Associative conditioning tunes transient dynamics of early olfactory processing.
Associative conditioning tunes transient dynamics of early olfactory processing.
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DOI：
10.1523/jneurosci.1874-09.2009
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发表时间：
2009-08-19
期刊：
影响因子：
--
通讯作者：
Smith BH
中科院分区：
文献类型：
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作者：
Fernandez PC;Locatelli FF;Person-Rennell N;Deleo G;Smith BH
气味在昆虫触角叶（AL）和哺乳动物嗅球中引起复杂的时空反应。然而，时空编码的行为相关性仍然不清楚。在目前的工作中，我们结合行为分析与钙成像的气味诱导的活动在蜜蜂AL评估的相关性，这个时间维度的嗅觉代码。我们使用了一种新的方法来评估气味相似性的二元混合物的行为研究，其中涉及测试，如果气味采样时间的匹配是必要的训练和测试条件之间的气味识别在联想学习。使用混合比例的相似性的分级变化，我们发现这些混合物的行为泛化和AL输出中的激活梯度之间存在高度相关性。此外，500毫秒或更短的气味刺激影响气味与记忆模板的匹配程度，这一时间对应于从采样时间依赖性记忆到采样时间独立性记忆的转变。因此，根据成像研究，375 ms对应于时空AL活动模式达到最大分离所需的时间。最后，我们比较了训练和未经训练的动物的二元混合物的时空表示。通过调节来改变AL活性以改善气味表征的分离。这些数据表明，强化的一个作用是“调整”AL，使相关的气味变得更加可辨。
Odors evoke complex spatiotemporal responses in the insect antennal lobe (AL) and mammalian olfactory bulb. However, the behavioral relevance of spatiotemporal coding remains unclear. In the present work we combined behavioral analyses with calcium imaging of odor induced activity in the honey bee AL to evaluate the relevance of this temporal dimension in the olfactory code. We used a new way for evaluation of odor similarity of binary mixtures in behavioral studies, which involved testing if a match of odor sampling time is necessary between training and testing conditions for odor recognition during associative learning. Using graded changes in the similarity of the mixture ratios, we found high correlations between the behavioral generalization across those mixtures and a gradient of activation in AL output. Furthermore, short odor stimuli of 500 ms or less affected how well odors were matched with a memory template, and this time corresponded to a shift from a sampling-time-dependent to a sampling-time-independent memory. Accordingly, 375 ms corresponded to the time required for spatiotemporal AL activity patterns to reach maximal separation according to imaging studies. Finally, we compared spatiotemporal representations of binary mixtures in trained and untrained animals. AL activity was modified by conditioning to improve separation of odor representations. These data suggest that one role of reinforcement is to “tune” the AL such that relevant odors become more discriminable.