Environmental Attenuation of Brain-Lesion Symptoms

Long-term impoverished housing effects on morris maze performance after a fimbria lesion

“…It is well-known that post-operative housing in enriched environments can affect behavioural deficits after cortical and hippocampal lesions [3,9,31,32]. In a different study we have shown in an experiment somewhat similar to the design of the present study that postoperative environmental enrichment (lasting 6 weeks) could also attenuate the Morris maze deficit arising after a fimbria-fornix lesion [34]when animals with a lesion were compared to standard housed animals.…”

“…This test also shows that even though both housing conditions can affect the performance of animals with brain lesions, the effects of each housing condition possibly do not rely on the same principle. The effect of enrichment is often supposed to rely on an enhancement of the adaptive capacity of the animals [9] which could help the animals with a lesion to switch more easily to alternative search strategies [34], but whereas the effect of impoverishment, though not fully understood, may rely on a difference in arousability, a different reaction to stress or a higher reactivity to cues [6,10,14]. However, it is not clear from the present data whether the impoverished rats may have also used the alternative search strategy mentioned in the enrichment study, since the search pattern of the animals has not been studied in greater detail.…”

“…[16,25,27,29]). Since it is generally accepted that post-operative housing in enriched environments can affect behavioural deficits after cortical and hippocampal lesions [3,9], the present study concerned itself with the possible effects of postoperative impoverishment after a fimbria lesion. Lesions to the Fimbria, as well as slightly larger lesions to the FimbriaFornix disrupt spatial learning in several tasks [2,21,22,25,27] (note: in some of these studies rats were housed individually), and this effect is still present after 7 months [33].…”

Effects of early protein undernutrition and later frontal cortex damage on habit acquisition and reversallearning in the rat

“…For example, under some conditions it is known that age at the time of insult can affect the degree of functional sparing (Johnson & Almli, 1978), as can the speed of growth or "momentum" of the lesion (Finger, 1978b). In addition, nonspecific environmental "enrichment" has also been shown to enhance behavioral recovery, at least on simple maze-learning tasks following cortical or hippocampal lesions (Finger, 1978a).A variable that has only recently been explored in this context is the early nutritional history of the sub-[ect. Early undernutrition can affect several indices of brain function, including cellular growth and differentiation and synapse formation and myelination, and it has also been established that some behaviors can be affected if undernutrition is experienced during the period of rapid brain growth (Winick, 1976).…”

“…For example, under some conditions it is known that age at the time of insult can affect the degree of functional sparing (Johnson & Almli, 1978), as can the speed of growth or "momentum" of the lesion (Finger, 1978b). In addition, nonspecific environmental "enrichment" has also been shown to enhance behavioral recovery, at least on simple maze-learning tasks following cortical or hippocampal lesions (Finger, 1978a).…”