I received my BS dual degree in Biology and Psychology from the University of Georgia as part of the Honors Program. There I pursued undergraduate research under the mentorship of L. Stephen Miller Ph.D. on the neural substrates of emotional conflict processing and neuroimaging signatures of traumatic brain injury. After a brief hiatus from the academic world working as a veterinary technician, I enrolled in the San Diego State University/University of California-San Diego Joint Doctoral Program in Clinical Psychology. My primary research mentors were Murray B. Stein, M.D., M.P.H., and Martin P. Paulus, M.D. My graduate research focused on the functional neuroanatomy and developmental determinants of negative valence systems in anxiety and traumatic stress disorders. I also pursued a clinical specialization in the psychotherapeutic treatment of anxiety and traumatic stress disorders through practicum work at the VA San Diego Healthcare System Anxiety Disorders Clinic and PTSD Clinical Team. I received specialized training in Prolonged Exposure (PE) and Eye Movement Desensitization and Reprocessing (EMDR), and I am a certified Level 1 EMDR provider. I completed my clinical internship at the Memphis VA Medical Center and continued to pursue a clinical specialization in the treatment of traumatic stress disorders. There, I completed VA training and certification to deliver Cognitive Processing Therapy (CPT), an empirically-supported cognitive-behavioral treatment for PTSD. Seeking less humidity and greater sunshine, I returned to California in September 2013 to begin a T32 Biobehavioral Research Fellowship in the Department of Psychiatry and Behavioral Sciences at Stanford University School of Medicine under the mentorship of Dr. Amit Etkin. My postdoctoral research encompasses brain imaging approaches to characterizing heterogeneity in posttraumatic stress disorder, establishing neural mechanisms and functional neurophenotypes moderating responses to psychotherapy in PTSD and antidepressant treatment in depression, and investigation of novel computerized cognitive and affective training interventions for individuals with PTSD. My long-term career goal is to understand mechanisms responsible for the emergence, expression, and resolution of trauma and stress-related symptomatology, and to leverage this knowledge towards the refinement of existing treatments and the development of novel treatments and preventative interventions.

Honors & Awards

  • Domestic Travel Fellowship Award, Society of Biological Psychiatry (May 2018)
  • Underrepresented Minority Post-Travel Award Additional Funding, American College of Neuropsychopharmacology (December 2017)
  • Travel Award, American College of Neuropsychopharmacology (December 2016)
  • Top 10 Reviewer (#4) for Neuropsychopharmacology, American College of Neuropsychopharmacology (2015)
  • T-32 Biobehavioral Research Fellowship, Department of Psychiatry, Stanford University School of Medicine (September 2013-August 2015)
  • Alan J. Jaworski Men in Science Award, University of Georgia (2005)
  • Member of Phi Beta Kappa Honors Soceity, Phi Beta Kappa (2004)
  • Cota-Robles Fellowship, University of California-San Diego (2007-2009)
  • Charter Scholarship, University of Georgia (2001-2005)
  • Vice Presidential Scholarship, University of Georgia (2001-2005)
  • James E. Casey Scholarship, National Merit Scholarship (2001-2005)
  • Presidential Scholar, University of Georgia (2001-2005)

Boards, Advisory Committees, Professional Organizations

  • Member, American Psychological Association (2011 - Present)
  • Member, Anxiety and Depression Association of America (2013 - 2014)
  • Member, Society for Neuroscience (2011 - 2012)

Professional Education

  • Doctor of Philosophy, San Diego State University/University of California-San Diego Joint Doctoral Program, Clinical Psychology (2013)
  • Bachelor of Science, University of Georgia, Biology, Psychology (2005)

Stanford Advisors

Community and International Work

  • San Francisco Center for Integrative Anxiety Solutions, 870 Market St, Ste 958, San Francisco, CA 94102


