Support
A limited bedding and nesting (LBN) paradigm, rodent model for chronic early-life stress (ELS), was conducted during postnatal day (PND) 2-9 with 4 litters of Sprague Dawley rats (n = 51). On PND 24, weaning, one litter from LBN and Control were combined by sex and were put into Extra Enrichment (EE) housing (n = 27) and the other LBN and Control litter were pair housed by sex and litter and had Normal Enrichment (NE) housing (n = 24). Between PND 71-73, lever-press learning was evaluated through an autoshaping operant chamber program as a measure for learning and found that EE rats learned at a quicker rate how to lever press compared to the NE rats, but there were no group differences found. Between PND 74-84, fixed interval (FI) schedules of 2, 4, 8, 10, and 12 were evaluated and found no differences in group or housing for the number of lever presses or response per minute.