Trisal Swati, VijayRaghavan K, Ramaswami Mani
National Centre for Biological Sciences, TIFR, Bangalore, India.
School of Chemical and Biotechnology, Shanmugha Arts, Science, Technology & Research Academy University, Thanjavur, India.
Bio Protoc. 2023 Dec 5;13(23):e4891. doi: 10.21769/BioProtoc.4891.
Habituation, the process by which animals learn to ignore insignificant stimuli, facilitates engagement with salient features of the environment. However, neural mechanisms underlying habituation also allow responses to familiar stimuli to be reinstated when such stimuli become potentially significant. Thus, the habituated state must allow a mechanism for habituation override. The remarkably precise knowledge of cell identity, connectivity, and information coding in sensory circuits, as well as the availability of tools to genetically target these cells, makes a valuable and important organism for analysis of habituation and habituation-override mechanisms. Studies of olfactory and gustatory habituation in suggest that potentiation of GABAergic neurons underlies certain timescales of habituation and have specified some elements of a gustatory habituation-override pathway. More detailed understanding of gustatory habituation and habituation-override mechanisms will benefit from access to robust behavioral assays for (a) the proboscis extension reflex (PER) elicited by a sweet stimulus, (b) exposure paradigms that result in PER habituation, and, most critically, (c) manipulations that result in PER-habituation override. Here, we describe simple protocols for persistent sucrose exposure of tarsal hairs that lead to habituation of proboscis extension and for presentation of a novel appetitive stimuli that reinstate robust PER to habituated flies. This detailed protocol of gustatory habituation provides (a) a simple method to induce habituation by continuous exposure of the flies to sucrose for 10 min without leading to ingestion and (b) a novel method to override habituation by presenting yeast to the proboscis. Key features • A protocol for stimulation of 's taste (sugar) sensory neurons that induces gustatory habituation without satiation due to ingestion. • A chemical (yeast) stimulation protocol that rapidly induces habituation override/dishabituation in sugar-habituated .
习惯化是动物学会忽略无关紧要刺激的过程，它有助于动物与环境中的显著特征建立联系。然而，习惯化背后的神经机制也使得当熟悉的刺激变得具有潜在重要性时，对这些刺激的反应能够恢复。因此，习惯化状态必须允许一种打破习惯化的机制。由于在感觉回路中对细胞身份、连接性和信息编码有非常精确的了解，并且有对这些细胞进行基因靶向的工具，这使得它成为分析习惯化和打破习惯化机制的有价值且重要的生物体。对果蝇嗅觉和味觉习惯化的研究表明，GABA能神经元的增强作用是特定时间尺度习惯化的基础，并确定了味觉习惯化打破途径的一些要素。更详细地了解味觉习惯化和习惯化打破机制将受益于获得用于以下方面的强大行为分析方法：（a）由甜味刺激引发的喙伸展反射（PER）；（b）导致PER习惯化的暴露范式，以及最关键的（c）导致PER习惯化打破的操作。在这里，我们描述了简单的实验方案，用于持续用蔗糖刺激跗节毛，从而导致喙伸展的习惯化，以及用于呈现新的食欲刺激物，使习惯化的果蝇恢复强烈的PER。这种详细的味觉习惯化实验方案提供了：（a）一种通过将果蝇连续暴露于蔗糖10分钟来诱导习惯化而不会因摄入导致饱腹感的简单方法；（b）一种通过向喙部呈现酵母来打破习惯化的新方法。关键特征：• 一种刺激果蝇味觉（糖）感觉神经元的实验方案，该方案可诱导味觉习惯化而不会因摄入导致饱腹感。• 一种化学（酵母）刺激实验方案，可快速诱导对糖习惯化的果蝇的习惯化打破/去习惯化。
