Biomedical Sciences, Faculty of Medicine, and Department of Psychology, Faculty of Science, Memorial University of Newfoundland, St. John's, Newfoundland, Canada, A1B 3V6.
J Neurosci. 2013 Sep 18;33(38):15126-31. doi: 10.1523/JNEUROSCI.2503-13.2013.
The present study examines synaptic plasticity in the anterior piriform cortex (aPC) using ex vivo slices from rat pups given lateralized odor preference training. In the early odor preference learning model, a brief 10 min training session yields 24 h memory, while four daily sessions yield 48 h memory. Odor preference memory can be lateralized through naris occlusion as the anterior commissure is not yet functional. AMPA receptor-mediated postsynaptic responses in the aPC to lateral olfactory tract input, shown to be enhanced at 24 h, are no longer enhanced 48 h after a single training session. Following four spaced lateralized trials, the AMPA receptor-mediated fEPSP is enhanced in the trained aPC at 48 h. Calcium imaging of aPC pyramidal cells within 48 h revealed decreased firing thresholds in the pyramidal cell network. Thus multiday odor preference training induced increased odor input responsiveness in previously weakly activated aPC cells. These results support the hypothesis that increased synaptic strength in olfactory input networks mediates odor preference memory. The increase in aPC network activation parallels behavioral memory.
本研究使用在接受偏侧气味偏好训练的大鼠幼仔中获得的离体脑片，检查了前梨状皮层（aPC）中的突触可塑性。在早期的气味偏好学习模型中，10 分钟的短暂训练即可产生 24 小时的记忆，而每天进行四次训练则可产生 48 小时的记忆。通过鼻侧阻塞可以使气味偏好记忆偏向一侧，因为前连合尚未起作用。对 aPC 中侧嗅束输入的 AMPA 受体介导的突触后反应在 24 小时增强，而在单次训练后 48 小时不再增强。经过四次间隔的偏侧试验后，在训练的 aPC 中，AMPA 受体介导的 fEPSP 在 48 小时增强。在 48 小时内对 aPC 锥体神经元进行钙成像显示，在锥体细胞网络中，放电阈值降低。因此，多日的气味偏好训练增加了先前弱激活的 aPC 细胞对气味输入的反应性。这些结果支持了这样的假设，即增加嗅觉输入网络中的突触强度介导了气味偏好记忆。aPC 网络激活的增加与行为记忆平行。
