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Morita, T.

Publications and source records attributed to Morita, T..

At least 19 recordsLinked to original sources
bioRxiv2026

Causal contribution of motor-parietal network to conscious kinesthetic perception

Bodily awareness, including the conscious experience of limb movement (kinesthesia), is a fundamental form of human consciousness. Tendon vibration-induced kinesthetic illusions provide a tractable model for probing its neural basis. Although previous studies have reported coactivation of the primary motor cortex (M1), the right inferior parietal lobule (IPL), and the right inferior frontal gyrus (IFG) during illusory movement, their causal contributions to conscious kinesthetic experience remain unclear. Here, we combined functional MRI and regional facilitative dual-site transcranial direct current stimulation (tDCS) to establish a causal link between these cortices and illusory foot movement. fMRI revealed that the M1-IPL network supports kinesthetic illusion elicited by bottom-up sensory processing, whereas the IFG plays a role in top-down monitoring of the kinesthetic experience. Critically, concurrent facilitative dual-site tDCS applied to the M1 and IPL significantly enhanced the subjective strength of the illusion, compared with the sham and concurrent tDCS to the M1 and IFG. This effect was replicated without increasing muscle activity in another tDCS study and exceeded those observed with single-site (M1 or IPL) or concurrent higher-order IPL-IFG tDCS. Our findings provide the first compelling causal evidence that conscious kinesthetic perception can be augmented through coordinated interactions between the modality-specific kinesthetic-motor cortex (M1) and the higher-order right inferior parietal cortex (IPL). This coordinated interaction between modality-specific and higher-order cortical regions underlying conscious kinesthetic perception is consistent with the Global Neuronal Workspace hypothesis. Our findings have therefore extended the applicability of this framework from exteroceptive perception to bodily awareness.

neuroscience↗
bioRxiv2026

PCP-dependent polarity propagation across neuronal columns in the Drosophila medulla

Planar cell polarity (PCP) signaling establishes coordinated tissue polarity through asymmetric localization of core PCP factors and propagation of polarity information between neighboring cells. While PCP mechanisms are well characterized in continuous epithelial tissues, whether PCP-dependent polarity propagation can operate across discontinuous neuronal structures remains unclear. During pupal development of the Drosophila medulla, R8 photoreceptor axon terminals transiently form horseshoe-shaped structures whose orientation reflects neuronal column polarity. Here, we show that Frizzled (Fz) progressively becomes asymmetrically localized within developing horseshoe structures, whereas Van Gogh (Vang) transiently accumulates in adjacent glial cells during early developmental stages. Conditional disruption of Vang in glial cells impaired asymmetric Fz localization and disrupted horseshoe orientation polarity. Glial Vang localization preceded the emergence of robust Fz asymmetry, suggesting that glial Vang functions during an early polarity establishment phase. Furthermore, mosaic knockdown of fz in R8 neurons altered Fz localization in neighboring R8 terminals, suggesting local propagation of polarity information between adjacent neuronal columns. Together, our results suggest that PCP-dependent polarity propagation operates across discontinuous neuronal columns in the developing medulla and provide a framework for understanding coordinated polarity formation in neural tissues lacking continuous epithelial organization.

developmental biology↗
bioRxiv2026

Identification of Novel Gamma Radiation-Responsive Genes in the Thiosulfate-Oxidizing Bacterium Limnobacter thiooxidans

