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躯体感觉皮层，特别是处理来自被称为Postero Medial Barrel Sub Field（PMBSF）的胡须的信息的细分。我们已经证明，在PMBSF的晶须功能表示（WFR）的大小是大的，因此与其他晶须的WFR广泛重叠。我们还证明，在感觉输入模式发生变化后，皮层中WFR的大小是可变的。例如，在移除所有其相邻晶须之后，备用（剩余）WFR可以显著地扩展。然而，当这些被剥夺胡须的大鼠被从它们的笼子里移出来，并给予短暂的机会去探索一个新的环境时，发现备用胡须的WFR出现了意想不到的强烈收缩。备用胡须WFR的收缩程度随着用剩余胡须探索环境的实际时间的增加而变得更加明显。我们建议将这些发现从胡须剥夺大鼠非剥夺大鼠。我们的一般假设是，将实验室大鼠单独禁闭在典型的小而裸露的笼子里是一种无意的感觉剥夺形式，导致皮层的感觉表征异常扩大。如果正确的话，促进大鼠自然，先天行为的条件，如隧道挖掘，导航，觅食和社会互动-通过将大鼠从他们的家笼转移到一种新的“丰富的环境”（EE）-可以通过诱导皮质表征的收缩来改善皮质功能组织，从而减少它们的重叠，我们的初步结果验证了这一改进。使用功能成像，单单位记录和解剖技术，我们建议的特点功能和解剖方面的可塑性，它的时间过程中，其对PMBSF内的神经元活动模式和感受野特性的影响。我们还建议研究是否暴露于EE赋予皮质一些免疫力的剥夺标准笼的影响。我们的提案的成功完成应该对基础和临床研究都有重大影响，因为他们质疑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.