Mai Jiaying Xu

Ph.D. student in Psychology, University of Hong Kong. My research is on how brain and body interact to sustain fear and anxiety, and on the mechanisms that make an intervention work. My current project uses targeted memory reactivation during sleep to weaken conditioned fear.

Previously a Research Fellow at the State Key Laboratory of Cognitive Science and Mental Health, Institute of Psychology, Chinese Academy of Sciences, working on the neurobiology of early adversity. M.A. in Experimental Psychology and B.A. in Philosophy and Psychology, Brandeis University.

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Publications

Peer-reviewed

Xu, M. J., Zhao, C., Qin, H., Ye, H., Wang, W., & Xu, H. (2026). Diagnostic comparisons of PTSD and complex PTSD in clinical adolescents: Detection rates and ACEs as risk factors. European Journal of Psychotraumatology, 17(1), 2685473.

Preprints

Qin, H., Xu, M. J., Wang, J., Wang, W., & Xu, H. (2025). Brain structural underpinnings of the differential effects of threat and deprivation on executive function: A UK Biobank study. medRxiv.

Technical Expertise

📊 Computational & Statistical: Causal machine learning, Mendelian randomization and genetically informed designs, Bayesian estimation, longitudinal and multilevel modeling, and meta-analysis. R, Python, MATLAB, Mplus.

🧠 Human Neuroscience: Structural and functional MRI (FSL, FreeSurfer), EEG/ERP and sleep EEG, targeted memory reactivation (TMR), and TMS.

👁️ Psychophysiology: Fear conditioning paradigms (acquisition, generalization, extinction, return of fear), eye tracking and pupillometry, autonomic recording, and thermal pain paradigms.

🐭 Preclinical: Stereotaxic surgery and craniotomy in C57BL/6 mice, fiber and electrode implantation, whole-cell patch-clamp, in vivo EEG/EMG, fiber photometry, standard behavioral batteries, and Golgi-Cox staining.

🧬 Genomics: GWAS, polygenic risk scores, and sequencing.

🌍 Languages: Mandarin (native), English (fluent).

Research Experience
HKU Psychology PhD Student, The University of Hong Kong (HKU) (Sept 2026–Present)

Doctoral student in the Psychology PhD program at HKU, in Prof. Charlene Lam's lab (see the lab page for project details and participation). My first-year project uses targeted memory reactivation (TMR) during sleep as an intervention for fear and anxiety. It combines fear acquisition, generalization, extinction, and return-of-fear paradigms with sleep EEG (cued reactivation during slow-wave sleep), multimodal psychophysiology (skin conductance, heart rate, blood pressure, respiration, and pupillometry), eye tracking, and follow-up fMRI. I also work with transcranial magnetic stimulation (TMS) and structural and functional MRI. The broader aim is to identify the mechanisms through which an intervention changes fear and anxiety, and the conditions under which those changes hold.
CAS Research Fellow, Chinese Academy of Sciences, Institute of Psychology (June 2025–Aug 2026)

Worked with Dr. Hang Xu and Dr. Weiwen Wang on the neurobiological and psychological impacts of early adversity, and continue to collaborate on several ongoing projects. On the human side, I led multi-method studies on childhood adversity, resilience, and intervention mechanisms across large-scale datasets (UK Biobank), clinical adolescent cohorts, neuroimaging, inflammatory biomarkers, and juvenile intervention trials.

On the animal side, I worked with C57BL/6 mice across a full preclinical pipeline:
Electrophysiology & recording: whole-cell patch-clamp recording, in vivo EEG/EMG, and fiber photometry, including craniotomy and stereotaxic surgery, optical fiber and electrode implantation, tethered recording in freely moving animals, and post-surgical care.
Behavioral phenotyping: sucrose preference, open field, elevated plus maze, novel object recognition, three-chamber social interaction, tail suspension, and forced swim tests.
Molecular & histology: gene sequencing and Golgi-Cox staining for dendritic morphology.
Harvard Research Assistant, Emotion and Psychopathology in Context (EPIC) Lab (Feb 2025–March 2026)

Contributed to a meta-analysis on the role of emotion regulation in mental health across cultural contexts, examining the impact of cognitive reappraisal and expressive suppression on depression, anxiety, and well-being. Work included literature screening, data extraction, data cleaning, and analysis.
Harvard Research Fellow, Lab for Youth Mental Health (Oct 2024-Present)

Engaging in comprehensive research on youth mental health interventions, with a focus on school-based settings. This includes conducting a meta-analysis of approximately 300 studies addressing social, emotional, and behavioral (SEB) problems in K-12 students, such as depression, anxiety, ADHD, and conduct issues. Responsibilities include testing the overall effectiveness of these interventions, analyzing factors that enhance or diminish their outcomes, and examining the relationship between improved mental health and academic performance.
Brandeis Graduate Research Assistant, Brandeis University (June 2023–May 2025)

Completed my master's thesis, "Alcohol as a Predictor of Sexual Aggression Recidivism", using archival data from the Massachusetts Treatment Center. Selected for presentation at ATSA 2025.
CAS Summer Research Assistant, Chinese Academy of Sciences (May 2021-Sept 2021)

At the Chinese Academy of Sciences, Institute of Psychology, I contributed to research on poverty-related psychological issues, female parenting behavior, and the relationship between income and happiness. As part of Dr. Xiufeng Chen's project, I was trained in data collection and entry while also providing support in the analysis and writing process for work that was later published in Applied Research in Quality of Life.
Teaching Experience
Brandeis Graduate Course Assistant, Brandeis University

Developmental Psychology (Fall 2024)
Statistics (Fall 2024)
Introduction to Psychology (Spring 2025)
Statistics with R (Spring 2025)
Industrial Experience
Boston Children's Hospital Psychology Student Intern, Boston Children's Hospital, Pediatric Physicians' Organization at Children's (PPOC) (Aug 2023 – June 2024)

At Boston Children's Hospital, I worked on the front lines of clinical practice, gaining extensive experience in patient-centered care. I led a project to develop a digital tool aimed at enhancing the effectiveness of treatment by fostering stronger connections between clinicians and their patients. Utilizing Umbrella, SurveyMonkey, and Qualtrics, I designed and distributed surveys to clinicians across Massachusetts, collected and cleaned the data using RStudio, and analyzed key priorities for the tool's development.
Awards

Merit Scholarship, Brandeis University, 2023-24

GSAS Grant, Brandeis University, 2023-24

Cum Laude, Brandeis University, 2023

Dean's List, Brandeis University 2021-23


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