Ionizing radiation induces DNA damage and oxidative stress; however, the genes and molecular mechanisms involved in bacterial stress responses have not been sufficiently identified. In this study, we used Limnobacter thiooxidans strain CS-K2, which is the closest relative to the bacteria detected in torus room water at the Fukushima Daiichi Nuclear Power Plant according to 16S rRNA gene sequences, and evaluated its response to {gamma}-ray irradiation using integrated transcriptomic and proteomic analyses. We identified three previously uncharacterized genes (LT3105, LT3115, and LT3126) that were strongly induced at the mRNA and protein levels. These genes exhibited low basal expression but were markedly upregulated by {gamma}-ray irradiation. Notably, LT3126 encodes a protein containing VIT (vault protein inter--trypsin) and VWA (von Willebrand factor type A) domains and showed the strongest induction. Overexpression of LT3126 increased survival after 500 Gy irradiation by approximately 200-fold compared with the control bacteria, demonstrating a direct contribution to survival under high-dose stress. Comparative genomic analysis showed that these genes are not widely conserved across bacteria but are unevenly distributed among specific lineages. Taken together, this study identified a novel set of {gamma}-ray-responsive genes and demonstrated a functional role for LT3126 in radiation resistance, providing new insights into molecular adaptation in radiation-associated environments. IMPORTANCEWe identified a novel set of {gamma}-ray-responsive genes (LT3105, LT3115, and LT3126) in the non-model bacterium Limnobacter thiooxidans. These genes are located in relatively close genomic proximity and are coordinately induced upon irradiation, suggesting a shared functional role in stress response. Overexpression of LT3126 increased survival by approximately 200-fold after 500 Gy irradiation compared with the control bacteria, demonstrating a substantial contribution to survival under high-dose stress. These genes were also induced by heat shock and oxidative stress, indicating that their function extends beyond radiation-specific responses to broader environmental stress adaptation. Consistent with this, comparative genomic analysis showed that these genes are not widely conserved across bacteria but are unevenly distributed among specific lineages. Taken together, these findings highlight previously unrecognized molecular strategies that may support bacterial survival in radiation-associated environments.

microbiology↗
bioRxiv2026

Disruption of the NTCP-EGFR receptor complex as a strategy for selective inhibition of hepatitis B and D virus entry

Hepatitis B and D virus (HBV, HDV) enter hepatocytes through a coordinated process mediated by a receptor complex consisting of sodium taurocholate co transporting polypeptide (NTCP) and its entry cofactors, including epidermal growth factor receptor (EGFR). Here, we established an in vitro assay to evaluate the NTCP-EGFR interaction and identified Oxy229, an oxysterol-based compound that disrupted this molecular interaction. Oxy229 selectively inhibited HBV and HDV infection to HepG2-NTCP cells and primary human hepatocytes. Mechanistic analysis revealed that Oxy229 impaired the relocalization of the HBV-NTCP complex from plasma membrane to intracellular vesicles. Notably, Oxy229 did not compromise the physiological functions of NTCP and EGFR, i.e., bile acid transport and activation of downstream EGFR signaling pathways including Ras-MAPK and PI3K-Akt pathways, indicating selective inhibition of viral entry. Compound derivative analysis identified Oxy283, which acquired dual inhibitory activity against both NTCP-EGFR interaction and NTCP multimerization, resulting in enhanced anti-HBV potency. These findings establish the functional significance of the NTCP-receptor complex formation in HBV/HDV entry and highlight this machinery as a potential target for antiviral intervention.

microbiology↗
bioRxiv2025

A cattle-derived human H5N1 isolate suppresses innate immunity despite efficient replication in human respiratory organoids

