Biology subjects

Noguchi, Y.

Publications and source records attributed to Noguchi, Y..

8 recordsLinked to original sources

bioRxiv2026

Dual Developmental Origins and Activity-dependent Specification of Mammalian Subplate Neurons

Subplate neurons (SpNs) are among the earliest-generated cortical neurons and are essential for neocortical circuit assembly. Despite this central role, they have long been considered a mammalian innovation, yet their evolutionary origin remains unresolved. Here, using comparative single-cell and spatial transcriptomics across amniotes (mice, chicks, and turtles), we identify two distinct developmental and evolutionary origins of SpNs: atypical SpNs (aSpNs), an Nr4a2-negative population conserved across amniotes and originating from the medial pallium, and mammalian-type SpNs (mSpNs), an Nr4a2-positive population preferentially expanded in mammals and arising from early-born cortical neurons. Cross-species analyses show that early-born pallial neurons in non-mammalian amniotes differentiate into thalamic input neurons, whereas this ancestral program is repurposed in mammals, with early-born neurons transiently adopting a subplate identity. We further show that this fate switch is controlled by Zbtb18 repression linked to thalamic input. Collectively, these findings establish a dual-origin model for SpNs and provide a unifying framework for understanding neocortical evolution. One-Sentence SummaryDevelopmental rewiring of an ancestral input-neuron program gave rise to the mammalian subplate.

evolutionary biology↗

bioRxiv2025

Temporal coding of conceptual distances in the human language area

It is largely unknown how the brain encodes semantic distances between conceptual (verbal) knowledge. I presently show that the information on semantic distances is mainly embedded in a temporal measure (oscillation frequency) of human EEG waveforms. Participants judged a semantic relation between two words (synonym, antonym, thematically-related, taxonomically-related, or unrelated) sequentially presented. Brain rhythms (8-30 Hz) over the left language region, especially the anterior temporal lobe (ATL), were accelerated when a word pair with a high conceptual similarity (e.g. synonym) was presented. Importantly, this change in brain rhythm reflected an inter-word closeness as concepts (holistic similarity, typically seen in synonyms or thematically-related pairs), rather than an inter-word overlap of semantic features (partial similarity, typically seen in antonyms or taxonomically-related pairs). These results highlight a role of temporal measures of neural activity in semantic processing, which explains an inconsistency over previous results using hemodynamic measures. Significance statementVerbal concepts are connected with each other in the brain, although neural (electric) signals encoding their semantic distances remain unknown. In the present study, I show that the information about inter-conceptual similarity is embedded in speed (not amplitude) of neural oscillatory signals in the healthy human brain. This approach using a temporal measure further revealed the concept-based (not feature-based) processing of word meanings unique to the left language areas.

neuroscience↗

bioRxiv2025

Efficient Production of Pseudopregnant Female Mice Using Non-Estrous Individuals and the Whitten Effect

Pseudopregnant recipient females are essential for transplanting early mouse embryos during individualization. Traditionally, pseudopregnancy is induced through mating stimulation with vasectomized males, targeting females in proestrus or estrus. However, group housing of females in animal facilities often leads to fewer females entering estrus due to the Lee-Boot effect. This study focused on utilizing non-estrous females and the Whitten effect to produce pseudopregnant females. Females exhibiting characteristics of non-estrous states were visually selected and paired monogamously with vasectomized males for three consecutive days. This approach resulted in a high copulation success rate of 72.1% (CLEA Japan, Inc.) and 77.0% (Japan SLC, Inc.) on the expected third day. Subsequent embryo transfer using successfully copulated females resulted in offspring from 93.5% of ICR females from CLEA Japan, Inc. and 89.6% of ICR females from Japan SLC, Inc. Additionally, the suitability for embryo transfer could be determined by observing the condition of the ampulla of the oviduct. While this method requires a three-day preparation period compared to conventional approaches, it offers an effective alternative for creating pseudopregnant females for embryo transfer, potentially reducing animal use and associated costs.

bioengineering↗

bioRxiv2024

Harnessing the Biosynthetic Diversity of Actinomycetes: Discovery of Unique Natural Products through Comparative Genomic and Metabolic Analysis

Actinomycetes, rich in biosynthetic gene clusters (BGCs), are important sources of natural products (NPs). However, the rate of discovering novel NPs from actinomycetes has declined, indicating the need for a new strategy to obtain NPs. Herein, we present a strategy for the efficient discovery of novel NPs. First, we performed a comprehensive analysis of BGCs in actinomycetes, evaluating the average number and types of BGCs per genus to identify prolific NP producers. Our analysis revealed that certain actinomycetes strains, such as those in the family Pseudonocardiaceae, possess a greater number of BGCs than Streptomyces. In addition, these strains tend to possess strain-specific BGCs compared with others. To facilitate the identification of strain-specific compounds, we developed a comparative metabolic analysis method using molecular networking. Applying this method to eight Pseudonocardiaceae strains, we successfully discovered two novel peptides, lentindoles A (1) and B (2), featuring a 6/5/6 and 6/5/5 tricyclic ring system, respectively, along with their possible biosynthetic precursor, lentindole C (3). Our result demonstrates that the effectiveness of our developed strategy, which is expected to accelerate the discovery of novel NPs.

