Integrated Program in Nseuroscience, McGill University, Montreal, Quebec, Canada.
Integrated Program in Nseuroscience, McGill University, Montreal, Quebec, Canada; Department of Physiology, McGill University, Montreal, Quebec, Canada.
Neuroimage. 2024 Oct 1;299:120813. doi: 10.1016/j.neuroimage.2024.120813. Epub 2024 Aug 23.
In response to sensory deprivation, the brain adapts according to contemporary demands to efficiently navigate a modified perceptual environment. This reorganization may result in improved processing of the remaining senses-a phenomenon referred to as compensatory crossmodal plasticity. One approach to explore this neuroplasticity is to consider the macrostructural changes in neural tissue that mirror this functional optimization. The current study is the first of its kind to measure MRI-derived gray matter (GM) volumes of control felines (n=30), while additionally identifying volumetric differences in response to perinatal deafness (30 ototoxically-deafened cats). To accomplish this purpose, regional and morphometric methods were performed in parallel. The regional analysis evaluated volumetric alterations of global GM, as well as the volumes of 146 regions of interest (ROIs) and 12 functional subgroupings of these ROIs. Results revealed whole-brain GM preservation; however, somatosensory and visual cortices exhibited an overall increase in volume. On a smaller scale, this analysis uncovered two auditory ROIs (second auditory cortex, A2, and ventral auditory field, VAF) that decreased in volume alongside two visual regions (anteromedial lateral suprasylvian area, AMLS and splenial visual area, SVA) that increased-all localized within the right hemisphere. Comparatively, the findings of tensor-based morphometry (TBM) generally aligned with those of the ROI-based method, as this voxel-wise approach demonstrated clusters of expansion coincident with visual- and somatosensory-related loci; although, it failed to detect any GM reductions following deafness. As distinct differences were identified in each analysis, the current study highlights the importance of employing multiple methods when exploring MRI volumetry. Overall, this study proposes that volumetric alterations within sensory loci allude to a redistribution of cortical space arising from modified perceptual demands following auditory deprivation.
为了应对感觉剥夺，大脑会根据当代需求进行调整，以有效地在经过修改的感知环境中导航。这种重新组织可能会导致剩余感觉的处理得到改善——这种现象被称为补偿性跨模态可塑性。探索这种神经可塑性的一种方法是考虑反映这种功能优化的神经组织的宏观结构变化。目前的研究是首例测量控制猫（n=30）的磁共振成像（MRI）衍生灰质（GM）体积的研究，同时还确定了围产期耳聋（30 只耳毒性耳聋猫）对其产生的体积差异。为了实现这一目标，同时进行了区域和形态计量学方法。区域分析评估了 GM 的整体体积变化，以及 146 个感兴趣区域（ROI）的体积变化，以及这些 ROI 的 12 个功能亚组的体积变化。结果显示大脑 GM 整体得到了保存；然而，感觉和视觉皮质的总体体积增加。在较小的范围内，该分析发现了两个听觉 ROI（第二听觉皮质 A2 和腹侧听觉场 VAF）的体积减小，以及两个视觉区域（前内侧外侧上顶叶区 AMLS 和穹窿状视觉区 SVA）的体积增加——都位于右半球。相比之下，基于张量的形态计量学（TBM）的发现与 ROI 方法的发现大致一致，因为这种体素方法显示了与视觉和感觉相关的扩张簇；尽管，它未能检测到耳聋后任何 GM 的减少。由于在每种分析中都发现了明显的差异，因此本研究强调了在探索 MRI 体积时采用多种方法的重要性。总体而言，本研究提出，感觉部位的体积变化暗示了由于听觉剥夺后感知需求的改变而导致的皮质空间的重新分配。