The H5N1 high pathogenicity avian influenza virus (HPAIV) of clade 2.3.4.4b, which spreads globally via wild birds, has become a major public health concern because it can infect a variety of mammals, including humans. In 2024, infection of dairy cattle with H5N1 HPAIV clade 2.3.4.4b was confirmed in the United States, and subsequent human cases were reported. Although these viruses are highly pathogenic in animal models, human infections have generally been mild, revealing a striking discrepancy. Here, we characterized the cattle-derived human H5N1 isolate A/Texas/37/2024 (TX37-H5N1) using three-dimensional human respiratory organoids derived from induced pluripotent stem (iPS) cells. Despite efficient replication, TX37-H5N1 induced minimal interferon and inflammatory cytokine responses. Bulk and single-cell RNA sequencing revealed reduced STAT1-mediated transcriptional activity in TX37-H5N1-infected organoids compared to the historic H5N1 human isolate A/Vietnam/1203/2004. These findings suggest that TX37-H5N1 fails to trigger the strong innate responses, including robust cytokine production, that are typically associated with severe H5N1 disease and are thought to contribute to cytokine storm-medicated pathogenesis. This attenuated response may help explain the discrepancy between the high pathogenicity of TX37-H5N1 in animal models and its mild clinical presentation in humans. While zoonotic influenza risk is often assessed using cell lines or animal models, our study highlights the value of using human respiratory organoids to evaluate human-specific virus-host interactions. This platform provides a complementary tool for assessing the risk of emerging avian influenza viruses. HighlightsO_LIHuman respiratory organoids were used to model zoonotic B3.13 H5N1 infections. C_LIO_LIA cattle-derived human isolate, TX37-H5N1, replicated more efficiently than historical VN1203-H5N1. C_LIO_LITX37-H5N1 suppressed STAT-IRF-mediated innate immune responses. C_LIO_LITX37-H5N1 was sensitive to baloxavir and oseltamivir but less sensitive to favipiravir. C_LIO_LIHuman respiratory organoids offer a complementary platform for zoonotic influenza risk assessment. C_LI In briefOur study used human iPSC-derived respiratory organoids to investigate the mild clinical presentation of zoonotic B3.13 H5N1 viruses. We found that TX37-H5N1 replicates efficiently but suppresses innate immune responses, providing mechanistic insight into species-specific pathogenesis and highlighting the utility of human organoids for zoonotic risk assessment.

microbiology↗
bioRxiv2025

Evaluation of therapeutic effect of baloxavir marboxil against high pathogenicity avian influenza virus infection in duck model

Since 2020, high pathogenicity avian influenza virus (HPAIV) infections in wild birds have been frequently reported. Because HPAIV infection has occasionally caused outbreaks in captive rare birds, application of antiviral drugs for treatment purposes against them has been considered from the perspective of conservation medicine. In this study, the therapeutic efficacy of baloxavir marboxil (BXM) was evaluated using a duck model to help establish the post-infection treatment for rare birds. Sixteen four-week-old ducks were divided into four groups and intranasally inoculated with the HPAIV strain A/crow/Hokkaido/0103B065/2022 (H5N1). BXM was orally administered once daily at doses of 12.5, 2.5, 0.5, and 0 mg/kg to each of the four groups from 2 to 6 days post-infection. Blood samples were collected at 2, 8, and 24 hours after the initial BXM administration to measure the plasma concentrations of its active form, baloxavir acid (BXA). All ducks were monitored until 14 days post-infection, and their oral and cloacal swabs were collected for virus recovery. All eight ducks administered with 12.5 or 2.5 mg/kg of BXM survived, demonstrating a significant reduction in virus recovery compared to the 0 mg/kg group. Pharmacokinetic/pharmacodynamic (PK/PD) analysis of BXA suggested that parameters such as Cmax and AUC0-24hr were correlated with the suppression of virus shedding. These findings demonstrated that BXM administration within 48 hours post-HPAIV infection in ducks effectively reduced mortality and virus shedding. The comparison of PK parameters may help estimate efficient BXM dosing strategies in rare birds. HighlightBXM prevented death of HPAIV-infected ducks when given within 48 hr of inoculation. Doses of 2.5 mg/kg rapidly suppressed and eliminated infectious virus shedding. AUC0-24hr and Cmax correlated with suppression of virus shedding.

microbiology↗
bioRxiv2025

Internal desynchrony of the circadian clock system in middle-aged mice under social jet lag-like conditions

