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The effects of environmental diversity on well‐fed and previously undernourished rats: I. Body and brain measurements
Author(s) -
Bhide P. G.,
Bedi K. S.
Publication year - 1982
Publication title -
journal of comparative neurology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.855
H-Index - 209
eISSN - 1096-9861
pISSN - 0021-9967
DOI - 10.1002/cne.902070411
Subject(s) - forebrain , biology , environmental enrichment , fixative , analysis of variance , zoology , body weight , medicine , endocrinology , anatomy , physiology , central nervous system , biochemistry , cytoplasm
Rats were undernourished from the 16th day of gestation to 25 postnatal days of age and then weaned on to an ad libitum diet. Around 35 days of age, 12 previously undernourished (PU) male pups were assigned to an “enriched environmental condition” (EC) and 12 to an “isolated environmental condition” (IC). Well‐fed controls were similarly assigned. After 30 days in these conditions all rats were killed by perfusion with fixative. Body and “forebrain” weights, and forebrain lengths and widths, were determined for each animal. The forebrains were subsequently embedded in paraffin wax and serially sectioned. Ten sections, identified by subcortical landmarks, were taken from each brain and used for cortical depth measurements. The whole experiment was carried out on two separate occasions. In both the well‐fed and PU groups the EC rats were between 3% and 9% lighter in body weight and between 4% and 9% heavier in “forebrain” weight than IC animals. A two‐way analysis of variance (two‐way ANOVA) indicated significant effects of nutrition and environment on body and forebrain weights but no significant interaction. Nutrition, but not environment, also had significant effects on “forebrain” width and length measurements. For the well‐fed groups, only one section out of all those measured from the two experimental series showed a significant effect of environment onthe cortical depth measurements. For the PU groups, in experiment one the cortical thickness of the EC rats was significantly greater than their IC counterparts in four out of theten sections analyzed. In the second experiment only two sections exhibitedsignificant results. In contrast to experiment one, these showed that the IC rats had a slightly but significantly thicker cortex than the EC rats. A two‐way ANOVA of the data on cortical depths showed no significant effects of, or interaction between, nutrition and environment. These observations are discussed in the context of previously publishedresults on the effects of a differential environment on body and brain measurements.