Our research primarily focuses on identifying pathophysiological mechanisms in the central and autonomic nervous systems that contribute to negative symptoms in schizophrenia. Historically, this has involved studies examining reward processing and cognition-emotion interactions. We are exploring the overarching hypothesis that dysfunctional cortico-striatal interactions prevent intact hedonic responses from guiding decision-making processes needed to initiate goal-directed activity in schizophrenia.
We have been involved with the development of two next-generation clinical rating scales (Brief Negative Symptom Scale; Prodromal Inventory of Negative Symptoms) designed to assess negative symptoms in schizophrenia. We are currently testing the reliability and validity of mobile technology for assessing negative symptoms via the Ecological Momentary Assessment approach.
In collaboration with colleagues, we have conducted a series of studies examining the efficacy of oxytocin as a treatment for negative symptoms of schizophrenia.
Most recently, we have started exploring pathophysiological mechanisms contributing to negative symptoms in youth at clinical high-risk for developing a psychotic disorder (i.e., those with a prodromal syndrome).
Schizophrenia is associated with a generalized neurocognitive deficit (i.e., performing 1 standard deviation below the general population on a range of cognitive domains). We are currently exploring a novel "motivational" hypothesis of the generalized deficit as resulting from dysfunctional neural processes underlying cognitive effort. We are using computational modeling in combination with pupil dilation, EEG, and fMRI to index cognitive effort.
We are using multiple methods (EEG, eye tracking, pupillometry, ECG, EMA) to explore different phases of the emotion regulation process (identification, selection, implementation, monitoring) and pathophysiological mechanisms contributing to difficulty up and down-regulating positive and negative emotions in schizophrenia and youth at clinical high-risk for psychosis.
Our fMRI studies are conducted at UGA's Biomedical Imaging Research Center (BIRC): https://birc.uga.edu/. The BIRC houses a state-of-the-art, General Electric 16-channel fixed-site Signa HDx 3.0 Tesla Magnetic Resonance Imaging (MRI) magnet. The magnet makes available multiple magnetic resonance imaging techniques including magnetic resonance imaging for structural tissue imaging (MRI), functional neuroimaging (fMRI) for studies of brain activation in real time, magnetic resonance spectroscopy (MRS) for the study of chemical changes in the brain, and magnetic resonance angiography (MRA) for the study of vascular changes throughout the system. Multinuclear spectroscopy (MNS) is available for enhanced spectroscopic studies and includes phosphorous-31.
We use EEG to examine the time-course of neural activity in relation to various emotional and cognitive processes. EEG involves recording electrical activity along the scalp. EEG measures voltage fluctuations resulting from ionic current flows within neurons. In our studies, we have primarily been interested in Event Related Potentials (ERPs), which are averaged EEG responses that are time-locked to stimuli in an experiment. For example, we have examined time-locked response to pleasant, unpleasant, and neutral images to explore the time-course of affective response in people with schizophrenia compared to controls. Our EEG studies are conducted within our laboratory in the Psychology Department. We have a 64-channel Brain Vision ActiChamp System.
We use eye-tracking to measure the role of visual attention in various cognitive and emotional processes. We do this by measuring point of gaze or motion of the eyes relative to the head and a stimulus presented on the computer screen using an eye-tracker. The eye-tracker monitors the position of the pupil, pupil size, and corneal reflection as a participant views images on the screen. We have used eye-tracking to explore individual components of attention and how they interact with emotional vs. neutral stimuli in people with schizophrenia and controls. We are also interested in how pupil dilation is impacted by various manipulations of emotion and cognitive load. Our lab has two SR Research Eyelink 1000 systems that are used to measure attentional allocation and pupil dilation. This desktop mounted system allows for a remote and headfree evaluation of eye-movements at a very high sampling rate. We also interface EEG/ERPs and eye-tracking in the lab and fMRI and eye tracking at the BIRC.
We use the wireless Bionomadix recording system from Biopac to examine facial electromyography, respiration, heart rate, and skin conductance. These psychophysiological measures allow us to explore the timecourse of psychophysiological response in relation to emotional reactivity and emotion regulation tasks, as well as the coherence between subjective, neural, and peripheral psychophysiological response when used in conjunction with our other measures. We use the wireless bionomadix system in our studies involving social interaction, as well as more traditional computerized laboratory paradigms examining emotion.
We use EMA to explore real-world reports of emotion and behavior. Participants are asked to carry a smart phone and wear a digital band that collects psychophysiology for several days in the context of everyday life. Participants report their current activities, as well as their emotional experience during those activities at several points throughout the day. We are using EMA to explore hypotheses related to the symptom of anhedonia in schizophrenia, as well as emotion regulation. EMA provides a more ecologically valid look into the emotional lives of people with and without schizophrenia.
We obtain salivary and blood samples to test hypotheses related to neuroendocrine (e.g., cortisol) and immune (cytokines) function in relation to task performance. Salivary samples are obtained and stored in a -40 freezer located in our lab in the Psychology building. Blood samples are obtained and stored at the BIRC on UGA's main campus or the Clinical Translational Research Unit on the UGA Medical School campus.
