Biology subjects

Hwang, M.

Publications and source records attributed to Hwang, M..

6 recordsLinked to original sources

bioRxiv2025

Real-time fMRI neurofeedback modulates auditory cortex activity and connectivity in schizophrenia patients with auditory hallucinations: A controlled study

Background and HypothesisWe have reported previously a reduction in superior temporal gyrus (STG) activation and in auditory verbal hallucinations (AHs) after real-time fMRI neurofeedback (NFB) in schizophrenia patients with AHs. Study DesignWith this randomized, participant-blinded, sham-controlled trial, we expanded our previous results. Specifically, we examined neurofeedback effects from the STG, an area associated with auditory hallucinations. The effects were compared to Sham-NFB from the motor cortex, a region unrelated to hallucinations. Twenty-three adults with schizophrenia or schizoaffective disorder and frequent medication-resistant hallucinations performed mindfulness meditation to ignore pre-recorded strangers voices while receiving neurofeedback either from the STG (n=10, Real-NFB) or motor cortex (n=13 Sham-NFB). Individuals randomized to Sham-NFB received Real-NFB in a subsequent visit, providing a within-subject Real-after-Sham-NFB comparison. Study ResultsBoth groups showed reduced AHs after NFB, with no group differences. Compared to the Sham-NFB group, the Real-NFB group showed more reduced activation in secondary auditory cortex (AC) and more reduced connectivity between AC and cognitive control regions including dorsolateral prefrontal cortex (DLPFC) and anterior cingulate. The connectivity reduction was also observed in the Real-after-Sham-NFB condition. Secondary AC-DLPFC connectivity reduction correlated with hallucination reduction in the Real-NFB group. Replicating prior results, both groups showed reduced primary auditory cortex activation, suggesting mindfulness meditation may regulate bottom-up processes involved in hallucinations. ConclusionsOur findings emphasize delivering NFB from brain regions involved in medication-resistant AHs. They provide insights into auditory cortex and cognitive control network interactions, highlighting complex processing dynamics and top-down modulation of sensory information.

neuroscience↗

bioRxiv2025

Real-time fMRI neurofeedback reduces default mode network and auditory cortex functional connectivity in schizophrenia

Background and HypothesisAuditory verbal hallucinations (AHs) are a cardinal symptom of schizophrenia that can cause distress but are not always responsive to antipsychotic medications. There is a critical need to develop novel interventions that target neural mechanisms underlying AHs. We developed a real-time fMRI neurofeedback (NFB) paradigm for AHs that aims at modulating default mode network (DMN) functional connectivity. Study DesignPatients with schizophrenia or schizoaffective disorders who were experiencing AHs (N = 25) attempted to decrease brain activation while listening to sentences recorded in another persons voice and increase brain activation while listening to sentences recorded in their own voice. Participants randomly assigned to the real group (n = 12) received neurofeedback based on signals from their auditory cortex in the superior temporal gyrus (STG) and those assigned to the sham group (n = 13) received neurofeedback based on motor cortex signals. Study ResultsAnalyzing resting state fMRI data collected pre- and post-NFB, we found that: (1) at baseline, stronger within-DMN connectivity between the medial prefrontal cortex (MPFC) and posterior cingulate cortex was associated with higher AHs severity; (2) after NFB, participants in the real group, compared to those in the sham group, showed greater reduction in functional connectivity between the MPFC and auditory cortices in the STG and middle temporal gyrus (MTG). Notably, the reduction in MPFC-STG/MTG connectivity was found in all participants in the real group. ConclusionsThese findings suggest that NFB can effectively and non-invasively modulate functional connectivity in regions associated with AHs in psychosis.

neuroscience↗

bioRxiv2023

A Template for Translational Bioinformatics: Facilitating Multimodal Data Analyses in Preclinical Models of Neurological Injury

BackgroundPediatric neurological injury and disease is a critical public health issue due to increasing rates of survival from primary injuries (e.g., cardiac arrest, traumatic brain injury) and a lack of monitoring technologies and therapeutics for the treatment of secondary neurological injury. Translational, preclinical research facilitates the development of solutions to address this growing issue but is hindered by a lack of available data frameworks and standards for the management, processing, and analysis of multimodal data sets. MethodsHere, we present a generalizable data framework that was implemented for large animal research at the Childrens Hospital of Philadelphia to address this technological gap. The presented framework culminates in an interactive dashboard for exploratory analysis and filtered data set download. ResultsCompared with existing clinical and preclinical data management solutions, the presented framework accommodates heterogeneous data types (single measure, repeated measures, time series, and imaging), integrates data sets across various experimental models, and facilitates dynamic visualization of integrated data sets. We present a use case of this framework for predictive model development for intra-arrest prediction of cardiopulmonary resuscitation outcome. ConclusionsThe described preclinical data framework may serve as a template to aid in data management efforts in other translational research labs that generate heterogeneous data sets and require a dynamic platform that can easily evolve alongside their research.

