Biology subjects

Tanaka, N. K.

Publications and source records attributed to Tanaka, N. K..

3 recordsLinked to original sources

bioRxiv2025

Rhodopsin 7 is indispensable for regulating the firing rates of olfactory sensory neurons in response to extracellular field potential changes in Drosophila melanogaster

Although extracellular field potential changes are commonly observed in the nervous systems, it remains controversial if extracellular electrical activity contributes to neural processing or whether it is an epiphenomenon associated with neural activity. We previously reported that the extracellular field potential change in compound eyes in response to light stimulation induces firing rate changes in olfactory sensory neurons in female Drosophila melanogaster. Through further investigation, we found that the extracellular field potential within the olfactory sensillum is regulated by octopaminergic neurons in response to the light stimulation and that rhodopsin 7 mediates the firing rate changes in the olfactory sensory neurons in response to field potential changes in a light-independent manner. Structural analysis suggests a voltage-dependent gating mechanism for rhodopsin 7 to respond to the field potential change. This study reveals that the nervous system actively controls the field potential in response to sensory input, resulting in alteration of behavioral patterns as well as neural firing patterns in a context-dependent manner. Significance statementAlthough extracellular electrical activity has been recorded to diagnose neuropsychiatric disorders, it remains uncertain how it can be controlled by the nervous system. Moreover, it is difficult to investigate how neurons change their excitability by responding to the change in the extracellular field potential, as synaptic communication interferes in the ability to isolate the function of extracellular electrical activity. We here show that the extracellular field potential within the olfactory sensillum in Drosophila melanogaster is actively regulated by octopaminergic neurons in response to sensory input. We also provide evidence that rhodopsin, a major light sensor protein, mediates responses to extracellular electrical signals, resulting in alternation of behavioral patterns as well as neural firing patterns in a context-dependent manner.

neuroscience↗

bioRxiv2025

Relative value learning in Drosophila melanogaster larvae

The ability to learn from past experiences to inform future decision-making is crucial for humans and animals alike. One question with important implications for adaptive decision-making is whether we learn about the absolute values of cues we encounter (how good or bad?), or about their relative values (how much better or worse than the alternative?). Humans have been shown to use relative value learning, even when it leads to suboptimal decisions. In this study, we ask whether insects employ absolute or relative value learning. Using the larvae of the fruit fly Drosophila melanogaster, we designed associative odour-taste learning experiments to distinguish both kinds of learning and find that larvae learn about the relative rather than the absolute values of both rewards and punishments, irrespective of the number and sequence of training trials. This suggests that relative value learning is a facility shared across the animal kingdom from maggots to humans, and can be accomplished even by small insect brains. Given the potential of D. melanogaster as a model organism for in-depth neurobiological analyses, our study opens up an opportunity to reveal the detailed mechanisms underlying relative value learning.

neuroscience↗

bioRxiv2021

The color pattern inducing gene wingless is expressed in specific cell types of campaniform sensilla of a polka-dotted fruit fly, Drosophila guttifera

A polka-dotted fruit fly, Drosophila guttifera, has a unique pigmentation pattern on its wings and is used as a model for evo-devo studies exploring the mechanism of evolutionary gain of novel traits. In this species, a morphogen-encoding gene, wingless, is expressed in species-specific positions and induces a unique pigmentation pattern. To produce some of the pigmentation spots on wing veins, wingless is thought to be expressed in developing campaniform sensilla cells, but it was unknown which of the four cell types there express(es) wingless. Here we show that two of the cell types, dome cells and socket cells, express wingless, as indicated by in situ hybridization together with immunohistochemistry. This is a unique case in which non-neuronal SOP (sensory organ precursor) progeny cells produce Wingless as an inducer of pigmentation pattern formation. Our finding opens a path to clarifying the mechanism of evolutionary gain of a unique wingless expression pattern by analyzing gene regulation in dome cells and socket cells.

developmental biology↗