    Anxiety disorders, post-traumatic stress disorder, mood disorders

    Populations Served

    San Francisco Bay Area


    Bay Area

    Ongoing Project


    Opportunities for Student Involvement


Research & Scholarship

Lab Affiliations



All Publications

  • Selective Effects of Psychotherapy on Frontopolar Cortical Function in PTSD AMERICAN JOURNAL OF PSYCHIATRY Fonzo, G. A., Goodkind, M. S., Oathes, D. J., Zaiko, Y. V., Harvey, M., Peng, K. K., Weiss, M., Thompson, A. L., Zack, S. E., Mills-Finnerty, C. E., Rosenberg, B. M., Edelstein, R., Wright, R. N., Kole, C. A., Lindley, S. E., Arnow, B. A., Jo, B., Gross, J. J., Rothbaum, B. O., Etkin, A. 2017; 174 (12): 1175–84
  • PTSD Psychotherapy Outcome Predicted by Brain Activation During Emotional Reactivity and Regulation AMERICAN JOURNAL OF PSYCHIATRY Fonzo, G. A., Goodkind, M. S., Oathes, D. J., Zaiko, Y. V., Harvey, M., Peng, K. K., Weiss, M., Thompson, A. L., Zack, S. E., Lindley, S. E., Arnow, B. A., Jo, B., Gross, J. J., Rothbaum, B. O., Etkin, A. 2017; 174 (12): 1163–74
  • Affective neuroimaging in generalized anxiety disorder: an integrated review DIALOGUES IN CLINICAL NEUROSCIENCE Fonzo, G. A., Etkin, A. 2017; 19 (2): 169–79


    Affective neuroimaging has contributed to our knowledge of generalized anxiety disorder (GAD) through measurement of blood oxygenation level-dependent (BOLD) responses, which facilitate inference on neural responses to emotional stimuli during task-based functional magnetic resonance imaging (fMRI). In this article, the authors provide an integrated review of the task-based affective fMRI literature in GAD. Studies provide evidence for variable presence and directionality of BOLD abnormalities in limbic and prefrontal regions during reactivity to, regulation of, and learning from emotional cues. We conclude that understanding the sources of this variability is key to accelerating progress in this area. We propose that the cardinal symptom of GAD-worry-predominantly reflects stimulus-independent mental processes that impose abnormal, inflexible functional brain configurations, ie, the overall pattern of information transfer among behaviorally relevant neural circuits at a given point in time. These configurations that are inflexible to change from the incoming flux of environmental stimuli may underlie inconsistent task-based findings.

    View details for Web of Science ID 000418014300009

    View details for PubMedID 28867941

    View details for PubMedCentralID PMC5573561

  • Learning in Generalized Anxiety Disorder Benefits From Neither the Carrot Nor the Stick. American journal of psychiatry Etkin, A., Fonzo, G. A. 2017; 174 (2): 87-88

    View details for DOI 10.1176/appi.ajp.2016.16111267

    View details for PubMedID 28142268

  • Brain Connectivity Reflects Mental and Physical States in Generalized Anxiety Disorder BIOLOGICAL PSYCHIATRY Fonzo, G. A., Etkin, A. 2016; 80 (10): 733-735
  • Greater preference consistency during the Willingness-to-Pay task is related to higher resting state connectivity between the ventromedial prefrontal cortex and the ventral striatum. Brain imaging and behavior Mackey, S., Olafsson, V., Aupperle, R. L., Lu, K., Fonzo, G. A., Parnass, J., Liu, T., Paulus, M. P. 2016; 10 (3): 730-738


    The significance of why a similar set of brain regions are associated with the default mode network and value-related neural processes remains to be clarified. Here, we examined i) whether brain regions exhibiting willingness-to-pay (WTP) task-related activity are intrinsically connected when the brain is at rest, ii) whether these regions overlap spatially with the default mode network, and iii) whether individual differences in choice behavior during the WTP task are reflected in functional brain connectivity at rest. Blood-oxygen-level dependent (BOLD) signal was measured by functional magnetic resonance imaging while subjects performed the WTP task and at rest with eyes open. Brain regions that tracked the value of bids during the WTP task were used as seed regions in an analysis of functional connectivity in the resting state data. The seed in the ventromedial prefrontal cortex was functionally connected to core regions of the WTP task-related network. Brain regions within the WTP task-related network, namely the ventral precuneus, ventromedial prefrontal and posterior cingulate cortex overlapped spatially with publically available maps of the default mode network. Also, those individuals with higher functional connectivity during rest between the ventromedial prefrontal cortex and the ventral striatum showed greater preference consistency during the WTP task. Thus, WTP task-related regions are an intrinsic network of the brain that corresponds spatially with the default mode network, and individual differences in functional connectivity within the WTP network at rest may reveal a priori biases in choice behavior.