bioinformatics↗

bioRxiv2023

Interruption of the Intratumor CD8:Treg Crosstalk Improves the Efficacy of PD-1 Immunotherapy

PD-1 blockade unleashes the potent antitumor activity of CD8 cells but can also promote immunosuppressive T regulatory (Treg) cells, which may worsen response to immunotherapy. Tumor Treg inhibition is a promising strategy to overcome therapeutic resistance; however, the mechanisms supporting tumor Tregs during PD-1 immunotherapy are largely unexplored. Here, we report that PD-1 blockade increases tumor Tregs in mouse models of immunogenic tumors, including melanoma, and metastatic melanoma patients. Unexpectedly, Treg accumulation was not caused by Treg-intrinsic inhibition of PD-1 signaling but instead depended on an indirect effect of activated CD8 cells. CD8 cells colocalized with Tregs within tumors and produced IL-2, especially after PD-1 immunotherapy. IL-2 upregulated the anti-apoptotic protein ICOS on tumor Tregs, causing their accumulation. ICOS signaling inhibition before PD-1 immunotherapy resulted in increased control of immunogenic melanoma. Thus, interrupting the intratumor CD8:Treg crosstalk is a novel strategy that may enhance the efficacy of immunotherapy in patients.

immunology↗

bioRxiv2020

Keeping things in mind for future thinking: Arithmetic booster reduces delay discounting

People have higher preference for immediate over delayed rewards, and it is suggested that such an impulsive tendency is governed by ones ability to simulate future rewards. Consistent with this view, recent studies have shown that enforcing individuals to focus on episodic future thoughts reduces their impulsivity. Inspired by these successful reports, we hypothesized that administration of a simple cognitive task which is linked with future thinking might also function as an effective tool for modulating individuals preference for immediate (or delayed) rewards. Specifically, we used one associative memory task and one working memory task that each of which was administered to intervene acquired amount of information and individuals ability to construct a coherent future event, respectively. Among the set of cognitive tasks, we found that only the arithmetic working memory task had a significant effect of reducing individuals impulsivity. However, in our follow-up experiment, this result was not replicated. Across these two independent experiments, we observed a significant main effect of repetition in individuals impulsivity measure, such that participants showed more patient choices at the second compared to the first assessment task. In conclusion, there was no clear evidence supporting that our suggested intervention tasks effectively reduce individuals impulsivity, while the current results call attention to the importance of taking into account task repetition effects in studying the impacts of cognitive training and intervention.

neuroscience↗

bioRxiv2018

Altered Gene Regulatory Networks are Associated with the Transition from C3 to Crassulacean Acid Metabolism in Erycina (Oncidiinae: Orchidaceae)

Crassulacean acid metabolism (CAM) photosynthesis is a modification of the core C3 photosynthetic pathway that improves the ability of plants to assimilate carbon in water-limited environments. CAM plants fix CO2 mostly at night, when transpiration rates are low. All of the CAM pathway genes exist in ancestral C3 species, but the timing and magnitude of expression are greatly altered between C3 and CAM species. Understanding these regulatory changes is key to elucidating the mechanism by which CAM evolved from C3. Here we use two closely related species in the Orchidaceae, Erycina pusilla (CAM) and Erycina crista-galli (C3), to conduct comparative transcriptomic analyses across multiple time points. Clustering of genes with expression variation across the diel cycle revealed some canonical CAM pathway genes similarly expressed in both species, regardless of photosynthetic pathway. However, gene network construction indicated that 149 gene families had significant differences in network connectivity and were further explored for these functional enrichments. Genes involved in light sensing and ABA signaling were some of the most differently connected genes between the C3 and CAM Erycina species, in agreement with the contrasting diel patterns of stomatal conductance in C3 and CAM plants. Our results suggest changes to transcriptional cascades are important for the transition from C3 to CAM photosynthesis in Erycina.

plant biology↗