Desenvolvimento de metodos opticos para o estudo do acoplamento neuro-vascular-metabolico intrinseco a dinamica cerebral / Development of optical methods to the study of neuro-metabolic-vascular coupling underlying cerebral dynamics

AUTOR(ES)
DATA DE PUBLICAÇÃO

2009

RESUMO

Task-associated neuronal activity leads to a complex chain of biological events within the brain. The increased energetics gives rise to elevated glucose and oxygen consumption in the tissue. Biochemical and neuronal factors induce changes in blood vessels and variations in blood ow, volume and oxygenation. Although it has been extensively investigated, this cascade of events is still poorly understood and highly debated. In this project, the aim was to describe the coupling among the cellular, metabolic and vascular levels associated to functional brain activation. Using electrophysiological measurements, we modeled the neuro-vascular and neuro-metabolic systems in order to describe cerebral hemodynamics as seen through optical techniques. Results obtained in rats during whisker-barrel stimulation showed that the determination of a response function for each system, assumed as linear, can describe the hemodynamic behavior and allow the study of the vascular and metabolic states characterized by the measurements. From multimodal experiments of NIRS and fMRI, we developed unique methods to the determination of metabolic images, which can predict changes in oxygen consumption with good temporal and spatial resolution. Finally, we analyzed the in uence of the physiology in the optical signal, and showed the importance of taking into account blood pressure oscillations into this signal. Measurements of temporal correlation were projected to generate vascular correlation maps that may be useful to the study of cerebral vascular connectivity, both in normal subjects and in patients with cerebral pathologies

ASSUNTO(S)

near-infrared spectroscopy neuroimagem funcional acoplamento neurovascular neurovascular coupling tomografia otica de difusão functional neuroimaging espectroscopia no infravermelho proximo diffuse optical imaging

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