The Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, 315 Ferst Drive, Atlanta, GA 30332, USA.
Neuroscience. 2013 Sep 5;247:102-16. doi: 10.1016/j.neuroscience.2013.05.020. Epub 2013 May 21.
A growing interest in sensory system plasticity in the natural context of motherhood has created the need to investigate how intrinsic physiological state (e.g., hormonal, motivational, etc.) interacts with sensory experience to drive adaptive cortical plasticity for behaviorally relevant stimuli. Using a maternal mouse model of auditory cortical inhibitory plasticity for ultrasonic pup calls, we examined the role of pup care versus maternal physiological state in the long-term retention of this plasticity. Very recent experience caring for pups by Early Cocarers, which are virgins, produced stronger call-evoked lateral-band inhibition in auditory cortex. However, this plasticity was absent when measured post-weaning in Cocarers, even though it was present at the same time point in Mothers, whose pup experience occurred under a maternal physiological state. A two-alternative choice phonotaxis task revealed that the same animal groups (Early Cocarers and Mothers) demonstrating stronger lateral-band inhibition also preferred pup calls over a neutral sound, a correlation consistent with the hypothesis that this inhibitory mechanism may play a mnemonic role and is engaged to process sounds that are particularly salient. Our electrophysiological data hint at a possible mechanism through which the maternal physiological state may act to preserve the cortical plasticity: selectively suppressing detrimental spontaneous activity in neurons that are responsive to calls, an effect observed only in Mothers. Taken together, the maternal physiological state during the care of pups may help maintain the memory trace of behaviorally salient infant cues within core auditory cortex, potentially ensuring a more rapid induction of future maternal behavior.
人们对母婴自然环境下感觉系统可塑性的兴趣日益浓厚,这就需要研究内在生理状态(例如激素、动机等)如何与感觉体验相互作用,从而推动与行为相关刺激的适应性皮质可塑性。我们使用听觉皮层抑制性可塑性的母鼠模型来研究幼鼠护理与母体生理状态在这种可塑性的长期保留中的作用。最近,初产者(处女鼠)在照顾幼鼠时的体验会导致听觉皮层中对超声波幼鼠叫声的外侧带抑制作用增强。然而,当在断奶后对照顾者进行测量时,这种可塑性就不存在了,尽管在同时期的母亲中仍然存在,因为母亲的幼鼠体验是在母体生理状态下发生的。在一项二择一的声音趋性任务中,我们发现具有更强外侧带抑制作用的相同动物组(初产者和母亲)也更喜欢幼鼠叫声而不是中性声音,这种相关性与以下假设一致,即这种抑制机制可能具有记忆作用,并被用来处理特别突出的声音。我们的电生理数据提示了一种可能的机制,即母鼠在照顾幼鼠时的生理状态可能有助于维持核心听觉皮层中与行为相关的显著幼鼠线索的记忆痕迹,这可能确保未来的母性行为更快地诱导。