Ensemble coding in olfactory cortex

摘要 感觉信息的皮质处理在感觉辨别中起着关键作用， 物体识别和记忆。大脑皮层感觉加工已经被证明是 高度动态，过去的经验、当前的背景和预期如何塑造 世界是在每时每刻都被感知的。感觉加工障碍 构成中枢神经系统疾病和衰老引起的损伤的主要组成部分，如 以及先天性疾病，如精神分裂症和自闭症。在嗅觉上 (梨状)皮质不同的刺激特征被合成为知觉整体 通过传入和固有的纤维会聚和可塑性，允许熟悉的气味 要记住的对象。初级皮质内固有的联结纤维系统是 广泛的，基于解剖学数据和新的生理数据，由 R21到co-Pi‘s，在塑造大脑皮层整体活动方面发挥作用 气味刺激物。因此，我们的数据表明，气味唤起了分布式单位 梨状皮质前叶(APCX)的整体活动及其个别成分 对多种气味的表现做出贡献的合奏。在现在 提案，它扩展了R21支持的研究，我们建议解决三个问题 关于嗅觉中的皮质集合功能的先前未经检验的假设 麻醉和清醒大鼠的多电极阵列和成对单单位记录。 目标1将检验这样的假设，即细胞集合成员大小和 配对单位中的相关活动在后PCX(PPCX)中将大于 在APCX中，由于pPCX中存在更广泛的固有兴奋性联想纤维系统。 目标2将检验神经调节剂ACh和NE的操作以 PCX选择性地影响固有的纤维突触效能，将调节整体 配对的成员规模、气味特异性和相关活动的概率 单元制。最后，目标3将测试行为状态将调节的假设 细胞对中的集合大小、气味特异性和相关活动的概率， 可能通过胆碱或去甲肾上腺素能机制。这些目标加在一起，将 开始探索皮质集合如何融合由编码的无数气味特征 以及注意力和觉醒是如何调节的 气味歧视。叙事 大脑皮层对信息的处理在感觉知觉、记忆、 运动和认知。因此，了解大脑皮层内的回路如何处理 信息是理解和治疗信息障碍的重要因素 正在处理。该方案利用了相对简单的大脑皮层回路( 梨状皮质)执行相对复杂的信息处理任务(气味对象 歧视)，以探索神经元组如何作为一个整体一起工作 解读感官输入。

ABSTRACT Cortical processing of sensory information plays a critical role in sensory discrimination, object recognition and memory. Cortical sensory processing has been shown to be highly dynamic, with past experience, current context and expectations shaping how the world is perceived on a moment by moment basis. Disorders of sensory processing constitute a major component of impairments induced by CNS disease and aging, as well as congenital disorders such as schizophrenia and autism. In the olfactory sensory (piriform) cortex diverse stimulus features are synthesized into perceptual wholes through afferent and intrinsic fiber convergence and plasticity, allowing familiar odor objects to be remembered. The intrinsic, association fiber system in priform cortex is extensive, and based on anatomical data and new physiological data supported by an R21 to the co-PI's, plays a role in shaping cortical ensemble activity in response to odorant stimuli. Thus, our data demonstrate that odorants evoke distributed unit ensemble activity throughout anterior piriform cortex (aPCX), with individual components of the ensemble contributing to mulitple odorant representations. In the present proposal, which extends the R21-supported research, we propose to address three previously untested hypotheses regarding cortical ensemble function in olfaction using multi-electrode array and paired single-unit recording in anesthetized and awake rats. Aim 1 will test the hypothesis that cell ensemble membership size and the probability of correlated activity in paired single-units will be greater in the posterior PCX (pPCX) than in aPCX due to the more extensive intrinsic excitatory association fiber system in pPCX. Aim 2 will test the hypothesis that manipulations of the neuromodulators ACh and NE to PCX, which selectively affect intrinsic fiber synaptic efficacy, will modulate ensemble membership size, odorant specificity and probability of correlated activity in paired single-units. Finally, Aim 3 will test the hypothesis that behavioral state will modulate ensemble size, odorant specificity and probability of correlated activity in cell pairs, potentially via a cholinergc or noradrenergic mechanism. Together, these aims will begin to explore how cortical ensembles merge the myriad odorant features encoded by peripheral circuits into odorant objects, and how attentiona and arousal may modulate odor discrimination. NARRATIVE Cortical processing of information plays a critical role in sensory perception, memory, movement and cognition. Thus, understanding how circuits within the cortex process information is important for understanding and treating disorders of information processing. This proposal takes advantage of a relatively simple cortical circuit (the piriform cortex) performing relatively complex information processing tasks (odor object discrimination) to explore how groups of neurons work together as an ensemble to interpret sensory input.