Overview
The behavioral measures have focused on reaction time, with the goal of distinguishing age-related changes in specific cognitive abilities from more general effects arising from a slowing in elementary perceptual processes. The cognitive abilities of interest include selective attention as measured in visual search tasks, semantic and episodic memory retrieval, and executive control processes.
The behavioral measures are necessary to define the cognitive abilities of interest, and the neuroimaging techniques help define the functional neuroanatomy of those abilities. The PET and fMRI measures provide information regarding neural activity during cognitive performance. DTI is a recently developed technique that images the structural integrity of white matter. The white matter tracts of the brain provide critical pathways linking the gray matter regions, and thus this work will complement the studies using PET and fMRI that focus on gray matter activation.
A current focus of the research program is the functional connectivity among regions, not only during cognitive task performance but also during rest. These latter measures, referred to as intrinsic functional connectivity, are beginning to show promise as an index of overall brain functional efficiency, which can be assessed without the implementation of a specific cognitive task. From DTI, information can be obtained regarding how anatomical connectivity constrains intrinsic functional connectivity. It will be important to determine the relative influence of white matter pathway integrity, intrinsic functional connectivity, and task-related functional connectivity, as mediators of age-related differences in behavioral measures of cognitive performance.
Ultimately, the research program can help link age-related changes in cognitive performance to changes in the structure and function of specific neural systems. The results also have implications for clinical translation, in terms of the identification of neural biomarkers for the diagnosis of neural pathology and targeting rehabilitation procedures.
Current Appointments & Affiliations
Professor in Psychiatry and Behavioral Sciences
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2021 - Present
Psychiatry & Behavioral Sciences, Behavioral Medicine & Neurosciences,
Psychiatry & Behavioral Sciences
Chair of the Scientific Review Committee in the Center for Brain Imaging and Analysis
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2013 - Present
Duke-UNC Brain Imaging and Analysis Center,
Institutes and Centers
Professor of Psychology and Neuroscience
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2013 - Present
Psychology & Neuroscience,
Trinity College of Arts & Sciences
Member of the Center for Cognitive Neuroscience
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2009 - Present
Center for Cognitive Neuroscience,
Duke Institute for Brain Sciences
Faculty Network Member of the Duke Institute for Brain Sciences
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2011 - Present
Duke Institute for Brain Sciences,
University Institutes and Centers
Recent Publications
Depthwise cortical iron relates to functional connectivity and fluid cognition in healthy aging.
Journal Article Neurobiology of aging · April 2025 Age-related differences in fluid cognition have been associated with both the merging of functional brain networks, defined from resting-state functional magnetic resonance imaging (rsfMRI), and with elevated cortical iron, assessed by quantitative suscept ... Full text Open Access CiteCharacterizing positive and negative quantitative susceptibility values in the cortex following mild traumatic brain injury: a depth- and curvature-based study.
Journal Article Cerebral cortex (New York, N.Y. : 1991) · March 2025 Evidence has linked head trauma to increased risk factors for neuropathology, including mechanical deformation of the sulcal fundus and, later, perivascular accumulation of hyperphosphorylated tau adjacent to these spaces related to chronic traumatic encep ... Full text Open Access CitePredilection for Perplexion: Preoperative microstructural damage is linked to postoperative delirium.
Journal Article medRxiv · January 9, 2025 Postoperative delirium is the most common postsurgical complication in older adults and is associated with an increased risk of long-term cognitive decline and Alzheimer's disease (AD) and related dementias (ADRD). However, the neurological basis of this i ... Full text Link to item CiteRecent Grants
High resolution diffusion imaging of brain connectivity in healthy aging and Alzheimer's disease
FellowshipPrincipal Investigator · Awarded by National Institute on Aging · 2024 - 2027Effects of Healthy Aging and Mild Cognitive Impairment on Memory Representations
ResearchCo Investigator · Awarded by National Institutes of Health · 2021 - 2025Neuroimaging of Visual Attention in Aging
ResearchPrincipal Investigator · Awarded by National Institutes of Health · 2011 - 2025View All Grants
Education, Training & Certifications
University of California, Davis ·
1977
Ph.D.
University of Victoria (Canada) ·
1974
M.A.
University of California, Davis ·
1972
B.A.