Presurgical handling and exploratory behavior of rats with septal lesions

Abstract

Behavioral effects of septal lesions are altered by presurgical history of the experimental animal. We examined the interactions between presurgical handling of young adult rats and subsequent septal lesions on postsurgical exploratory behavior in an open field . Sixty·day·old male rats were either handled twice daily for 20 days prior to surgery or left undisturbed during this period. All rats were tested in a dimly illuminated open field for 5 min on both Days 10 and 11 following surgery. Surgical control rats stood up more frequently and crossed more squares than those with septal lesions; these measures also indicated that handled animals were more active than their nonhandled counterparts. However, only non handled control rats displayed a marked decrease on these measures from Day 1 to Day 2 of testing. The behavioral effects of septal lesions are differentially influenced by the specifics of the presurgical manipulations and the test situation.

Handling: Effects on eight-arm-maze behavior and hippocampal trace metals

“…While both holding and stroking may increase corticosteroid levels (Hemsworth, Barnett, & Hamen, 1981;Hennessy & LeVine, 1978;Seggie et al, 1974), stroking may be additionally associated with increased somatosensory stimulation (Lam our et al, 1983), and increased levels of steroids (Hemsworth et al, 1981), both of which may be expected to have effects on hippocampal neurons (McEwen & Wallach, 1973;Vinogradova, 1975). Both added stimulation (Bengelloun et al, 1977;Donovick, Burright, & Swidler, 1973;Doty, 1968) and corticosteroid levels (Ogren & Fuxe, 1977) have been shown to have effects on behaviors and/or cortical systems associated with learning or exploration, so that it would be invaluable to take direct measures of the physiological effects of these manipulations. In any case, our dissociation of the two kinds of handling-holding and stroking-could be due to increased steroid levels, to increased somatosensory stimulation, or to an interaction of the two acting on hippocampal systems.…”

“…The behaviors observed for this task included: total time to choose eight arms (TT), average time spent in the center octagon between choices (AT), number of errors (E), turning bias (RT and LT), and number of rearings (R), groomings (GM), sniffings (S), and head raises (UH). It was considered important to study the typical exploratory behaviors in addition to the eight-arm-maze behavior because of the well-known effects of infantile handling on adult exploration (DeNelsky & Denenberg, 1967) and beCause adult handling may also affect exploration (Bengelloun, Finklestein, Burright, & Donovick, 1977).…”

“…These manipulations were conducted daily for 4 weeks, and then three consecutive daily behavioral observations were recorded. The behavioral observations additionally included open-field activity and rearing (Bengelloun et al, 1977). The animals were permitted 3 min exploration time in the open field.…”