Social jet lag (SJL) refers to the discrepancy in sleep patterns between weekdays and weekends, leading to a misalignment between the internal clock and social time. In this study, we investigated the effects of weekly shifts in light-dark (LD) conditions: two days per week with 6-h delayed LD cycles (simulating Saturday and Sunday), followed by a 6-h advance on Monday. Core body temperature rhythms rapidly entrained to the delayed LD cycles on weekends, and these delayed rhythms persisted even after the LD cycle was advanced on Monday. In contrast, plasma corticosterone rhythms on Mondays were aligned with the LD cycle but exhibited reduced amplitude. In the livers of SJL mice on Monday, the expression rhythms of Per1, Per2, and Hsp70 were delayed by 3-5 h compared to that in the controls, whereas Rev-erb expression rhythms remained comparable to those of the controls. The expression of lipid and glucose metabolism-related genes in the liver showed either delayed rhythms or no significant changes. To determine whether the dissociation of gene expression rhythms resulted from gene-specific responses to circadian body temperature and hormonal signals, we conducted ex vivo culture experiments using mouse liver slices. High-temperature stimulation induced Per2 and Hsp70 expression, while dexamethasone induced Per1 expression. High temperature and dexamethasone affected distinct sets of metabolic genes, whereas insulin induced only minor changes. Moreover, these responses were strongly influenced by the age and light exposure of the mice. We also examined the effect of weekly housing by providing environmental enrichment (EE), which had minimal impact on circadian parameters but promoted anti-aging effects on bone density and behavior. Overall, our findings indicate that weekly shifts in LD cycles induce internal desynchronization within the hepatic molecular clock and metabolic pathways by uncoupling core body temperature rhythms, hormonal rhythms, and gene-specific responses to stimuli.

physiology↗
bioRxiv2025

Glycogen metabolism in mouse embryonic Sertoli cells sustains the germ line through the lactate shuttle

Metabolites are key regulators of cell fate decisions, epigenetic remodeling, and lineage commitment. While genetic pathways governing testis differentiation are well studied, the role of metabolism remains poorly understood. In this study, we investigated a transient, male-specific accumulation of glycogen in supporting (Sertoli) cells of embryonic testis in mice. Although glycogen metabolism was dispensable for Sertoli cell differentiation, its disruption led to reduced lactate production and impaired PGCs ability to colonize the newly forming testis cords. Inhibiting lactate transport further revealed a critical metabolic coupling between Sertoli and germ cells during early testis development. Surprisingly, external lactate or glucose supplementation failed to rescue the germ cell phenotype. These findings suggest that glycogen accumulation supports a critical developmental window in which both Sertoli and germ cells are metabolically constrained and unable to rely on external carbon sources. This highlights a sensitive period during testicular development where nutrient scarcity could have long-term consequences for fertility.

developmental biology↗
bioRxiv2025

Heat-off responses of epidermal cells sensitize Drosophila larvae to noxious inputs

Perception of external thermal stimuli is critical to animal survival, and although an animals skin is the largest contact surface for thermal inputs, contributions of skin cells to noxious temperature sensing have not been extensively explored. Here, we show that exposure to heat transiently sensitizes Drosophila larvae to subsequent noxious stimuli. This sensitization is induced by prior stimulation of epidermal cells but not nociceptors, suggesting that epidermal cells modulate nociceptor function in response to heat exposure. Indeed, we found that Drosophila epidermal cells are intrinsically thermosensitive, exhibiting robust heat-off responses following warming to noxious temperatures as well as responses to cooling below comfortable temperatures. Further, we found that epidermal heat-off calcium responses involve influx of extracellular calcium and require the store-operated calcium channel Orai and its activator Stim. Finally, epidermal heat-off responses and heat-evoked nociceptive sensitization exhibit similar temperature dependencies, and we found that Stim and Orai are required in epidermal cells for heat-evoked nociceptive sensitization. Hence, epidermal thermosensory responses provide a form of adaptive sensitization to facilitate noxious heat avoidance.

neuroscience↗
bioRxiv2025

Mosquito Cell Atlas: A single-nucleus transcriptomic atlas of the adult Aedes aegypti mosquito

The female Aedes aegypti mosquitos remarkable ability to hunt humans and transmit pathogens relies on her unique biology. Here, we present the Aedes aegypti Mosquito Cell Atlas, a comprehensive single-nucleus RNA sequencing dataset of more than 367,000 nuclei from 19 dissected tissues of adult female and male Aedes aegypti, providing cellular-level resolution of mosquito biology. We identify novel cell types and expand our understanding of sensory neuron organization of chemoreceptors to all sensory tissues. Our analysis uncovers male-specific cells and sexually dimorphic gene expression in the antenna and brain. In female mosquitoes, we find that glial cells in the brain, rather than neurons, undergo the most extensive transcriptional changes following blood feeding. Our findings provide insights into the cellular basis of mosquito behavior and sexual dimorphism. The Aedes aegypti Mosquito Cell Atlas resource enables systematic investigation of cell type-specific expression across all mosquito tissues.

