I study the structure and function of the brain. I am particularly interested in methods of measuring the timing of functional MRI signals and the correlations between them, and in applications of these methods to the study of neurological and mental disorders.

I am currently involved in a series of studies of hippocampal structure and function in epilepsy and psychosis, using ultra high field MRI with new methods of measuring functional connectivity and statistical approaches appropriate for the large data sets involved. Recent methodological work is focused on understanding dynamic variation in functional connectivity over short time scales (minute to minute).

Our group's research interests focus on the use of synthetic and colloidal chemistry in the development of novel molecular probes. Through our use of emerging imaging technologies, we foresee such probes being employed to investigate and define the mechanisms that lead to pathological diseases.

Our ongoing investigation emphasizes on cell therapy using a transgenic and preclinical mouse model. In addition, we have employed integrated nanotechnology-based platforms to achieve a multifunctional and multiplexed vaccine delivery system for cancer therapy. Aside from highlighting the contrast properties and carrier features available in nanotechnology, the overall goals of our studies are to (i) provide microanatomical and functional imaging feedback of the therapeutic process and (ii) realize an approach for longitudinal treatment and monitoring.     Our second project focuses on the development of a novel synthetic chemistry approach to the generation of probes intended specifically for imaging Alzheimer's disease (AD). The significance of this work lies in the development of a versatile vehicle which, after being loaded with imaging cargo, can be delivered to the brain. Furthermore, our laboratory currently maintains a clone of a double transgenic mouse model of AD to enable testing of these probes. Considering the tremendous contribution made by imaging in understanding the pathogenesis of AD, the results obtained through this research will have a strong influence on current efforts to find reliable biomarkers of this disease.

My research has two major thrusts: 1.) the development of high-resolution, multi-pinhole SPECT capabilities, and 2.) the use of CT, SPECT, and PET in preclinical research studies across a wide range of applications.

We are developing novel semiconductor radiation detector technology for use in innovative multi-pinhole SPECT systems. 2.) We are involved in a number of collaborative projects in which we our role is to refine and validate image acquisition and analysis techniques to improve quantitative PET and SPECT capabilities.

I am interested in translating quantitative MR techniques to the clinic to better understand the pathological changes in the brain and spinal cord associated with neurological diseases such as multiple sclerosis.

My research is focused on developing quantitative MR methodologies for the brain and spinal cord with a current emphasis on improving thoracic and lumbar spinal cord MRI. This work is also part of an effort to improve our understanding of the effects of biological sex on pathological changes associated with neurological diseases such as multiple sclerosis.

I am interested in the development of new fMRI methods including advances in both image acquisition and image analysis. I am particularly interested in methods involving imaging at ultra high field (7T).

Currently, I have several parallel research paths I am pursuing. First, I am developing methods for pushing the spatial resolution of whole brain fMRI data. The goal of this project is to obtain images with the highest possible isotropic spatial resolution while minimizing geometric distortions of the images and maintaining reasonable temporal resolution. Second, I am developing methods for similarly pushing the temporal resolution of fMRI data while maintaining spatial resolutions similar to those typically used at lower field strengths. These acquisitions will be used for measuring cognitive latencies and validating methods for removing physiological noise.

My lab works closely with the departments of Neurology and Neurosurgery to develop Magnetic Resonance Imaging (MRI) methods to improve neurosurgical outcomes, particularly for patients with epilepsy. We directly support clinical care by developing and providing functional MRI to localize eloquent cortex in the brain to aid in surgical planning to minimize functional and cognitive deficits post surgery. Our research focuses on mapping functional and structural brain networks in epilepsy before and after surgical treatment. Ultimately, we aim to use MRI to fully characterize the spatial and temporal impacts of seizures across the brain to optimize management of epilepsy patients. The Morgan lab has on-going research collaborations with the BIEN (Englot) Lab, the Medical Imaging Processing Laboratory (Dawant), the MASI Lab (Landman) and researchers throughout the Vanderbilt Institute of Imaging Science (VUIIS).

My interest is primarily in translational research that aims at detecting cancer, delivering targeted therapy and monitoring anti-tumor drug efficacy.  For this work, I am using a number of established mouse models of cancer to test a variety of customized activatable imaging and therapeutic agents including compounds delivered using dendrimeric scaffold nanomaterials (NDs)

We have developed 'proteolytic beacons' (PBs) that can be used to image the elevated activity of specific proteinases, such as the matrix metalloproteinases (MMPs) within the tumor microenvironment.  Our developing library of PBs exhibits selectivity for different classes of MMPs.  With various mouse models of colon, breast and lung cancers, we have demonstrated selective illumination of tumors by PBs using either optical (fluorescent) or MRI contrast.  We are currently developing new types of PBs and are exploring uses of PBs in cancer and other diseases, e.g., for measuring proteinase activation associated with tumor growth and metastasis, for assessing early response of tumors to therapy and for imaging MMP activities in non-tumor pathologies such as inflammation and wound healing.  Another endeavor is to adapt the beacon platform to generate dendrimeric nanomaterials (NDs) that not only interrogate tumors but also simultaneously target delivery of prodrugs.  These kinds of prodrugs are designed to become active after proteolytic cleavage, e.g., in the microenvironment of tumors.  Our novel bifunctional prodrug ND-PB therapeutic agents are being optimized to enhance targeted delivery of cytotoxic drugs to tumors so as improve therapeutic efficacy while reducing systemic toxicity.

My interests are diffusion tensor image analysis, functional MRI analysis and pattern recognition of anatomical features.

My current study is 'Resting state connectivity in the white matter'. The goals of this study are to investigate and evaluate recent new discoveries about the nature of temporal variations in magnetic resonance imaging signals from the human brain, acquired in a resting state, which potentially provides a completely new basis for quantifying the functional architecture of white matter.

I am interested in the evaluation of diffusion imaging and other technologies in cancer imaging.

I am interested in using computational modeling to understand the biological basis of MRI signal and quantitative measures derived from MRI. I am also interested in using numerical techniques to improve image acquisition and reconstruction.

I am currently using computational models and experiments in rat spinal cord to understand the relationship between quantitive MRI measures of myelin (myelin water fraction, magnetization transfer, and ultrashort T2 signal).