Scholars@Duke
K. Ranga Rama Krishnan

K. Ranga Rama Krishnan

Professor Emeritus of Psychiatry and Behavioral Sciences
Psychiatry & Behavioral Sciences, Behavioral Medicine & Neurosciences
Box 2741 Med Ctr, Durham, NC 27710
2424 Erwin Road, Durham, NC 27710

Overview

I have validated in vivo methods of estimating volumes of subcortical structures utilizing MRI and sterology. These studies have suggested that depressed patients have smaller caudate, smaller putamen, altered water balance in the hippocampus, a smaller medulla and cerebellar vermis, and enlarged ventricles. Our group has demonstrated that late-life depression patients have increased MRI lesions in the fronto-parietal white matter and subcortical gray; and, have lesions in the caudate increase the risk of delirium with ECT and antidepressants. In the last year, we have developed high resolution MR proton spectroscopy methods to measure the concentration of a variety of physico-chemical moieties, including choline, lactic acid, water, glucose, N-acetylaspartate and glutamate in volumes of < one ml. We are utilizing this technique to study affective disorder, Alzheimer's disease and social phobia and the effect of psychotropic medications on these parameters. In an initial study, a state dependent increase in choline in depressed patients has been demonstrated; and, in Alzheimer's disease, a reduction in N-acetyl asparatate and an increase in Inositol which progresses as the disease advances. In addition, we are examining the relationship between fluoxetine concentrations in the brain using MRS and therapeutic efficacy. We currently use MR methods to assess drug efficacy in various disorders and in the development of new drugs. We have developed protocols to compare drugs developed for Alzheimer's disease based on their known effects on MRS parameters in dogs.

Current Appointments & Affiliations

Professor Emeritus of Psychiatry and Behavioral Sciences · 2015 - Present Psychiatry & Behavioral Sciences, Behavioral Medicine & Neurosciences, Psychiatry & Behavioral Sciences

In the News

Published October 9, 2014
Dr. Ranga Krishnan: Peer learning in the age of technology
Published August 22, 2013
Ranga Krishnan: Understanding motivation and apathy is key to education
Published July 8, 2013
Ranga Krishnan: Emotions are just as important in education

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Recent Publications

The Singapore Health Services and Duke University–National University of Singapore Graduate Medical School Academic Medical Center: Transforming Medicine Through Collaborative Innovation

Journal Article Academic Medicine · September 1, 2025 Singapore Health Services (SingHealth) and Duke University–National University of Singapore Graduate Medical School (Duke-NUS) established an academic partnership, which was born out of a single vision to transform medicine and improve lives. This partners ... Full text Cite

Brain-computer-interface-based intervention increases brain functional segregation in cognitively normal older adults.

Journal Article Age Ageing · August 29, 2025 Brain-computer interface (BCI)-based cognitive training systems have shown promise in enhancing cognitive performance in cognitively normal older adults. However, the brain network changes underlying these behavioural improvements remain poorly understood. ... Full text Link to item Cite

Peripheral inflammation is associated with brain atrophy and cognitive decline linked to mild cognitive impairment and Alzheimer's disease.

Journal Article Sci Rep · July 29, 2024 Inflammation is an important factor in Alzheimer's disease (AD). An NMR measurement in plasma, glycoprotein acetyls (GlycA), captures the overall level of protein production and glycosylation implicated in systemic inflammation. With its additional advanta ... Full text Link to item Cite
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Recent Grants

FMRI: Prediction of Mild Cognitive Impairment in Geriatric Depression

ResearchCo-Mentor · Awarded by National Institutes of Health · 2008 - 2012

Recovery Act Funds for Administrative Supplements for Conte Center grant programs

ResearchPrincipal Investigator · Awarded by National Institutes of Health · 2010 - 2011

Conte Centers for the Neuroscience of Depression

ResearchPrincipal Investigator · Awarded by National Institutes of Health · 2001 - 2011

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Education

University of Madras (India) · 1978 M.B.B.S.