1. R21- MH112925 (PI GP Strauss) 04/01/2017- 03/31/2019 NIMH $275,000 Modeling anhedonia in schizophrenia: A stochastic dynamical systems approach This grant applies mathematical models to ecological momentary assessment data to test novel theories about anhedonia reflecting abnormalities in the temporal dynamics of emotion in schizophrenia. Role: PI
2. University of Georgia (PI GP Strauss) 10/15/2017-6/30/2018 Clinical Translational Research Unit Pilot Grant $25,200 The Effects of Inflammation on Neurocomputationally Derived Reinforcement Learning Profiles in Schizophrenia This grant examines whether cytokines predict computationally derived measures of reinforcement learning in schizophrenia to index the contributions of inflammation to negative symptoms.
3. University of Georgia (PI GP Strauss) 11/01/2017-06/30/2017 Owens Institute for Behavioral Research Pilot Grant $10,000 Neurocomputational Models of Reinforcement Learning in Youth at Clinical High-Risk for Psychosis The study examines a computational neuroscience framework for understanding delusions and avolition in youth at clinical high-risk for psychosis using computational models of reinforcement learning.
4. NSF Graduate Research Fellowship (PI: KH Frost) 08/31/2015-08/30/2018 National Science Foundation $105,600 The Effects of Acute Social Stress on Reward Processing in Humans This mentored grant examines sex differences in the effects of acute social stress on reward processing in humans, including implicit reinforcement learning, prediction error signaling, value representation, reward anticipation, reward consummation, effort-cost computation, and action selection. Role: Mentor
1. R34-MH100362 (PI: RW Buchanan) 3/31/14 – 3/31/2016 NIMH $191,875 Combined Oxytocin and CBSST for Social Function in People with Schizophrenia The study examines the efficacy of oxytocin combined with cognitive behavior therapy social skills training (CBSST) at improving social outcome in people with schizophrenia. Role: Co-Investigator
2. Wechsler Early Career Grant for Innovative Work in Cognition 10/01/2015-2/30/2017 American Psychological Foundation (APF) $25,000 A Cognitive Neuroscience Account of Low Cognitive Effort in Schizophrenia This grant explores a novel account of low effort in schizophrenia as resulting from failure to detect cognitive demands and adjust effort levels accordingly to maximize cognitive performance. Role: PI
3. Interdisciplinary Collaborative Grant (PI: GP Strauss) 05/01/2015 – 12/30/2016 State University of New York $10,000 Using Network Analysis to Explore the Temporal Dynamics of Emotion in Schizophrenia. This study uses network analysis to Ecological Momentary Assessment data in people with schizophrenia to determine whether anhedonia reflects abnormal temporal dynamics of emotional experience. Role: PI
4. Transdisciplinary Areas of Excellence Grant (PI: GP Strauss) 05/01/2015-12/30/2016 State University of New York $20,000 Predicting Conversion to Psychosis in At-Risk Youth: The Role of Stress-Inflammation Interactions. The study examines whether biomarkers of stress and inflammation following an acute social stressor predict symptoms of attenuated psychosis and conversion to a psychotic disorder in at-risk youth. Role: PI
5. K23-MH092530 (PI: GP Strauss) 09/08/10 – 09/30/2015 NIMH $796,699 Motivated Attention and Avolition in Individuals with Schizophrenia The study examines early emotion processing abnormalities in schizophrenia, and attempts to identify precise cognitive mechanisms that contribute to abnormal attention-emotion interactions in schizophrenia. Career development activities include training in Event Related Potential and Eye-Tracking technology, as well as the theoretical basis of cognitive/affective neuroscience. Role: PI
6. Department of Veterans Affairs (PI: GP Strauss) 10/01/2011 –09/30/2013 MIRECC VISN 5 $50,000 Oxytocin and Social Cognition in Schizophrenia The study examined the role of the oxytocin receptor gene and plasma oxytocin levels in deficits in social cognition, emotional experience, emotion perception, and emotional memory in people with schizophrenia. Role: PI
7. Department of Veterans Affairs (PI: GP Strauss) 10/01/2012 –09/30/2013 MIRECC VISN 5 $25,000 A Study of Subjective Emotional Experience and Emotion Regulation in Schizophrenia using an Experience Sampling Approach The study used experience sampling methodology to examine differences in prospective, retrospective, and in-the-moment reports of positive and negative emotion in people with schizophrenia and healthy controls, as well as the effectiveness of various emotion regulation strategies in the context of every-day life. Role: PI
8. Department of Veterans Affairs (PI: GP Strauss) 10/01/2010 –09/30/2011 MIRECC VISN 5 $25,000 Cognitive Behavioral Social Skills Training to Enhance Consumer Recovery in Schizophrenia The study examined the efficacy of Cognitive Behavioral Social Skills Therapy enhanced with new techniques that foster optimism, hope, mastery, empowerment, and self-esteem for consumer-oriented recovery in schizophrenia. Role: PI
9. T32-MH067533 (PI : WT Carpenter) 07/01/2010-06/30/2015 NIMH $106,515 Multidisciplinary Schizophrenia Research Training The major goals of the project are to provide young investigators with research training in schizophrenia research to facilitate their goals of becoming an independent investigator. Role: Co-Investigator
10. P50-MH082999 (PI: WT Carpenter) 07/01/10- 09/30/10 NIMH $1,999,879 MPRC Centers for Intervention Development and Applied Research (CIDAR) This application proposes to establish a Center for Intervention Development and Applied Research (CIDAR) in response to PAR-05-039. Its focus will be to advance drug discovery using innovative evaluation platforms and testing drugs with novel molecular targets to address negative symptoms and cognitive impairments in schizophrenia. Role: Co-Investigator