Biology subjects

Kitazawa, S.

Publications and source records attributed to Kitazawa, S..

3 recordsLinked to original sources

bioRxiv2024

Dietary zinc restriction mimics protein restriction and extends lifespan in Drosophila

Dietary restriction extends lifespan in model organisms, mainly through dietary amino acids. Compared to macronutrients, the effect of dietary micronutrients on organismal lifespan has not been intensively investigated. Here, using a synthetic diet, we test whether restriction of each micronutrient, including vitamins and minerals, affects lifespan and fecundity in adult Drosophila. While restriction of many of these micronutrients have either negative or no impact on lifespan, zinc (Zn) restriction alone can increase it. Dietary Zn restriction (ZnR) decreases fecundity, increases starvation resistance, and promotes preference for feeding amino acids, in adult females, phenocopying dietary amino acid restriction. Our study demonstrates that dietary intake of trace elements has profound impacts on physiology and lifespan, and that limiting dietary zinc may be a strategy to improve the healthspan of animals.

physiology↗

bioRxiv2020

Neural correlates of temporal presentness in theprecuneus: a crosslinguistic fMRI study based on speech stimuli

AbstractsThe position of any event in time could be either present, past, or future. This temporal discrimination is vitally important in our daily conversations, but it remains elusive how the human brain distinguishes among the past, present, and future. To address this issue, we searched for neural correlates of presentness, pastness, and futurity, each of which is automatically evoked when we hear sentences such as it is raining now, it rained yesterday, or it will rain tomorrow. Here, we show that sentences that evoked presentness activated the bilateral precuneus more strongly than those that evoked pastness or futurity. Interestingly, this contrast was shared across native speakers of Japanese, English, and Chinese, languages which vary considerably in their verb tense systems. The results suggest that the precuneus serves as a key region that provides the origin, the Now, to our time perception irrespective of differences in tense systems across languages.

neuroscience↗

bioRxiv2018

Causal explanation of individual differences in human sensorimotor memory formation

Sensorimotor cortex mediates the formation of adaptation memory. Individuals differ in the rate at which they acquire, retain, and generalize adaptation. We present a mechanistic explanation of the neurochemical and computational causes of this variation in humans. Neuroimaging identified structural, functional and neurochemical covariates of a computational parameter that determines memory persistence. To establish causality, we increased sensorimotor cortex excitability during adaptation, using transcranial direct current stimulation. As predicted, this increased retention. Inter-individual variance in the stimulation-induced E:I increase predicted the computational change, which predicted the memory gain. These relations did not hold, and memory was unchanged, with stimulation applied before adaptation. This cognitive state dependent effect was modulated by the BDNF val66met genetic polymorphism. Memory was enhanced by stimulation in Val/Val carriers only, implicating a mechanistic role for activity-dependent BDNF secretion. Sensorimotor cortex E:I causally determines the time constant of memory persistence, explaining phenotypic variation in adaptation decay.

neuroscience↗