Trainee Research Descriptions


Undergraduate Fellows

Matthew Rubin
Emory College Senior

I am a senior at Emory majoring in Economics and Math with a minor in History. For my Honors Thesis, I am researching ways to use economic incentives to induce more honest self-reporting. Specifically, I am pursuing this by looking at the neural pathways of emotion, and whether the brain processes identities of people based on their actions or their attributes. I am working under the supervision of Dr. Gregory Berns with assistance from Dr. Michael Prietula and Dr. Monica Capra.

Since receiving the fellowship, I have designed a behavioral questionnaire and had 10 subjects complete this. I ran various statistical analyses on this data to identify groupings of adjectives and verbs that account for the variance in responses. After scanning two members of my research team, I compared these groupings to the brain activation data and created contrast models to locate Regions of Interest (ROIs) in my subjects. I am currently researching Multi-Voxel Pattern Analysis, a statistical method to investigate the representational content of regions (instead of just looking at the involvement of different regions), and will begin implementing this analysis on my two subjects at the end of August. After the MVPA, I plan to recruit more subjects and compare their behavioral responses to their brain activation patterns.

Mentors: Drs. Greg Berns and Monica Capra

Ryan Makinson
Emory College Senior

This summer, I helped to characterize the emotional reactivity of my subjects through standardized testing procedures. This included the approach-avoidance test (A/A) which presents novel objects that vary in degree of threatening qualities. In the A/A test, subjects are placed in a test-cage and presented with objects within tactile reach. Each object was presented for 5min in a stimulus presentation box directly in front of the cage. Objects included a cup, a plastic bear with large eyes, a coiled rope, a rubber snake, a large yellow ball and a pink pig that moves and makes noises. A jelly bean was placed in front of the object for each trial requiring the subject to actively reach into the box to retrieve it. All tests were digitally recorded in 30-minute intervals and later quantified using an established ethogram designed to assess a range of behaviors in rhesus monkeys, including anxiety and fear-related behaviors. The responses were summarized and analyzed via repeated measures ANOVA statistical approach.

Puberty represents a critical and vulnerable period of time for proper emotional and neurological development. In females, the onset of puberty initiates the release of estradiol (E2): an important sex hormone in females that contributes to the maturation of brain regions important for emotional regulation. Pre-pubertal psychosocial stressors, however, could compromise this development by delaying the release of E2. Furthermore, genetic predisposition can exacerbate the effects of adverse environmental conditions placing these individuals at increased risk for developing psychiatric disorders. Together, this ongoing investigation is exploring how hormonal, genetic and environmental interactions combine to influence emotional development and brain maturation in female adolescent rhesus monkeys.

Mentors: Drs. Mark Wilson and Mar Sanchez


Graduate Fellows

Andrew Brooks
Third Year Graduate Student, Graduate Division of Biological and Biomedical Sciences, Program in Neuroscience

Research Description: My interests lie at the interface between behavioral finance, economics, and neuroscience. More specifically, I'm interested in how brain structures involved in decision making encode information about financial choices, and how these choices are affected by hormonal signals.

Mentors: Drs. Greg Berns and Monica Capra

Ming-fai Fong
Third Year Graduate Student, Graduate Division of Biological and Biomedical Sciences, Program in Neuroscience

Neural networks are dynamical systems that can function in a variety of behavioral contexts. Individual cells within these networks can regulate their own excitability in order to keep overall network activity within a healthy dynamic range. I am developing new electrophysiological approaches for examining the mechanisms by which these cells compensate for aberrant or pathological network activity.

Since receiving this award, I have completed several concurrent patch clamp + multielectrode array recordings using the rig I built (described in my proposal). I have also designed a perfusion system for the recording chamber in order to allow for fast switching between pharmacological agents. I am currently writing software for automatic detection and sorting of postsynaptic currents.

Mentors: Drs. Peter Wenner and Steve Potter


Postdoctoral Fellows

Alexandre Franco
Postdoctoral Fellow in Department of Psychiatry & Behavioral Sciences

Dr. Franco is primarily interested in developing methods to analyze allocation of resources in the human brain. He is also interested developing signal processing methods to analyze functional MRI data.

