O.A. Solovieva – Associative Research Scientist, V.B. Shvyrkov lab. of Psychophysiology, Institute of Psychology of RAS; Assistant Researcher, lab. of Neurochemistry, P.K. Anokhin Institute of Normal Physiology (Moscow). Email: SAolga@yandex.ru
E.A. Kuzina – Associative Research Scientist, V.B. Shvyrkov lab. of Psychophysiology, Institute of Psychology of RAS (Moscow). E-mail: firstname.lastname@example.org
Yu.R. Chistova – Post-graduate Student, State Academic University of Humanitarian Sciences (Moscow). E-mail: email@example.com
A.G. Gorkin – Ph.D. (Psychol.), Senior Research Scientist, V.B. Shvyrkov lab. of Psychophysiology, Institute of Psychology of RAS (Moscow). E-mail: firstname.lastname@example.org
The enrichment of the environment contribute to the improvement of delayed learning in animals of different age . It might be suggested that short-term extension of the repertoire of adult animals will positively affect their learning in the old age.
The aim of the study was to compare the dynamics of learning of the cyclic instrumental food-procuring behavior (CIFP) in adult and old naive rats with those old animals that formed a variety of behavioral skills in a different experimental apparatus in their adulthood.
The study was conducted on adult (6–12 months, n=8) and old (older than 20 months, n=13) Long-Evans rats. Old rats were divided into two groups: one group (trained, n=5) in adulthood (12–18 months) formed drinking skills, inter-individual and defensive behaviors (n=3) and additionally CIFP (n=2) in the experimental setup No. 1 prior to the formation of their CIFP in old age in the apparatus No. 2; the second group of old rats (naive, n=8), and adult rats were trained CIFP in the apparatus No. 2 without prior formation of additional skills.
Animals learned CIFP in stages, one behavioral act a day . The criterion of acquisition of the CIFP was realization no less than 60 cycles during the session, including 10 cycles in a row without switching to the inefficient side of the apparatus.
The time to reach the criterion in adult rats (median, Med, –308 s, Min–Max=18–1619 s), was significantly less than in the old naive rats – (Med–973 s, Min–Max= 59–1737 s) (Mann–Whitney test: U=15, Z= –1.785, p (1–sided)=0.041). Old rats that were additionally trained in adulthood (Med–427 s, Min–Max= 278–876) didn’t differ significantly from other groups by this parameter (adults vs. old trained: U=13, Z= –1.025, p=0.177; old naive vs. old trained: U=11, Z=–1.317, р=0.111), thus ranking an «intermediate» position between groups of adult and old naive rats.