Development behaviors: delayed appearance in monkeys asphyxiated at birth

Perinatal anoxia degrades auditory system function in rats

Little is known about the neural bases of the reduced auditory and cortical processing speeds that have been recorded in language-impaired, autistic, schizophrenic, and other disabled human populations. Although there is strong evidence for genetic contributions to etiologies, epigenetic factors such as perinatal anoxia (PA) have been argued to be contributors, or causal, in a significant proportion of cases. In this article, we explored the consequences of PA on this elementary aspect of auditory behavior and on auditory system function in rats that were briefly perinatally anoxic. PA rats had increased acoustic thresholds and reduced processing efficiencies recorded in an auditory behavioral task. These rats had modestly increased interpeak intervals in their auditory brainstem responses, and substantially longer latencies in poststimulus time histogram responses recorded in the primary auditory cortex. The latter were associated with degraded primary auditory cortex receptive fields and a disrupted tonotopy. These processing deficits are consistent with the parallel behavioral and physiological deficits recorded in children and adults with a history of language-learning impairment and autism.

Aberrant parenting and delayed offspring development in rats exposed to lithium

Natural lithium (Li) salts, including those used routinely in manic depressive illness, consist of two stable nonradioactive isotopes: lithium-7 (Li-7) (92.6%) and lithium-6 (Li-6) (7.4%). Female rats (3 months old) were treated with either Li-7 chloride or Li-6 chloride or were untreated prior to and during gestation and lactation. Birth weights were lower for Li-treated animals than for normal pups. Maternal behavior of all Li-treated mothers was altered. Li-7 mothers ignored their pups and nursed them infrequently. Li-6 mothers groomed and nursed their pups more often than normal mothers. All pups showed delays in development, especially in the maturation of depth perception. Although Li-6-treated dams were over-protective mothers, their offspring showed longer developmental delays than those of Li-7-treated offspring.