I received a bachelors of science 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 as well as functional 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 function in anxiety and traumatic stress disorders. I 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 he I am a certified 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, neural mechanisms underlying the therapeutic effects of prolonged exposure therapy, and investigation of novel computerized cognitive and affective training interventions for veterans with PTSD. My long-term career goal is to define the emotional valence-related neural 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

  • Cota-Robles Fellowship, University of California-San Diego (2007-2009)
  • Alan J. Jaworski Men in Science Award, University of Georgia (2005)
  • Member of Phi Beta Kappa Honors Soceity, Phi Beta Kappa (2004)
  • Presidential Scholar, University of Georgia (2001-2005)
  • James E. Casey Scholarship, National Merit Scholarship (2001-2005)
  • Vice Presidential Scholarship, University of Georgia (2001-2005)
  • Charter Scholarship, University of Georgia (2001-2005)

Boards, Advisory Committees, Professional Organizations

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

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

Lab Affiliations

Journal Articles

  • Common and disorder-specific neural responses to emotional faces in generalised anxiety, social anxiety and panic disorders. The British journal of psychiatry : the journal of mental science Fonzo, G. A., Ramsawh, H. J., Flagan, T. M., Sullivan, S. G., Letamendi, A., Simmons, A. N., Paulus, M. P., Stein, M. B. 2015


    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 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


  • Disruption of limbic networks in anxiety shaped by childhood emotional maltreatment: Generalizable pattern of dysfunction while processing threat-related emotional faces

    Time Period


    Presented To

    Anxiety and Depression Association of America


    Baltimore, MD

  • Childhood maltreatment is associated with anterior insula response to social cues of fear in women with intimate-partner violence PTSD

    Time Period


    Presented To

    Society for Neuroscience


    San Diego, CA

  • Common and specific limbic dysfunction in generalized anxiety, social anxiety, and panic disorders during emotional face processing

    Time Period


    Presented To

    Society of Biological Psychiatry


    San Francisco, CA