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. Author manuscript; available in PMC: 2009 Nov 1.
Published in final edited form as: Neurotoxicology. 2008 Jul 10;29(6):1127–1130. doi: 10.1016/j.neuro.2008.06.01

Figure 2.

Figure 2

Percentage of freezing behavior observed on 4 days of extinction observations in Control and Pb2+-exposed rats in each of the behavioral groups. There were low levels of freezing behavior observed in the Control and Pb2+-exposed IS group on all 4 Extinction Days. The Control FC group had a steady decrease in freezing time over the 4 days until they nearly reached the levels of the IS group. However, the freezing time of the Pb2+-exposed FC group remained significantly higher (F3,102=34.7; p=0.0001) than all other groups on day 4. A repeated measures ANOVA showed significant differences across the days of extinction observations. Data are expressed as mean ± s.e.m.