This has been my first year in Dr. Mayberg's lab, where the main focus is the study of clinically depressed patients through brain imaging. In this first year of the postdoctoral position I have been responsible on reevaluating and developing novel methods to analyze Functional MRI (FMRI) data acquired from patients and healthy controls. In this context, I have been responsible for developing and implementing both standard and novel analyses of baseline data for a project on deep brain stimulation, and have been supervising and training two neuroscience graduate students on basic and advanced signal/imaging processing methods. I have been attending weekly meetings at the BITC and CBIS enhancing the collaboration between these labs with Dr. Mayberg's lab.

Prior to arriving to the lab, a large dataset (N>300 patients) of FMRI data had been acquired, and the plan was that these data would be used for my project. However, it was discovered that most of the data contained an imaging acquisition error. With the joint help of Dr. Xiaoping and his lab members, we were able to detect the source of the error and through statistical and signal processing techniques I developed a method to correct these corrupted data (paper currently being written).

The resource allocation model proposed for the fellowship using task data has been presented at an OHBM (organization for human brain mapping), and was received with great enthusiasm (full manuscript is under review by other co-authors). In order to extend the model to resting state data, I have developed a new dynamic method to evaluate resting state functional connectivity, which looks at changes in connectivity of the brain in a 7.5 minute period. More specifically, we are observing the difference in the dynamics of resting state networks between patients and controls (poster will be presented in September at the International Resting State Brain Connectivity conference).

Furthermore, I have helped on organizing the infrastructure for storing large imaging datasets using XNAT. This will facilitate for data sharing with collaborating labs and also facilitate the transition of future lab members. Finally, I have also been advising other Emory researches on data processing techniques.

Mentors: Drs. Helen Mayberg, F. Dubois Bowman and Xiaoping Hu

Wendy Hasenkamp
Postdoctoral Fellow in Departments of Psychology and Psychiatry & Behavioral Sciences

My research interests center around understanding how meditation may lead to improved mental and physical health. Specifically, my goal is to understand which brain networks may be altered with repeated practice, and whether these changes are related to increased well-being in people who meditate. I use functional magnetic resonance imaging (fMRI) technology to investigate these questions, and am developing methodology to incorporate first-person subjective information into analysis of brain imaging data. I am currently exploring the neural correlates and temporal dynamics of changing brain states (such as mind-wandering and focused attention) that are experienced during meditation.

Activities since receiving the fellowship: I have finished running subjects and data analysis for Aim 1 of my project. I have presented this work at two conferences and have submitted a manuscript for publication to NeuroImage. Another peripheral publication is under review from this project at NeuroImage as well. I am currently working on writing a K99/R00 grant to extend my work and transition to independence after this fellowship terminates. I am also working on an R21 grant with my mentor.

Mentors: Drs. Larry Barsalou, Charles Raison, John Dunne and Erica Duncan

Paul J. Marvar
Postdoctoral Fellow in Department of Cardiology

Title:  Stress-induced hypertension and the role of the neuroimmune system
Project Summary:  Psychological stress, hypertension and inflammation have been linked to cardiovascular disease progression, however the central and peripheral mechanisms are unclear. The adaptive immune response, in particular T lymphocytes have been shown to play an important role in the pathophysiology of hypertension and more recently in psychological stress and depression related disabilities. Our studies are designed to investigate the role of the adaptive immune response in stress-induced hypertension and to further characterize the underlying neurocircuitry in the forebrain. The central nervous system (CNS) plays an essential role in the regulation of blood pressure and has long been known to have bi-directional communication with the immune system. This project tests the hypothesis that stress induced changes in blood pressure and peripheral adaptive immunity are linked to specific neurohormonal stress circuits in the forebrain. These studies will provide additional insight regarding the central and peripheral mechanisms linking stress, hypertension and inflammation.

Mentors: Drs. David Harrison, Kerry Ressler and C. Weyand