    View details for DOI 10.1007/s11682-015-9435-z

    View details for PubMedID 26271206

  • Early life stress and the anxious brain: evidence for a neural mechanism linking childhood emotional maltreatment to anxiety in adulthood. Psychological medicine Fonzo, G. A., Ramsawh, H. J., Flagan, T. M., Simmons, A. N., Sullivan, S. G., Allard, C. B., Paulus, M. P., Stein, M. B. 2016; 46 (5): 1037-1054


    Childhood emotional maltreatment (CEM) increases the likelihood of developing an anxiety disorder in adulthood, but the neural processes underlying conferment of this risk have not been established. Here, we test the potential for neuroimaging the adult brain to inform understanding of the mechanism linking CEM to adult anxiety symptoms.One hundred eighty-two adults (148 females, 34 males) with a normal-to-clinical range of anxiety symptoms underwent structural and functional magnetic resonance imaging while completing an emotion-processing paradigm with facial expressions of fear, anger, and happiness. Participants completed self-report measures of CEM and current anxiety symptoms. Voxelwise mediation analyses on gray-matter volumes and activation to each emotion condition were used to identify candidate brain mechanisms relating CEM to anxiety in adulthood.During processing of fear and anger faces, greater amygdala and less right dorsolateral prefrontal (dlPFC) activation partially mediated the positive relationship between CEM and anxiety symptoms. Greater right posterior insula activation to fear also partially mediated this relationship, as did greater ventral anterior cingulate (ACC) and less dorsal ACC activation to anger. Responses to happy faces in these regions did not mediate the CEM-anxiety relationship. Smaller right dlPFC gray-matter volumes also partially mediated the CEM-anxiety relationship.Activation patterns of the adult brain demonstrate the potential to inform mechanistic accounts of the CEM conferment of anxiety symptoms. Results support the hypothesis that exaggerated limbic activation to negative valence facial emotions links CEM to anxiety symptoms, which may be consequent to a breakdown of cortical regulatory processes.

    View details for DOI 10.1017/S0033291715002603

    View details for PubMedID 26670947

  • History of childhood maltreatment augments dorsolateral prefrontal processing of emotional valence in PTSD. Journal of psychiatric research Fonzo, G. A., Huemer, J., Etkin, A. 2016; 74: 45-54


    Posttraumatic stress disorder (PTSD) is characterized by conflicting findings of both increased and decreased amygdala and prefrontal reactivity to threat or trauma stimuli. Childhood maltreatment (CM), a potent risk factor for PTSD, exerts long-lasting influences on threat processing and prefrontal-amygdala function. This suggests that CM history may influence PTSD neural phenotypes related to threat processing. Here, we adapt a well-characterized emotional conflict paradigm to investigate CM effects on both emotional conflict and emotional valence processing within PTSD stratified by task relevance. Forty-two individuals with PTSD (22 reporting extensive CM history (PTSD-CM)) and 20 trauma-exposed healthy controls (TEHCs) underwent functional magnetic resonance imaging while identifying affect of emotional faces (fear and happy) overlaid with a goal-irrelevant emotional distractor word ("FEAR" or "HAPPY"). We examined effects of CM on conflict, conflict adaptation, valence-related activation (fear vs. happy) for goal-relevant (face) and goal-irrelevant stimuli (word), and valence effects in interaction with goal-relevancy (face vs. word). Though no activation differences between groups were observed for conflict contrasts nor for valence effects in the amygdala, CM status interacted with valence processing differences as a function of goal relevance in the left dorsolateral prefrontal cortex (dlPFC). Here, PTSD-CM displayed greater activation relative to PTSD to negative valence when stimuli were goal-irrelevant. CM history also moderated relationships between activation abnormalities and PTSD re-experiencing symptoms. These findings provide initial evidence that CM history augments dorsolateral prefrontal bias to implicitly processed stimulus valence in PTSD.

