Learning modulates the ensemble representations for odors in primary olfactory networks
Learning modulates the ensemble representations for odors in primary olfactory networks
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DOI：
10.1073/pnas.0401902101
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发表时间：
2004-07-13
影响因子：
11.1
通讯作者：
Hildebrand, JG
中科院分区：
文献类型：
--
作者：
Daly, KC;Christensen, TA;Hildebrand, JG
最近的证据表明，昆虫触角叶(AL)中的气味驱动反应可以通过联合和非联合过程来改变，就像脊椎动物嗅球所显示的那样。然而，对嗅觉学习作出反应的具体网络变化仍不清楚。为了表征学习过程中AL网络活动的变化，我们在Manduca sexta中开发了一种活体方案，允许在嗅觉条件反射过程中连续监测神经集合和摄食行为。在这里，我们表明巴甫洛夫条件作用产生了在条件作用后持续存在的整个AL的反应神经元的净招募。只有当气味可靠地预测食物时，才会进行招募。相反，当气味不能预测食物时，反应单位的净损失就会发生。对取食反应的同步测量表明，特定处理的神经招募模式与昆虫对气味的行为反应的变化呈正相关。除了招募，条件反射还在16%的记录单位的时间反应中产生了一致和深刻的变化。这些结果表明，气味在AL中的表征是动态的，并与嗅觉记忆的巩固有关。我们进一步提供证据表明，AL中依赖学习的变化的基础不仅仅是代表气味的神经网络活动的增加。相反，学习产生了AL中对气味的网络反应的空间和时间成分的重组。
Recent evidence suggests that odor-driven responses in the insect antennal lobe (AL) can be modified by associative and nonassociative processes, as has been shown in the vertebrate olfactory bulb. However, the specific network changes that occur in response to olfactory learning remain unknown. To characterize changes in AL network activity during learning, we developed an in vivo protocol in Manduca sexta that allows continuous monitoring of neural ensembles and feeding behavior over the course of olfactory conditioning. Here, we show that Pavlovian conditioning produced a net recruitment of responsive neural units across the AL that persisted after conditioning. Recruitment only occurred when odor reliably predicted food. Conversely, when odor did not predict food, a net loss of responsive units occurred. Simultaneous measures of feeding responses indicated that the treatment-specific patterns of neural recruitment were positively correlated with changes in the insect's behavioral response to odor. In addition to recruitment, conditioning also produced consistent and profound shifts in the temporal responses of 16% of recorded units. These results show that odor representations in the AL are dynamic and related to olfactory memory consolidation. We furthermore provide evidence that the basis of the learning-dependent changes in the AL is not simply an increase in activity in the neural network representing an odorant. Rather, learning produces a restructuring of spatial and temporal components of network responses to odor in the AL.