Research

Pathophysiology of Negative Symptoms

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. Most recently, we have been exploring whether these same abnormalities predict negative symptoms in youth at clinical high-risk for psychosis.

Assessment of Negative Symptoms

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.  

Treatment of Negative Symptoms

In collaboration with colleagues, we have conducted a series of studies examining the efficacy of oxytocin as a treatment for negative symptoms of schizophrenia. 

Our Methods

Electroencephalography (EEG)

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 two 64-channel Brain Vision ActiChamp Systems. 

Eye Tracking

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.  

Functional Magnetic Ressonance Imaging (fMRI)

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.  

Psychophysiology

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.  

Ecological Momentary Assessment

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.   

Blood Draw/Saliva

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.   

Grant Funding

National Institute of Mental Health

National Science Foundation

Brain & Behavior Research Foundation

American Psychological Foundation

VA MIRECC

UGA Internal

ACTIVE 

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.   NARSAD Young Investigator Grant (PI GP Strauss)  01/15/2019-01/15/2021

Brain & Behavior Research Foundation  $70,000

Neurocomputational models of psychosis risk

This grant uses computational modeling approaches to examine mechanisms underlying positive and negative symptoms involved with conversion to a psychotic disorder in youth at clinical high-risk for psychosis.

Role: PI


3. University of Georgia (PI GP Strauss) 10/15/2017-6/30/2019 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. 

Role: PI 


COMPLETED

  

1. 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.

Role: PI


2. 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


3. R34-MH100362 (PI: RW Buchanan)  3/31/13 – 3/31/2016  

NIMH    $690,750

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


4. 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


5. 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


6. 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


7. 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


8. 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


9. 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


10. 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


11. 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


12. P50-MH082999 (PI: WT Carpenter) 09/01/08- 08/31/12  

 NIMH   $9,708,330

 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