Odor modality is transmitted to cortical brain regions from the olfactory bulb
Odor modality is transmitted to cortical brain regions from the olfactory bulb
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DOI：
10.1152/jn.00101.2023
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发表时间：
2023-11-04
影响因子：
2.5
通讯作者：
Ly，Cheng
中科院分区：
文献类型：
--
作者：
Craft，Michelle F.;Barreiro，Andrea K.;Ly，Cheng
气味感知是重要动物行为的推动力，有两种主要的处理模式：吸气和嗅时气味通过鼻子前部（鼻前），或呼气和进食时通过后部（鼻后）。尽管嗅觉对于动物的健康很重要，并且嗅觉自然发生，但尚不清楚这种方式（正向与逆向）如何传递到皮质大脑区域，这可能会显着影响气味的处理和感知方式。在气管切开麻醉大鼠中使用多电极阵列记录，将正向-逆向模式与呼吸分离，我们表明，大鼠嗅球中的二尖瓣细胞可以可靠、直接地用丁酸乙酯（一种常见的食物气味）传递正鼻与鼻后模式。通过 GABAA 影响突触抑制的药物操作会导致正向解码与逆向解码更差，与整体抑制是否增加或减少无关，这表明嗅球回路可能自然有利于编码气味的这一重要方面。详细的数据分析与捕获峰值统计中的群体趋势的发射率模型相结合，显示了该电路如何编码气味模态。我们不仅证明了正射/逆射信息被编码到下游大脑区域，而且还使用建模来证明这种编码的合理机制；由于突触适应，鼻后刺激的时间进程较慢，导致鼻后反应比正鼻反应更强，且对抑制性药物操作的敏感性较低。新的和值得注意的是，正向（嗅气味）与逆向（呼气和进食）是否是从嗅球编码到其他大脑区域尚不完全清楚。使用麻醉大鼠的多电极阵列记录，我们表明嗅球通过尖峰向下游传输此信息。改变抑制平均会降低正向/逆向信息。我们使用理论和计算来解释我们的结果，考虑到只有食物气味发生在鼻后，这应该对皮质处理产生影响。
Odor perception is the impetus for important animal behaviors with two predominate modes of processing: odors pass through the front of the nose (orthonasal) while inhaling and sniffing, or through the rear (retronasal) during exhalation and while eating. Despite the importance of olfaction for an animal’s well-being and that ortho and retro naturally occur, it is unknown how the modality (ortho vs. retro) is even transmitted to cortical brain regions, which could significantly affect how odors are processed and perceived. Using multielectrode array recordings in tracheotomized anesthetized rats, which decouples ortho-retro modality from breathing, we show that mitral cells in rat olfactory bulb can reliably and directly transmit orthonasal versus retronasal modality with ethyl butyrate, a common food odor. Drug manipulations affecting synaptic inhibition via GABAAlead to worse decoding of ortho versus retro, independent of whether overall inhibition increases or decreases, suggesting that the olfactory bulb circuit may naturally favor encoding this important aspect of odors. Detailed data analysis paired with a firing rate model that captures population trends in spiking statistics shows how this circuit can encode odor modality. We have not only demonstrated that ortho/retro information is encoded to downstream brain regions but also used modeling to demonstrate a plausible mechanism for this encoding; due to synaptic adaptation, it is the slower time course of the retronasal stimulation that causes retronasal responses to be stronger and less sensitive to inhibitory drug manipulations than orthonasal responses.NEW & NOTEWORTHYWhether ortho (sniffing odors) versus retro (exhalation and eating) is encoded from the olfactory bulb to other brain areas is not completely known. Using multielectrode array recordings in anesthetized rats, we show that the olfactory bulb transmits this information downstream via spikes. Altering inhibition degrades ortho/retro information on average. We use theory and computation to explain our results, which should have implications on cortical processing considering that only food odors occur retronasally.