Discrimination analysis of excitatory and inhibitory neurons using Raman spectroscopy

We have succeeded in discriminating between intact excitatory and inhibitory neuronal cells with Raman analysis. Excitatory and inhibitory neurons have several differences in their electric activities, but it can be difficult to determine their types based only on visual appearances. As Raman spectroscopy does not require any staining or labeling, its use in live neuronal cells is possible. In the present study, we used primary neurons obtained from rat cerebral cortexes, which we cultured on a glial feeder layered culturing dish for 15 days. The Raman spectra of the intact neurons on the dish were obtained; the neurons were then immunostained and their types determined. Partial least squares regression-discriminant analysis (PLSR-DA) was employed for classification of the excitatory and inhibitory neurons. The results demonstrated a high feasibility for use of Raman spectroscopy for discrimination analysis of inhibitory and excitatory neurons in a nondestructive manner.