Victor Laboratory

Jonathan D. Victor, M.D., Ph.D.
Fred Plum Professor of Neuroscience​

Our Mission

The mission of the laboratory is to advance the understanding of higher brain function at the level of circuits and systems, and how it is altered in disease.  We focus on sensory systems, especially vision, as models to understand design principles for neural computations, how these design principles are implemented in neural hardware, and how the properties of individual neurons relate to the function of large populations.

Lab Members

Mary Conte, PhD Senior Research Associate
Tamar Melman, Graudate Fellow
Daniel Thengone, Graduate Fellow

Lab Webpage

http://www-users.med.cornell.edu/~jdvicto/labonweb.html

Goals

The laboratory’s long-term goals are to advance the understanding of how the brain carries out its integrative functions, and how these functions are affected by major neurologic disease. 

One main thrust of the research is directed at understanding the design principles of sensory processing, both in the sensory periphery and in the brain, and how these design principles are implemented in biological hardware.  We seek to determine the aspects of sensory information that are represented, the features of the activity of individual neurons and neural populations that support these representations, and realistic models for how these representations are transformed.  These questions are addressed primarily in the visual system, via neurophysiologic studies at the single-cell and multineuronal level (with Keith Purpura) and via psychophysical studies (with Mary Conte).  Experimental investigations are complemented by theoretical studies, including (a) the development of approaches to analyze multineuronal activity and (b) strategies for stimulus design that bridge the gap between methods motivated by analytical convenience, such as white noise and sinusoids, and methods based on ethologically relevant stimuli, such as natural scenes.

The second main thrust of the research is directed at understanding the derangements of integrative function in disease. In many neurologic diseases, including epilepsy and chronic brain injury, alterations in the dynamics of neuronal populations plays a major role in pathogenesis and/or symptomatology.  In conjunction with Nicholas Schiff and colleagues, we are analyzing EEG, functional imaging, and anatomical imaging in brain injury patients to probe these dynamics and their relationship to spontaneous and induced fluctuations in cognitive ability and behavior.  Population models of thalamocortical interactions play an important role in shaping the analytical approach. An integral part of the research is the development of dimension-reduction and statistical methods for analysis of multichannel datasets such as the EEG, which contain rich dynamical information, but also nonstationarity, noise, and artifacts with complex statistical structure.

Achievements

• Development of a class of approaches (“spike train metrics”) for analysis of neural data (with Keith Purpura)
• Development of a class of approaches (“binless embedding”) for assessing the information content of neural data
• Measurement of human visual sensitivity to a comprehensive set of local image features (with Mary Conte), and their correspondence to statistical regularities of natural images (with Vijay Balasubramanian and colleagues)
• Identification of the neural basis for visual sensitivity to high-order correlations, which in turn delineate image features
• Identification of a novel type of visual local motion signal (“glider motion”), and characterization of its occurrence in naturalistic movies 
• Delineating the mathematical underpinnings of how fixational eye movements decorrelate the retinal image (with Michele Rucci)
• Identification of a temporal code for the representation of taste (with Patricia Di Lorenzo)

Selected Recent Publications

For a complete listing, please see: http://www-users.med.cornell.edu/~jdvicto/labpubs.html

1. Schmid, A.M., Purpura, K.P., and Victor, J.D. (2014) Responses to orientation discontinuities in V1 and V2: physiological dissociations and functional implications.  J. Neurosci., accepted.
2. Ohiorhenuan, I.E., Mechler, F., Purpura, K.P., Schmid, A.M., Hu, Q., and Victor, J.D. (2014) Cannabinoid neuromodulation in the adult early visual cortex.  PLOS One, 9, e87362.
3. Williams, S.T., Conte, M.M., Goldfine, A.M., Noirhomme, Q., Gosseries, O., Thonnard, M., Beattie, B.J., Hersh, J., Katz, D., Victor, J.D., Laureys, S., and Schiff,  N.D. (2013) Common resting brain dynamics indicate a possible mechanism underlying zolpidem response in severely brain-injured subjects. eLife 2:e01157.
4. Kuang, X., Poletti, M., Victor, J.D., and Rucci, M. (2012) Temporal encoding of spatial information during active visual fixation. Current Biology 22, 510-514.
5. Victor, J.D., and Conte, M.M. (2012) Local image statistics: maximum-entropy constructions and perceptual salience. Journal of the Optical Society of America A, 29, 1313-1345.
6. Mechler, F., Victor, J., Ohiorhenuan, I.E., Schmid, A., and Hu, Q. (2011) Three-dimensional localization of neurons in cortical tetrode recordings.  J. Neurophysiol. 106, 828-848.
7. Hu, Q., and Victor, J.D.  (2010) A set of high-order spatiotemporal stimuli that elicit motion and reverse-phi percepts.  Journal of Vision 10, 9, doi: 10.1167/10.3.9
8. Drover, J.D., Schiff, N.D., and Victor, J.D. (2010) Dynamics of coupled thalamocortical modules.  Journal of Computational Neuroscience 28, 605- 616.
9. Ohiorhenuan, I.E., Mechler, F., Purpura, K.P., Schmid, A.M., and Victor, J.D. (2010) Sparse coding and high-order correlations in fine-scale cortical networks.  Nature 466, 617–621.
10. Tkačik, G., Prentice, J., Victor, J.D., and Balasubramanian, V. (2010) Local statistics in natural scenes predict the saliency of synthetic textures.  Proc. Natl. Acad. Sci. USA  107, 18149-18154.
11. Di Lorenzo, P., Chen, J.-Y., and Victor, J.D. (2009) Quality time:  Representation of a multidimensional sensory domain through temporal coding. J. Neurosci. 29, 9227-9238.
12. Victor, J.D., and Nirenberg, S. (2008)  Indices for testing neural codes.  Neural Computation 20, 2895-2936.
13. Schiff, N.D., Giacino, J.T., Kalmar, K., Victor, J.D., Baker, K., Gerber, M., Fritz, B., Eisenberg, B., Biondi, T., O'Connor, J., Kobylarz, E.J., Farris, S., Machado, A., McCagg, C., Plum, F., Fins, J.J., and Rezai, A. R. (2007) Behavioural improvements with thalamic stimulation after severe traumatic brain injury.  Nature 448, 600-603.
14. Victor, J.D. (2005) Spike train metrics.  Current Opinion in Neurobiology  15, 585–592.

 

Secondary Appointments

Department of Neurology (WCMC)

Graduate Field Memberships

Neuroscience (WGSMS)
Physiology, Biophysics, and Structural Biology (WGSMS)
Graduate Field of Biomedical Engineering (Cornell-Ithaca)
Tri-institutional Program in Computational Biology
Tri-institutional MD/PhD Program

Adjunct Faculty Appointments

Laboratory of Biophysics, The Rockefeller University
Biomathematical Sciences, Mount Sinai School of Medicine

Hospital Appointments

The New York Presbyterian Hospital
The Rockefeller University Hospital
Memorial Sloan Kettering Cancer Center
The Hospital for Special Surgery

Collaborators

Keith Purpura
Nicholas Schiff
Sheila Nirenberg
Daniel Gardner