Dendritic morphologies of four groups of mouse hippocampal interneurons

Computational modelling of hippocampal network mechanisms requires real-life morphological features of the dendritic arbors of interneurons (INs) in the CA1 area. There are several different groups of hippocampal interneurons. We investigated four groups. Hippocampo-septal (HS) INs project both locally and to the medial septum. Oriens-lacunosum-moleculare (OLM) INs are typical local feedback inhibitory neurons. Parvalbumin (PV)- and calretinin (CR)-containing INs represent two different groups of local INs. Here, using viral tracing and immunohistochemistry, we labeled these classes of INs and using scanning electron microscopy (SEM), we measured their dendritic cross-sectional areas and perimeters along the dendritic segments of these neurons. We estimated their volumes with and without mitochondria and estimated their dendritic surface areas as well. We measured and corrected all changes during tissue processing, therefore, all physical parameters represent the real life parameters of these dendrites.