Development of a neural probe to measure potassium during a cortical spreading depression in-vivo

Cortical Spreading Depression (CSD) is a key event in migraine; during a CSD a wave of depolarization spreads through the brain, starting in the visual cortex. We present the design and fabrication of a novel probe that can be functionalized to measure multiple parameters, relevant to a CSD, in-vivo simultaneously. In this work, we focus on the functionalization of the fabricated probes to measure extracellular potassium with a potentiometric sensor. The sensor response is approximately linear from 2-40 mM, and has a response of 55 mV/log[K⁺]. Measurements where performed in-vivo in a WT mouse and clearly indicated raised potassium levels during the evoked CSD.