Intraoperative Frontal Alpha-Band Power Correlates with Preoperative Neurocognitive Function in Older Adults.

Research efforts are focused primarily in the area of functional genomics. Work has centered on investigating genetic polymorphisms in the surgical intensive care population that would predispose one to the development of the sepsis syndrome. As an extension of this work, there is ongoing investigation working to identify genetically susceptible populations at risk for developing various types of perioperative organ dysfunction. Parallel studies involve identification of a panel of biomarkers that would enable early diagnosis and intervention for those patients, both surgical and non-surgical that develop the sepsis syndrome. There is also active investigation in the human pharmacology laboratory in the department of anesthesiology involving the phase 1 testing of novel pharmaceutical agents in healthy volunteers.

Dr. Browndyke is an Associate Professor of Behavioral Health & Neurosciences in the Department of Psychiatry & Behavioral Sciences.  He has a secondary appointment as Assistant Professor of Cardiovascular & Thoracic Surgery.

Dr. Browndyke's research interests involve the use of advanced neurocognitive and neuroimaging techniques for perioperative contributions to delirium and later dementia risk, monitoring of late-life neuropathological disease progression, and intervention/treatment outcomes.  His research also involves novel telehealth methods for remote neurocognitive evaluation and implementation of non-invasive neuromodulatory techniques to assist in postoperative recovery and dementia risk reduction.

Dr. Browndyke's clinical expertise is focused upon geriatric neuropsychology with an emphasis in the assessment, diagnosis, and treatment of dementia and related disorders in adults and US veteran patient populations.

Current research interests include:
1. The relationship between white matter patency, functional connectivity (fMRI) and neurocognitive function following cardiac surgery.
2. The relationship between global and regional cortical beta-amyloid deposition and postoperative cognitive decline.
3. The effect of lidocaine infusion upon neurocognitive function following cardiac surgery.
4. The association between genotype and outcome after cardiac surgery.
5. Atrial fibrillation following cardiopulmonary bypass.

Dr. Woldorff's main research interest is in the cognitive neuroscience of attention. At each and every moment of our lives, we are bombarded by a welter of sensory information coming at us from a myriad of directions and through our various sensory modalities -- much more than we can fully process. We must continuously select and extract the most important information from this welter of sensory inputs. How the human brain accomplishes this is one of the core challenges of modern cognitive neuroscience. Dr. Woldorff uses a combination of electrophysiological (ERP, MEG) and functional neuroimaging (fMRI) methods to study the time course, functional neuroanatomy, and mechanisms of attentional processes. This multimethodological approach is directed along several main lines of research: (1) The influence of attention on sensory and perceptual processing; (2) Cognitive and attentional control mechanisms; (3) The role of attention in multisensory environments; (4) The interactive relationship between attention and reward; and (5) The role of attention in perceptual awareness.

My research team focuses on 3 areas:

1) We are interested in the mechanisms of postoperative neurocognitive disorders such as delirium, and the relationship between these disorders and Alzheimer's Disease and Related Dementias (ADRD). Towards these ends, we use a combination of methods including pre and postoperative CSF and blood sampling, functional neuroimaging, EEG recordings, rigorous biochemical assays, and cognitive testing and delirium screening. In the long run, this work has the potential to help us improve long term neurocognitive outcomes for the more than 20 million Americans over age 60 who undergo anesthesia and surgery each year.

2) We are interested in the idea that altered anesthetic-induced brain EEG waveforms can serve as indicators of specific types of preclinical/prodromal neurodegenerative disease pathology, specific cognitive domain deficits, and postoperative delirium risk. We are studying this topic in the ALADDIN study, a 250 patient prospective cohort study in older surgical patients at Duke. Many people have viewed anesthesia and surgery as a "stress test" for the aging brain; we hope that this work will help us learn how to develop a real-time EEG readout of this "perioperative stress test" for the aging brain, just as ECG analysis can provide a real-time readout of cardiac treadmill stress tests. 

3) We are interested in how the APOE4 allele damages brain circuitry throughout the adult lifespan, and how this contributes to increased risk of late onset Alzheimer's disease as well as worse outcomes following other acute brain disorders such as stroke and traumatic brain injury (TBI). In particular, we are investigating the hypothesis that the APOE4 allele leads to increased CNS complement activation throughout adult life, which then contributes to increased synaptic phagocytosis and long term neurocognitive decline. We are also studying whether acutely modulating APOE signaling in older surgical patients with the APOE mimetic peptide CN-105 is sufficient to block postoperative CSF neuroinflammation and complement activation. 

Our work is transdisciplinary, and thus our team includes individuals with diverse scientific and clinical backgrounds, ranging from neuropsychology and neuroimaging to proteomics, flow cytometry and behavioral neuroscience in animal models. What unites us is the desire to better understand mechanisms of age-dependent brain dysfunction, both in the perioperative setting and in APOE4 carriers.