Cells rely on the ability to sense and respond to small spatial differences in chemoattractant concentrations for survival. There is growing evidence that this is accomplished by setting the signaling system near the threshold for activation in an excitable system and using the spatial heterogeneities to alter the threshold, thereby biasing cell activity in the direction of the gradient. Here we consider a scheme by which the set point is adaptively set near the bifurcation point, but without explicit knowledge of this point. Through simulation, we show that the method would improve chemotactic efficiency of cells. The results of this paper are based on pioneering work by Eduardo Sontag and coworkers, to whom this paper is dedicated in honor of his 70th birthday.

细胞依靠感知和响应化学引诱剂浓度的微小空间差异的能力来生存。越来越多的证据表明，这是通过将信号系统设置在可兴奋系统中激活阈值附近并使用空间异质性改变阈值来实现的，从而使细胞活动偏向梯度方向。在这里，我们考虑一种方案，通过该方案将设定点自适应地设置在分叉点附近，但无需明确了解该点。通过模拟，我们表明该方法可以提高细胞的趋化效率。本文的成果基于 Eduardo Sontag 及其同事的开创性工作，本文谨献给他们，以纪念他的 70 岁生日。