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| Author(s): |
Nathalia Lopes Vieira Peixoto
Total Authors: 1
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| Document type: | Doctoral Thesis |
| Press: | São Paulo. |
| Institution: | Universidade de São Paulo (USP). Escola Politécnica (EP/BC) |
| Defense date: | 2001-03-22 |
| Examining board members: |
Francisco Javier Ramírez Fernandez;
Andre Fabio Kohn;
Josuê Bruginski de Paula;
Luiz Carlos de Lima Silveira;
Maria Lucia Furlan Wada
|
| Advisor: | Francisco Javier Ramírez Fernandez |
| Abstract | |
This work reports results on a series of interactions between micro-fabricated structures and dissociated neuronal cultures. Main outcomes range from axonal branching modification as a consequence of substrate mechanical manipulations to spiking behavior control depending on electrical stimulus frequency. Microelectrode arrays are designed, fabricated and characterized aiming at extracellular signal acquisition, electrical stimulation, and culturing of neural cells extracted from Helix aspersa maxima. Visualization of stimuli and spiking triples is accomplished by means of the sequential interval state-space representation. The partitional clustering technique is employed in order to evaluate neuronal responses to electrical \"stimuli\". A clear beating behavior is observed for train stimuli of up to 1 Hz and pulse period of 100ms, whereas response pattern becomes stimuli-independent for higher train frequencies. Among the results obtained with individually cultured neurons one may enumerate the observation of contact inhibition and the estimation of charge density threshold from decimals to units of \'MICROMETROS\'/\'cm POT. 2\', establishing a lower limit for extracellular stimulation. In short, maintenance of one or a few cells in culture on microstructured substrates has proven useful for the investigation of cell development and spiking behavior analysis, to an extent not yet possible with either neural nets or planar multielectrode arrays. (AU) | |
| FAPESP's process: | 98/02911-9 - Neuro-electronic matrices |
| Grantee: | Nathalia Lopes Vieira Peixoto |
| Support Opportunities: | Scholarships in Brazil - Doctorate |