Institute of Biology, Neurobiology, Freie Universität Berlin, Berlin, Germany.
Department of Physiology and Biophysics, Institute of Biological Sciences, Federal University of Minas Gerais, Belo Horizonte, Brazil.
PLoS One. 2024 Sep 12;19(9):e0310282. doi: 10.1371/journal.pone.0310282. eCollection 2024.
Color vision in honeybees is a well-documented perceptual phenomenon including multiple behavioral tests of trichromaticity and color opponency. Data on the combined color/space properties of high order visual neurons in the bee brain is however limited. Here we fill this gap by analyzing the activity of neurons in the anterior optic tract (AOT), a high order brain region suggested to be involved in chromatic processing. The spectral response properties of 72 units were measured using UV, blue and green light stimuli presented in 266 positions of the visual field. The majority of these units comprise combined chromatic-spatial processing properties. We found eight different neuron categories in terms of their spectral, spatial and temporal response properties. Color-opponent neurons, the most abundant neural category in the AOT, present large receptive fields and activity patterns that were typically opponent between UV and blue or green, particularly during the on-tonic response phase. Receptive field shapes and activity patterns of these color processing neurons are more similar between blue and green, than between UV and blue or green. We also identified intricate spatial antagonism and double spectral opponency in some receptive fields of color-opponent units. Stimulation protocols with different color combinations applied to 21 AOT units allowed us to uncover additional levels of spectral antagonism and hidden inhibitory inputs, even in some units that were initially classified as broad-band neurons based in their responses to single spectral lights. The results are discussed in the context of floral color discrimination and celestial spectral gradients.
蜜蜂的颜色视觉是一种经过充分记录的感知现象，包括对三色性和颜色对立的多种行为测试。然而，关于蜜蜂大脑中高级视觉神经元的综合颜色/空间特性的数据有限。在这里，我们通过分析前视神经束（AOT）中神经元的活动来填补这一空白，该区域被认为参与了色觉处理。使用 UV、蓝色和绿色光刺激在视野的 266 个位置测量了 72 个单位的光谱响应特性。这些单位中的大多数都包含组合的色觉-空间处理特性。根据它们的光谱、空间和时间响应特性，我们发现了 8 种不同的神经元类别。在 AOT 中最为丰富的神经类别是颜色对立神经元，它们具有大的感受野和活动模式，通常在 UV 和蓝色或绿色之间呈对立关系，特别是在 ON-TONIC 响应阶段。这些颜色处理神经元的感受野形状和活动模式在蓝色和绿色之间比在 UV 和蓝色或绿色之间更为相似。我们还在一些颜色对立单位的感受野中发现了复杂的空间拮抗和双光谱对立。对 21 个 AOT 单位应用不同颜色组合的刺激方案使我们能够揭示额外的光谱拮抗和隐藏的抑制输入水平，即使在最初根据对单个光谱光的反应分类为宽带神经元的一些单位中也是如此。结果在花卉颜色辨别和天体光谱梯度的背景下进行了讨论。
