The thalamic reticular nucleus (TRN), a cluster of GABAergic cells, modulates sensory attention and perception through its inhibitory projections to thalamic nuclei. Cortical and thalamic topographic projections to the auditory TRN are thought to compose tonotopic organizations for modulation of thalamic auditory processing. The present study determined tonotopies in the TRN and examined interactions between probe and masker sounds to obtain insights into temporal processing associated with tonotopies. Experiments were performed on anesthetized rats, using juxta-cellular recording and labeling techniques. Following determination of tonotopies, effects of sub-threshold masker sound stimuli on onset and late responses evoked by a probe sound were examined. The main findings are as follows. Tonotopic organizations were recognized in cell location and axonal projection. Tonotopic gradients and their clarities were diverse, depending on sound intensity, response type and the tiers of the TRN. Robust alterations in response magnitude, latency and/or burst spiking took place following masker sounds in either a broad or narrow range of frequencies that were close or far away from the probe sound frequency. The majority of alterations were suppression recognizable up to 600 ms in the interval between masker and probe sounds, and directions of alteration differed depending on the interval. Finally, masker sound effects were associated with tonotopic organizations. These findings suggest that the auditory TRN is comprised of sound intensity-dependent multiple tonotopic organizations, which could configure temporal interactions of auditory information across sound frequencies and impose complex but spatiotemporally structured influences on thalamic auditory processing.

丘脑网状核 (TRN) 是一组 GABA 能细胞，通过其对丘脑核的抑制性投射来调节感觉注意力和感知。对听觉 TRN 的皮质和丘脑地形投影被认为构成了用于调节丘脑听觉处理的音调组织。本研究确定了 TRN 中的音调，并检查了探针和掩蔽声音之间的相互作用，以深入了解与音调相关的时间处理。实验是在麻醉大鼠上进行的，使用细胞旁记录和标记技术。在确定音调之后，检查了亚阈值掩蔽声音刺激对探测声音引起的起始和迟到响应的影响。主要发现如下。Tonotopic 组织在细胞位置和轴突投影中得到识别。音调梯度及其清晰度各不相同，具体取决于声音强度、响应类型和 TRN 的层级。响应幅度、延迟和/或突发尖峰的稳健变化发生在靠近或远离探头声音频率的宽或窄频率范围内的掩蔽声音之后。在掩蔽声和探测声之间的间隔中，大多数变化是可识别的抑制，最长可达 600 毫秒，变化的方向因间隔而异。最后，掩蔽音效与音调组织有关。这些发现表明听觉 TRN 由依赖于声音强度的多个音调组织组成，