Professor of Cell and Developmental Biology
Professor of Ophthalmology and Visual Sciences
Professor of Psychology, Emeritus
The overall goal of our research is to understand how the visual thalamus and cortex interact to construct our perceptual world.
The first project explores the unconventional proposal that the primary sensory information received by the visual cortex from the visual thalamus [e.g., the lateral geniculate nucleus (LGN)] is not purely visual but rather visual information, primed by inputs from other sensory modalities. In this project, we hypothesize that the primate brain achieves fast and accurate decision-making in part due to its ability to focus, right from the beginning, on relevant aspects of inputs from all sense organs without appreciating all the details presented by each sense organ. Our specific hypothesis is that auditory and visual information are combined in a task dependent manner in the visual thalamus before this message is processed in cortex.
In a second project, we test the hypothesis that all thalamic nuclei contain some cell groups that act as drivers (send the main message) and some that act as modulators for multiple cortical areas, thus mediating the generation of an array of diverse cortical functions. The thalamus is not simply a passive relay to cortex. Instead, just as primary visual cortex (V1) depends on LGN, the secondary visual area (V2) and the middle temporal visual area (MT) depend on a combination of dedicated pathways through the thalamus (e.g., pulvinar) and direct feedforward connections from V1.This arrangement allows new properties to emerge at both the thalamic and cortical levels through dynamic loops.
A third project focuses on communication between cells in different areas of visual cortex and examines how visual messages are coded and transmitted from lower to higher visual areas and what the role of feedback is in this process.
We use a variety of electrophysiological, anatomical, and imaging approaches to address these questions including single unit and multielectrode recording in both anesthetized and awake behaving primates, light, electron microscopic and confocal examination of cells and circuits, optical imaging of intrinsic signals and pharmacological manipulation. Our laboratory also has had a long standing interest in the evolution of the visual system. Therefore, we continue to use a comparative approach to examine for similarities and differences in the organization of the visual system in a variety of primate species.
Jiang, Y., Purushothaman G. and Casagrande. V.A. (2015) A computational relationship between thalamic sensory neural responses and contrast. Frontiers in Neural Circuits 9. PMCID: PMC4597482;DOI: 10.3389/fncir.2015.00054; 9: 54.
Jiang, Y., Purushothaman G. and Casagrande. V.A. (2015) The Functional Asymmetry of ON and OFF Channels in the Perception of Contrast. Journal of Neurophysiology. Vol. 114, 2816-2829; PMCID: PMC4737415.
Jiang, Y., Yampolsky, D., Casagrande, V.A. and Purushothaman, G. (2015) Perceptual Decision Related Activity in the Lateral Geniculate Nucleus (LGN). Journal of Neurophysiology, J Neurophysiol, 114(1), 717-35, 2015.
Purushothaman, G., Chen, X., Yampolsky, D. and Casagrande, V.A. (2014) Neural mechanisms of coarse-to-fine discrimination in the visual cortex. Journal of Neurophysiology,112:2822-2833. PCMCID: PMC4254879.
Ichida, J.M., Mavity-Hudson, J.A. and Casagrande, V.A. (2014) Distinct patterns of corticogeniculate feedback to different layers of the lateral geniculate nucleus (LGN). NIHMSID 666822, Eye and Brain, 6:57-73.
Shostak, Y., Wenger, A.E., Mavity-Hudson, J.A. and Casagrande, V.A. (2014) Metabotropic glutamate receptor 5 (mGluR5) shows different patterns of localization within the parallel visual pathways in macaque and squirrel monkeys. Eye and Brain, in press.
Ichida, J.M., Mavity-Hudson, J.A. and Casagrande, V.A. (2014) Distinct patterns of corticogeniculate feedback to different layers of the lateral geniculate nucleus (LGN). Eye and Brain, in press.
Li, K., Patel, J., Purushothaman, G., Marion, R.T. and Casagrande, V. A. (2013). Retinotopic maps in the pulvinar of bush baby (Otolemur garnettii) Journal of Comparative Neuroscience, in press.
Purushothaman, G. and Casagrande, V.A. (2013) A generalized ideal observer model for decoding sensory neural responses. Frontiers in Psychology, in press.
Marion, R., Purushothaman, G., Jiang, Y., Casagrande, V.A. (2013) Morphological and neurochemical comparisons between pulvinar and V1 projections to V2. Journal of Comparative Neurology,521: 813–832.
