Grabe Veit, Sachse Silke
Max Planck Institute for Chemical Ecology, Department of EvolutionaryNeuroethology, Hans-Knoell-Str. 8, 07745 Jena, Germany.
Max Planck Institute for Chemical Ecology, Department of EvolutionaryNeuroethology, Hans-Knoell-Str. 8, 07745 Jena, Germany.
Biosystems. 2018 Feb;164:94-101. doi: 10.1016/j.biosystems.2017.10.010. Epub 2017 Oct 17.
Sensory coding represents a basic principle of all phyla in nature: species attempt to perceive their natural surroundings and to make sense of them. Ultimately, sensory coding is the only way to allow a species to make the kinds of crucial decisions that lead to a behavioral response. In this manner, animals are able to detect numerous parameters, ranging from temperature and humidity to light and sound to volatile or non-volatile chemicals. Most of these environmental cues represent a clearly defined stimulus array that can be described along a single physical parameter, such as wavelength or frequency; odorants, in contrast, cannot. The odor space encompasses an enormous and nearly infinite number of diverse stimuli that cannot be classified according to their positions along a single dimension. Hence, the olfactory system has to encode and translate the vast odor array into an accurate neural map in the brain. In this review, we will outline the relevant steps of the olfactory code and describe its progress along the olfactory pathway, i.e., from the peripheral olfactory organs to the first olfactory center in the brain and then to the higher processing areas where the odor perception takes place, enabling an organism to make odor-guided decisions. We will focus mainly on studies from the vinegar fly Drosophila melanogaster, but we will also indicate similarities to and differences from the olfactory system of other invertebrate species as well as of the vertebrate world.
物种试图感知其自然环境并理解这些环境。最终，感觉编码是使物种能够做出导致行为反应的关键决策的唯一途径。通过这种方式，动物能够检测众多参数，从温度、湿度到光、声音，再到挥发性或非挥发性化学物质。这些环境线索中的大多数代表了一个明确界定的刺激阵列，可以沿着单一物理参数（如波长或频率）进行描述；相比之下，气味剂则不能。气味空间包含大量几乎无限的各种刺激，无法根据它们在单一维度上的位置进行分类。因此，嗅觉系统必须将大量的气味阵列编码并转化为大脑中的精确神经图谱。在这篇综述中，我们将概述嗅觉编码的相关步骤，并描述其在嗅觉通路中的进展，即从外周嗅觉器官到大脑中的第一个嗅觉中枢，再到发生气味感知的更高处理区域，使生物体能够做出气味引导的决策。我们将主要关注黑腹果蝇的研究，但也会指出与其他无脊椎动物物种以及脊椎动物世界嗅觉系统的异同。