microbiology↗

bioRxiv2023

Combinatorial binding of semantic information through the sharing of neural oscillatory signals

We comprehend linguistic inputs (e.g. sentence) by retrieving semantic memory of each element (e.g. word) and integrating them. How semantic information is represented and bound as neural (electric) signals is an unsolved issue. I presently used a simple sentence composed of a noun phrase (NP) and a verb (V), comparing human electroencephalography (EEG) responses to a congruent sentence in which the NP and V were semantically related (e.g. "grass grows") with those to an incongruent sentence (e.g. "a key grows"). In the left temporo-parietal cortex, neural oscillation patterns (8 - 30 Hz) to the second stimulus (V) shifted toward those to the first stimulus (NP), thereby producing coherent (faster and more regular) neural responses to the congruent sentence. No such NP-V interaction was observed in the incongruent sentence. These results indicate that the "semantic unification" as a linguistic concept actually takes place in neural oscillatory signals of the healthy human brain.

neuroscience↗

bioRxiv2022

Harmonic memory signals in the human cerebral cortex induced by sematic relatedness of words

When we memorize multiple words simultaneously, semantic relatedness among those words assists memory. For example, the information of "apple", "banana" and "orange" will be connected via a common concept of "fruits" and become easy to retain and recall. Neural mechanisms underlying this semantic integration in verbal working memory remain unclear. Here I used electroencephalography (EEG) and investigated neural signals when healthy human participants memorized five nouns semantically related (Sem trial) or not (NonSem trial). The regularity of oscillatory signals (8 - 30 Hz) during the retention period was found to be lower in NonSem than Sem trials, indicating that memorizing words unrelated to each other induced a non-harmonic (irregular) waveform in the temporal cortex. These results suggest that (i) semantic features of a word are retained as a set of neural oscillations at specific frequencies and (ii) memorizing words sharing a common semantic feature produces harmonic brain responses through a resonance or integration (sharing) of the oscillatory signals.

neuroscience↗

bioRxiv2021

Almost nontoxic tetrodotoxin analog, 5,6,11-trideoxytetrodotoxin, as an olfactory chemoattractant for the grass puffer

Toxic puffers contain the potent neurotoxin, tetrodotoxin (TTX). Although TTX is considered to serve as a defense substance, previous behavioral studies have demonstrated that TTX acts as an attractive pheromone for some toxic puffers. To elucidate the physiological mechanism of putative pheromonal action of TTX, we examined whether grass puffers Takifugu alboplumbeus can detect TTX. Electroolfactogram (EOG) results suggest that the olfactory epithelium (OE) of grass puffers responded to a type of TTX analog (5,6,11-trideoxyTTX), although it did not respond to TTX. We also examined the attractive action of 5,6,11-trideoxyTTX on grass puffers by recording their swimming behavior under dark conditions. Grass puffers preferred to stay on the side of the aquarium where 5,6,11-trideoxyTTX was administered, and their swimming speed decreased. Additionally, odorant-induced labeling of olfactory sensory neurons by immunohistochemistry against neural activity marker (phosphorylated extracellular signal regulated kinase; pERK) revealed that labeled olfactory sensory neurons were localized in the region surrounding "islets" where there was considered as nonsensory epithelium. 5,6,11-trideoxyTTX has been known to accumulate in grass puffers, but its toxicity is much lower (almost nontoxic) than TTX. Our results suggest that toxic puffers may positively use this TTX analog, which has been present in their body with TTX but whose function was unknown, as an odorant for chemical communication or effective TTX accumulation.

zoology↗

bioRxiv2020

Temporal codes of visual working memory in the human cerebral cortex

Visual working memory (vWM) is an important ability required for various cognitive tasks although its neural underpinnings remain controversial. While many studies have focused on theta (4-7 Hz) and gamma (> 30 Hz) rhythms as a substrate of vWM, here we show that temporal signals embedded in alpha (8-12 Hz) and beta (13-30 Hz) bands can be a good predictor of vWM capacity. Neural activity of healthy human participants was recorded with magnetoencephalography when they performed a classical vWM task (change detection). We analyzed changes in inter-peak intervals (IPIs) of oscillatory signals along with an increase in WM load (a number of to-be-memorized items, 1-6). Results showed a load-dependent reduction of IPIs in the parietal and frontal regions, indicating that alpha/beta rhythms became faster when multiple items were stored in vWM. Furthermore, this reduction in IPIs was positively correlated with individual vWM capacity, especially in the frontal cortex. Those results indicate that vWM is represented as a change in oscillation frequency in the human cerebral cortex.

neuroscience↗