Effects of early experiences on one-trial avoidance conditioning

Abstract

Several studies have reported that early life experiences significantly influence the learning process, especially avoidance behavior, at maturity. Most often it has been found that handling facilitates the acquisition of avoidance responses, although there are discrepancies in the data which may be attributable to procedural as well as strain differences (Ader, 1965;Denenberg & Karas, 1960;Denenberg & Smith, 1963;King & Eleftheriou, 1959;Levine, 1956;Levine & Wetzel, 1963). Extinction of avoidance behavior has not received comparable attention, nor has it been conclusively established that the observed effects are the result of early as distinguished from previous experience. In the present study we investigated the effects of handling and electric shock stimulation experienced before and after weaning on the extinction of an avoidance response conditioned in one trial. MethodLitters of Charles River (CD) rats were split within 24 h of birth and randomly divided into Handled (H), Shocked (S), and Control (C) groups. Half the Hand S groups were manipulated as previously described (Ader, 1965) during the first 21 days of life and half were manipulated during the 21 days immediately after weaning. The Ss were approximately 125 day old females randomly selected from this population and otherwise undisturbed until the beginning of avoidance training.Animals were placed on a 2 x 4 in. platform situated in the center and elevated 2 in. above the floor of a 9 x 8 x 8 in. Plexiglas chamber. The time required to descend from the platform to the grid floor with three paws was recorded. Animals received five training trials per day with an intertrial interval of 2 min. On the day after an animal left the platform in 5 sec or less on three consecutive trials (a criterion usually achieved within the first five trials), Psychon. Sci., 1968, Vol. 10 (7) it was returned to the apparatus and upon descending from the platform (with a latency:5 5 sec) was subjected to electric shock (1.0 mAl. In one experiment a single 1 sec shock was administered, and, in a second (variable shock) experiment, shock was administered continuously until the animal returned to the platform. Thereafter, no electric shock was applied in either procedure and each animal received one trial per day for 21 days. Animals were returned to their home cages upon descending from the platform or after a latency of 30 sec. ResultsThe rates at which the differentially manipulated animals reached the preshock criterion did not differ in either experiment. Significant differences in extinction were observed, and these data are shown in Fig. 1.The 1 sec shock and variable shock experiments were analyzed separately. Also, since the unmanipulated control animals could not be dichotomized on an "age at manipulation" continuum, separate analyses were used to compare the performance of H and S groups before analysis of any of the manipulated groups relative to the controls.Under the 1 sec shock procedure, S animals had longer latencies than H animals (F=15.49, df=1/23, p ...

Infantile experience and play motivation

“…Furthermore, recent research has shown early-handling effects on neurotransmitter systems relevant to social emotions and motivations, such as opioids, oxytocin, and vasopressin in critical brain regions such as the periaqueductal gray, hypothalamus, amygdala, and hippocampus (Francis et al, 2002;Gustafsson, Oreland, Hoffmann, & Nylander, 2008;Irazusta et al, 1999;Kiosterakis, Stamatakis, Diamantopoulou, Fameli, & Stylianopoulou, 2009;Ploj, Roman, Bergström, & Nylander, 2001;Ploj, Roman, & Nylander, 2003;Todeschin et al, 2009), in conjunction with selective effects on N-methyl-d-aspartate (NMDA) receptors in the amygdala and hippocampus as well as the prelimbic, anterior cingulated, and somatosensory cortex . These results cohere with the presumed action mechanism of early handling (Gonzalez et al, 2001;Jutapakdeegul et al, 2003;Liu et al, 1997;Zhang & Meaney, 2010) in that R&T has a strong somatosensory component deriving from reciprocal pouncing and pinning, in addition to being a highly demanding cognitive activity where the making of predictions about the behavior of the other rat and the selection of appropriate responses have to be orchestrated quickly; that early handling improves performance on several cognitive tasks would be consistent with the increase in R&T as a cognitively mediated activity (Ader & Schaefer, 1968;Aguilar, Escorihuela, Gil, Tobeña, & Fernández-Teruel, 2002;Burton, Lovic, & Fleming, 2006;Gschanes, Eggenreich, Windisch, & Crailsheim, 1995Peters, Gray, & Joseph, 1991;Pryce, Bettschen, Nanz-Bahr, & Feldon, 2003;Wilson, Willner, Kurz, & Nadel, 1986;Wong, 1972;Wong & Jamieson, 1968;Wong & Wong, 1978). In any event, while these findings are clearly important to provide a biological basis to expect direct effects of early handling on socially motivated behaviors such as R&T, the critical evidence to empirically anchor this hypothesis has ultimately to come from behavioral studies.…”

Effects of early experiences on shock‐and illness‐induced passive avoidance behaviors

“…The observation that passive avoidance behavior was influenced by stimulation experienced during early life is consistent with our previous observations (Ader & Schaefer, 1968), but the direction of the differences observed are not consistent with these previous data. In our previous study, the pattern of differences varied with changes in a "step-down'' conditioning procedure.…”

“…In a previous study, Ader and Schaefer (1968) showed that differences in the passive avoidance behavior of rats differentially manipulated during early life varied as a function of the procedures used to induce the passive avoidance behavior. The same basic phenomenon was evident in the present investigation.…”

An apparatus and procedure for effective instrumental training of neonatal and infant rats

“…In the laboratory, these experiences have taken the form of environmental enrichment and impoverishment (Brown, 1968;Manosevitz, 1970), emotional trauma (Ader & Schaefer, 1968), undernutrition (Ottinger & Tanabe, 1968;Slob, Snow, & Mathot, 1973), drug states (Gauron & Rowley, 1972), etc. Research has indicated that some of these experiences can adversely affect behavior (e.g., Ottinger & Tanabe, 1968).…”