Ruthig Philip, Müller Gesine Fiona, Fink Marion, Scherf Nico, Morawski Markus, Schönwiesner Marc
Faculty of Life Sciences, Leipzig University, Leipzig, Germany.
Paul Flechsig Institute-Centre of Neuropathology and Brain Research, Medical Faculty, University of Leipzig, Leipzig, Germany.
Eur J Neurosci. 2025 Jan;61(2):e16675. doi: 10.1111/ejn.16675.
Communication sound processing in mouse AC is lateralized. Both left and right AC are highly specialised and differ in auditory stimulus representation, functional connectivity and field topography. Previous studies have highlighted intracortical functional circuits that explain hemispheric stimulus preference. However, the underlying microstructure remains poorly understood. In this study, we examine structural lateralization of AC on the basis of immunohistochemically stained and tissue-cleared adult mouse brains (n = 11). We found hemispheric asymmetries of intracortical myelination, most prominently in layer 2/3, which featured more intercolumnar connections in the right AC. Furthermore, we found a larger structural asymmetry in the right AC. We also investigated sex differences. In male mice, myelination direction in the right AC is tilted to the anterior side. This pattern is inverted in female mice. However, the spatial distribution of neuronal cell bodies in the left and right AC along the laminar axis of the cortex was remarkably symmetric in all samples. These results suggest that basic developmentally defined structures such as cortical columns remain untouched by lateral specialisation, but more plastic myelinated axons show diverse hemispheric asymmetries. These asymmetries may contribute to specialisation on lateralized tasks such as vocal communication processing or specialisation on spectral or temporal complexity of stimuli.
小鼠听觉皮层中的交流声音处理具有侧向化。左右听觉皮层都高度特化，在听觉刺激表征、功能连接和场拓扑结构方面存在差异。先前的研究强调了能够解释半球刺激偏好的皮质内功能回路。然而，其潜在的微观结构仍知之甚少。在本研究中，我们基于免疫组织化学染色和组织透明化的成年小鼠大脑（n = 11），研究了听觉皮层的结构侧向化。我们发现皮质内髓鞘形成存在半球不对称性，最明显的是在第2/3层，右侧听觉皮层的柱间连接更多。此外，我们发现右侧听觉皮层存在更大的结构不对称性。我们还研究了性别差异。在雄性小鼠中，右侧听觉皮层的髓鞘形成方向向前倾斜。在雌性小鼠中，这种模式则相反。然而，在所有样本中，左右听觉皮层中神经元细胞体沿皮质层状轴的空间分布非常对称。这些结果表明，诸如皮质柱等基本的发育定义结构未受侧向特化影响，但更具可塑性的有髓轴突表现出多样的半球不对称性。这些不对称性可能有助于在诸如声音交流处理等侧向任务上的特化，或在刺激的频谱或时间复杂性上的特化。
