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. Author manuscript; available in PMC: 2009 Aug 1.
Published in final edited form as: Nat Neurosci. 2009 Jan 11;12(2):182–189. doi: 10.1038/nn.2250

Figure 3. LTP is impaired in rats trained to self-administer cocaine.

Figure 3

a, Upper panel: Representative experiment inducing LTP in a control rat after HFS (50 Hz). HFS was delivered at the arrow. Insets show an average of 5 consecutive fEPSP before (1) and after (2) HFS. Middle panel: Representative experiment of LTP failure in a cocaine rat after HFS (50 Hz). Lower panel: HFS (50 Hz) failed to induce LTP in the cocaine (n=13) compared to control animals (n= 8 yoked saline, n= 8 naive). A two-way repeated measures ANOVA revealed a significant effect of cocaine treatment: F(1,1458)= 11.05, p= 0.003. b, Upper and middle panels: LTP was induced in control animals only at 50 HZ (30Hz, 50Hz, 100Hz, group F(2,247)= 4.094, p= 0.042, time F(19,247)= 2.23, p= 0.003, and LTP in the cocaine animals could not be induced by any stimulation protocol (30Hz, 50Hz, 100Hz). Lower panel: Percentage potentiation from baseline of 30, 50, and 100 Hz HFS in cocaine and control goups. Each bar represents an average of the 5 min time bin immediately before (baseline) and 15-20 min after HFS. n is shown in the bars. A one-way ANOVA revealed effect of frequency only in control rats. F(3,31)= 6.243, p< 0.001. Data shown as mean ± s.e.m.

* p< 0.05 compared to baseline using a Bonferronni post hoc analysis