    View details for DOI 10.1016/j.jpsychires.2015.12.015

    View details for PubMedID 26741277

  • Common and disorder-specific neural responses to emotional faces in generalised anxiety, social anxiety and panic disorders BRITISH JOURNAL OF PSYCHIATRY Fonzo, G. A., Ramsawh, H. J., Flagan, T. M., Sullivan, S. G., Letamendi, A., Simmons, A. N., Paulus, M. P., Stein, M. B. 2015; 206 (3): 206-215


    Background Although evidence exists for abnormal brain function across various anxiety disorders, direct comparison of neural function across diagnoses is needed to elicit abnormalities common across disorders and those distinct to a particular diagnosis. Aims To delineate common and distinct abnormalities within generalised anxiety (GAD), panic and social anxiety disorder (SAD) during affective processing. Method Fifty-nine adults (15 with GAD, 15 with panic disorder, 14 with SAD, and 15 healthy controls) underwent functional magnetic resonance imaging while completing a facial emotion matching task with fearful, angry and happy faces. Results Greater differential right amygdala activation to matching fearful v. happy facial expressions related to greater negative affectivity (i.e. trait anxiety) and was heightened across all anxiety disorder groups compared with controls. Collapsing across emotional face types, participants with panic disorder uniquely displayed greater posterior insula activation. Conclusions These preliminary results highlight a common neural basis for clinical anxiety in these diagnoses and also suggest the presence of disorder-specific dysfunction.

    View details for DOI 10.1192/bjp.bp.114.149880

    View details for Web of Science ID 000351478900006

    View details for PubMedID 25573399

  • Cognitive-behavioral therapy for generalized anxiety disorder is associated with attenuation of limbic activation to threat-related facial emotions. Journal of affective disorders Fonzo, G. A., Ramsawh, H. J., Flagan, T. M., Sullivan, S. G., Simmons, A. N., Paulus, M. P., Stein, M. B. 2014; 169: 76–85


    The neural processes underlying the benefits of cognitive behavioral treatment (CBT) for generalized anxiety disorder (GAD) are not well understood.Twenty-one (n=21) adults with a principal diagnosis of GAD and eleven (n=11) non-anxious healthy controls (HC) underwent functional magnetic resonance imaging while completing a facial emotion processing task. Responses to threat-related emotionality (i.e., the contrast of fear and angry vs. happy faces) were assessed at pretreatment and again following 10 sessions of CBT in the GAD group and a comparable waiting period in the HC group.At pretreatment, GAD participants displayed blunted responses in the amygdala, insula, and anterior cingulate to the happy face-processing comparison condition, and greater amygdalo-insular connectivity. CBT was associated with attenuated amygdalar and subgenual anterior cingulate activation to fear/angry faces and heightened insular responses to the happy face comparison condition, but had no apparent effects on connectivity. Pre-treatment abnormalities and treatment-related changes were not associated with symptoms of worry.There was no active control condition (e.g., treatment waitlist) for comparison of treatment effects.Taken together, these results provide evidence for a dual-process psychotherapeutic model of neural systems changes in GAD in which cingulo-amygdalar reactivity to threat-cues is attenuated while insular responses to positive facial emotions are potentiated. Future work is needed to determine the clinical implications of these changes and their specificity to CBT.

    View details for DOI 10.1016/j.jad.2014.07.031

    View details for PubMedID 25171782

  • Neural functional and structural correlates of childhood, maltreatment in women with intimate-partner violence-related posttraumatic stress disorder PSYCHIATRY RESEARCH-NEUROIMAGING Fonzo, G. A., Flagan, T. M., Sullivan, S., Allard, C. B., Grimes, E. M., Simmons, A. N., Paulus, M. P., Stein, M. B. 2013; 211 (2): 93-103


    Childhood maltreatment (CM) is a strong risk factor for development of posttraumatic stress disorder (PTSD) upon adult exposure to extreme adverse events. However, the neural underpinnings of this relationship are not well understood. Here, we test the hypothesis that severity of CM history is positively correlated with emotion-processing limbic and prefrontal brain activation/connectivity and negatively correlated with prefrontal gray matter volumes in women with PTSD due to intimate-partner violence (IPV-PTSD). Thirty-three women with IPV-PTSD underwent structural and functional magnetic resonance imaging while completing a facial emotion processing task. Multivariate regressions examined the relationship of CM to patterns of activation, connectivity, and gray matter volumes. CM severity was: (a) positively correlated with ventral ACC activation while processing angry faces; (b) negatively correlated with dorsal ACC and insula activation while processing fear and angry faces, arising from positive correlations with the shape-matching baseline; (c) positively correlated with limbic-prefrontal connectivity while processing fear faces but negatively correlated with amygdalo-insular connectivity while processing fear and angry; and (d) negatively correlated with prefrontal gray matter volumes. These results suggest CM exposure may account for variability in limbic/prefrontal brain function and prefrontal structure in adulthood PTSD and offer one potential mechanism through which CM confers risk to future development of PTSD.

