Memory consolidation and reconsolidation of an inhibitory avoidance task in mice. Effects of a new different learning task

BOCCIA MM; BLAKE MG; ACOSTA GB; BARATTI CM

San Diego, EEUU

Congreso; Neurons and Memory. The 2nd Neuron Satellite Meeting; 2004

Society for Neuroscience

CF-1 male mice were trained in an inhibitory avoidance task using a high footshock (1,2 mA, 50 Hz, 1s) in order to reduce the influence of extinction on retention performance (Boccia MM et al., Neurosci., 124, 735-741, 2004). A single session of 5 min exposure to a hole-board (nose-poke behavior) (Boccia et el., Acta Phys. Pharm. Therap., 49, 155-160, 1999), either immediately after training or the first retention test (memory reactivation) impaired retention performance over two consecutive days. The effects were time-dependent since they were not observed when the exposure to the hole-board was delayed 3 hours. When mice were habituated to the hole-board (5 min/day, 6 days), and then trained in an inhibitory avoidance task, the immediately post-training or memory reactivation exposure to the hole-board did not modify retention performance over two consecutive days. The effects of the post-reactivation acute exposure to the hole-board were long-lasting (21 days). The non-spontaneous recovery of retention performance over 21-days suggests that the impairment of retention performance observed was not probably due to a deficit in memory retrieval. These findings suggest that the exposure to a potential new learning situation impairs not only memory consolidation but also memory reconsolidation of the original learning task.