Behaviorally Induced Cortical Plasticity

描述（由申请人提供）：我们的长期研究兴趣是了解成人感觉皮层的功能组织及其可塑性。我们的研究目标是成年大鼠的体感觉皮层，特别是处理来自须的信息的细分，即后内侧桶子场（PMBSF）。我们已经证明，PMBSF中的晶须功能表征（WFR）的大小很大，因此与其他晶须的WFR广泛重叠。我们还证明，随着感觉输入模式的变化，皮层中WFR的大小是可变的。例如，在去除所有邻近的晶须后，剩余的WFR可能会急剧扩大。然而，当这些没有胡须的老鼠从它们的家庭笼子中被移走，并给予短暂的机会去探索一个新的环境时，发现没有胡须的老鼠的WFR出人意料地强烈收缩。随着使用剩余须探索环境的实际时间的增加，剩余须WFR的收缩程度变得更加明显。我们建议将这些发现从无须大鼠扩展到非无须大鼠。我们的一般假设是，将实验室大鼠单独囚禁在典型的小而空的笼子里，是一种无意的感觉剥夺形式，导致皮层中异常扩大的感觉表征。如果正确的话，通过将老鼠从家里的笼子转移到一种新的“丰富环境”（EE），促进老鼠自然的、天生的行为，如隧道挖掘、导航、觅食和社会互动，可以通过诱导皮层表征的收缩来改善皮质功能组织，从而减少它们的重叠，我们的初步结果证实了这一改进。利用功能成像、单单元记录和解剖学技术，我们提出表征这种可塑性的功能和解剖学方面，它的时间过程，以及它对PMBSF中神经元活动模式和感受野特征的影响。我们还建议研究暴露于情感表达是否赋予皮层对标准笼剥夺效应的某些免疫力。我们的建议的成功完成应该对基础研究和临床研究都有重大意义，因为他们质疑关在笼子里的实验室大鼠大脑作为自然环境中人类大脑模型的相关性。此外，这些发现可能对成人知觉/运动障碍的治疗具有重要意义。

DESCRIPTION (provided by applicant): Our long-range research interest is to understand the functional organization of the adult sensory cortex and its plasticity. The target of our research is the somatosensory cortex of the adult rat, especially the subdivision that processes information from the whiskers known as Postero Medial Barrel Sub Field (PMBSF). We have demonstrated that the size of a whisker functional representation (WFR) in the PMBSF is large and consequently overlap extensively with the WFRs of other whiskers. We have also demonstrated that the size of the WFR in the cortex is mutable following changes in the patterns of sensory input. For example, after removal of all its neighboring whiskers, a spared (remaining) WFR could expand dramatically. However, when such whisker-deprived rats were removed from their home cages and given brief opportunity to explore a novel environment, an unexpected strong contraction of the spared whisker's WFR was found. The degree of contraction of the spared whisker WFR became more pronounced with increasing amount of time actually spent exploring the environment with the remaining whiskers. We propose to extend these findings from whisker-deprived rats to non-deprived rats. Our general hypothesis is that solitary confinement of the laboratory rat to the typical small and bare cage is an inadvertent form of sensory deprivation that lead to abnormally expanded sensory representation in the cortex. If correct, conditions that promote natural, innate behavior in rats such as tunnel digging, navigation, foraging and social interactions - by transferring rats from their home cage to a new kind of an 'enriched environment' (EE) - can refine cortical functional organization by inducing a contraction of cortical representations and consequently reducing their overlap, a refinement verified by our preliminary results. Using functional imaging, single unit recordings and anatomical techniques we propose to characterize functional and anatomical aspects of such plasticity, its time course, and its effects on neuronal activity patterns and receptive field characteristics within PMBSF. We also propose to study whether exposure to an EE endows the cortex with some immunity to the deprivation effects of the standard cage. Successful completion of our proposal should have major implications for both basic and clinical research because they question the relevance of caged, laboratory rat brain to serve as a model for the brain of humans in their natural environments. In addition, such findings could have important implications for treatment of adult perceptual/motor disorders.