Fig. 2.

Both the frequency of 5-HT- and hypocretin-induced EPSCs and total length of apical tuft branches are reduced in layer V pyramidal cells after repeated immobilization stress. (A and B) Projection images show two examples each of apical tufts in control (A) and chronic stress cells (B) (one thin tuft and one thick tuft). EPSC responses to 5-HT are shown below each image. Regression plot (Upper Right) in the control group shows a high correlation between the total length of apical tuft branches and the frequency of 5-HT-induced EPSCs; in the stress group this correlation is disrupted by greater variability and a disproportionate reduction in EPSC frequency at the upper end of the curve. Note the position of the four illustrated cells (1 to 4) on the regression plots are labeled by numbers and arrows. (C) Total apical tuft branch length and EPSCs induced by 5-HT and hypocretin are decreased in the same cells after chronic stress.