Long-Term Tracking and Dynamically Quantifying of Reversible Changes of Extracellular Ca2+ in Multiple Brain Regions of Freely Moving Animals.

Understanding physiological and pathological processes in the brain requires tracking the reversible changes in chemical signals with long-term stability. We developed a new anti-biofouling microfiber array to real-time quantify extracellular Ca2+ concentrations together with neuron activity across many regions in the mammalian brain for 60 days, in which the signal degradation was < ca. 8 %. The microarray with high tempo-spatial resolution (ca. 10 μm, ca. 1.3 s) was implanted into 7 brain regions of free-moving mice to monitor reversible changes of extracellular Ca2+ upon ischemia-reperfusion processes. The changing sequence and rate of Ca2+ in 7 brain regions were different during the stroke. ROS scavenger could protect Ca2+ influx and neuronal activity after stroke, suggesting the significant influence of ROS on Ca2+ overload and neuron death. We demonstrated this microarray is a versatile tool for investigating brain dynamic during pathological processes and drug treatment.