    View details for DOI 10.1016/j.pscychresns.2012.08.006

    View details for Web of Science ID 000316828400001

    View details for PubMedID 23154098

  • Red Brain, Blue Brain: Evaluative Processes Differ in Democrats and Republicans PLOS ONE Schreiber, D., Fonzo, G., Simmons, A. N., Dawes, C. T., Flagan, T., Fowler, J. H., Paulus, M. P. 2013; 8 (2)


    Liberals and conservatives exhibit different cognitive styles and converging lines of evidence suggest that biology influences differences in their political attitudes and beliefs. In particular, a recent study of young adults suggests that liberals and conservatives have significantly different brain structure, with liberals showing increased gray matter volume in the anterior cingulate cortex, and conservatives showing increased gray matter volume in the in the amygdala. Here, we explore differences in brain function in liberals and conservatives by matching publicly-available voter records to 82 subjects who performed a risk-taking task during functional imaging. Although the risk-taking behavior of Democrats (liberals) and Republicans (conservatives) did not differ, their brain activity did. Democrats showed significantly greater activity in the left insula, while Republicans showed significantly greater activity in the right amygdala. In fact, a two parameter model of partisanship based on amygdala and insula activations yields a better fitting model of partisanship than a well-established model based on parental socialization of party identification long thought to be one of the core findings of political science. These results suggest that liberals and conservatives engage different cognitive processes when they think about risk, and they support recent evidence that conservatives show greater sensitivity to threatening stimuli.

    View details for DOI 10.1371/journal.pone.0052970

    View details for Web of Science ID 000315970300009

    View details for PubMedID 23418419

  • A meta-analysis of cognitive functioning in older adults with PTSD JOURNAL OF ANXIETY DISORDERS Schuitevoerder, S., Rosen, J. W., Twamley, E. W., Ayers, C. R., Sones, H., Lohr, J. B., Goetter, E. M., Fonzo, G. A., Holloway, K. J., Thorp, S. R. 2013
  • Exaggerated and Disconnected Insular-Amygdalar Blood Oxygenation Level-Dependent Response to Threat-Related Emotional Faces in Women with Intimate-Partner Violence Posttraumatic Stress Disorder BIOLOGICAL PSYCHIATRY Fonzo, G. A., Simmons, A. N., Thorp, S. R., Norman, S. B., Paulus, M. P., Stein, M. B. 2010; 68 (5): 433-441


    Intimate-partner violence (IPV) is one of the most common causes of posttraumatic stress disorder (PTSD) among women. PTSD neuroimaging studies have identified functional differences in the amygdala and anterior cingulate cortex (ACC)/medial prefrontal cortex during emotion processing. Recent investigations of the limbic sensory system and its associated neural substrate, the insular cortex, have demonstrated its importance for emotional awareness. This study examined the hypothesis that women with IPV-PTSD show a dysregulation of this limbic sensory system while processing threat-related emotional faces.12 women with IPV-PTSD and 12 nontraumatized comparison women underwent blood oxygenation level-dependent functional magnetic resonance imaging while completing an emotional face-matching task.IPV-PTSD subjects relative to comparison subjects displayed increased activation of the anterior insula and amygdala and decreased connectivity among the anterior insula, amygdala, and ACC while matching to fearful versus happy target faces. A similar pattern of activation differences was also observed for angry versus happy target faces. IPV-PTSD subjects relative to comparison subjects also displayed increased dorsal ACC/medial prefrontal cortex activation and decreased ventral ACC activation when matching to a male versus a female target, and the extent of increased dorsal ACC activation correlated positively with hyperarousal symptoms.Women with IPV-PTSD display hyperactivity and disconnection among affective and limbic sensory systems while processing threat-related emotion. Furthermore, hyperactivity of cognitive-appraisal networks in IPV-PTSD may promote hypervigilant states of awareness through an exaggerated sensitivity to contextual cues, i.e., male gender, which relate to past trauma.

    View details for DOI 10.1016/j.biopsych.2010.04.028

    View details for Web of Science ID 000281126800006

    View details for PubMedID 20573339

  • Transverse patterning dissociates human EEG theta power and hippocampal BOLD activation PSYCHOPHYSIOLOGY Meltzer, J. A., Fonzo, G. A., Constable, T. R. 2009; 46 (1): 153-162