Experience Dependent Plasticity of The Developing Cortex

描述（由申请人提供）：我们的长期研究兴趣是了解感觉皮层的功能组织，其可塑性及其与行为的关系。我们的研究目标是大鼠的躯体感觉皮层，特别是处理来自面部胡须的信息的细分，称为Postero Medial Barrel Sub Field（PMBSF）。使用慢性功能成像和单单位记录，我们已经证明，在成年大鼠的PMBSF中的晶须功能表示（WFR）的大小是大的，因此与其他晶须的WFR广泛重叠。令人惊讶的是，我们发现WFR的这种描述仅在生活在标准笼（SC）中的大鼠中有效。如果大鼠被允许离开笼子，从而能够表达通常在SC中不表达的先天行为，例如胡须依赖性导航，WFR收缩并减弱，从而使它们的重叠最小化，但是如果大鼠留在其SC中，WFR扩展并加强。在成年剥夺大鼠中，除了一个胡须外，所有胡须都被去除，（备用胡须），并允许在笼外航行几分钟，或在正常情况下，在自然栖息地（NH）中度过一个月的非剥夺成年大鼠-一种新型的居住环境，通过使大鼠能够进行探索，挖掘隧道，地下导航觅食和社会互动由于皮层是特别敏感的环境影响在发展过程中，我们建议调查的假设，即表达先天行为的能力，因为出生后被提出的NH，可能有解剖，功能和行为的后果，将完善皮层更好地优化胡须的歧视能力相比，SC提出的大鼠。为了验证这一假设，我们建议比较的解剖结构，神经生理学和胡须依赖的歧视行为的NH提高与SC提高大鼠。该提案的成功完成将突出在发育过程中表达先天行为的重要性，以实现与此行为相关的皮质结构和功能的最佳成熟。这些发现可能对人类行为发育异常的最佳治疗以及损伤或疾病后的再生具有重要意义。此外，这些结果将有助于重新评估SC饲养的大鼠作为正常人脑模型的适当性。

DESCRIPTION (provided by applicant): Our long-range research interest is to understand the functional organization of sensory cortex, its plasticity and their relationship to behavior. The target of our research is the somatosensory cortex of the rat, especially the subdivision that processes information from the facial whiskers known as Postero Medial Barrel Sub Field (PMBSF). Using chronic functional imaging and single unit recordings we have demonstrated that in the adult rat the size of a whisker functional representation (WFR) in the PMBSF is large and consequently overlaps extensively with the WFRs of other whiskers. Surprisingly, we found that this description of the WFRs is valid only in rats that live in a standard cage (SC). If rats are allowed out of the cage and thus are able to express innate behaviors that are not typically expressed in the SC, such as whisker-dependent navigation, the WFRs contract and weaken and thus minimize their overlap, but if the rat stays in its SC the WFRSs expand and strengthen. The contraction of WFRs was found both in adult deprived rats that experienced a removal of all whiskers except one (spared whisker) and were allowed a few minutes of navigation outside the cage, or in normal, non deprived adult rats that were spending a month in a naturalistic habitat (NH) - a new type of housing environment that imitates the rat's natural environment by enabling rats to engage in innate behaviors such as exploration, tunnel digging, subterranean navigation, foraging and social interactions. Because the cortex is especially sensitive to environmental influences during development, we propose to investigate the hypothesis that the ability to express innate behaviors since birth by being raised in the NH, may have anatomical, functional and behavioral consequences that would refine the cortex to be better optimized for whisker discrimination abilities compared to SC-raised rats. To test the hypothesis, we propose to compare the anatomy, neurophysiology and whisker-dependent discrimination behavior of NH-raised rats vs. SC-raised rats. Successful completion of the proposal would highlight the importance of expressing innate behaviors during development for the optimal maturation of cortical structure, function that is associated with this behavior. Such findings could have implications for the optimal treatment of developmental abnormalities of behavior in humans, and regeneration after injury or disease. Further, such results would help in reassessment of the appropriateness of SC-raised rats to serve as models for the normal human brain.