Researchers examined the effects of neonatal handling on learned helplessness (LH) in rats. They discuss prior research that showed a variety of benefits associated with neonatal handling such as improved escape latency and lower emotional reactivity. They express that rats who have been handled have a permanent augmentation of the glucocorticoid receptors in their hippocampi.
In this study researchers used Wistar Rats and sorted them into two groups. One group received daily 15 minute handling and the other received no handling. After 21 days mice were tested for emotional reactivity in an open field test. LH was induced 72 hours after the completion of the open field test using an automated shuttle box shock chamber.
Results showed that on the first day escape failures for both the handled group and the non-handled group were similar. On the second and third day escape failures dramatically reduced for the handled group. However the non-handled group did not see a similar reduction in escape failures and only saw a slight reduction.
They then went on to examine escape latency times and avoidance behavior. Like the escape failures, both handled groups and non-handle groups had similar times on the first day for both measurements. On the second and third day the handled group showed increasingly better escape times and increasingly more avoidance behavior. The non-handled group did better on each subsequent day but the improvement was modest.
Researchers observed that handled rats showed more avoidance escape behavior when they were subjected to uncontrollable shocks. They speculate that the changes are the result of locomotor activity changes induced by the neonatal handling.
Costela, C., Tejedor-real, P., Mico, J.A., & Gibert-Rahola, J. (1995) Effect of neonatal Handling on learned helplessness model of depression. Physiology And Behavior. 57(2), 407-410.