Lesniak Daine R, Gerling Gregory J
Department of Systems and Information Engineering, University of Virginia, Charlottesville, VA, USA.
Math Biosci. 2009 Jul;220(1):15-23. doi: 10.1016/j.mbs.2009.03.007. Epub 2009 Apr 9.
Slowly adapting type I (SA-I) mechanoreceptors encode the edges and curvature of touched objects by generating neural spikes in response to indentation of the skin. Beneath this general input-output relationship, models are of great utility for understanding the sub-processes, as SA-I transduction sites are inaccessible to whole-cell recording. This work develops and validates a SA-I skin-receptor model that combines a finite element model of skin mechanics, a sigmoidal function of transduction, and a leaky integrate-and-fire model of neural dynamics. The model produced a R(2)=0.80 goodness of fit between predicted and observed firing rates for 3 and 5mm grating stimuli. In addition, modulation indices of predicted firing rates for 3 and 5mm gratings are 0.46 and 0.59, respectively, compared to the 0.71 and 0.72 found in vivo. An analysis of predicted first spikes indicates their latency may also be enhanced by edges, as edge proximity shortened first spike latencies by 26.2 and 41.8 ms for the 3 and 5mm gratings, respectively. The model described here bridges the gap between those models that transform sustained indentation to firing rates and those that transform vibration to spike times.
慢适应性I型（SA-I）机械感受器通过在皮肤受到压痕时产生神经冲动来编码被触摸物体的边缘和曲率。在这种一般的输入-输出关系之下，由于SA-I转导位点无法进行全细胞记录，模型对于理解这些子过程非常有用。这项工作开发并验证了一个SA-I皮肤感受器模型，该模型结合了皮肤力学的有限元模型、转导的S形函数以及神经动力学的泄漏积分发放模型。对于3毫米和5毫米的光栅刺激，该模型在预测发放率和观察到的发放率之间产生了R(2)=0.80的拟合优度。此外，3毫米和5毫米光栅的预测发放率调制指数分别为0.46和0.59，而在体内发现的分别为0.71和0.72。对预测的第一个冲动的分析表明，边缘也可能会延长其潜伏期，因为对于3毫米和5毫米的光栅，边缘接近度分别使第一个冲动潜伏期缩短了26.2毫秒和41.8毫秒。这里描述的模型弥合了将持续压痕转换为发放率的模型与将振动转换为冲动时间的模型之间的差距。
