FIGURE 1.

Physical activity increases dendritic spine density and alters dendritic complexity in multiple cell types. (A) Running increased the density of dendritic spines on the basal dendrites of Golgi-impregnated pyramidal cells in the entorhinal cortex (EC); increased spine density was also observed in the basal and apical dendritic trees of neurons in the hippocampal CA1 region. As previously reported (Eadie et al., 2005; Redila et al., 2006), running increased the density of dendritic spines on dentate gyrus granule neurons (DG). (B) We also used the lipophilic tracer DiI to visualize spines within the same group of animals, and observed similar results. DiI-labeled neurons in the brains of runners show increased spine density in the same regions where changes were observed with Golgi impregnation. (C) Running was associated with increased dendritic length in the DG. (D) Physical activity increased the number of branch points in the apical dendritic tree of CA1 pyramidal neurons, and in DG granule neurons. (*) indicates significance (P < 0.05) following 2-tailed unpaired student's t-test. EC, entorhinal cortex; CA1, hippocampal CA1 field; DG, dentate gyrus.