Study of neurovascular coupling functions for transient focal cerebral ischemia in rats using electrocorticography functional photoacoustic microscopy (ECoG-fPAM).

Recently, the functional photoacoustic microscopy (fPAM) system has been proven to be a reliable imaging technique for measuring the total hemoglobin concentration (HbT), cerebral blood volume (CBV) and hemoglobin oxygen saturation (SO2) in single cerebral blood vessels of rats. In this study, we report for the first time the combination of electrocorticography (ECoG) recordings and fPAM (ECoG-fPAM) to investigate functional hemodynamic changes and neuro-vascular coupling in single cortical arterioles of rats with electrical forepaw stimulation after photothrombotic stroke. Because of the optical focusing nature of our fPAM system, photo-induced ischemic stroke targeting on single cortical arterioles can be easily conducted with simple adaptation. Functional cerebral HbT, CBV and SO2 changes associated with the induced stroke in selected arterioles from the anterior cerebral artery system were imaged with a 36 × 65-µm spatial resolution. The ECoG-fPAM system complements existing imaging techniques and has the potential to offer a favorable tool for explicitly studying cerebral hemodynamics and neuro-vascular coupling in small animal models of photo-induced ischemic stroke.