Heldt S A, Falls W A
Department of Psychology, Northern Illinois University, De Kalb, IL 60115, USA.
Brain Res. 1998 Dec 7;813(2):274-82. doi: 10.1016/s0006-8993(98)01047-6.
The auditory thalamus is part of a neural circuit that mediates the expression of fear to auditory stimuli. Bilateral lesions of the auditory thalamus prevent the expression of fear to an auditory stimulus paired with shock. The present study assessed whether bilateral lesions of the auditory thalamus would also disrupt the inhibition of fear to an auditory stimulus paired with the absence of shock. Rats were given bilateral lesions of the auditory thalamus followed by Pavlovian conditioned inhibition training in which a light was paired with shock and a noise and light compound was presented in the absence of shock. Fear and the inhibition of fear were measured with the fear-potentiated startle effect. Lesions of the auditory thalamus did not disrupt the ability of the noise to inhibit the expression of fear to the light. However, these lesions did disrupt the ability of the noise to produce fear-potentiated startle after it had been subsequently paired with shock. These results suggest that although the auditory thalamus is an essential part of a neural circuit that mediates the expression of fear to auditory stimuli, it is not an essential part of the circuit that mediates the inhibition of fear to auditory stimuli.
听觉丘脑是一个神经回路的一部分，该神经回路介导对听觉刺激的恐惧表达。听觉丘脑的双侧损伤会阻止对与电击配对的听觉刺激产生恐惧表达。本研究评估了听觉丘脑的双侧损伤是否也会破坏对与无电击配对的听觉刺激的恐惧抑制。给大鼠进行听觉丘脑的双侧损伤，然后进行巴甫洛夫条件性抑制训练，其中一个灯光与电击配对，而一个噪音和灯光的复合刺激在无电击时呈现。通过恐惧增强惊吓效应来测量恐惧和恐惧抑制。听觉丘脑的损伤并未破坏噪音抑制对灯光的恐惧表达的能力。然而，这些损伤确实破坏了噪音在随后与电击配对后产生恐惧增强惊吓的能力。这些结果表明，虽然听觉丘脑是介导对听觉刺激的恐惧表达的神经回路的重要组成部分，但它不是介导对听觉刺激的恐惧抑制的神经回路的必要组成部分。
