Universität Jena, Institut für Allgemeine Zoologie und Tierphysiologie, Erbertstraße 1, 07743 Jena, Germany.
Universität Jena, Institut für Allgemeine Zoologie und Tierphysiologie, Erbertstraße 1, 07743 Jena, Germany.
Neuroimage. 2017 Oct 1;159:459-472. doi: 10.1016/j.neuroimage.2017.07.037. Epub 2017 Jul 20.
It has been suggested that primary sensory cortices do not work in isolation but receive subthreshold inputs originating from other senses. However, repercussions of an acute loss of one sense on multimodal sensory processing remain elusive. Here we investigated the early effects of acute hearing loss on visual processing in adult mice. For this, we developed a method to simultaneously map the primary auditory (A1) and visual cortex (V1) using periodic intrinsic optical imaging. We found that reducing sound evoked A1 responsiveness due to the induction of conductive hearing loss (CHL) led to a concomitant increase of visually driven V1 activity. Accordingly, using the neuronal activity marker c-fos we found the number of stained pyramidal cells to be increased in V1 layer 2/3 after CHL. In contrast, numbers of c-fos positive parvalbumin (PV) and somatostatin (SOM) expressing inhibitory neurons were reduced after CHL. Finally, we adapted the periodic intrinsic imaging method to determine V1 contrast and spatial frequency tuning. Using this method we could show that visual acuity and contrast sensitivity were improved after CHL. In addition, retrograde tracing experiments revealed direct anatomical projections from A1 to V1 which could potentially serve as a substrate for the observed effects. In summary, our results suggest that CHL rapidly disrupts the functional interplay between A1 and V1 leading to altered visually evoked V1 responses.
有人提出，初级感觉皮层不是孤立工作的，而是接收来自其他感觉的亚阈值输入。然而，急性丧失一种感觉对多模态感觉处理的影响仍然难以捉摸。在这里，我们研究了急性听力损失对成年小鼠视觉处理的早期影响。为此，我们开发了一种同时使用周期性内源光学成像来映射主要听觉（A1）和视觉皮层（V1）的方法。我们发现，由于传导性听力损失（CHL）的诱导，降低声音诱发的 A1 反应性导致视觉驱动的 V1 活性相应增加。因此，使用神经元活性标志物 c-fos，我们发现 CHL 后 V1 层 2/3 中染色的锥体神经元数量增加。相比之下，CHL 后，c-fos 阳性的 parvalbumin（PV）和 somatostatin（SOM）表达抑制性神经元的数量减少。最后，我们采用周期性内源成像方法来确定 V1 的对比度和空间频率调谐。使用这种方法，我们可以证明 CHL 后视觉敏锐度和对比度灵敏度得到了提高。此外，逆行追踪实验显示了从 A1 到 V1 的直接解剖投射，这可能是观察到的效应的基础。总之，我们的结果表明，CHL 迅速破坏了 A1 和 V1 之间的功能相互作用，导致视觉诱发的 V1 反应发生改变。
