M.S., Physics, Ukraine National University, Kiev, Ukraine
Ph.D., Physics, Michigan State University
Sloan-Swartz Postdoctoral Fellow, University of California, San Francisco
Our group works on theoretical principles of how the brain processes information. We are interested in how sensory processing in the brain is shaped by the animal's need to create parsimonious representations of events in the outside world. Our approaches are often derived from methods in statistical physics, mathematics, and information theory.
We also work on methods for analyzing neural data, including methods for analyzing neural responses to natural stimuli, such as a short video clip or sound recording during a stroll on a forest trail. In the past, scientists had to rely on simplified objects on a computer screen or random stimuli to garner information on how the brain processes visual information. Natural stimuli are often much better for probing neural responses than random noise stimuli. Using approaches designed to work with natural stimuli, we hope to achieve a more complete picture of how the brain processes information.
"Neurobiologists are on a perennial quest to understand
how the brain codes stimuli in the environment. In the past,
scientists had to rely on simplified objects on a computer
screen. I try to take it a step further and analyze how brain
cells respond to stimuli typical of our natural environment."
Sharpee's lab works on theoretical principles
of how the brain processes information and
explores how sensory processing in the
brain is shaped by our need to create representations
of events in the outside world.
Researchers used to rely on simplified objects
on a computer screen or random stimuli
to garner information on how the brain processes
visual information. But our brains are
meant to operate in a remarkably complex
and fast-changing world, so these methods
offered limited insight into the brain's
workings. In contrast, natural stimuli, such
as a short video clip or sound recorded during
a stroll on a forest trail, are often much better
for probing neural responses. This is particularly
true when studying intermediate and
high-level neurons in the brain that translate
sensory stimuli from the environment into
meaningful information. These neurons rarely
respond to simple patterns that are devoid
of recognizable real-world objects, but they
will respond to the rich ensemble of object
combinations found in our environment.
Sharpee and her colleagues are developing
methods to identify which features of natural
stimuli cause a response in high-level neurons
and how the brain prioritizes and makes
sense of this information. A key obstacle to
understanding how our brain functions is that
neurons respond in highly nonlinear ways to
complex stimuli, meaning that signals are
amplified and suppressed in unexpected
ways. As a result, stimulus-response relationships
are extremely difficult to discern.
To address this, Sharpee's team has worked
out rigorous statistical methods for modeling
how visual and auditory stimuli are coded and
decoded through nonlinear transformations
in different brain centers. These studies
are beginning to uncover the common principles
of hierarchical information processing
in the brain and will help us better understand
how neurological disorders and injuries
interrupt these crucial processes. Knowing
how information moves through our sensory
systems may offer new strategies for helping
people with impairments, such as improving
the performance of retinal implants that
could help restore vision in the blind.
Awards and Honors
- 2010 Helen McLoraine Developmental Chair in Neurobiology
- 2009 W.M. Keck Foundation Research Excellence Award
- 2009 McKnight Scholar
- 2008 Ray Thomas Edwards Foundation Career Development Award in the Biomedical Sciences
- Mentored Quantitative Research Career Development Award from the National Institute of Mental Health, 2004-2009
- Alfred P. Sloan Research Fellowship 2008
- 2008 Searle Scholar
J.D. Fitzgerald, R. J. Rowekamp, L.C. Sincich and T.O. Sharpee, (2011) "Second order dimensionality reduction using minimum and maximum mutual information models", PLoS Computational Biology, 7(10): e1002249
J.D. Fitzgerald, L.C. Sincich and T.O. Sharpee, (2011) "Minimal models of multidimensional computations", PLoS Computational Biology, 7(3): e1001111.
J. Jeanne, J. Thompson, T.O. Sharpee, and T. Gentner, (2011) "Emergence of learned categorical representations within an auditory forebrain circuit", Journal of Neuroscience, 31 (7), pp.2595-2606.
K. Imaizumi, N. Priebe, T.O. Sharpee, S. Cheung, and C.E. Schreiner, (2010) "Encoding of Temporal Information by Timing, Rate, and Place in Cat Auditory Cortex", PLoS ONE 5(7): e11531.
J. D. Fitzgerald and T. O. Sharpee, (2009) "Maximally informative pairwise interactions in networks", Phys. Rev. E, 80, 031914.
Y. Liu, C. F. Stevens, and T. O. Sharpee, (2009) "Predictable irregularities in retinal receptive fields", PNAS, 38, 16499-16504.
M. J. Kouh and T. O. Sharpee, (2009) "Estimating linear-nonlinear neural models using Renyi divergences", Network: Computation in Neural Systems, 20(2): 49-68.
L. C. Sincich, J. C. Horton, and T. O. Sharpee, (2009) "Preserving information in neural transmission", Journal of Neuroscience, 29(19), 6207-6216.
T.O. Sharpee and J.D. Victor, (2009) "Contextual modulation of V1 receptive fields depends on their spatial symmetry", Journal of Computational Neuroscience, 26(2): pp. 203-218.
T. O. Sharpee, K. D. Miller, and M. P. Stryker, (2008) "On the importance of the static nonlinearity in estimating spatiotemporal neural filters with natural stimuli", Journal of Neurophysiology 99(5): 2496-2509.
T. Sharpee and W. Bialek, (2007) "Neural decision boundaries for maximal information transmission", PLoS ONE 2(7): e646.
T. Sharpee, (2007) "Comparison of information and variance optimization strategies for characterizing neural feature selectivity", Statistics in Medicine 26 (21), pp. 4009-4031.
T. Sharpee, H. Sugihara, A. Kurgansky, S. Rebrik, M.P. Stryker, and K.D. Miller, (2006) Adaptive filtering enhances information transmission in visual cortex, Nature 439, pp. 936-942.
T. Sharpee, N. C. Rust, and W. Bialek, (2004) Analyzing neural responses to natural signals: Maximally informative dimensions, Neural Computation, 16 (2), pp. 223-250 2004.
M.I. Dykman, T. Sharpee , P.M. Platzman, (2001) "Enhancement of tunneling from a correlated 2D electron system by a many-electron Mauer-type recoil in a magnetic field", Phys. Rev. Lett. 86, pp. 2408-2411 (2001).
T. Barabash-Sharpee, M.I. Dykman, P.M. Platzman, (2000) Tunneling transverse to magnetic field, and its occurence in correlated 2D electron systems, Phys. Rev. Lett. 84 , pp. 2227-2230.
Salk News Releases
- Salk Institute promotes three top scientists, April 12, 2013
- What the brain saw, March 30, 2011
- Salk Scientist wins the 2009 McKnight Scholar Award, May 15, 2009
- Distinguishing between two birds of a feather, August 7, 2008
- Salk Researcher Named 2008 Searle Scholar, May 22, 2008
- Salk Researcher Receives Prestigious Sloan Research Fellowship, February 21, 2008
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