Figure 2.

DiOlistic cell labelling, dendritic tree analysis. (A) Schematic representation of a caudal hippocampal section. Information flow through the hippocampal circuit: sensory inputs from layer II entorhinal cortex (EC) to all fields of the hippocampal formation, including the dentate gyrus (DG) and all CA fields (including CA1 and CA3) is organized via three synaptic perforant path (PP); layer III EC cells project to CA1 via the temporo-ammonic pathway (TA). (B) Composite confocal image of DiOlistically labelled hippocampal section. Neurons are labelled red and green by fluorescent dyes. Only CA1 pyramidal neurons were quantified in this study. Cell nuclei are labelled in blue with Hoechst staining. We imaged on average at least nine well-labelled neurons per subject and traced most of the imaged cells. (C) Labelled CA1 neuron imaged with confocal microscope ×20 and apical dendrite traced with Imaris software. (WT—top, Opa1^+/− bottom). (D) Sholl plots, representing complexity of apical dendrites as a function of distance from the cell body. (E) Average dendrite length. The data represented as whisker plots summary of all imaged cells (92 cells in total grouped by gender and genotype, with the smallest group containing 17 cells). The parameter was reduced in female mutants (P < 0.01). (F, G) Average Sholl plots for each gender and genotype highlight possible differences in dendrite’s length and complexity. The n represents the number of labelled CA1 pyramidal cells analysed for each group. The data were obtained from 12 animals, 6 WT and 6 Opa1 +/− (3 males and 3 females in each group). We used non-parametric Kruskal–Willis test to compare results of Sholl plot and average dendrite length. All data are presented as mean and SE, P-values <0.05, <0.01, <0.01 are encoded as one, two or three stars accordingly.