, Nara Women's University, Nara, Japan; and.
Graduate School of Humanities and Sciences, Nara Women's University, Nara, Japan.
Am J Physiol Regul Integr Comp Physiol. 2015 Dec 1;309(11):R1387-96. doi: 10.1152/ajpregu.00280.2015. Epub 2015 Oct 14.
Herein, we investigated the effects of passive heat stress on human somatosensory processing recorded by somatosensory-evoked potentials (SEPs). Fifteen healthy subjects received a median nerve stimulation at the left wrist under two thermal conditions: Heat Stress and normothermic Time Control. The latencies and amplitudes of P14, N20, P25, N35, P45, and N60 at C4' and P14, N18, P22, and N30 at Fz were evaluated. Under the Heat Stress condition, SEPs were recorded at normothermic baseline (1st), early in heat stress (2nd), when esophageal temperature had increased by ~1.0°C (3rd) and ~2.0°C (4th), and after heat stress (5th). In the Time Control condition, SEPs were measured at the same time intervals as those in the Heat Stress condition. The peak latencies and amplitudes of SEPs did not change early in heat stress. However, the latencies of P14, N20, and N60 at C4' and P14, N18, and P22 at Fz were significantly shorter in the 4th session than in the 1st session. Furthermore, the peak amplitudes of P25 and N60 at C4', and P22 and N30 at Fz decreased with increases in body temperature. On the other hand, under the Time Control condition, no significant differences were observed in the amplitudes or latencies of any component of SEPs. These results suggested that the conduction velocity of the ascending somatosensory input was accelerated by increases in body temperature, and hyperthermia impaired the neural activity of cortical somatosensory processing.
在此，我们研究了被动热应激对体感诱发电位（SEP）记录的人体体感加工的影响。15名健康受试者在两种热条件下接受左手腕正中神经刺激：热应激和常温时间对照。评估了C4'处P14、N20、P25、N35、P45和N60以及Fz处P14、N18、P22和N30的潜伏期和波幅。在热应激条件下，在常温基线（第1次）、热应激早期（第2次）、食管温度升高约1.0°C（第3次）和约2.0°C（第4次）时以及热应激后（第5次）记录SEP。在时间对照条件下，与热应激条件下相同的时间间隔测量SEP。热应激早期SEP的峰潜伏期和波幅没有变化。然而，第4次记录时C4'处P14、N20和N60以及Fz处P14、N18和P22的潜伏期明显短于第1次记录时。此外，C4'处P25和N60以及Fz处P22和N30的峰波幅随体温升高而降低。另一方面，在时间对照条件下，SEP任何成分的波幅或潜伏期均未观察到显著差异。这些结果表明，体温升高加速了体感传入神经的传导速度，热应激损害了皮层体感加工的神经活动。
