Role of Sensory Experience in Parcellation of Sensory Neocortex

9511430帕拉斯这项研究的总体目标是确定大脑皮层的不同区域如何变得专门化以处理不同类型的感觉信息，以及在发育和进化过程中，功能专门化的大脑回路如何从非专门化的脑组织中产生。 正在测试的假设是，皮层在发育过程中接受的感觉输入在组织皮层中的特定回路中起着关键作用。 为了验证这一假设，将在三组动物中研究听觉皮层;一组在出生时将听觉皮层的感觉输入移除，另一组通过小手术将视觉输入转移到出生时的听觉通路，第三组由正常的未操纵动物组成。 然后，我们将研究听觉皮层的回路是如何受到这些感官经验操纵的影响的。使用重新布线操作，先前已经表明，听觉皮层可以通过从出生时就向其提供视觉输入而“变成”视觉皮层。 尚待研究的问题是，这是因为早期的视觉输入改变了听觉皮层的回路，还是因为听觉皮层与视觉皮层非常相似，它具有适当处理视觉输入的内在能力。 初步结果表明，视觉输入确实会引起电路的变化。 然后，我们将使用解剖学方法来检查听觉皮层的电路，以确定这些变化究竟是什么，以及它们如何产生已经观察到的功能变化。 了解感觉输入在发育过程中如何影响皮层回路，将提供有关感觉器官的进化变化如何最终被中枢神经系统所适应的信息。 因此，这项研究将提供有关皮质发育机制和中枢神经系统复杂结构进化的基础信息。

9511430 Pallas The overall goal of this research is to determine how different areas of the cerebral cortex become specialized to process different types of sensory information, and how functionally specialized brain circuitry is created from non-specialized brain tissue during development and evolution. The hypothesis being tested is that the sensory inputs received by cortex during development play a critical role in organizing specific circuits in cortex. To test this hypothesis, auditory cortex will be studied in three groups of animals; one group which has had sensory input to auditory cortex removed at birth, another group which, by a minor surgical procedure, has had visual input diverted into the auditory pathway at birth, and a third group which consists of normal, unmanipulated animals. How the circuitry of auditory cortex is affected by these manipulations of sensory experience will then be examined. Using the rewiring manipulation, it has been shown previously that auditory cortex can be "turned into" visual cortex by supplying it with visual input from birth. The question yet to be investigated is whether this occurs because the early visual inputs have changed the circuitry of auditory cortex, or because auditory cortex is so similar to visual cortex that it it has an intrinsic capability for processing visual input appropriately. Preliminary results suggest that the visual inputs do induce changes in circuitry. The circuitry of auditory cortex, then, will be examined using anatomical methods to determine exactly what these changes are and how they produce the functional changes that have been observed. Knowledge of how sensory input influences cortical circuitry during development will provide information about how evolutionary changes in sensory organs might ultimately be accommodated by the central nervous system. This research, therefore, will provide fundamental information about both cortical developmental mechanisms and the evolution o f complex structures in the central nervous system.