Li L, Frost B J
Department of Psychology, Queen's University, Kingston, Ontario, Canada.
Brain Res Bull. 2000 Jan 1;51(1):95-100. doi: 10.1016/s0361-9230(99)00215-4.
Previous studies have indicated that the auditory midbrain, the inferior colliculus, is important for both sound localization and mediation of prepulse inhibition of the startle reflex. The present study investigated the azimuthal directional sensitivity of prepulse inhibition of the pinna startle reflex in decerebrate rats. The pinna startle reflex was measured by recording multi-unit action potentials from the cervicoauricular muscles. The startling noise burst (94 dB SPL) was produced by a stationary speaker at 0 degrees azimuth, and the non-startling prepulse noise burst (46 dB SPL) was produced by a movable speaker whose direction was changed in the frontal azimuthal plane. The interval between the onset of the prepulse sound and the onset of the startling sound was 100 ms. The pinna reflex to the startling sound was strongly inhibited by the prepulse sound, and the inhibited startle response exhibited a flat azimuthal directional curve. In addition to further confirming that the neural pathways mediating prepulse inhibition are located in the brainstem, the present results indicate that interaural disparities of binaural inputs used for sound localization are not capable of modulating prepulse inhibition of the startle reflex.
先前的研究表明，听觉中脑，即下丘，对于声音定位和惊跳反射的前脉冲抑制介导都很重要。本研究调查了去大脑大鼠耳廓惊跳反射前脉冲抑制的方位角方向敏感性。通过记录颈耳肌的多单位动作电位来测量耳廓惊跳反射。94分贝声压级的惊跳噪声脉冲由位于0度方位角的固定扬声器产生，46分贝声压级的非惊跳前脉冲噪声脉冲由一个可移动扬声器产生，该扬声器的方向在额面方位角平面内改变。前脉冲声音开始与惊跳声音开始之间的间隔为100毫秒。前脉冲声音强烈抑制了对惊跳声音的耳廓反射，并且被抑制的惊跳反应呈现出一条平坦的方位角方向曲线。除了进一步证实介导前脉冲抑制的神经通路位于脑干外，本研究结果还表明，用于声音定位的双耳输入的双耳差异无法调节惊跳反射的前脉冲抑制。
