Perceived target–masker separation unmasks responses of lateral amygdala to the emotionally conditioned target sounds in awake rats
Perceived target–masker separation unmasks responses of lateral amygdala to the emotionally conditioned target sounds in awake rats
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DOI：
10.1016/j.neuroscience.2012.08.022
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发表时间：
2012-12
期刊：
影响因子：
3.3
通讯作者：
Y. Du;Q. Wang;Y. Zhang;X. Wu;L. Li
中科院分区：
文献类型：
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作者：
Y. Du;Q. Wang;Y. Zhang;X. Wu;L. Li
在（模拟的）混响环境中，人类听众和实验室大鼠都能够在感知上整合声源的直达波与声源的反射，从而产生来自声源周围位置的融合图像（优先效应）。这种感知分组效应产生声源之间的感知空间分离，并促进对目标源的选择性注意。然而，知觉空间分离的暴露效应的神经相关性尚未在文献中报道。杏仁核外侧核（LA）对于处理生态学上显著的感觉信号（例如，威胁的声音）和调节听觉恐惧条件反射。如果声音是恐惧条件的，则LA神经元对声音的反应增加。本研究探讨是否在清醒大鼠的知觉融合诱导的分离之间的恐惧条件的目标声音和噪声掩蔽增强LA反应的目标。结果表明，频率跟随响应（FFR，即，基于神经元群体对周期性声音波形的锁相放电的持续电位）记录在LA中的对被宽带噪声掩蔽的音调复合体的持续电位在音调复合体变成恐惧条件化后增强。更重要的是，恐惧条件性音调复合波（而非伪条件性音调复合波）在被感知为与掩蔽物分离时比被感知为与掩蔽物位于同一位置时引起更大的LA FFR。结果表明，在LA存在一个神经相关的选择性注意生态显着的声音具有高度的刺激特异性。
In a (simulated) reverberant environment, both human listeners and laboratory rats are able to perceptually integrate the direct wave of a sound source with the reflections of the source, leading to a fused image as coming from the location around the source (the precedence effect). This perceptual grouping effect produces perceived spatial separation between sound sources and facilitates selective attention to the target source. However, the neural correlates of the unmasking effects of perceived spatial separation have not been reported in the literature. The lateral nucleus of the amygdala (LA) is critical for processing ecologically salient sensory signals (e.g., threatening sounds) and mediating auditory fear conditioning. LA neuronal responses to a sound increase if the sound is fear conditioned. This study investigated whether in awake rats the perceptual fusion-induced separation between a fear-conditioned target sound and a noise masker enhances LA responses to the target. The results show that frequency-following responses (FFRs, i.e., sustained potentials based on phase-locked firing of neuron populations to periodical sound waveforms) recorded in the LA to a tone-complex, which was masked by a wideband noise, were enhanced after the tone-complex became fear conditioned. More importantly, the fear-conditioned tone-complex, but not the pseudo-conditioned tone-complex, elicited further larger LA FFRs when it was perceived as separated from the masker than when it was perceived as co-located with the masker. The results suggest that in the LA there exists a neural correlate of selective attention to ecologically significant sounds with a high degree of stimulus specificity.