Principal Investigators //
- Corey Hill Allen, PhD >
- Nathaniel Anderson, PhD >
- Felicha Candelaria-Cook, PhD >
- Arvind Caprihan, PhD >
- Aparna Gullapalli, PhD >
- Carla Harenski, PhD >
- Jon Houck, Ph.D. >
- Kent A. Kiehl, PhD >
- Jeffrey D. Lewine, PhD >
- J. Michael Maurer, PhD >
- Andrew R. Mayer, PhD
- John Phillips, MD >
- Sephira Ryman, PhD, MS >
- Julia M. Stephen, PhD >
- Andrei Vakhtin, Ph.D. >
- Claire E. Wilcox, MD >
Andrew R. Mayer, PhD
Director, 3T Core
Vice President of Interdisciplinary Science
Professor of Translational Neuroscience
The Mind Research Network
Adjunct Associate Professor of Neurology and Psychiatry
University of New Mexico Health Science Center
Dr. Mayer’s research primarily focuses on using multimodal neuroimaging and other biomarkers to systematically examine the pathophysiology of traumatic brain injury in Veterans, civilian adults, children, and preclinical models. His lab was one of the first to serially assess the natural course of recovery following mild traumatic brain injury from the sub-acute to chronic phase for biomarkers of diffusion, cerebral vascular reactivity and functional connectivity (March 2016 issue of The Economist). He has also examined the impact of repetitive head injuries in mixed martial artists and collegiate athletes. Dr. Mayer currently has two large grants from the National Institutes of Health to examine how concussion affects youth up to one year post-injury. More recently, Dr. Mayer has teamed up with several other investigators to examine how neuromodulation may reverse some of the neurobehavioral and pathophysiological deficits following head injury in Veterans through funding from the Department of Defense.
Dr. Mayer has a longstanding interest in understanding the attentional architecture of the brain across a number of other neuropsychiatric conditions (psychotic spectrum disorders and substance abuse), especially for the processing of multisensory information. He also works on the development and application of cutting-edge neuroimaging techniques, such as multi-modal data fusion techniques and advanced modeling of the hemodynamic response function. As director of the 3T Core, Dr. Mayer works with other investigators to ensure that MRN’s state-of-the-art resources are available to support cutting edge research here in New Mexico.
For more information on Dr. Mayer, please refer to his Curriculum Vitae.
Selected Publications //
- Neuroimaging Biomarkers of New-Onset Psychiatric Disorders Following Traumatic Brain Injury. >
- Comparison of Methods for Classifying Persistent Post-Concussive Symptoms in Children >
- Survival Rates and Biomarkers in a Large Animal Model of Traumatic Brain Injury Combined With Two Different Levels of Blood Loss. >
- Proactive inhibition deficits with normal perfusion after pediatric mild traumatic brain injury >
- Advanced Biomarkers of Pediatric Mild Traumatic Brain Injury: Progress and Perils >
- Recovery of cerebral blood flow following sports-related concussion >
- Diffusion tensor imaging findings in semi-acute mild traumatic brain injury. >
- Impact of analysis methods on the reproducibility and reliability of resting-state networks. >
- A functional MRI study of multimodal selective attention following mild traumatic brain injury >
- Head injury or head motion? Assessment and quantification of motion artifacts in diffusion tensor imaging studies >
- The spectrum of mild traumatic brain injury: A review >
- Longitudinal assessment of white matter abnormalities following sports-related concussion >
- Functional magnetic resonance imaging of mild traumatic brain injury >
- Functional Imaging of the Hemodynamic Sensory Gating Response in Schizophrenia >
- Functional connectivity in mild traumatic brain injury >
The Impact of Diffuse Mild Brain Injury on Clinical Outcomes in Children
There has been a lack of methodologically sound neuroimaging studies that have examined the diagnostic utility and predictive validity of more research-based neuroimaging techniques, such as fMRI and DTI, in traumatic brain injuries. This study aims to investigate the neuronal and behavioral correlates of attentional orienting and selective attention in a population of TBI patients post injury to determine if either aspect of attention is more affected by neuronal insult. With the use of fMRI, the project will investigate two aspects of attentional functioning (orienting and selective attention) in a well-characterized (neuropsychiatric testing) sample of patients with TBI during both the acute and recovery stages of injury.
Multi-Modal Imaging of Traumatic Brain Injury and Medical Cannabis
Medical Cannabis has gained recognition for the management of a variety of conditions associated with traumatic brain injury due to its recent legal status in many states. However, there have not been any empirical studies exploring the beneficial and adverse effects of medical cannabis in persons with TBI using an extensive clinical and cognitive battery or multimodal neuroimaging before. This pilot study represents the first step in reducing the knowledge gap caused by the lack of empirical evidence supporting the use of medical cannabis for TBI, as it will serve as a guide for which measures of therapeutic targets and adverse outcomes should be included in future randomized control trials. At the end of this study, it is expected that the medical community will, for the first time, have preliminary data about the potential safety profile of using medical cannabis to treat neuropsychiatric symptoms following TBI, and whether the safety profile may vary according to the ratio of CBD to THC.
