Ding Yu, Jiang Huan, Xu Na, Li Liang
School of Psychology, Beijing Language and Culture University, Beijing 100083, China; School of Psychological and Cognitive Sciences, Peking University, Beijing 100080, China.
School of Psychology, Beijing Language and Culture University, Beijing 100083, China.
Neuroscience. 2025 Feb 6;566:112-123. doi: 10.1016/j.neuroscience.2024.12.047. Epub 2024 Dec 24.
Prepulse inhibition (PPI) refers to the phenomenon in which a weak sensory stimulus before a strong one significantly reduces the startle reflex caused by the strong stimulus. Perceptual spatial separation, a phenomenon where auditory cues from the prepulse and background noise are distinguished in space, has been shown to enhance PPI. This study aims to investigate the neural modulation mechanisms of PPI by the spatial separation between the prepulse stimulus and background noise, particularly in the deep superior colliculus (deepSC). The experiment used 11 anesthetized male Sprague-Dawley rats, with electrodes implanted in the left deepSC nd the right inferior colliculus (IC). The prepulse stimulus was a segment of narrowband noise, with interaural time differences adjusted so that the prepulse stimulus and background noise were perceived as either ipsilaterally leading or contralaterally leading, resulting in perceptual spatial fusion or spatial separation. The results showed that under conditions of spatial separation, the stimulus-response coherence of the envelope and fine structure components of the prepulse stimulus in the deepSC was significantly enhanced, the response of the deepSC to the stimulus was significantly reduced in the presence of the prepulse stimulus, and the envelope component of the prepulse stimulus was positively correlated with the inhibitory effect. The above results suggest that perceptual spatial dissociation can significantly enhance the expression of deepSC, particularly the precision of the envelope component, thereby significantly affecting the electrophysiological response of PPI.
前脉冲抑制（PPI）是指在强刺激之前的弱感觉刺激会显著降低由强刺激引起的惊吓反射的现象。感知空间分离是一种在空间上区分前脉冲和背景噪声的听觉线索的现象，已被证明能增强PPI。本研究旨在探讨前脉冲刺激与背景噪声之间的空间分离对PPI的神经调制机制，特别是在深层上丘（deepSC）中的机制。实验使用了11只麻醉的雄性Sprague-Dawley大鼠，电极植入左侧deepSC和右侧下丘（IC）。前脉冲刺激是一段窄带噪声，调整双耳时间差，使前脉冲刺激和背景噪声被感知为同侧领先或对侧领先，从而导致感知空间融合或空间分离。结果表明，在空间分离条件下，deepSC中前脉冲刺激的包络和精细结构成分的刺激-反应相干性显著增强，在前脉冲刺激存在的情况下，deepSC对刺激的反应显著降低，且前脉冲刺激的包络成分与抑制作用呈正相关。上述结果表明，感知空间解离可显著增强deepSC的表达，特别是包络成分的精度，从而显著影响PPI的电生理反应。
