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. Author manuscript; available in PMC: 2007 Dec 1.
Published in final edited form as: Epilepsy Behav. 2006 Oct 12;9(4):557–563. doi: 10.1016/j.yebeh.2006.09.002

Figure 1.

Figure 1

DL-p-chlorophenylalanine (PCPA) increases fear-potentiated startle (FPS) selectively in rats housed individually. Rats were assigned to one of four treatment groups in a 2 x 2 design with housing and drug treatment as between-groups factors: group/saline (n = 10), group/PCPA (n = 10), individual/saline (n = 12), or individual/PCPA (n = 13). Animals were either group or individually housed for 13 days, and received either PCPA (300 mg/kg i.p.; black bars) or isovolumetric 0.9% saline (SAL; white bars) on days 1 and 10. FPS was tested on day 13 and is expressed as percent (mean ± SE) potentiated startle amplitude (Methods). In the group housed condition, there is no significant difference in FPS between saline (33 ± 7%) and PCPA (35 ± 7) treated animals (p > 0.05). However, in the individually housed condition PCPA treated rats show 60 ± 8 % FPS compared to 38 ± 7 % in saline treated controls (p < 0.05). Thus, PCPA increased FPS selectively in the individually-housed rats. * indicates significant difference from individually-housed, SAL-treated control (P < 0.05, Bonferroni multiple comparisons post-hoc test).