Mushroom body output neurons MBON-a1/a2 define an odor intensity channel that regulates behavioral odor discrimination learning in larval Drosophila.
Mushroom body output neurons MBON-a1/a2 define an odor intensity channel that regulates behavioral odor discrimination learning in larval Drosophila.
复制标题
DOI：
10.3389/fphys.2023.1111244
复制
发表时间：
2023
影响因子：
4
通讯作者：
中科院分区：
文献类型：
--
作者：
必须调节动物对感官输入的敏感性，以确保信号被检测到并可辨别。然而，电路如何调节对感觉刺激的敏感性的动态范围尚不清楚。给定的气味在昆虫蘑菇体 (MB) 中通过凯尼恩细胞 (KC) 的稀疏组合编码来表示，形成气味质量表示。为了解决在 MB 输入区域（花萼）水平如何处理感觉刺激强度的问题，我们描述了一组优先对高气味浓度做出反应的新型蘑菇体输出神经元。我们发现一对 MB 花萼输出神经元 MBON-a1/2 位于 MB 花萼的突触后，它们接收来自 KC 树突、抑制性反馈神经元 APL 和章鱼胺能 sVUM1 神经元的大量突触输入，但来自投射神经元的输入相对较少。这种模式在第三龄幼虫和第一龄幼虫连接组中大致一致。 MBON-a1/a2 突触前末梢支配同侧和对侧大脑半球中紧邻 MB 内侧叶输出区域的区域。通过使用 jRCamP1b 监测钙活性，我们发现 MBON-a1/a2 反应依赖于气味浓度，仅对高于 200 倍稀释度的乙酸乙酯 (EA) 浓度做出反应，而 MB 神经元则更具有浓度不变性，并对低至 10-4 的 EA 稀释度做出反应。起源于 SEZ（食管下区）的花萼支配的 sVUM1 调节神经元的光遗传学激活并未显示出对 MBON-a1/a2 气味反应的可检测到的影响。与对照组相比，使用 CsChrimson 光遗传学激活 MBON-a1/a2 损害了气味辨别学习。我们认为 MBON-a1/a2 形成花萼的输出通道，汇总会聚的感觉和调节输入，优先激发高气味浓度，并可能影响下游 MB 目标的活性。
The sensitivity of animals to sensory input must be regulated to ensure that signals are detected and also discriminable. However, how circuits regulate the dynamic range of sensitivity to sensory stimuli is not well understood. A given odor is represented in the insect mushroom bodies (MBs) by sparse combinatorial coding by Kenyon cells (KCs), forming an odor quality representation. To address how intensity of sensory stimuli is processed at the level of the MB input region, the calyx, we characterized a set of novel mushroom body output neurons that respond preferentially to high odor concentrations. We show that a pair of MB calyx output neurons, MBON-a1/2, are postsynaptic in the MB calyx, where they receive extensive synaptic inputs from KC dendrites, the inhibitory feedback neuron APL, and octopaminergic sVUM1 neurons, but relatively few inputs from projection neurons. This pattern is broadly consistent in the third-instar larva as well as in the first instar connectome. MBON-a1/a2 presynaptic terminals innervate a region immediately surrounding the MB medial lobe output region in the ipsilateral and contralateral brain hemispheres. By monitoring calcium activity using jRCamP1b, we find that MBON-a1/a2 responses are odor-concentration dependent, responding only to ethyl acetate (EA) concentrations higher than a 200-fold dilution, in contrast to MB neurons which are more concentration-invariant and respond to EA dilutions as low as 10–4. Optogenetic activation of the calyx-innervating sVUM1 modulatory neurons originating in the SEZ (Subesophageal zone), did not show a detectable effect on MBON-a1/a2 odor responses. Optogenetic activation of MBON-a1/a2 using CsChrimson impaired odor discrimination learning compared to controls. We propose that MBON-a1/a2 form an output channel of the calyx, summing convergent sensory and modulatory input, firing preferentially to high odor concentration, and might affect the activity of downstream MB targets.
登录
查看更多内容
DOI：
10.1111/j.1460-9568.2009.06644.x
发表时间：
2009-03
期刊：
The European journal of neuroscience
影响因子：
--
作者：
Homma R;Cohen LB;Kosmidis EK;Youngentob SL
通讯作者：
Youngentob SL
影响因子：
8.8
作者：
Jenett, Arnim;Rubin, Gerald M.;Zugates, Christopher T.
通讯作者：
Zugates, Christopher T.
影响因子：
34.7
作者：
Gottfried, Jay A.
通讯作者：
Gottfried, Jay A.
影响因子：
16.2
作者：
Gordon, Michael D.;Scott, Kristin
通讯作者：
Scott, Kristin
影响因子：
7.7
作者：
Dana, Hod;Mohar, Boaz;Kim, Douglas S.
通讯作者：
Kim, Douglas S.