Neurovascular coupling study of PTZ-induced seizure in rats by simultaneous real-time 3D PAT and EEG at two wavelengths

Neurovascular coupling in epilepsy is poorly understood, the study of which requires simultaneous monitoring of hemodynamic changes and neural activity in the brain. Here we for the first time present a combined real-time 3D Photoacoustic tomography (PAT) and electro-physiology (EEG) system for the study of neurovascular coupling in epilepsy, whose ability was demonstrated with a pentylenetetrazol (PTZ) induced generalized seizure model in rats. Two groups of experiments were carried out with different wavelengths to detect the changes of oxy-hemoglobin (HbO2) and deoxy-hemoglobin (Hbr) signals in the rat brain. We extracted the average PAT signals of the superior sagittal sinus (SSS), and compared them with the EEG signal. Results showed that the seizure process can be divided into three stages. A `dip´ lasting for 1-2 minutes in the first stage and the following hyperfusion in the second stage were observed. The oxy-hemoglobin (HbO2) signal and the deoxy-hemoglobin (Hbr) signal were generally negatively correlated. Compared to other existing functional neuroimaging tools, the proposed method here enables reliable tracking of hemodynamic signal with both high spatial and temporal resolution in 3D, so it´s more suitable for neurovascular coupling study of epilepsy.