Fan, R.H., Baldwin, M.K., Jermakowicz, W.J., Casagrande, V.A., Kaas, J.H., Roe, A.W. (2012) Intrinsic signal optical imaging evidence for dorsal V3 in the prosimian galago (Otolemur garnettii)Journal of Comparative Neurology 520: 4254–4274.
Purushothaman, G., Marion, R., Li, K., and V. A. Casagrande (2012) Gating and control of primary visual cortex by pulvinar. Nature Neuroscience, 15, 905–912
Casagrande, V.A. and R.T. Marion, (2011) Processing in the Primary Visual Cortex In Adler’s Physiology of the Eye, 11th edition (A. Alm, P.L. Kaufman, (lead) L.A. Levin, S.F.E. Nilsson, J. Ver Hoeve and S.M. Wu, eds) Mosby, Elsevier, pp 586-598.
Casagrande, V.A. and J.M. Ichida (2011) Processing in the Lateral Geniculate Nucleus (LGN) In Adler’s Physiology of the Eye, 11th edition (A. Alm, P.L. Kaufman, (lead) L.A. Levin, S.F.E. Nilsson, J. Ver Hoeve and S.M. Wu, eds) Mosby, Elsevier, pp. 574-585.
Casagrande, V.A. and G. Purushothaman, (2009) Modularity. In Encyclopedia of Perception (E. Bruce Goldstein, ed). Thousand Oaks, CA: Sage Publications, pp 561-566.
Purushothaman, G., I. Khaytin, and V.A. Casagrande (2009) Quantification of optical images of cortical responses for inferring functional maps. J. Neurophysiol., 101, 2708-2724.
Jermakowicz, W.J., X. Chen, I. Khaytin, A.B. Bonds and V.A. Casagrande (2009) Relationship between spontaneous and evoked spike-time correlations in primate visual cortex. J. Neurophysiol., 101, 2279-2789.
Khaytin, I, Xin Chen, D.W. Royal, O. Ruiz, W.J. Jermakowicz, R.M. Siegel and Vivien A. Casagrande, (2008) Functional organization of temporal frequency selectivity in primate visual cortex.Cerebral Cortex 18: 1828-1842. PDF
Boyd, J.D., I. Khaytin, and V. A. Casagrande (2008) Comparative Evolutionary Aspects across Orders. In Encyclopedia of Neuroscience (Marc D., Hirokawa, Nobutaka, and Windhorst, U eds –Field editor A. Butler), Springer Berlin Heidelberg, pp. 1448-1455.
Casagrande, V.A., I. Khaytin, and J. Boyd (2008) Evolution of the Visual System: Mammals—Color Vision and the Function of Parallel Visual Pathways in Primates. In Encyclopedia of Neuroscience (Marc D., Hirokawa, Nobutaka, and Windhorst, U eds –Field editor A. Butler), Springer Berlin Heidelberg, pp. 1472-1475.
Jermakowicz, W.J. and Casagrande, V.A. (2007) Neuronal networks a century after Cajal. In A Century of Neuroscience Discovery: Reflecting on the 1906 Nobel Prizes to Golgi and Cajal. InBrain Research Reviews (L. Swanson, ed.), Elsevier, pp. 264-284 . PDF
Casagrande, V. A., F. Yazar, K.D. Jones, and Y. Ding (2007) The morphology of the koniocellular (K) axon pathway in the macaque monkey. Cerebral Cortex (17):2334-45. PDF
Xu, X,, Anderson, T.J., Casagrande, V.A. (2007) How do functional maps in primary visual cortex vary with eccentricity? Journal of Comparative Neurology 501, 741-755. PDF
Casagrande, V.A., Chen, X. and Jermakowicz, W.J. (2007) What language is spoken here? Conversations between neurons in primate visual cortex. In Advances in Cognitive Neurodynamics (R. Wang, F. Gu, E. Shen, eds.), Springer, pp. 27-30.
Casagrande, V.A., Chen*, X. and Jermakowicz*, W.J. (2007) What language is spoken here? Conversations between neurons in primate visual cortex. Advances in Cognitive Neurodynamics (Proceedings of the 1st International Conference on Cognitive Neurodynamics (ICCN-07)) and 3rd International conference on Physiological Biophysics – Cognitive Neurodynamics (ICCN2007 proceedings).
