Using derivatives to compare cortical waves across preparations

Abstract

Visual stimulation evokes waves of depolarization that propagate within and between cytoarchitectually distinct cortical areas in the turtle visual cortex. These waves appear to reflect underlying low-dimensional characteristics that can be captured using Karhunen–Loéve (KL) decomposition. This paper compares structure across in vivo, in vitro and simulated preparations of turtle visual cortex using derivative–response relationships. The derivatives of the projections on the low-order KL modes exhibit distinguishing characteristics based on the stimulus. The derived modes corresponding to these derivatives provide a low-order approximation to the initial response with structure similar to that of a traveling wave.