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 primarily 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. 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, Down syndrome, autism, 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 (the fragile X-associated tremor ataxia syndrome, FXTAS). Dr. Hessl (in collaboration with Dr. Susan Rivera) directs an NIMH-funded project examining the trajectory of changes over time in brain structure, neuropsychology, and neurological/motor functioning in these FMR1 premutation carriers.

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, including 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.

Andrew Dakopolos, Ph.D., M.A., M.S.

Andrew DakopolosDr. Andrew Dakopolos is postdoctoral scholar in the T-PAL lab, primarily working on the Cognitive Test Battery for Intellectual Disabilities (Toolbox) Study. Andy received his Ph.D. from Teachers College, Columbia University with a focus in Intellectual Disability and Autism. He also holds an MS in Applied Statistics from Teachers College, as well as an MA in Teaching from Willamette University. Andy’s background is in education, and he has over 10 years of experience teaching special education and working with graduate-level special education teacher candidates in Oregon, Los Angeles, New York City, and San Francisco. His research interests include cognitive measurement and assessment, executive function, emotion regulation, and early social communication in children with autism and other developmental and intellectual disabilities. 

Andrea Drayton, B.S.

Andrea DraytonStaff Research Associate
Andrea Drayton received her Bachelor's of Science in Cognitive Science from UC Merced in 2015. She has been a member of the T-PAL team since 2016, and is currently assisting with the FXCRC FORWARD study and the Cognitive Testy Battery in Intellectual Disabilities study. She is interested in neurodevelopmental disabilities and language. She plans to pursue a Master's degree in Speech-Language Pathology.

Jessica Famula, M.S.

Jessica Famula, M.S. , M.S., CGCStaff Research Associate
Jessica Famula is the clinical research coordinator for the Longitudinal Study of Brain and Cognition in Fragile X Premutation Carriers. She holds a Bachelor’s degree in Cognitive Science from the University of California, San Diego and a Master’s degree in Cognitive Science and Language from the University of Barcelona. She has been a member of the fragile X research team at the MIND Institute since 2011, during which time her work has focused on human development both in infants (Newborn Screening for Fragile X and Family Follow Up) and adults (Longitudinal Study of Brain and Cognition in Fragile X Premutation Carriers). Jessica is pursuing a career in research and her main area of interest is psycholinguistics.

Jessica Johnston, MPH

Jessica JohnstonJessica Johnston is the clinical research coordinator for the Cognitive Test Battery for Intellectual Disabilities (Toolbox) study. Prior to joining the T-PAL team, she received her Bachelor’s degree in Psychology and Master’s degree in Public Health (MPH), both from UC Davis. Jessica’s research interests include adaptive functioning, reducing health disparities for individuals with intellectual and developmental disabilities, and promoting well-being in families/caregivers of individuals with intellectual and developmental disabilities.

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.  

Rebecca Shields, M.S.

Rebecca ShieldsGraduate Student
Rebecca is currently a graduate student in the Human Development Ph.D. program at UC Davis working with Dr. Hessl. She holds a Master's degree in Child Development and has been a member of T-PAL since 2014. She coordinates the multi-site Cognitive Test Battery in Intellectual Disabilities study. Her research interests are in cognitive assessment and measurement, executive function, and heart rate variability in neurodevelopmental disorders.