【作者】 杜忆； 吴玺宏； 李量；

【Author】 Du Yi Wu Xihong Li Liang Department of Psychology,Speech and Hearing Research Center,Key Laboratory on Machine Perception (Ministry of Education),Peking University,Beijing,100871

【机构】 北京大学心理系,言语与听觉研究中心,机器感知教育部重点实验室；

【摘要】 作为感觉运动门控的操作模型,惊反射的前脉冲抑制在人类和实验动物中都可被注意强化。本实验试图考察以下三个前脑结构:初级听觉皮层(皮层加工声音信号的第一站),杏仁核外侧核(恐惧条件化的重要结构)和后项叶(空间注意加工的关键结构)分别在大鼠听觉前脉冲抑制自上而下调节中的作用。结果显示,在噪音掩蔽条件下,对前脉冲刺激的恐惧条件化能以一种刺激特异性的方式增强前脉冲抑制,而条件化后的前脉冲刺激与掩蔽噪音间的知觉空间分离引发的空间注意增强可进一步提高前脉冲抑制。可逆性地阻断初级听皮层的谷氨酸受体活动可同时破坏恐惧条件化和知觉空间分离引发的前脉冲抑制增强。阻断杏仁核外侧核选择性消除了恐惧条件化引发的增强,而阻断后项叶则选择性破坏了知觉空间分离引发的增强。因此,对前脉冲抑制自上而下的调节是结构差异化的,依赖于不同的前脑结构。得益于高级认知过程的精细化调节,前脉冲抑制的门控功能才能更灵活地适应复杂的环境需求。更多还原

【Abstract】 As an operational measure of sensorimotor gating,prepulse inhibition(PPI) of the startle reflex can be attentionally enhanced in both humans and laboratory animals.This study investigated whether the following three forebrain structures,which are critical for initial cortical processing of auditory signals,auditory fear conditioning/memories,and spatial attention,respectively,play a role in the top-down modulation of PPI in rats:the primary auditory cortex(A1),lateral nucleus of the amygdala(LA),and posterior parietal cortex(PPC).The results show that under noise masking conditions,PPI was enhanced by fear conditioning of the prepulse in a prepulse-specific manner,and PPI was further increased by facilitated spatial attention induced by perceptual separation between the conditioned prepulse and the noise masker.Reversibly blocking glutamate receptors in the A1 eliminated both the conditioning-induced and perceptual-separation-induced PPI enhancements.Blocking the LA selectively eliminated the conditioning-induced PPI enhancement,and blocking the PPC specifically eliminated the perceptual-separation-induced PPI enhancement.Thus,the top-down modulation of PPl is differentially organized and depends on operations of various forebrain structures.Due to the fine-tuned modulation by higher-order cognitive processes,the gating function of PPI can be more flexible to complex environments.更多还原