Before revision:  Here, by adopting a widely used modeling framework of directional sensing, i.e., local excitation and global inhibition (LEGI), we propose the hypothesis that the two scaling behaviors stem from a single design principle, namely, invariance of the governing equations to a scale transformation of the input level.
After revision:  Here, by adopting a widely used modeling framework of directional sensing, local excitation and global inhibition (LEGI), we propose the hypothesis that the two scaling behaviors stem from a single design principle, namely, invariance of the governing equations to a scale transformation of the input level.