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UC Davis MIND Institute

UC Davis MIND Institute

Research Team

Translational Psychophysiology and Assessment Laboratory (T-PAL)

T-PAL Lab Team


David Hessl, Ph.D.

David Hessl, Ph.D.
Principal Investigator

Dr. David Hessl is currently the director of the Translational Psychophysiology and Assessment Laboratory (T-PAL).  His research focuses on genetic, brain, environmental and neuroendocrine factors affecting cognition and behavior in individuals with fragile X-associated disorders. One important focus of the work in T-PAL is to develop and evaluate novel behavioral, cognitive and psychophysiological outcome measures of individuals with neurodevelopmental disorders.  These measures are designed to be used to detect improvement in functioning within controlled treatment trials.  Current psychophysiological studies have examined abnormalities in social gaze, sensorimotor gating, sympathetic nervous system activity, hypothalamic-pituitary-adrenal axis function, and potentiated startle responses.  Other recent studies have been aimed at improving aberrant behavior and cognitive measurements in individuals with fragile X syndrome, autism spectrum, intellectual disabilities, and other neurodevelopmental disorders.  A second major focus of Dr. Hessl’s work is the study of premutation carriers of fragile X.  As children these individuals are at increased risk for attention deficit hyperactivity disorder and autism and as older adults they become at risk for a neurodegenerative disease involving tremor, ataxia, and dementia.  Dr. Hessl (in collaboration with Dr. Susan Rivera) directs an NIMH-funded project examining genetics and the brain’s limbic system underlying emotional and psychiatric symptoms in men and women with the premutation.

Dr. Hessl earned his Ph.D. in clinical psychology from the University of Washington where his work focused on emotional and brain development in infants of depressed mothers under the supervision of Geraldine Dawson, Ph.D. He went on to a clinical internship at the Department of Psychiatry and Behavioral Sciences and the Lucile Packard Children's Hospital at Stanford University.  He also completed a MacArthur postdoctoral fellowship in psychophysiology under the supervision of W. Thomas Boyce, M.D. at the Institute of Human Development at UC Berkeley. His training continued at the Behavioral Neurogenetics Research Center at Stanford where he began his work on gene-brain-behavior studies in fragile X syndrome with Allan Reiss, M.D. He obtained an NIMH Career Development Award (K23) to examine the association between anxiety and autism symptoms in children with fragile X syndrome and the physiology underlying social anxiety problems such as gaze avoidance in these individuals.  Dr. Hessl is a licensed psychologist and his clinical interests involve cognitive, emotional, and behavioral evaluation of children, adolescents and adults with neurodevelopmental disorders, fragile X syndrome, autism spectrum disorders, ADHD, learning disabilities, and Tourette's syndrome. He conducts collaborative studies with researchers from several disciplines, including neuroscience, molecular genetics, and neuropathology in an effort to understand links between genetics, brain function and behavior.


Cindy Johnston, M.S., CGC

Cindy Johnston, M.S., CGC
Staff Research Associate IV

Cindy Johnston is a board-certified Genetic Counselor currently focusing her research efforts on the investigation of clinical characteristics associated with the fragile X premutation.  After receiving her Bachelor of Science in Psychology from Brown University, she gained five years of experience as a Research Coordinator at the Behavioral Neurogenetics Research Center at Stanford University.  It was here that she discovered her passion for fragile X syndrome as she studied factors influencing brain development and outcome in children with fragile X.  At this time, she also became particularly interested in examining the fragile X premutation, and first-authored an early publication demonstrating psychiatric symptoms in women with CGG repeats over 100.  After earning her Master’s degree in Genetic Counseling at the University of Colorado in 2006, Cindy worked primarily as a pediatric genetic counselor at University of California, San Francisco.  In clinical settings, she has focused on the counseling, management, and treatment of patients with inborn errors of metabolism.  Cindy’s long-term curiosity in the characterization of the premutation phenotype, along with her interest in treatment advances for FMR1-associated disorders, has brought her back to research and the fragile X community. 


Stephanie Sansone 

Stephanie Sansone
Graduate Student Researcher

Stephanie Sansone is currently a third year doctoral student in Human Development. She graduated in the spring of 2007 with a BS in Biological Sciences from the University of California, Irvine (UCI). While attending UCI, she was part of a research team focused on understanding the relationship with reading difficulties and Attention-Deficit/Hyperactivity Disorder. In 2011, Ms. Sansone was the recipient of the National Science Foundation (NSF) Graduate Research Fellowship and the UC Davis Graduate Research Mentorship Fellowship.  She joined Dr. David Hessl’s T-PAL research team in the summer of 2010, in which she has coordinated a multi-site collaboration to examine the psychometric properties of the Aberrant Behavior Checklist in a large population of individuals with fragile X syndrome.  The results of the study supported a modified fragile X-specific scoring algorithm that has been important in the interpretation of the outcome data in several ongoing and completed treatment trials. Her current research uses a gene-environment interaction approach to examine (1) the increased susceptibility of some women with the fragile X permutation to develop autoimmune-related diseases, and (2) cortisol as a possible biological mechanism underlying this phenomenon.


Andrea Schneider, Ph.D. 

Andrea Schneider, Ph.D.
Assistant Researcher

Dr. Andrea Schneider is an Assistant Researcher at the University of California at Davis, MIND Institute.  From very early on in her academic career, she focused on interdisciplinary research with brain-behavior interactions and acquired broad knowledge in clinical psychology and medical neuroscience, with specific training and expertise in ADHD, learning disabilities, and fragile X.  As a graduate student, she studied the neurophysiological bases of ADHD (Attention-Deficit and Hyperactivity-Disorder) and dyslexia.  Being also a clinical psychologist, her other area of interest is intervention research.  She completed a pilot study of a phytopharmacological intervention (Ginkgo biloba) in dyslexia, and a study about the efficacy of neurofeedback in ADHD.  Currently, her main research interest is the association between genetic and brain abnormalities underlying the neuropsychopathology, behavioral, and psychiatric symptoms in individuals with the fragile X mutations and the development of EEG as an outcome measure for targeted treatment trials.  She is an active member of the Social Skills Program at the MIND Institute since 2008.  She is an affiliate of the ARTP (Autism Research and Treatment) program at the MIND Institute, a member of the FENS (Federation of European Neuroscience Society), and the Center for Cognitive Studies, University Potsdam, Germany.  

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