Department of Physiology, Wakayama Medical University, Wakayama, Japan.
J Comp Neurol. 2020 Jul 15;528(11):1917-1941. doi: 10.1002/cne.24865. Epub 2020 Feb 5.
Cross-modal auditory influence on cell activity in the primary visual cortex emerging at short latencies raises the possibility that the first-order visual thalamic nucleus, which is considered dedicated to unimodal visual processing, could contribute to cross-modal sensory processing, as has been indicated in the auditory and somatosensory systems. To test this hypothesis, the effects of sound stimulation on visual cell activity in the dorsal lateral geniculate nucleus were examined in anesthetized rats, using juxta-cellular recording and labeling techniques. Visual responses evoked by light (white LED) were modulated by sound (noise burst) given simultaneously or 50-400 ms after the light, even though sound stimuli alone did not evoke cell activity. Alterations of visual response were observed in 71% of cells (57/80) with regard to response magnitude, latency, and/or burst spiking. Suppression predominated in response magnitude modulation, but de novo responses were also induced by combined stimulation. Sound affected not only onset responses but also late responses. Late responses were modulated by sound given before or after onset responses. Further, visual responses evoked by the second light stimulation of a double flash with a 150-700 ms interval were also modulated by sound given together with the first light stimulation. In morphological analysis of labeled cells projection cells comparable to X-, Y-, and W-like cells and interneurons were all susceptible to auditory influence. These findings suggest that the first-order visual thalamic nucleus incorporates auditory influence into parallel and complex thalamic visual processing for cross-modal modulation of visual attention and perception.
跨模态听觉对初级视皮层细胞活动的短潜伏期影响提出了这样一种可能性，即被认为专门用于单模态视觉处理的一级视丘脑核可能有助于跨模态感觉处理，正如在听觉和体感系统中所表明的那样。为了检验这一假设，使用细胞外记录和标记技术，在麻醉大鼠中检查了声音刺激对背外侧膝状体核中视觉细胞活动的影响。通过光（白色 LED）刺激引起的视觉反应可被同时或光后 50-400ms 给予的声音（噪声突发）调制，尽管单独的声音刺激不会引起细胞活动。在 80 个细胞中有 71%（57/80）的细胞观察到视觉反应的变化，表现为反应幅度、潜伏期和/或爆发性 spike 的变化。在响应幅度调制中，抑制占主导地位，但联合刺激也诱导了新的反应。声音不仅影响起始反应，还影响后期反应。后期反应可被起始反应之前或之后的声音调制。此外，双光刺激（间隔 150-700ms）中的第二个光刺激引起的视觉反应也可被与第一个光刺激一起给予的声音调制。在标记细胞的形态分析中，投射细胞类似于 X、Y 和 W 样细胞和中间神经元，它们都容易受到听觉影响。这些发现表明，一级视丘脑核将听觉影响纳入平行和复杂的丘脑视觉处理中，以实现对视觉注意力和感知的跨模态调制。
