Department of Mathematics, 200 Ukrop Way, Jones Hall, William & Mary Williamsburg, VA, 23187, USA.
Courant Institute of Mathematical Sciences, 251 Mercer Street, New York University, New York, NY 10012, USA.
J Theor Biol. 2021 Aug 7;522:110700. doi: 10.1016/j.jtbi.2021.110700. Epub 2021 Apr 2.
In this review, we focus on the antennal lobe (AL) of three insect species - the fruit fly, sphinx moth, and locust. We first review the experimentally elucidated anatomy and physiology of the early olfactory system of each species; empirical studies of AL activity, however, often focus on assessing firing rates (averaged over time scales of about 100 ms), and hence the AL odor code is often analyzed in terms of a temporally evolving vector of firing rates. However, such a perspective necessarily misses the possibility of higher order temporal correlations in spiking activity within a single cell and across multiple cells over shorter time scales (of about 10 ms). Hence, we then review our prior theoretical work, where we constructed biophysically detailed, species-specific AL models within the fly, moth, and locust, finding that in each case higher order temporal correlations in spiking naturally emerge from model dynamics (i.e., without a prioriincorporation of elements designed to produce correlated activity). We therefore use our theoretical work to argue the perspective that temporal correlations in spiking over short time scales, which have received little experimental attention to-date, may provide valuable coding dimensions (complementing the coding dimensions provided by the vector of firing rates) that nature has exploited in the encoding of odors within the AL. We further argue that, if the AL does indeed utilize temporally correlated activity to represent odor information, such an odor code could be naturally and easily deciphered within the Mushroom Body.
在这篇综述中，我们专注于三种昆虫物种的触角叶（AL）——果蝇、天蛾和蝗虫。我们首先回顾了每种物种早期嗅觉系统的实验阐明的解剖结构和生理学；然而，对 AL 活动的经验研究通常侧重于评估放电率（在大约 100 毫秒的时间尺度上平均），因此 AL 气味代码通常根据放电率的时间演化向量进行分析。然而，这种观点必然会忽略单个细胞和多个细胞在较短时间尺度（约 10 毫秒）内的尖峰活动中更高阶的时间相关性的可能性。因此，我们随后回顾了我们之前的理论工作，在果蝇、天蛾和蝗虫中构建了具有生物物理细节的特定于物种的 AL 模型，发现在每种情况下，尖峰活动的高阶时间相关性自然从模型动力学中出现（即，没有先验地包含旨在产生相关活动的元素）。因此，我们利用我们的理论工作来论证这样一种观点，即在短时间尺度上的尖峰活动中的时间相关性，迄今为止受到的实验关注较少，可能提供有价值的编码维度（补充由放电率向量提供的编码维度），自然界在 AL 中对气味的编码中利用了这些维度。我们进一步认为，如果 AL 确实利用时间相关的活动来表示气味信息，那么这种气味代码可以在蘑菇体中自然而轻松地破译。
