GPR88 and Anxiety: This cluster included genes related to the anxiety-related response that, as noted above, were also up-regulated in the virgin P1 amygdala (Adora2a, Gpr88, Pde10a, Rasd2, Ppp1r1b, Tac1, Syndigl1) (Fig 3; S2D, S2E Table); this finding suggested the possibility that mothers might also experience a similar anxiety-related reaction soon after pups were born.