Ensemble coding in olfactory cortex

描述（由申请人提供）：摘要感觉信息的皮层处理在感觉辨别、物体识别和记忆中起着关键作用。大脑皮层的感觉处理被证明是高度动态的，过去的经验，当前的背景和期望塑造了世界是如何被感知的。感觉处理障碍是中枢神经系统疾病和衰老以及先天性疾病如精神分裂症和自闭症引起的损伤的主要组成部分。在嗅觉感觉（梨状）皮层中，不同的刺激特征通过传入和内在纤维会聚和可塑性合成为感知整体，允许熟悉的气味物体被记住。内在的，在priform皮层的关联纤维系统是广泛的，并基于解剖数据和新的生理数据支持的R21的co-PI的，在塑造皮质合奏活动响应于气味刺激的作用。因此，我们的数据表明，气味唤起整个前梨状皮质（aPCX）的分布式单元合奏活动，与合奏的单个组件有助于多个气味的表示。在本提案中，它扩展了R21支持的研究，我们建议解决三个以前未经检验的假设，在嗅觉皮层合奏功能，使用多电极阵列和成对的单单位记录在麻醉和清醒的大鼠。目的1将测试的假设，即细胞合奏成员的大小和概率的相关活动在成对的单单位将更大的后PCX（pPCX）比在aPCX由于更广泛的内在兴奋性协会纤维系统在pPCX。目的2将测试的假设，操纵的神经调质ACh和NE PCX，选择性地影响内在的纤维突触的功效，将调制合奏成员的大小，气味特异性和概率的相关活动配对的单一单位。最后，目标3将测试的假设，行为状态将调节合奏大小，气味特异性和概率的相关活动的细胞对，可能通过胆碱能或去甲肾上腺素能机制。总之，这些目标将开始探索皮层集合如何将由外围回路编码的无数气味特征合并为气味对象，以及注意力和唤醒如何调节气味辨别。信息的皮层处理在感官知觉、记忆、运动和认知中起着关键作用。因此，了解皮层内的回路如何处理信息对于理解和治疗信息处理障碍非常重要。该提案利用相对简单的皮质回路（梨状皮质）执行相对复杂的信息处理任务（气味物体辨别）来探索神经元组如何作为整体一起工作来解释感官输入。

DESCRIPTION (provided by applicant): 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 multiple 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 cholinergic 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 attention and arousal may modulate odor discrimination. PUBLIC HEALTH RELEVANCE 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.