Casagrande, V.A., I. Khaytin, I., and J. Boyd (2007) The evolution of parallel visual pathways in primates. In Evolution of the Nervous System (T.M. Preuss and J. Kaas, eds.), vol. 4, pp. 87-108.PDF
Xu , X., Collins C.E., Khaytin, I., Kaas J. H., and V. A. Casagrande (2006). Unequal representation of cardinal versus oblique orientations in the middle temporal (MT) visual area. Proceedings for the National Academy of Sciences 103(46):17490-95. PDF
Ruiz, O., D. Royal, G. Sáry, X. Chen, J. D. Schall, and V. A. Casagrande (2006) Low-threshold Ca 2+ associated bursts are rare events in the LGN of the awake behaving monkey. Journal of Neurophysiology, 95:3401-13 . PDF
Elston, G.N., R. Benavides-Piccione, A. Elston, B. Zietsch, J. DeFelipe, P. Manger, V. Casagrande and J. Kaas (2006) Specializations of the granular prefrontal cortex of primates: implications for cognitive processing. Anatomical Record Part A 288A:26-35. PDF
Royal, D. W., Gy. Sáry, J.D. Schall, and V.A. Casagrande (2006) Correlates of motor planning and integration across visual fixations in the macaque monkey lateral geniculate nucleus (LGN).Experimental Brain Research 168:62-75. PDF
Xu, X., Bosking W. H., White, L. E., Fitzpatrick, D., & Casagrande, V.A. (2005) Functional organization of visual cortex in the prosimian bush baby revealed by optical imaging of intrinsic signals.Journal of Neurophysiology 94:2748–2762. PDF
Collins, C. E., X. Xu, I. Khaytin, P. M. Kaskan, V. A. Casagrande, J. H. Kaas (2005) Optical imaging of visually evoked responses in MT after deactivation of V1 in adult New World and prosimian primates. Proceedings for the National Academy of Sciences 102(15): 5594-5599. PDF
Casagrande, V. A., Gy. Sáry, D. Royal, and O. Ruiz (2005) On the impact of attention and motor planning on the lateral geniculate nucleus. In Cortical Function: A View from the Thalamus. ( V. A. Casagrande, S. M. Sherman and R. W. Guillery, eds). In Progress in Brain Research, vol. 149, pp. 11-29. PDF
Casagrande, V.A., R. Guillery, and S. Sherman, eds. (2005) Cortical function: a view from the thalamus (book). In Progress in Brain Research vol. 149, Amsterdam: Elsevier.
Elston, E., A. Elston, V. Casagrande, and J. H. Kaas (2005) Areal specialization of pyramidal cell structure in the visual cortex of the tree shrew (Tupaia belangeri): a new task revealed in the evolution of cortical circuitry. Experimental Brain Research 163:13-20. PDF
Elston, E., A. Elston, V. Casagrande, and J. H. Kaas (2005) Pyramidal neurons in granular prefrontal cortex of the bush baby complexity in the evolution of the psychic cell. Anatomical RecordPart A 285A:610–618. PDF
Elston, E., A. Elston, V. Casagrande, and J. H. Kaas (2005) Regional specialization of pyramidal cell structure in the cerebral cortex of the bush baby (Otolemur garnetti). Brain, Behavior, and Evolution, Vol. 66:10-20. PDF
Casagrande, V.A., Royal, D.W., Sáry, Gy. (2005) Extraretinal inputs and feedback mechanisms to the lateral geniculate nucleus (LGN). In The Primate Visual System: A Comparative Approach (Jan Kremers, ed.) Hoboken , New Jersey : John Wiley and Sons, pp. 191-206. PDF
- 1967-1968; 1970-72 NIH Predoctoral Traineeships
- 1972-1973 NIH NRSA Postdoctoral Fellowship
- 1977-1980 Academic Investigator Salary Award
- 1981 The Charles Judson Herrick Award for meritorious contributions to comparative neurology, presented by the American Association of Anatomists
- 1981-1986 Research Career Development Award
- 1998 President, Cajal Club
- 2006 AAAS Elected Fellow
- 2011 Fellow of the American Association of Anatomists
- 2012 Charles R. Park Award for Basic Research Revealing Insights into Physiology and Pathophysiology
- 2013 Chancellor's Award for Research
- Outstanding Teacher of the Year 2015-2016, Vanderbilt Brain Institute