Localized Induction of Cortical Spreading Depression Waves in Brain Slices Using Microfluidic Injection

Advanced in vitro experimental tools for locally stimulating and probing brain slices can greatly facilitate systematic studies of neuronal phenomena and rapid drug screening. A major challenge in developing such tools is to achieve precise spatial and temporal control of local chemical environments of brain slices while maintaining their viability. This paper reports an improved design of a brain slice perfusion chamber with integrated microfluidic ports for controlled local introduction and confinement of soluble chemicals on slice surfaces. As a concrete example of potential clinical relevance, we present a systematic characterization of the area-dependent threshold concentration of potassium ions for the induction of cortical spreading depression (CSD) waves.