Biology subjects

Kanzaki, R.

Publications and source records attributed to Kanzaki, R..

6 recordsLinked to original sources

bioRxiv2024

Adaptive decision-making by ants in response to past, imminent, and predicted adversity

Many animals exhibit innate behaviours, which are often interpreted as hard-wired, reflex-like responses, particularly in insects. Among these behaviours, beacon-aiming--an approach towards dark areas or objects--is observed in many animals; however, its functional significance remains unclear, and some ant species do not exhibit it. Here we show that in one such species, Camponotus japonicus, the behaviour was triggered only under adverse substrate conditions, such as during the crossing of liquid-covered surfaces, regardless of the locomotor patterns like walking or swimming, or the mere presence of water, or when walking upside-down. Once initiated, beacon-aiming persists even under normal substrate conditions, as demonstrated by ants transitioning from water-covered to dry substrates suitable for comfortable walking. This behavioural flexibility indicates that the innate behaviour is not hard-wired but modulated by internal states. Furthermore, changes in internal states may serve adaptive decision-making, potentially allowing ants to prepare for future adverse conditions. The isolated ants on a water-surrounded platform gradually established an attraction to the direction of the beacon before ultimately swimming towards it. These findings suggest that beacon-aiming is regulated by internal states, especially anxiety-like states formed in response to past, imminent, and predicted adverse substrate conditions in ants.

animal behavior and cognition↗

bioRxiv2022

High performance, large-scale multi-compartment Hodgkin-Huxley simulation of Drosophila's whole-brain neural circuit model

A major challenge in neurosciences is the elucidation of neural mechanisms in brains that are crucial for the processing of sensory information and the generation of adaptive behavior. In conjunction with the ever-growing body of experimental data, computational simulations have become crucial in integrating information and testing hypotheses, requiring fast large-scale simulators. We constructed a whole-brain neural circuit model of the fly Drosophila with biophysically detailed multi-compartment Hodgkin-Huxley models based on the morphologies of individual neurons published in open databases. Performance tuning of the simulator enabled near real-time simulation of the resting state of the Drosophila whole-brain model in the large-scale computational environment of the supercomputer Fugaku, for which we achieved in excess of 630 TFLOPS using 480k cores. In our whole-brain model, neural circuit dynamics related to a standard insect learning paradigm, the association of taste rewards with odors could be simulated.

neuroscience↗

bioRxiv2022

Inherent evolutionary unpredictability in cancer model system

Despite the advent of personalized medicine, it is still difficult to predict how a cancer develops over time at the level of the individual patient or even in cancer model systems which begs the question whether certain aspects of cancer can ever be predicted or if there is an inherent unpredictability in cancer, similar to other complex biological systems, We demonstrate by a combination of agent-based mathematical modelling and analysis of data from patient-derived xenograft systems from multiple cancer types that certain conditions may invoke chaotic fluctuations in the clonal landscape of cancer cells. Our findings indicate that under those conditions, the cancer genome behaves as a complex dynamic system, making its long-term evolution inherently unpredictable.

evolutionary biology↗

bioRxiv2021

Pheromone binding protein shapes olfactory temporal resolution

Male moths are capable of orienting towards conspecific females using sex pheromones. Since pheromones are distributed as discontinuous plumes owing to air turbulence, tracking intermittent stimuli with high temporal resolution is suggested to be important for efficient localisation. Here, using a pheromone binding protein (BmPBP1) knockout silkmoth, we revealed that the loss of functional pheromone binding protein altered antennal response kinetics resulting in reduced temporal resolution to intermittent pheromone stimuli on the antennae. Behavioural analysis revealed that BmPBP1-knockout males exhibited significantly less straight walking, which occurs when detecting pheromone stimuli, especially to high frequency stimuli. Accordingly, BmPBP1-knockout males took a significantly longer time to locate pheromone sources and females than did wild-type males. Together, BmPBP1 plays a critical role in determining temporal antennal response kinetics and that an appropriate range of temporal sensory and behavioural resolutions is essential for tracking pheromone plumes for efficient pheromone source localisation in the silkmoth.

neuroscience↗

bioRxiv2018

Parallelized analysis of spatial gene expression patterns by database integration

We developed a computational framework for automated integration of a large number of two-dimensional (2D) images with three-dimensional (3D) image datasets located in the standard 3D coordinate. We applied the framework to 2,810 para-sagittal sectioned mouse brain 2D images of in situ hybridization (ISH), archived in the BrainTx database (http://www.cdtdb.neuroinf.jp). We registered the ISH images into the mouse standard coordinate space for MR images, Waxholm space (WHS, https://www.nitrc.org/projects/incfwhsmouse) by linearly transforming them into each of a series of para-sagittal MR image slices, and identifying the best-fit slice by calculating the similarity metric value ({delta}). Transformed 2D images were compared with 3D gene expression image datasets, which were made using a microtomy-based microarray assay system, Transcriptome Tomography, and archived in the ViBrism DB (http://vibrism.neuroinf.jp): the 3D images are located in the WHS.\n\nWe first transformed ISH images of 10 regionally expressed genes and compared them to signals of corresponding 3D expression images in ViBrism DB for evaluating the integration schema: two types of data, produced with different modalities and originally located in different dimensions, were successfully compared after enhancing ISH signals against background noise. Then, for the massive transformation of BrainTx database images, we parallelized our framework, using the IPython cluster package, and implemented it on the PC cluster provided for the Brain Atlasing Hackathon activity hosted by Neuroinformatics Japan Center in Japan. We could identify the best-fit positions for all of the ISH images. All programs were made available through the GitHub repository, at the web site of neuroinformatics/bah2016_registration (https://github.com/neuroinformatics/bah2016_registration).

neuroscience↗

bioRxiv2018

Descending pathways from the lateral accessory lobe and posterior slope in the brain of the silkmoth Bombyx mori

A population of descending neurons connect the brain and thoracic motor center, playing a critical role in controlling behavior. We examined the anatomical organization of descending neurons (DNs) in the brain of the silkmoth Bombyx mori. Moth pheromone orientation is a good model to investigate the neuronal mechanisms of olfactory behavior. Based on mass staining and single-cell staining, we evaluated the anatomical organization of neurite distribution by DNs in the brain. Dense innervation was observed in the posterior ventral part of the brain, called the posterior slope (PS). We examined the morphology of DNs innervating the lateral accessory lobe (LAL), which is assumed to be important for moth olfactory behavior. We observed that the LAL DNs also innervate the PS, suggesting the integration of signals from the LAL and PS. We also identified a set of DNs innervating the PS, but not the LAL. These DNs were sensitive to sex pheromones, suggesting a role of the PS in motor control for pheromone orientation. The organization of descending pathways for pheromone orientation is discussed.

neuroscience↗