Navegando por Autor "Rennó-Costa, César"
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Artigo Computational models of memory consolidation and long-term synaptic plasticity during sleep(2018-10-11) Rennó-Costa, César; Silva, Ana Cláudia Costa da; Blanco, Wilfredo; Ribeiro, Sidarta Tollendal GomesThe brain stores memories by persistently changing the connectivity between neurons. Sleep is known to be critical for these changes to endure. Research on the neurobiology of sleep and the mechanisms of long-term synaptic plasticity has provided data in support of various theories of how brain activity during sleep affects long-term synaptic plasticity. The experimental findings – and therefore the theories – are apparently quite contradictory, with some evidence pointing to a role of sleep in the forgetting of irrelevant memories, whereas other results indicate that sleep supports the reinforcement of the most valuable recollections. A unified theoretical framework is in need. Computational modeling and simulation provide grounds for the quantitative testing and comparison of theoretical predictions and observed data, and might serve as a strategy to organize the rather complicated and diverse pool of data and methodologies used in sleep research. This review article outlines the emerging progress in the computational modeling and simulation of the main theories on the role of sleep in memory consolidationArtigo Place and grid cells in a loop: implications for memory function and spatial coding(2017-07-12) Rennó-Costa, César; Tort, Adriano Bretanha LopesPlace cells in the hippocampus and grid cells in the medial entorhinal cortex have different codes for space. However, how one code relates to the other is ill understood. Based on the anatomy of the entorhinal-hippocampal circuitry, we constructed a model of place and grid cells organized in a loop to investigate their mutual influence in the establishment of their codes for space. Using computer simulations, we first replicated experiments in rats that measured place and grid cell activity in different environments, and then assessed which features of the model account for different phenomena observed in neurophysiological data, such as pattern completion and pattern separation, global and rate remapping of place cells and realignment of grid cells. We found that (1) the interaction between grid and place cells converges quickly; (2) the spatial code of place cells does not require - but is altered by - grid cell input; (3) plasticity in sensory inputs to place cells is key for pattern completion but not pattern separation; (4) grid realignment can be explained in terms of place cell remapping as opposed to the other way around; (5) the switch between global and rate remapping is self-organized; (6) grid cell input to place cells helps stabilize their code under noisy and/or inconsistent sensory input. We conclude that the hippocampus-entorhinal circuit uses the mutual interaction of place and grid cells to encode the surrounding environment and propose a theory on how such interdependence underlies the formation and use of the cognitive map.TCC Receptores ionotrópicos como força motriz da origem das sinapses(Universidade Federal do Rio Grande do Norte, 2020-11-30) Imparato, Danilo Oliveira; Dalmolin, Rodrigo Juliani Siqueira; Sequerra, Eduardo Bouth; Rennó-Costa, CésarA origem dos sistemas nervosos é um dos principais temas da biologia e seus mecanismos são majoritariamente determinados pela neurotransmissão sináptica. Uma dificuldade para explicar o estabelecimento das sinapses é que ortólogos sinápticos estão presentes em diversos organismos aneurais. Nós investigamos como as interações entre esses elementos evoluíram e até que ponto isso está relacionado com nosso entendimento da complexidade dos sistemas nervosos. Nós identificamos a rede de genes de neurotransmissão humana com base nos genes presentes nos sistemas GABAérgico, glutamatérgico, serotoninérgico, dopaminérgico e colinérgico. A rede final engloba 321 genes, dos quais 83 atuam exclusivamente no sistema nervoso. Nós reconstruímos o cenário evolutivo do surgimento da sinapse humana através da busca por ortólogos sinápticos em 476 espécies eucarióticas. O ancestral comum mais recente (ACMR) entre cnidários e humanos se apresentou como ponto de enraizamento de uma grande quantidade de genes humanos neuroexclusivos, em especial receptores ionotrópicos, que podem ter sido cruciais para o estabelecimento das sinapses. Poucos genes sinápticos enraizaram depois do ACMR Humano-Cnidaria. Também identificamos uma maior abundância de proteínas sinápticas em vertebrados, sugerindo um aumento na complexidade da rede de genes de neurotransmissão desses organismos.Artigo Synaptic Homeostasis and Restructuring across the Sleep-Wake Cycle(Aldo A Faisal, Imperial College London, UNITED KINGDOM, 2015-05-28) Blanco, Wilfredo; M. Pereira, Catia; R. Cota, Vinicius; C. Souza, Annie; Rennó-Costa, César; Santos, Sharlene; Dias, Gabriella; Guerreiro, Ana M. G.; Tort, Adriano Bretanha Lopes; D. Neto, Adrião; Ribeiro, Sidarta Tollendal Gomes