Figure 1.

Maternal immune activation (MIA) offspring exhibit abnormal responses to weaning. Although all animals demonstrate a species-typical attachment to their own mother, MIA offspring exhibit an unusual response in the attachment test. Second trimester MIA (MIA²) offspring produce significantly more distress or self-soothing behaviors (i.e., tantrums, convulsive jerk, self-clasp, infant crook tail) than control (CON) offspring. This group difference emerges over the 4 days of testing, with both MIA groups showing a different pattern over time than control animals (p < .001 and p < .003 for the differences in slopes, respectively). Thus, on the final day, MIA² offspring are highly reactive, control animals are moderately reactive, and first trimester MIA (MIA¹) offspring display little evidence of reactivity (p < .01 for difference from control animals for both MIA¹ and MIA² groups on day 4).