Limited impairments of associative learning in a mouse model of accelerated senescence

Abstract

Research concerning impairment of associative learning during aging remains limited. The senescence-accelerated mice (SAM) prone/8 (P8) has been proposed as a useful model for the study of aging, and SAM resistant/1(SAMR1) is its control as a normal aging strain. Classical eyeblink conditioning has long been served as a model of associative learning. In order to explore the effects of aging on associative learning in SAM, the present study successively tested three paradigms of eyeblink conditioning in SAMP8 and SAMR1: classical single cue trace eyeblink conditioning (TEC), discriminative trace eyeblink conditioning and reversal learning of TEC. Behavioral performance indicated that SAMP8 could acquire limited single-cue trace eyeblink conditioning task and two-tone discrimination trace eyeblink conditioning with a relative lower acquisition rate compared to SAMR1. Both SAMP8 and SAMR1 failed to acquire reversal learning of discriminative TEC, and SAMP8' startle reflex to tone CS was lower than SAMR1. These results indicated that the impairments of aging on associative learning were incomplete in SAMP8.

Keywords: Aging; CR; CS; DEC; Discriminative conditioning; PFC; Reversal learning; SAM; SAMP8; SEM; TEC; Trace eyeblink conditioning; UR; US; conditioned response; conditioned stimulus; delay eyeblink conditioning; prefrontal cortex; standard error of the mean; the senescence-accelerated mice; trace eyeblink conditioning; unconditioned response; unconditioned stimulus.