Characterization and classification of pyramidal cells and interneurons in vitro cell network using extracellular recordings

The goal of the research was to explore the electrophysiological features of the different neurons by cell network cultured on multi-microelectrode arrays (MEA). We used 16-channel detection meter for extracellular signal recording in vitro. We found that the neurons recorded contain two kinds: the principal pyramidal cells and interneurons. The principal cells with excitatory activity and interneurons with suppressed activity contribute differently to nerve signal transduction and integration, the identification and classification of extracellular recorded neurons is significant for neural information studies. The combination of several extracellular features, such as firing rate, action potential duration, pattern and spike waveforms and bursting propensity can be effectively separate the neurons into classes of interneurons and pyramidal cells. The firing rate of pyramidal cells was less than 5Hz and the firing rate of interneurons was higher than 5Hz. The half action potential duration of pyramidal cells was between 0.6~1.8ms and that of interneurons was less than 0.6ms. The principal cells had bursting propensity and interneurons had no bursting. The local field potential (LFP) of adjacent channels often affected by the firing of the action potential (AP), and a certain level of LFP fluctuations can be observed, and the decline and fall of interneurons experienced a process of gradual reduction in the firing rate. The identification and separation of neurons is of great value for neural information studies. First, different AP firing characteristics can distinguish neuron types to avoid missing some information. Second, different kinds of neurons corresponding to different types of neurotransmitters, the identification of neurons combined neurotransmitter detection can promote nerve dual studies to further explore the neural information mechanism.