F MRI STUDY OF TASTE CORTEX USING FOCAL STIMULI

这项提议的短期目标是确定人类皮层味觉处理的位置是否取决于舌头上味觉刺激的位置。 我们将构建并测试一种味觉刺激器，用于将化学味觉刺激施加到舌头的离散部分，并使用功能性磁共振成像（fMRI）观察由此产生的中枢激活。 我们假设，在初级味觉皮层以及在一些第二或更高级别的皮层味觉区的味觉加工将主要是在右半球的右手科目，无论一侧的舌头，刺激。 我们还假设，味觉信息从后舌的轮廓乳头将在不同的部分处理的初级味觉皮层比从菌状乳头的前舌。 长期目标包括左利手和右利手受试者的比较，以及检查对其他味蕾区域刺激的反应。长期目标是了解味觉系统外周损伤的生物学反应的性质和局限性。 人类味觉系统的外周部分包括5个不同的味蕾区域，由3个颅神经的至少4个分支支配。 因此，由外周病变或疾病引起的味觉功能丧失很少是完全的。 例如，味觉神经之一，鼓索，经常在口腔手术、中耳手术或疾病（例如贝尔氏麻痹）中受损。 剩余的完整味蕾和它们的神经纤维通常可以介导相对正常的感知。 中枢补偿机制可能是这种恢复的部分原因。 揭示这种补偿机制的一个必要步骤是建立正常的中枢激活模式，这些模式是由味蕾的各个区域的选择性刺激引起的。

The short term goals of this proposal are to determine whether the location of cortical taste processing in humans depends on the location of the taste stimulus on the tongue. We will construct and test a taste stimulator for applying chemical taste stimuli to discrete parts of the tongue and observe the resulting central activation with functional magnetic resonance imaging (fMRI). We hypothesize that taste processing in the primary gustatory cortex as well as in some second or higher order cortical taste areas will be mostly in the right hemisphere in right handed subjects regardless of the side of the tongue that was stimulated. We also hypothesize that taste information from the vallate papillae on the posterior tongue will be processed in a different part of the primary gustatory cortex than that from the fungiform papillae on the anterior tongue. Long term goals include the comparison of left and right handed subjects, and examination of responses to stimulation of other taste bud fields. A long term objective is to understand the nature and limitations of the biological response to peripheral damage to the taste system. The peripheral part of the human taste system includes 5 distinct fields of taste buds, innervated by at least 4 branches of 3 cranial nerves. Thus loss of taste function resulting from peripheral lesions or disease is rarely complete. For example, one of the taste nerves, the chorda tympani, is often damaged during oral surgery, middle ear surgery, or from disease (e.g. Bell's Palsy). The remaining intact taste buds and their innervating nerve fibers can often mediate relatively normal perception. Central compensatory mechanisms may be partially responsible for this recovery. A necessary step for revealing such compensatory mechanisms is to establish normal patterns of central activation resulting from selective stimulation of the individual fields of taste buds.