Developmental environment: Variables important for later learning and changes in cholinergic activity

Abstract

Brown, Cathryn P..; and King, M. G . (1971). Developmental Environment:Variables Important for Later Learning and Changes in Cholinergic Activity. DEVELOPMENTAL PSYCHOBIOLOGY, 4( 3): 275-286. Environmental experience of developing rats was manipulated in two ways. These were ( I ) providing increments in amount of visual stimulation vs. increased variety of novelty of visual stimulation, and ( 2 ) informal experience vs. formal training in discriminating between the given stimuli. At the conclusion of the developmental treatment an index of performance change was obtained by testing discrimination learning on a Lashley Jumping Stand. Effects on the cholinergic system, specifically, acetylcholinesterase ( AChE) and cholinesterase (ChE) activities, were also examined. Increments in variety of stimulation, but not increases UI amount, were found t o contribute significantly t o observed differences in AChE and ChE activity and in learning performance. Formal training in addition t o enriched informal experience added little t o either the biochemical effects or t o the observed improvement in performance on the relevant learning task. early environment visual experience variety novelty training discrimination learning cholinergic activity laboratory rat

Cerebral changes in rats exposed individually to an enriched environment.

“…Brown and King (1971) have reported that 80 days of exposure to varied stimulus objects is enough to produce significant effects in AChE and ChE activities in occipital cortex (no other measures were taken in their study). Brown's groups that were also given formal training did not show larger effects than those that had only informal experience.…”

“…::z: A number of investigators have reported that giving a group of rodents prolonged informal experience in an enriched environment produces significant changes in chemical and anatomical brain measures (e.g., Altman & Das, 1964;Bennett, Diamond, Krech, & Rosenzweig, 1964;Brown & King, 1971; Diamond, Law, Rhodes, Lindner, Rosenzweig, Krech, & Bennett, 1966;Henderson, 1970;Krech, Rosenzweig, & Bennett, 1960;La Torre, 1968;Mpllgaard, Diamond, Bennett, Rosenzweig, & Lindner, 1971;Rosenzweig & Bennett, 1969;Rosenzweig, Bennett, & Diamond, 1972a;Rosenzweig, Krech, Bennett, & Diamond, 1962;Walsh, Budtz-Olsen, Penny, & Cummins, 1969). Until now, the respective roles of the social grouping and of the enriched inanimate environment have not been determined, and doing so is the purpose of this study.…”

Early eyelid opening enhances spontaneous alternation and accelerates the development of perforant path synaptic strength in the hippocampus of juvenile rats

“…These manipulations are multifaceted and include variables such as isolation from the dam and littermates as well as the multimodal sensory experience of being placed in a novel environment. Thus, using these paradigms, the basic sensory features that impact the hippocampus are difficult to isolate (Brown & King, 1971;Henderson, 1977). Moreover, while the longterm behavioral implications have been demonstrated, the time course of the alterations and the mechanisms that support the behavioral modifications are not well understood.…”

Hippocampal CA1 cytoarchitecture and behaviour after combined neonatal cholinergic lesion and environmental enrichment in rats

“…Memory (specifically spatial memory) in several learning tasks is notably enhanced by enrichment. Animals exposed to enrichment perform better on complex maze tasks such as the Hebb-Williams maze and on simpler spatial learning procedures such as the Morris water maze and the T-maze (Brown and King, 1971;Will and Rosenzweig, 1976;Kelche and Will, 1978;Kolb and Whishaw, 1998;van Praag, Kempermann and Gage, 2000;Paban et al, 2005).Environmentally enriched animals also showed decreased anxiety-like behaviour compare to control animals when assessed on elevated plus maze by spending more time in the open arms. They also expressed less freezing behaviour on stress paradigm demonstrating valuable enrichment effect on anxiety-like behaviour (Chapillon et al, 1999;Benaroya-Milshtein et al, 2004).…”

“…The enriched animals performed significantly better on both distance and latency measures compared to rats housed in impoverished conditions. Early research showed that enrichment improves learning ability (Brown and King, 1971) and it was later demonstrated that major behavioural effects such as enhanced learning and spatial memory, increased exploratory activity and decreased anxiety can result from environmental enrichment (Nithianantharajah and Hannan 2006). The beneficial effect of enrichment is well known and widely reported on many different behavioural tasks including the Hebb-Williams maze, T-maze, open field and Morris water maze (Brown and King, 1971;Will and Rosenzweig, 1976;Kelche and Will, 1978;Ryan and Pappas, 1990;Kolb and Whishaw, 1998;Pappas et al, 1992;van Praag, Kempermann and Gage, 2000;Paban et al, 2005).…”