MRM FOR MAPPING FUNCTIONAL ARCHITECTURE OF VISUAL CORTEX IN FERRETS

灵长类视皮层表面的光学研究 (猫、猴子、雪貂)的研究表明，神经元是在 相互关联的群体有一种“花花公子”的外表。小组有一个 例如，条形物体对刺激的相关响应 给定的方位。其他重叠的群体也有类似的反应 到不同方向的酒吧。一个小组的大小约为 500微米。光学技术对 氧合血红蛋白--由于新陈代谢增强而发生的血红蛋白移动 当神经元受到刺激时。光学技术是有限的 到观察大脑中约100微米的深度。这样做的目的是 研究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达到的范围。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点研究，以 在100度雪貂的视皮层中获得3D图像(@7T) 动物受到视觉刺激时的微米各向同性分辨率 已经经过验证的刺激方案来评估 磁共振显微镜在这方面的应用潜力。该计划的目的是 试点项目将是制定一项足够的磁共振成像方案 功能成像。我们将尝试3D投影成像以及3D 自旋翘曲接近了。此外，还必须确保 雪貂可以在7T系统中得到足够的支撑，并且 光学刺激系统将在磁铁内部/附近起作用。备注 调查人员已经经常使用气体(氟烷) 在几个小时的时间里麻醉了这些动物 在该领域进行实验，并有经验和出版物。

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.