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David A. Leopold, Ph.D., Investigator |
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Dr. Leopold earned his B.S. in biomedical engineering from Duke University in 1991 and his Ph.D. from Baylor College of Medicine in 1997, where he studied neurophysiological mechanisms of multistable perception. During postdoctoral training with Nikos Logothetis at the Max Planck Institute for Biological Cybernitics in Tübingen, he worked on topics related to visual perception, face recognition and fMRI. Dr. Leopold came to the NIH in 2004 to establish the Unit on Cognitive Neurophysiology and Imaging and to head the Neurophysiology Imaging Facility Core. His laboratory combines electrophysiology, neuropharmacology, and functional imaging techniques to explore large scale mechanisms of brain function that underlie our visual perception.
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Staff:
- Steven Jennings, Postbaccalaureate IRTA, (301) 594-9268 jenningss@mail.nih.gov
- Alexander Maier, Ph.D., Postdoctoral Fellow, (301) 594-1129 maiera@mail.nih.gov
- David McMahon, Ph.D., Postdoctoral Fellow, (301) 594-9257 mcmahond@mail.nih.gov
- Sylvia Mrowka, Postbaccalaureate IRTA, (301) 594-0623 mrowkas@mail.nih.gov
- Kai-Markus Mueller, Predoctoral Fellow, (301) 594-0241 muellerkm@mail.nih.gov
- Eric Reavis, Postbaccalaureate IRTA, (301) 594-9268 reavise@mail.nih.gov
- Michael Schmid, Ph.D., Postdoctoral Fellow, (301) 443-7454 schmidm@mail.nih.gov
- Katy Smith, Technician Assistant, (301) 594-0854 smitkaty@mail.nih.gov
Research Interests:
The long-term goal of the Unit on Cognitive Neurophysiology and Imaging
(UCNI) is to understand the large-scale organization of visuoperceptual
processing in the brain. Our visual impression of the world arises as
the brain registers and interprets images falling on the retinae. It is
well known that neurons in different cortical areas respond selectively
to image features, and it is thought that this analysis proceeds in a
hierarchical fashion. Yet these insights leave open the question of
where and how visual perception emerges from neural responses. Our
perceptual experience has 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),
suggesting that its neural origins are complex. To study this
challenging topic, we combine several approaches for measuring brain activity,
namely microelectrode neurophysiology, and functional MRI. Using these
techniques, as well as carefully designed visual stimuli and illusions,
we attempt to understand how large-scale cortical and subcortical visual
circuits give rise to our perceptual experience.
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Selected Recent Publications:
Maier, A., Wilke, M., Aura, C., Zhu, C., Ye, F.Q., Leopold, D.A. (InPress) Divergence of electrical and fMRI signals in primary visual cortex during perceptual suppression., Nature Neuroscience.
Shmuel, A. and Leopold, D.A. (2008) Neuronal correlates of spontaneous fluctuations in fMRI signals in monkey visual cortex: implications for functional connectivity at rest., Human Brain Mapping 29(7), 751-761.
Maier A., Logothetis N.K., and Leopold, D.A. (2007) Context dependent perceptual modulation in monkey visual cortex., Proceedings of the National Academy of Sciences of the United States of America 104(13), 5620-5625.
Wilke M., Logothetis N.K., and Leopold, D.A. (2006) 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.
Leopold, D.A., Bondar, I., and Giese, M (2006) Norm-based face encoding by single neurons in the monkey inferotemporal cortex., Nature 442(7102), 572-5.
Leopold, D.A., Rhodes, G., Mueller K.-M., and Jeffrey, L (2005) The dynamics of visual adaptation to faces., Proceedings of the Royal Society, Series B 272(1566), 897-904.
Leopold, D.A., Murayama, Y. and Logothetis, N.K. (2003) Very slow activity fluctuations in monkey visual cortex: implications for functional imaging., Cerebral Cortex 13(4), 422-33.
All Selected Publications
Contact Information:
Dr. David A. Leopold
Unit on Cognitive Neurophysiology and Imaging
Laboratory of Neuropsychology, NIMH
Building 49, Room B2J-45, MSC-4400
49 Convent Dr.
Bethesda, MD 20892-4400
Telephone: (301) 594-0582 (office),
(301) 480-1644 (fax)
Email: leopoldd@mail.nih.gov
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