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Delayed spatial alternation deficits resulting from perinatal PCB exposure in monkeys
E D Levin1, S L Schantz, R E Bowman
1Department of Psychology, University of California, Los Angeles 90024.
Insights
Low-level perinatal polychlorinated biphenyls (PCBs) exposure caused long-term cognitive deficits in monkeys, impacting learning and attention even years after exposure ended.
Area of Science:
- Neuroscience
- Environmental Health
- Toxicology
Background:
- Polychlorinated biphenyls (PCBs) are persistent organic pollutants with known neurotoxic effects.
- Perinatal exposure to environmental toxins can lead to long-lasting health consequences.
- Understanding the long-term cognitive impact of low-level PCB exposure is crucial for public health.
Purpose of the Study:
- To investigate the long-term effects of chronic, low-level perinatal polychlorinated biphenyls (PCBs) exposure on cognitive function in non-human primates.
- To assess spatial learning and memory performance in adult monkeys with a history of in utero and early-life PCB exposure.
Main Methods:
- Monkeys were exposed to Aroclor 1248 (2.5 ppm) or Aroclor 1016 (1.0 ppm) via maternal diet during gestation and nursing until 4 months post-birth.
- Cognitive function was assessed at 4-6 years of age using the delayed spatial alternation (DSA) task.
- Performance accuracy at varying delay intervals was analyzed to differentiate between memory, attention, and association deficits.
Main Results:
- Monkeys exposed to 2.5 ppm Aroclor 1248 exhibited significant deficits in delayed spatial alternation (DSA) accuracy, particularly at shorter delays.
- A less pronounced deficit was observed in monkeys exposed to 1.0 ppm Aroclor 1016.
- The observed cognitive impairments persisted for over 3 years after the cessation of PCB exposure, suggesting long-term neurodevelopmental effects.
Conclusions:
- Chronic, low-level perinatal PCB exposure can result in persistent cognitive deficits in primates, affecting attentional and associational processes.
- These findings highlight the potential for long-term adverse neurodevelopmental consequences from environmental exposures during critical developmental windows.
- The study underscores the importance of minimizing PCB exposure to protect cognitive development and long-term neurological health.
Abstract:
Monkeys exposed to low, chronic levels of polychlorinated biphenyls (PCBs) in utero and during nursing until 4 months after birth were tested at 4-6 years of age on delayed spatial alternation (DSA), a spatial learning and memory task. Deficits in performance accuracy were detected in two cohorts of monkeys whose mothers had been fed 2.5 ppm of the PCB mixture, Aroclor 1248, in their diet for an 18-month period ending at least 12 months prior to pregnancy. The deficit was most apparent at the shorter delays, suggesting that it was not due to memory impairment, but may have been due to impairments in associational or attentional processes. There may also have been a deficit in a group of monkeys whose mothers were fed 1.0 ppm of the PCB mixture, Aroclor 1016. However, the deficit in this group was less pronounced than in the other groups. The appearance of a PCB-induced cognitive deficit more than 3 years after the end of exposure indicated the existence of very long-term adverse consequences of low-level perinatal PCB exposure.