MRM FOR MAPPING FUNCTIONAL ARCHITECTURE OF VISUAL CORTEX IN FERRETS

灵长类视皮层表面的光学研究 (cat，猴子，雪貂）已经表明，神经元是在 具有“斑点状”外观的相关组。 团体有 相关的反应，例如，刺激的条形物体， 一个给定的方向。 其他重叠组的反应相似 不同方向的酒吧。 一个群体的规模大约是 五百微米。 光学技术对 由于代谢增加而发生的氧合血红蛋白-血红蛋白转变 当神经元受到刺激时。 光学技术有限， 到大脑中大约100微米的可视深度。 这个目标 研究的目的是在不同的深度研究这种结构， 大脑皮层超出了光学手段所能到达的范围。 梯度回波 3D MR显微镜提供了一个独特的机会，作为唯一的方法， 进行这样的研究。 建议进行的是一项试验性研究， 在雪貂的视皮层中获得3D图像（@7T）， 当动物受到视觉刺激时， 使用已经验证的刺激方案来评估 MR显微镜在此应用中的潜力。 的目的 试点项目将制定一项MRI协议， 功能成像 我们将尝试3D投影成像以及3D 旋转曲速接近 此外，还必须确保 雪貂可以在7 T系统中得到充分的支持， 光学刺激系统将在磁体中/附近起作用。 注意 调查人员已经经常使用气体（氟烷） 在几个小时内对这些动物进行麻醉 实验，并在该领域的经验和出版物。

Optical studies of the surface of the optical cortex of primates (cat, monkey, ferret) have shown that the neurons are organized in correlated groups having a 'blobby' appearance. Groups have a correlated response to, for example, stimuli by bar-shaped objects of a given orientation. Other, overlapped groups have similar response to differently oriented bars. The size of a group is on the order of 500 microns. The optical techniques are sensitive to the oxyhemoglobin-hemoglobin shift that occurs due to increased metabolism when the neurons are stimulated. The optical techniques are limited to viewing depths in the brain of about 100 microns. The goal of this research is to study this structure at a variety of depths in the cerebral cortex beyond those reached by optical means. Gradient echo 3D MR microscopy offers a unique opportunity as the only method to perform this kind of study. What is proposed is a pilot study to obtain 3D images (@ 7T) in the optical cortex of a ferret with 100 micron isotropic resolution while the animal is visually stimulated with an already validated stimulation protocol to evaluate the potential of MR microscopy in this application. The purpose of the pilot project will be to develop an MRI protocol for adequate functional imaging. We will try 3D projection imaging as well as 3D spin warp approaches. In addition, it will be necessary to ensure that the ferret can be adequately supported in the 7T system and that the optical stimulation system will function in/near the magnet. Note that the investigators already routinely use gas (halothane) anesthesia on these animals over the course of a several hour experiment and have experience and publications in the area.