genomics↗
bioRxiv2025

SLFN11-mediated tRNA regulation induces cell death by disrupting proteostasis in response to DNA-damaging agents

DNA-damaging agents (DDAs) have long been used in cancer therapy. However, the precise mechanisms by which DDAs induce cell death are not fully understood and drug resistance remains a major clinical challenge. Schlafen 11 (SLFN11) was identified as the gene most strongly correlated with the sensitivity to DDAs based on mRNA expression levels. SLFN11 sensitizes cancer cells to DDAs by cleaving and downregulating tRNALeu(TAA). Elucidating the detailed mechanism by which SLFN11 induces cell death is expected to provide insights into overcoming drug resistance. Here, we show that, upon administration of DDAs, SLFN11 cleaves tRNALeu(TAA), leading to ER stress and subsequent cell death regulated by inositol-requiring enzyme 1 alpha (IRE1). These responses were significantly alleviated by SLFN11 knockout or transfection of tRNALeu(TAA). Our proteomic analysis suggests that tRNALeu(TAA) influences proteins essential for maintaining proteostasis, especially those involved in ubiquitin-dependent proteolysis. Additionally, we identified the cleavage sites of tRNALeu(TAA) generated by SLFN11 in cells, and revealed that tRNA fragments contribute to ER stress and cell death. These findings suggest that SLFN11 plays a crucial role in proteostasis by regulating tRNAs, and thus determines cell fate under DDA treatment. Consequently, targeting SLFN11-mediated tRNA regulation could offer a novel approach to improve cancer therapy. GRAPHICAL ABSTRACT O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=84 SRC="FIGDIR/small/632070v1_ufig1.gif" ALT="Figure 1"> View larger version (21K): org.highwire.dtl.DTLVardef@9a9e27org.highwire.dtl.DTLVardef@1053186org.highwire.dtl.DTLVardef@1f67ae4org.highwire.dtl.DTLVardef@fe3091_HPS_FORMAT_FIGEXP M_FIG C_FIG

molecular biology↗
bioRxiv2024

Gray matter volume increase in the retrosplenial/posterior cingulate cortices of blind soccer players

Spatial navigation is a crucial brain function that occurs when an individual moves from one location to another. This function normally relies on vision, and the retrosplenial/posterior cingulate cortices (RSC/PCC) and parahippocampal cortex (PHC) play crucial roles. However, an extraordinary adaptation can be observed in blind soccer players, where the human brain can perform spatial navigation without vision. Therefore, this study tested the possible increase in gray matter (GM) volume in the RSC/PCC and PHC in the brains of a worlds top blind soccer player and other blind soccer players. We collected structural magnetic resonance imaging (MRI) scans from six blind soccer players (including the worlds top player) and eight blind non-soccer players. Using voxel-based morphometry (VBM) analysis (single-case VBM approach), we examined GM volume increase in each participant compared to 250 sighted participants (all of whom had never played blind soccer). Compared with the sighted participants, the worlds top blind soccer player had a significant increase in GM volume in the bilateral RSC/PCC. Two of the other five blind soccer players also showed an increase in the left RSC/PCC. However, such an increase in GM volume was not observed in the blind non-soccer players. Eventually, the probability of a significant increase in the RSC/PCC was significantly higher in the blind soccer group than in the blind non-soccer group. In contrast, only one blind soccer player (not the top player) showed a significant increase in the PHC, and no between-group difference was observed in the probability of a significant increase in the PHC. This study, unveiling the characteristics of the brains of the worlds top blind soccer player and of other blind soccer players, for the first time demonstrates that blind soccer training, which requires spatial navigation based on non-visual cues, may enlarge the human RSC/PCC and provide findings that promote understanding the brains of challenged persons playing blind soccer.

neuroscience↗
bioRxiv2024

Theoretical proposal for restoration of hand motor function utilizing plasticity of motor-cortical interhemispheric interaction

