| | Principal Investigators
| David A. Leopold, Ph.D. |
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Dr. Leopold attained a B.S. in biomedical engineering from Duke University in 1991. He subsequently received his Ph.D. from Baylor College of Medicine in 1997, where he studied neurophysiological mechanisms of multistable perception. He then did his postdoctoral work in the Logothetis lab at the Max Planck Institute for Biological Cybernitics in Tübingen, where he worked on topics related to visual perception, face recognition and fMRI. Dr. Leopold arrived at the NIH in the beginning of 2004 to establish the Unit on Cognitive Neurophysiology and Imaging and to head the Neurophysiology Imaging Facility Core. |
| Research Interests |
Dr. Leopold’s present research explores the large-scale organization of brain activity related to the establishment and maintenance of a visual percept. Our visual impression of the world stems from the brain�s interpretation of images of the world projected onto the retina. These patterns of light contain information and the three-dimensional structure of a scene. The visual cortex automatically extracts meaningful information, such as objects identity, spatial relationships, and causality. The complex and highly evolved faculty of vision allows primates and most other animals to evaluate and interact with their surroundings from a distance.
Current research in the lab explores the neural basis of visual perception in the primate brain. Our percepts have simultaneous access to simple features (e.g. color and brightness), intermediate ones (e.g. shape and geometric arrangement), and semantic qualities (e.g. identity and meaning). Previous work has suggested that the neural underpinnings of a specific percept cannot easily be localized in the brain, but instead reflects the interplay among multiple brain areas. The current approach combine behavioral, neurophysiological, imaging, and neuropharmacological techniques in innovative ways that provide insights into the nature of perception that were previously out of reach. The aim is to learn through correlative and pharmacological studies how functional interactions among regions of the primate forebrain ultimately determine the contents of our perception. |
| Representative Selected Recent Publications: |
- Maier A, Wilke M, Aura C, Zhu C, Ye FQ, Leopold DA.:
Divergence of fMRI and neural signals in V1 during perceptual suppression in the awake monkey.
Nat Neurosci, Oct;11(10):1193-200, 2008.
- Shmuel A, Leopold DA:
Neuronal correlates of spontaneous fluctuations in fMRI signals in monkey visual cortex: Implications for functional connectivity at rest.
Hum Brain Mapp, Jul;29(7):751-61, 2008.
- Maier A., Logothetis N.K., and Leopold, D.A.:
Context dependent perceptual modulation in monkey visual cortex.
Proceedings of the National Academy of Sciences of the United States of America, 2104 (13):5620-5625, 2007.
- Wilke M., Logothetis N.K., and Leopold, D.A.:
Local field potential reflects perceptual suppression in monkey visual cortex. Proceedings of the National Academy of Sciences of the United States of America,,
103(46):17507-12, 2006.
- Leopold DA, Rhodes G, Mueller K-M, Jeffrey L:
The dynamics of visual adaptation to faces.Royal Society, Series B, 272: 897-904, 2005. (View PDF)
- Leopold, D.A., Murayama, Y. and Logothetis, N.K.:
Very slow activity fluctuations in monkey visual cortex: implications for functional imaging.
Cerebral Cortex, 13(4), 422-33, 2003. (View PDF)
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