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Gao Y.,Vanderbilt University | Brantley-Sieders D.,Vanderbilt University | Majumdar D.,Kennedy Center for Research on Human Development | Webb D.,Kennedy Center for Research on Human Development | Li D.,Vanderbilt University
ASME 2012 3rd International Conference on Micro/Nanoscale Heat and Mass Transfer, MNHMT 2012 | Year: 2012

Cells communicate with one another through a huge variety of extracellular soluble signaling molecules. A common method in biology to investigate the signaling pathways is to inactivate the gene coding the interested ligand or receptor from cells using modern DNA technology, known as gene knockout. Even though very effective, however, gene knockout is a timeconsuming and cost-prohibitive process and requires huge amount of efforts to conduct. Here we present a simple method to probe the extracellular signaling pathways through engineering a semi-permeable barrier between two cell populations. In this approach, ligand traps, receptor-coated nano/micro-particles, are embedded inside the nanoporous barrier. Because the receptors have the ability to selectively bind to certain ligand(s) with high affinity, the associated ligands can be 'trapped' inside the barrier when they try to perfuse from one cell population to the other. As a result, the targeted soluble ligands can be effectively blocked from the molecular exchange between the two cell populations. We have demonstrated the feasibility of this novel approach using fluorescent proteins. An analytical model has also been developed to guide the design of the ligand-trap-embedded barrier. Copyright © 2012 by ASME.


Royal D.W.,Kennedy Center for Research on Human Development | Krueger J.,Kennedy Center for Research on Human Development | Fister M.C.,Vanderbilt University | Wallace M.T.,Kennedy Center for Research on Human Development | Wallace M.T.,Vanderbilt University
Restorative Neurology and Neuroscience | Year: 2010

Purpose: Previous work has established that the integrative capacity of multisensory neurons in the superior colliculus (SC) matures over a protracted period of postnatal life (Wallace and Stein, 1997), and that the development of normal patterns of multisensory integration depends critically on early sensory experience (Wallace et al., 2004). Although these studies demonstrated the importance of early sensory experience in the creation of mature multisensory circuits, it remains unknown whether the reestablishment of sensory experience in adulthood can reverse these effects and restore integrative capacity. Methods: The current study tested this hypothesis in cats that were reared in absolute darkness until adulthood and then returned to a normal housing environment for an equivalent period of time. Single unit extracellular recordings targeted multisensory neurons in the deep layers of the SC, and analyses were focused on both conventional measures of multisensory integration and on more recently developed methods designed to characterize spatiotemporal receptive fields (STRF). Results: Analysis of the STRF structure and integrative capacity of multisensory SC neurons revealed significant modifications in the temporal response dynamics of multisensory responses (e.g., discharge durations, peak firing rates, and mean firing rates), as well as significant changes in rates of spontaneous activation and degrees of multisensory integration. Conclusions: These results emphasize the importance of early sensory experience in the establishment of normal multisensory processing architecture and highlight the limited plastic potential of adult multisensory circuits. © 2010 - IOS Press and the authors. All rights reserved.


PubMed | Kennedy Center for Research on Human Development
Type: Journal Article | Journal: Restorative neurology and neuroscience | Year: 2010

Previous work has established that the integrative capacity of multisensory neurons in the superior colliculus (SC) matures over a protracted period of postnatal life (Wallace and Stein, 1997), and that the development of normal patterns of multisensory integration depends critically on early sensory experience (Wallace et al., 2004). Although these studies demonstrated the importance of early sensory experience in the creation of mature multisensory circuits, it remains unknown whether the reestablishment of sensory experience in adulthood can reverse these effects and restore integrative capacity.The current study tested this hypothesis in cats that were reared in absolute darkness until adulthood and then returned to a normal housing environment for an equivalent period of time. Single unit extracellular recordings targeted multisensory neurons in the deep layers of the SC, and analyses were focused on both conventional measures of multisensory integration and on more recently developed methods designed to characterize spatiotemporal receptive fields (STRF).Analysis of the STRF structure and integrative capacity of multisensory SC neurons revealed significant modifications in the temporal response dynamics of multisensory responses (e.g., discharge durations, peak firing rates, and mean firing rates), as well as significant changes in rates of spontaneous activation and degrees of multisensory integration.These results emphasize the importance of early sensory experience in the establishment of normal multisensory processing architecture and highlight the limited plastic potential of adult multisensory circuits.

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