Early prenatal morphine exposure impairs performance of learning tasks and attenuates in vitro heterosynaptic long-term potentiation of intermediate medial mesopallium in day-old chicks

Based on our previous findings in day-old chicks with prenatal morphine-treated, embryonic days 5–8 is crucial for functional development of learning and memory, the underlying structure and cellular mechanisms were further explored. The prenatal morphine-exposed chicks showed deficits in passive avoidance learning and conditioned place preference, and attenuation in paired-pulse facilitation and heterosynaptic long-term potentiation in intermediate medial mesopallium (IMM) in vitro. These results suggest the altered synaptic plasticity of IMM by prenatal morphine exposure is involved in behavioral impairments.