Biology subjects

Noguchi, J.

Publications and source records attributed to Noguchi, J..

3 recordsLinked to original sources

bioRxiv2022

Imbalance of circuit plasticity and consolidation in autism model marmosets is adjusted by oxytocin administration

Alterations in the experience-dependent and autonomous elaboration of neural circuits are assumed to underlie autism spectrum disorder (ASD), though it is unclear what synaptic traits are responsible. Here, we used a valproic acid-induced ASD marmoset model, which shares common molecular features with idiopathic ASD, to investigate the structural dynamics of tuft dendrites of upper-layer pyramidal neurons and adjacent axons in the dorsomedial prefrontal cortex using two-photon microscopy. In model marmosets, dendritic spine turnover was upregulated, and spines were actively generated in clusters and subsequently survived more often than in control marmosets. Presynaptic boutons in local axons but not in commissural long-range axons showed hyperdynamic turnover in model marmosets, suggesting alterations in projection-specific plasticity. Intriguingly, nasal administration of oxytocin reduced the clustered spine emergence. Enhanced clustered spine generation, possibly unique to certain presynaptic partners, may be associated with ASD and may be a potential therapeutic target.

neuroscience↗

bioRxiv2020

Distinct synaptic and related transcriptional abnormalities in neonatal, childhood and mature autism model of primate: implications for early-age therapeutic intervention

Autism spectrum disorder (ASD) is a synapse-related disorder that is diagnosed at around 3 years of age. Earlier intervention is desirable for better ASD prognosis; however, there is limited biological literature regarding early-age ASD. This study aimed to assess altered cortical synapses and gene expression in the ASD model marmoset. There were distinct phenotypes in the model animals across the neonate, childhood, and mature stages in the dorsomedial prefrontal cortex (Brodmann area 8b/9). At the neonate stage, synapses were underdeveloped and modulated genes were enriched with synaptogenesis- and ASD-related genes. At the childhood stage, synaptic features and gene expressions associated with experience-dependent circuit remodeling were altered in model animals. At the mature stage, there were synapse overdevelopment and altered gene expression similar to those in human ASD. These early synaptic phenotypes and altered gene expressions could be novel targets of efficient therapy from a young age.

neuroscience↗

bioRxiv2019

Stringent structural plasticity of dendritic spines revealed by two-photon glutamate uncaging in adult mouse neocortex in vivo

Two-photon uncaging of glutamate is widely utilized to characterize structural plasticity in brain slice preparations in vitro. In this study, we investigated spine plasticity by using, for the first time, glutamate uncaging in the neocortex of adult mice in vivo. Spine enlargement was successfully induced in a smaller fraction of spines in the neocortex (22%) than in young hippocampal slices (95%), even under a low magnesium condition. Once induced, the time course and mean amplitudes of long-term enlargement were the same (81%) as those in vitro. However, low-frequency (1-2 Hz) glutamate uncaging caused spine shrinkage in a similar fraction (34%) of spines as in vitro, but spread to the neighboring spines less frequently than in vitro. Thus, we found that structural plasticity can occur similarly in the adult neocortex in vivo as in the hippocampus in vitro, although it happens stringently in a smaller subset of spines.

neuroscience↗