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. Author manuscript; available in PMC: 2012 Nov 30.
Published in final edited form as: Physiol Behav. 2011 Feb 24;105(1):138–144. doi: 10.1016/j.physbeh.2011.02.028

Figure 1.

Figure 1

Downregulation of hypothalamic IRs impairs contextually-conditioned fear responses. Contextually-conditioned freezing responses were examined in hypo-IRAS and hypo-Con rats. Freezing behavior on the day of acquisition was similar in both groups of rats. [F(2,46) = −0.453, P = 0.65] However, performance in the retention test 48 hours later revealed that hypo-IRAS rats exhibited significant decreases in freezing behavior when compared to hypo-Con rats. This decrease in freezing behavior is particularly evident during the last 3 minutes of the retention test (Reten bars; [F(5, 210)=76, P<0.0001]. These results demonstrate that hypo-IRAS rats exhibit deficits in a learning task that is dependent at least in part upon hippocampal function. [Data are expressed as percentage of time spent freezing and are based upon at least 14 rats per group. * = significantly different from hypo-Con rats. UC = unconditioned freezing; Acquis = freezing during acquisition; Reten = retention freezing behavior]