Bourgeois Elliot B, Johnson Brian N, McCoy Almedia J, Trippa Lorenzo, Cohen Akiva S, Marsh Eric D
Department of Pathology, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts, United States of America.
Department of Pediatrics, Division of Pediatric Neurology, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, United States of America.
PLoS One. 2014 Sep 26;9(9):e108686. doi: 10.1371/journal.pone.0108686. eCollection 2014.
Voltage-sensitive dye imaging (VSDI) can simultaneously monitor the spatiotemporal electrical dynamics of thousands of neurons and is often used to identify functional differences in models of neurological disease. While the chief advantage of VSDI is the ability to record spatiotemporal activity, there are no tools available to visualize and statistically compare activity across the full spatiotemporal range of the VSDI dataset. Investigators commonly analyze only a subset of the data, and a majority of the dataset is routinely excluded from analysis. We have developed a software toolbox that simplifies visual inspection of VSDI data, and permits unaided statistical comparison across spatial and temporal dimensions. First, the three-dimensional VSDI dataset (x,y,time) is geometrically transformed into a two-dimensional spatiotemporal map of activity. Second, statistical comparison between groups is performed using a non-parametric permutation test. The result is a 2D map of all significant differences in both space and time. Here, we used the toolbox to identify functional differences in activity in VSDI data from acute hippocampal slices obtained from epileptic Arx conditional knock-out and control mice. Maps of spatiotemporal activity were produced and analyzed to identify differences in the activity evoked by stimulation of each of two axonal inputs to the hippocampus: the perforant pathway and the temporoammonic pathway. In mutant hippocampal slices, the toolbox identified a widespread decrease in spatiotemporal activity evoked by the temporoammonic pathway. No significant differences were observed in the activity evoked by the perforant pathway. The VSDI toolbox permitted us to visualize and statistically compare activity across the spatiotemporal scope of the VSDI dataset. Sampling error was minimized because the representation of the data is standardized by the toolbox. Statistical comparisons were conducted quickly, across the spatiotemporal scope of the data, without a priori knowledge of the character of the responses or the likely differences between them.
电压敏感染料成像（VSDI）能够同时监测数千个神经元的时空电动力学，常用于识别神经疾病模型中的功能差异。虽然VSDI的主要优势在于能够记录时空活动，但目前尚无工具可用于在VSDI数据集的整个时空范围内可视化并进行活动的统计比较。研究人员通常仅分析部分数据，大部分数据集通常被排除在分析之外。我们开发了一个软件工具箱，它简化了对VSDI数据的目视检查，并允许在空间和时间维度上进行独立的统计比较。首先，将三维VSDI数据集（x、y、时间）进行几何变换，转化为二维时空活动图。其次，使用非参数置换检验对组间进行统计比较。结果是一个二维图，显示了空间和时间上所有显著差异。在这里，我们使用该工具箱来识别来自癫痫性Arx条件性敲除小鼠和对照小鼠的急性海马切片的VSDI数据中活动的功能差异。生成并分析时空活动图，以识别海马体两个轴突输入（穿通通路和颞叶-海马通路）各自刺激所诱发活动的差异。在突变型海马切片中，该工具箱识别出颞叶-海马通路诱发的时空活动普遍减少。在穿通通路诱发的活动中未观察到显著差异。VSDI工具箱使我们能够在VSDI数据集的时空范围内可视化并进行活动的统计比较。由于数据表示由该工具箱标准化，抽样误差降至最低。在数据的时空范围内快速进行统计比较，无需事先了解反应特征或它们之间可能存在的差异。
