Dr. Fidel Santamaria
My laboratory studies the structural properties of dendrites that allow them to implement computational functions to process information and store memories. The influence of dendritic structure on the electrical properties of neurons has been intensely studied over 50 years; however, the question of how dendritic structure affects biochemical computation remains a very open topic of research. For example, from my work as well as the work of others in the field, it is now clear that not only the physical structure of dendrites, but also their cytostolic structure and organization affect computation. My research therefore addresses dendritic structure over a wide range of spatial scales, from nanoscopic to the whole dendrite.
At present, our work is specifically focused on understanding how dendritic structure controls the reliability and specificity of the biochemical signals that underlie synaptic activity and plasticity. This is an important problem because it is not yet understood how the relatively low numbers of molecules in a synapse can support reliable memory storage especially given the inherently noise nature of biochemical cascades. Our recent work has specifically shown that the complexity of dendritic structure, in this case the diversity and density of dendritic spines modifies the environmental diffusion of dendrites breaking down the classical laws of diffusion, named anomalous diffusion. We have been able to map spine density to the dendrite’s biochemical environment measured as the level of anomalous diffusion. The biological implications of this break-down are that the reaction rates that were assumed to be noisy at low concentrations may actually be much more efficient than previously expected, resulting in more reliable synapses processes.
Each of our efforts are undertaken using combined and interacting computational, theoretical, and experimental approaches in order to develop a unified framework to understand how dendritic structure affects biochemical processing. We believe that this framework can be applied at multiple scales, from glutamate receptors moving in and out of the synapse, to large scale heterogeneous networks of spiking neurons.
For more information please visit my lab website http://www.utsa.edu/SantamariaLab
Kereselidze Z, Romero VH, Peralta XG, Santamaria F. (2012) Gold Nanostar Synthesis with a Silver Seed Mediated Growth Method. Journal of Visualized Experiments. DOI: 10.3791/3570
Santamaria F, Wils S, De Schutter E, Augustine GJ. (2011). The diffusional properties of dendrites depend on the density of dendritic spines. Eur. J. Neurosci. DOI: 10.1111/j.1460-9568.2011.07785.x.
Commentary: Anomalous diffusion imposed by dendritic spines (Commentary on Santamaria et al.) DOI: 10.1111/j.1460-9568.2011.07809.x
Valdez CM, Smith MA, Perry G, Phelyx DF, Santamaria F (2011) Modeling cholesterol metabolism by gene expression profiling in the hippocampus. Mol. Biosyst., DOI:10.1039/C0MB00282H
Santamaria F, Gonzalez J, Augustine GJ, and Ragavachari S. (2010). Quantifying the effects of elastic collisions and non-covalent binding on glutamate receptor trafficking in the post-synaptic density. PLoS Comp. Bio. 6(5):e1000780. doi:10.1371/journal.pcbi.1000780
Coop AD, Cornelis H, and Santamaria F (2010). Dendritic excitability modulates dendritic information processing in a Purkinje cell model. Front. Comput. Neurosci. 4:6. doi:10.3389/fncom.2010.00006.
Valdez CM , Smith MA, Perry G, Phelyx CF, Santamaria F (2010). Cholesterol homeostasis markers are localized to mouse hippocampal pyramidal and granule layers. Hippocampus. doi: 10.1002/hipo.20743.
Augustine GJ, Santamaria F, Wils S, DeSchutter E (2009) Trapping of diffusing molecules by dendritc spines Journal of Neurochemistry. pp 69-69.
Santamaria F and Bower JM (2008). Theoretical and Computational Neuroscience: Hodgkin-Huxley models. The New Encyclopedia of Neuroscience. Elsevier.