Fig. 4.

Extinction retention and pMAPK expression in infant rats.

Mean (± SEM) CS-elicited freezing during A: extinction training and B: test for standard-reared (SR), maternally-separated (MS), and maternally-separated, probiotic treated (MS-Pro) infant rats that received either Paired or Unpaired CS-US presentations at training. Mean (± SEM) number of pMAPK stained neurons in C: the prelimbic region (PL) and D: the infralimbic region (IL) of the medial prefrontal cortex (mPFC) of infant rats following the extinction retention test. Only MS-Paired rats showed increased pMAPK activation in the IL. † p =  .053, * p <  .05, *** p < .001.