Center for Basic Medical Research, International University of Health and Welfare, Otawara, Tochigi 324-8501, Japan.
Neurosci Lett. 2023 Jul 27;810:137328. doi: 10.1016/j.neulet.2023.137328. Epub 2023 Jun 8.
Rats emit 50-kHz ultrasonic vocalizations (USVs), which reflect positive affective states. Rhythmic stroking increases 50-kHz USVs via the mesolimbic dopaminergic system. However, little is known about the effect of tactile reward on rat brain activity. This study aimed to investigate the brain activity associated with positive emotions induced by tactile stimulation using a frontoparietal electroencephalogram (EEG) as well as through the analysis of 50-kHz USVs and behavioral activity in awake rats. During rhythmic stroking, the power of the middle theta band and harmonics calls significantly increased compared with baseline. After rhythmic stroking, fast theta oscillations significantly increased but slow theta significantly decreased, with abundant frequency-modulated (FM) calls. Light touch stimulation increased the fast theta power but decreased FM calls. However, there was no significant difference in behavior after stimulation with rhythmic stroking or light touch. These results suggest that the characteristic brain theta oscillations and 50-kHz USV profiles induced by tactile reward can detect positive affective states in rats.
老鼠会发出 50-kHz 超声波（USVs），这反映了它们积极的情绪状态。有节奏地抚摸会通过中脑边缘多巴胺系统增加 50-kHz USVs。然而，人们对触觉奖励对大鼠大脑活动的影响知之甚少。本研究旨在使用额顶叶脑电图（EEG）以及分析 50-kHz USVs 和清醒大鼠的行为活动来研究与触觉刺激引起的积极情绪相关的大脑活动。在有节奏地抚摸时，与基线相比，中间 theta 波段和谐波呼叫的功率显著增加。在有节奏地抚摸之后，快速 theta 振荡显著增加，而慢速 theta 振荡显著减少，伴随着丰富的调频（FM）呼叫。轻触刺激增加了快速 theta 功率，但减少了 FM 呼叫。然而，在经过有节奏地抚摸或轻触刺激后，行为上没有显著差异。这些结果表明，由触觉奖励引起的特征性大脑 theta 振荡和 50-kHz USV 谱可以检测大鼠的积极情绪状态。