After stroke, the poorer recovery of motor function of upper extremities compared to other body parts is a longstanding problem. Based on our recent functional MRI evidence on healthy volunteers, this perspective paper proposes systematic hand motor rehabilitation utilizing the plasticity of interhemispheric interaction between motor cortices and following its developmental rule. We first discuss the effectiveness of proprioceptive intervention on the paralyzed (immobile) hand synchronized with voluntary movement of the intact hand to induce muscle activity in the paretic hand. In healthy participants, we show that this bilateral proprioceptive-motor coupling intervention activates the bilateral motor cortices (= bilaterally active mode), facilitates interhemispheric motor-cortical functional connectivity, and augments muscle activity of the passively-moved hand. Next, we propose training both hands to perform different movements, which would be effective for stroke patients who become able to manage to move the paretic hand. This bilaterally different movement training may guide the motor cortices into left-right independent mode to improve interhemispheric inhibition and hand dexterity, because we have shown in healthy older adults that this training reactivates motor-cortical interhemispheric inhibition (= left-right independent mode) declined with age, and can improve hand dexterity. Transition of both motor cortices from the bilaterally active mode to the left-right independent mode is a developmental rule of hand motor function and a common feature of motor function recovery after stroke. Hence, incorporating the brains inherent capacity for spontaneous recovery and adhering to developmental principles may be crucial considerations in designing effective rehabilitation strategies.

neuroscience↗
bioRxiv2024

Younger adult brain utilizes interhemispheric strategy of recruiting ipsilateral dorsal premotor cortex for complex finger movement, but not aging brain

The ipsilateral sensorimotor cortices (dorsal premotor cortex [PMd], primary motor cortex [M1], primary somatosensory cortex [S1], and superior parietal cortex of Area 2) are often activated when the healthy younger and older adult brains perform complex finger movements. Prompted by clinical evidence that the ipsilateral PMd plays particularly important roles to complement the movements after stroke, we tested whether the ipsilateral PMd also plays particularly important (complementary) roles among the ipsilateral sensorimotor cortices when healthy younger adults perform a complex motor task by augmenting interhemispheric functional connectivity with the contralateral sensorimotor cortices. We also examined possible strategic difference when older adults with degraded interhemispheric inhibition perform the complex task when compared to younger adults with mature one. We addressed these questions by measuring brain activity with functional magnetic resonance imaging while healthy right-handed younger and older adults performed simple (button pressing with the right index finger) and complex (stick rotation requiring coordination between the right fingers) motor tasks. In younger group, the ipsilateral PMd, S1, Area 2 activated during the complex task, while the ipsilateral M1 remained deactivated as in the simple task, suggesting an existence of interregional difference. The ipsilateral PMd and S1/Area 2 more activated in the individuals with less dexterous performance. The anterior ipsilateral PMd enhanced interhemispheric functional coupling consistently with all of the contralateral sensorimotor cortices during the complex task. In contrast, in older group, all of the ipsilateral cortices including the M1 activated during the complex task, however, none of the cortices showed performance-related activity change. Increase in functional connectivity within the contralateral sensorimotor cortices rather than interhemispheric connectivity was observed during the complex task. The results suggest the importance and complementary role of the ipsilateral PMd for complex finger movement in the younger brains, and the strategic difference (interhemispheric vs. intrahemispheric) when the younger and aging brains perform the movement.

