FUNCTIONAL MODULARITY OF CORTEX

有许多关于处理 目前还没有答案的体感信息。为 实例中，哪些皮质区域依赖于来自 丘脑对它们的激活？哪些领域依赖于直接 用于激活的皮质输入？什么是串联和并行皮质 躯体信息通常被处理的途径是什么？此外, 虽然躯体感觉皮层区域之间的模块投影是已知的 为了生存，这种模块化组织对躯体的贡献 处理过程不被理解。最后，早期的研究已经证明 大脑皮层的躯体定位图具有惊人的能力 对周围或中央的扰动作出反应而重组 神经系统，即使在成年灵长类中也是如此。然而，通过这些机制 目前尚不清楚是否会发生这样的重组。通过进行组合 消融/记录实验我们将确定是否直接丘脑 到包括顶前的区域(3a、3b、1和2)的投射 大脑皮层(APC)足以激活这些神经元中的每一个 在没有皮质输入的情况下的单个区域，或者可替换地， 躯体是否需要来自其他APC区的皮质输入 激活这些区域。在APC内的相关实验中， 躯体激活的一个皮质区域对另一个皮质区域的依赖将 确定，并确定串行和并行处理路径。 当然，知道功能性的解剖学基础 激活APC中的神经元是获得完整图像的关键 体感信息是如何处理的。我们计划进行 生理标测与解剖示踪相结合的有序研究 在体视学上确定大脑皮质和皮质下的所有连接 APC内每个区域中的匹配部分，确定收敛或 这种连接在投影目标上的发散，相互关联 消融/记录实验的电生理发现 连接的层流模式，并确定功能 相互交错的投影的意义，如果有的话 APC内的区域到第二躯体感觉区，SII。其他内容 解剖学研究将确定脑干的正常投射 丘脑核团(三叉神经核或V脊束核) 可以解释以下大脑皮质中面部表征的扩展 背根切断术。在另一项研究中，我们将确定 丘脑、APC和SH的重组能力相似，或 不同，通过记录同一动物的所有三个结构 在手的外周去传入之后。了解 大脑皮层地形图功能重组的机制 损伤后的中枢和外周神经系统可能会让我们 利用大脑皮层这种巨大的重组能力 治疗效果。

There are a number of fundamental questions regarding processing of somatosensory information for which there are currently no answers. For instance, Which cortical areas are dependent upon direct projections from the thalamus for their activation? Which areas depend upon direct cortical inputs for activation? What are the serial and parallel cortical pathways by which somatic information is normally processed? In addition, while modular projections between somatosensory cortical areas are known to exist, the contribution of such modular organization to somatic processing is not understood. Finally, earlier studies have demonstrated that somatotopic maps in the cerebral cortex have a remarkable capacity to reorganize in response to perturbations of the peripheral or central nervous system, even in adult primates. However, the mechanisms by which such reorganization occurs is not known. By conducting combined ablation/recording experiments we will determine if direct thalamic projections to the areas (3a, 3b, 1 and 2) comprising anterior parietal cortex (APC) are sufficient to activate neurons in each of these individual areas in the absence of cortical inputs, or alternatively, whether cortical inputs from other APC areas are necessary for somatic activation of these areas. In related experiments within APC, the dependency of one cortical area on another for somatic activation will be determined, and serial and parallel processing pathways identified. Of course knowing the anatomical substrates underlying the functional activation of neurons in APC is essential to obtain a complete picture of how somatosensory information is processed. We plan to conduct combined physiological mapping and anatomical tracing studies in order to determine all cortical and subcortical connections of somatotopically matched portions in each area within APC, determine the convergence or divergence of such connections on projection targets, correlate electrophysiological findings from the ablation/recording experiments with laminar patterns of connections and determine the functional significance, if any, of the interdigitation of projections from each of the areas within APC to the second somatosensory area, SII. Additional anatomical studies will determine if normal projections from brain stem nuclei (trigeminal nucleus or the spinal nucleus of V) to the thalamus can account for expansion of-the face representation in cortex following dorsal rhizotomies. In another study we will determine if the reorganizational capacity of the thalamus, APC and SH is similar, or different, by recording from all three structures in the same animal after peripheral deafferentation of the hand. Understanding the mechanisms responsible for functional reorganization of cortical maps after injury to the central and peripheral nervous system may allow us to harness this immense reorganizational capacity of cortex for therapeutic benefit.