Flexible microelectrode array probe for simultaneous detection of neural discharge and dopamine in striatum of mice aversion system

Simultaneous detection of spike firing and neurotransmitters in mice is conducive to further understanding the mechanism of innate fear induced by aversive stimuli. As the key brain region of the dopamine aversion system, the synchronous changes of neural discharge and neurotransmitter concentration in the striatum under innate fear are less studied. This paper proposed a fabrication method for dual-mode high-sensitive flexible microelectrode array (MEA) probe based on Parylene. The microelectrode sites were modified with platinum black nanoparticles and conductive polymer PEDOT, which can realize single neuron action potential recording and dopamine concentration detection. The electrode sensitivity for dopamine detection can reach 162.3 pA/μM. We used this flexible MEA probe to simultaneously real-time detect electrophysiology activities and dopamine in the striatum of awake mice under aversive stimulation. The results showed that after fear, with the decrease of the mean activity of mice behavior, the action potential firing rate, local field potential (LFP) power in low-frequency (0–30 Hz), and dopamine concentration in the striatum of mice decreased synchronously. The spike firing rate decreased by about 32 %, and the dopamine concentration decreased by about 23.5 %. Our electrodes provide a powerful tool for multimodal neural information detection and our research provides new evidence for striatum involvement in the dopamine aversion system.