Este trabalho apresenta o desenvolvimento de um estimulador galvânico vestibular para ser usado em experimentos de imageamento por ressonância magnética funcional (fMRI). Em experiências de fMRI é necessário a produção de estímulos somatossensoriais no paciente. Os estímulos devem ser sincronizados com a sequência de pulsos da fMRI. O estimulador foi dividido em circuitos analógicos (colocados dentro da sala do magneto) e circuitos digitais (sala de comando do sistema de MRI). A comunicação entre os circuitos é feita através de fibra óptica. Experimentos de fMRI realizados com voluntários demonstraram que o estimulador proposto é capaz de manter a sincronização com sistema de fMRI e pode ser usado para localizar as áreas do cérebro que são ativados pelo sistema vestibular. / This work presents the development of a galvanic vestibular stimulator to be used in functional magnetic resonance imaging experiments (fMRI). In fMRI experiments it is required the production of somatosensory stimuli in the patient must be sincronized with the fMRI pulse sequence. The stimulator circuits were divided in analog circuits (placed within the magnet room) and digital circuits (placed in the MRI command room). The communication between the circuits is made through optical fiber. fMRI experiments performed with volunteers demonstrated that the proposed stimulator is able to keep the sincronization with the MRI system and can be used to locate the brain areas that are activated by the vestibular system.

Este trabalho apresenta o desenvolvimento de um estimulador galvânico vestibular para ser usado em experimentos de imageamento por ressonância magnética funcional (fMRI). Em experiências de fMRI é necessário a produção de estímulos somatossensoriais no paciente. Os estímulos devem ser sincronizados com a sequência de pulsos da fMRI. O estimulador foi dividido em circuitos analógicos (colocados dentro da sala do magneto) e circuitos digitais (sala de comando do sistema de MRI). A comunicação entre os circuitos é feita através de fibra óptica. Experimentos de fMRI realizados com voluntários demonstraram que o estimulador proposto é capaz de manter a sincronização com sistema de fMRI e pode ser usado para localizar as áreas do cérebro que são ativados pelo sistema vestibular. / This work presents the development of a galvanic vestibular stimulator to be used in functional magnetic resonance imaging experiments (fMRI). In fMRI experiments it is required the production of somatosensory stimuli in the patient must be sincronized with the fMRI pulse sequence. The stimulator circuits were divided in analog circuits (placed within the magnet room) and digital circuits (placed in the MRI command room). The communication between the circuits is made through optical fiber. fMRI experiments performed with volunteers demonstrated that the proposed stimulator is able to keep the sincronization with the MRI system and can be used to locate the brain areas that are activated by the vestibular system.