The current Phase III (P-III) COBRE project extends the Phase I and Phase II COBRE projects over the past 11 years. These successful projects have built up infrastructure and created a cutting edge brain imaging center. The Mind Research Network (MRN) houses an Elekta Neuromag 306-channel MEG System, a high density EEG lab, a 3T Siemens Trio MRI scanner, and two mobile 1.5T Siemens Avanto MRI scanners. Additional resources include a centralized neuroinformatics system, a strong IT management plan, and state-of-the-art image analysis expertise and tools. This Phase III COBRE continues this momentum and moves the technical cores we have developed into a position of long term sustainability. These include a multimodal data acquisition (MDA) core, algorithm and data analysis (ADA) core, and a biostatistics and neuro-informatics (BNI) core. These cores have begun to serve MRN and the greater community, as well as other institutions including extensive collaborations with IDeA funded projects in New Mexico and other states. The COBRE includes an extensive educational, mentoring, and faculty development program to carefully mentor and position faculty who use the cores to maximize their potential to successfully compete for external funding, thus fulfilling the ultimate goals of the COBRE program. This Phase III COBRE helps to sustain the Mind Research Network and New Mexico as one of the premier brain imaging sites.
Consequences of mTBI
Almost all of us will get “hit in the head” at some point in our lives. “How hard” we get hit will likely determine whether we have a life altering experience or just walk away from it. However, emerging evidence suggests that even mild TBI can have prolonged consequences, affecting how we perform at work and make critical daily decisions for months. More importantly, particularly for athletes or soldiers, repeat injuries may make us more vulnerable for experiencing long-term negative outcomes. Unfortunately, mild TBI is not detected using routine clinical brain imaging techniques, nor do we have sufficient understanding of its long-term effects on behavior.
In the Mild TBI Project at MRN, lead by Dr. Andrew Mayer, we are investigating the subtle structural and biochemical consequences of mild TBI using state-of-the-art neuroimaging techniques. Our preliminary findings have shown that mild TBI causes alterations in the brain’s structure, function and chemistry. We are exploring how these alterations correlate with neurobehavioral symptoms, and how these may change as a function of recovery.
Attentional Bias Modification (ABM)
Cocaine abuse and dependence are chronic, relapsing disorders for which there are few effective treatments. Changes in frontal and sub-cortical neural circuitry following prolonged drug exposure can last for years after cessation and may compromise an addict’s ability to suppress drug seeking when exposed to drug-related cues. Attentional Bias Modification (ABM) training purportedly reduces the attentional response to salient drug stimuli and has been shown to be efficacious in treating alcohol dependence; however, the efficacy of ABM in treating individuals with cocaine addiction has yet to be empirically determined. Previous research suggests that chronic cocaine users also exhibit a decreased neuronal response during inhibitory control in addition to the enhanced neuronal response to salient drug cues. Although extensive evidence of these two neuronal abnormalities exists, to date we are not aware of a study that has directly compared the differential validity of these two metrics (i.e., enhanced cue reactivity and decreased inhibitory control) for predicting relapse. Additionally, our preliminary data provides evidence of increased intrinsic neuronal activity (functional connectivity; fcMRI) within a frontal sub-cortical circuit in CCA relative to controls. Therefore, our current study has two primary objectives that are both clinically significant and highly innovative. First, we will investigate the efficacy and mechanism of action of ABM in treating cocaine addiction (Aim 1). Second, we will determine which of the three neuronal abnormalities (i.e., enhanced cue reactivity or abnormalities in inhibitory control or increased fcMRI) are more predictive of relapse and drug utilization (Exploratory Aim 1).
Mild Traumatic Brain Injury (mTBI)
Mild traumatic brain injury (mTBI) is associated with neurobehavioral deficits in a majority of patients during the semi-acute injury phase, with a minority of patients remaining symptomatic for months to years post-injury. Routine clinical imaging scans (MRI and CT) are usually negative, suggesting that alternative neuroimaging techniques such as fMRI, DTI and 1H-MRS are well-positioned to provide unique information about the putative “silent lesions” of mTBI and their impact on neurobehavioral functioning. To this end, published data from my lab provides preliminary evidence of tissue-specific dysfunction and self-reported neuropsychiatric disturbances in both children and adults following mTBI. These injuries include increased fractional anisotropy in white matter, likely resulting from cytotoxic edema, secondary inflammatory processes, and potential structural alterations in neurofilaments and myelin. The brain’s ability to respond to external stimuli also appears to be reduced in the semi-acute stage of mTBI, with individual brain networks failing to communicate properly with each other. An increased understanding of the mechanisms underlying these injuries and how/when they recover represents the crucial next step for determining when patients can safely resume physical activities.