neuroscience↗
bioRxiv2024

Stratification of viral shedding patterns in saliva of COVID-19 patients

Living with COVID-19 requires continued vigilance against the spread and emergence of variants of concern (VOCs). Rapid and accurate saliva diagnostic testing, alongside basic public health responses, is a viable option contributing to effective transmission control. Nevertheless, our knowledge regarding the dynamics of SARS-CoV-2 infection in saliva is not as advanced as our understanding of the respiratory tract. Here we analyzed longitudinal viral load data of SARS-CoV-2 in saliva samples from 144 patients with mild COVID-19 (a combination of our collected data and published data). Using a mathematical model, we quantified individual-level viral dynamics and stratified them into three groups using a clustering approach. Notably, the three groups exhibited distinct differences viral RNA detection durations: 11.5 days (95% CI: 10.6 to 12.4), 17.4 days (16.6 to 18.2), and 30.0 days (28.1 to 31.8), respectively. Surprisingly, this stratified grouping remained unexplained despite our analysis of 47 types of clinical data, including basic demographic information, clinical symptoms, results of blood tests, and vital signs. Additionally, we quantified the expression levels of 92 micro-RNAs in a subset of saliva samples, but these also failed to explain the observed stratification, although the mir-1846 level may have been weakly correlated with peak viral load. Our study provides insights into SARS-CoV-2 infection dynamics in saliva, highlighting the challenges in predicting the duration of viral RNA detection without indicators that directly reflect an individuals immune response, such as antibody induction. Given the significant individual heterogeneity in the kinetics of saliva viral shedding, identifying biomarker(s) for viral shedding patterns will be crucial for improving public health interventions in the era of living with COVID-19.

microbiology↗
bioRxiv2023

Structural and functional features characterizing the brains of individuals with higher controllability of motor imagery

Motor imagery is a higher-order cognitive brain function that mentally simulates movements without performing the actual physical one. Although many studies have dealt with motor imagery, neural bases that determine individual differences in motor imagery ability are not well understood. Using magnetic resonance imaging and controllability of motor imagery (CMI) test that can objectively evaluate individual ability to manipulate ones imaginary postures, we show that the bilateral superior frontoparietal white matter region expands in higher CMI test scorers. In addition, CMI test activates the bilateral dorsal premotor cortex (PMD) and superior parietal lobule (SPL); specifically, the left PMD and/or the right SPL enhance functional coupling with the visual body, somatosensory, and motor/kinesthetic areas in the higher scorers. This study elucidated the structural and functional features that characterize the brains of individuals with higher controllability of motor imagery, and advanced understanding of individual differences in motor imagery ability.

neuroscience↗
bioRxiv2023

Cross-modal sensory compensation increases mosquito attraction to humans

Sensory compensation is a process that allows individuals with a loss of one sense, for instance hearing or vision, to adapt to changes in their sensory abilities. Where this phenomenon has been observed, there is enhanced perception by another sense to compensate for deficiency of the lost sense. Such compensation is important for humans and non-human animals that use multisensory integration for effective navigation and the execution of vital tasks. Among these, female mosquitoes are sensory specialists that rely heavily on integrating multiple human-emitted cues in their quest for a suitable host to obtain a blood meal. Here, we identify a previously undescribed mechanism of sensory compensation in female Aedes aegypti mosquitoes. Mutant mosquitoes lacking the odorant receptor co-receptor Orco show specific enhancement in heat-seeking behavior. This s compensation does not require the antenna, which was previously assumed to be the primary mosquito thermosensitive organ. Instead, we found that the tips of the forelegs are required to detect heat, and that the heightened sensitivity in heat detection is mediated by increased neuronal activity in foreleg sensory neurons, which are distant from the head appendage neurons that express Orco. By comparative gene expression analysis in wildtype and Orco mutant legs, we identify Ir140, a foreleg-enriched member of the Ionotropic Receptor (IR) superfamily of sensory receptors, as strongly upregulated in Orco mutant legs. Emphasizing the important role of IRs in thermosensation, we find that mutant mosquitoes lacking the IR co-receptor, Ir25a, lose all responses to heat, and Ir140 mutants show strong deficits in responding to human skin temperatures. We generated an Ir140, Orco double mutant and show that these animals lose the remarkable sensory compensation seen in Orco mutants. This strongly suggests that upregulation of Ir140 in the foreleg is the mechanism of sensory compensation in Orco mutants. Odorant receptor expression is sparse in legs, suggesting an indirect, long-range mechanism of sensory compensation. Our findings reveal a novel compensatory mechanism in which loss of one sensory modality in female Aedes aegypti mosquitoes results in greater sensitivity in another to maintain the overall effectiveness of their host-seeking behavior, further enhancing their status as the most dangerous predator of humans.

neuroscience↗