Made available in DSpace on 2014-12-17T15:16:09Z (GMT). No. of bitstreams: 1 AdrianaJOB_DISSERT.pdf: 1566198 bytes, checksum: 766db20794ef85bc19aa4a81b03784d3 (MD5) Previous issue date: 2010-08-30 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / To the vertebrates, maintain body balance against the gravitational field and be able to orient themselves in the environment are fundamental aspects for survival, in which the participation of vestibular system is essential. As part of this system, the vestibular nuclear complex is the first central station that, by integrating many information (visual, proprioceptive), and the vestibular, assumes the lead role in maintaining balance. In this study, the vestibular nuclear complex was evaluated in relation to its cytoarchitecture and neurochemical content of cells and axon terminals, through the techniques of Nissl staining and immunohistochemistry for neuronal specific nuclear protein (NeuN), glutamate (Glu), substance P (SP), choline acetyltransferase (ChAT) (enzyme that synthesizes acetylcholine-Ach) and glutamic acid decarboxylase (GAD) (enzyme that synthesizes gamma-amino butyric acid-GABA). The common marmoset (Callithrix jacchus) was used as experimental animal, which is a small primate native from the Atlantic Forest in the Brazilian Northeast. As results, the Nissl technique, complemented by immunohistochemistry for NeuN allowed to delineate the vestibular nucleus superior, lateral, medial and inferior (or descending) in the brain of the common marmoset. Neurons and terminals immunoreactive to Glu and ChAT and only immunoreactive terminals to SP and GAD were seen in all nuclei, although in varying density. This study confirms the presence in the vestibular nuclei of the common marmoset, of Glu and SP in terminals, probably from the first order neurons of vestibular ganglion, and of GABA in terminals, presumably from Purkinge cells of the cerebellum. Second-order neurons of the vestibular nuclei seem to use Glu and Ach as neurotransmitters, judging by their expressive presence in the cell bodies of these nuclei in common marmosets, as reported in other species / Para os vertebrados, manter o equil?brio corporal contra o campo gravitacional e ser capaz de orientar-se no ambiente s?o aspectos fundamentais para a sobreviv?ncia, nos quais ? essencial a participa??o do sistema vestibular. Como parte deste sistema, o complexo nuclear vestibular ? a primeira esta??o central que, ao integrar v?rias informa??es (visual, proprioceptiva), al?m da vestibular, assume o papel principal na manuten??o do equil?brio. Neste estudo, o complexo nuclear vestibular do sagui foi avaliado com rela??o a sua citoarquitetura e conte?do neuroqu?mico de c?lulas e terminais ax?nicos, atrav?s das t?cnicas de colora??o de Nissl e imuno-histoqu?mica para prote?na neuronal nuclear espec?fica (NeuN), glutamato (Glu), subst?ncia P (SP), colina acetiltransferase (ChAT) (enzima de s?ntese da acetilcolina-Ach), e descarboxilase do ?cido glut?mico (GAD) (enzima de s?ntese do ?cido gama-amino-but?rico-GABA). Foi utilizado como animal experimental o sagui (Callithrix jacchus), um pequeno primata nativo da Mata Atl?ntica do Nordeste Brasileiro. Como resultados, a t?cnica de Nissl, complementada pela imuno-histoqu?mica para NeuN, permitiu delinear os n?cleos vestibulares superior, lateral, medial e inferior (ou descendente) no enc?falo do sagui. Neur?nios e terminais imunorreativos a Glu e ChAT e apenas terminais imunorreativos a SP e GAD foram vistos em todos os n?cleos, embora em densidade vari?vel. Este trabalho confirma a presen?a nos n?cleos vestibulares do sagui, de Glu e SP em terminais, provavelmente provenientes dos neur?nios de primeira ordem do g?nglio vestibular, e de GABA em terminais, supostamente provenientes das c?lulas de Purkinge do cerebelo. Neur?nios de segunda ordem dos n?cleos vestibulares parecem usar Glu e Ach como neurotransmissores, a julgar pela sua expressiva presen?a em peric?rios destes n?cleos no sag?i, como relatado em outras esp?cies

CAPES / This master thesis presents the further development of a galvanic vestibular stimulator for use in fMRI examinations developed in a previous thesis (MANCZAK, 2012). This thesis amends the GVS by circuits to measure feedback values and implements the stimulation circuit with digital components, such as a microcontroller and flyback integrated circuits. The microcontroller is used in order to control the current source and process the measured values. The communication between the PC, which allows user interaction through a graphical user interface, and the microcontroller is implemented through optical communication, which is defined by a communication protocol specification. The digital circuitry is designed to be placed within the MRI room, meeting the requirements imposed by strong magnetic fields and radio frequency pulses. The underlying hypothesis of the thesis is that the device can be placed within the MRI room without having a negative impact on the MRI image quality. Laboratory tests without the MRI confirmed the correct design of the galvanic vestibular stimulator.

CAPES / This master thesis presents the further development of a galvanic vestibular stimulator for use in fMRI examinations developed in a previous thesis (MANCZAK, 2012). This thesis amends the GVS by circuits to measure feedback values and implements the stimulation circuit with digital components, such as a microcontroller and flyback integrated circuits. The microcontroller is used in order to control the current source and process the measured values. The communication between the PC, which allows user interaction through a graphical user interface, and the microcontroller is implemented through optical communication, which is defined by a communication protocol specification. The digital circuitry is designed to be placed within the MRI room, meeting the requirements imposed by strong magnetic fields and radio frequency pulses. The underlying hypothesis of the thesis is that the device can be placed within the MRI room without having a negative impact on the MRI image quality. Laboratory tests without the MRI confirmed the correct design of the galvanic vestibular stimulator.