INFORMATION CODING IN THE RODENT PREFRONTAL CORTEX .2. ENSEMBLE ACTIVITY IN ORBITOFRONTAL CORTEX
INFORMATION CODING IN THE RODENT PREFRONTAL CORTEX .2. ENSEMBLE ACTIVITY IN ORBITOFRONTAL CORTEX
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DOI：
10.1152/jn.1995.74.2.751
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发表时间：
1995-08-01
影响因子：
2.5
通讯作者：
EICHENBAUM, H
中科院分区：
文献类型：
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作者：
SCHOENBAUM, G;EICHENBAUM, H
1.神经活动记录从大鼠的眶额皮质（OF）执行八气味辨别任务，包括特定的气味对之间的可预测的关联。采用改进的线性判别分析将任务的每次试验中的群体响应表征为N维活动空间中的点，其中N维中的一个维度上表示群体中每个细胞的发射率。群体反应在此活动空间中聚集在一起以重复给定条件的趋势反映了群体区分变量条件的能力。我们评估了描述气味采样期间的几个变量的编码，重点是反映在单神经元放电模式中的当前，过去和未来事件的方面，在每次试验中大鼠采样辨别刺激期间由22-138个细胞组成的活动。OF合奏表现良好，在辨别变量与相关的任务需求中表示的单神经元放电模式，特别是物理属性和分配奖励应急的当前气味，以及预期的奖励在接下来的试验中，可以推断出从特定的气味对之间的可预测的关联。在所有试验中，OF集合能够分别在高达52%（机会= 12.5%）和99%（机会= 50%）的情况下正确地识别当前气味的身份和分配的奖励偶然性，使得观察到的行为表现在气味身份的情况下需要5，364个气味响应细胞的群体，而在效价的情况下仅需要40个细胞。基于分配的反应偶然性和特定气味对之间的关联的关于即将到来的奖励的期望在所有试验中被正确分类高达67%（机会= 20%），使得观察到的行为表现水平需要3，169个细胞的群体。在单神经元放电模式中表示的其他信息，例如先前气味和特定气味-气味关联的身份和奖励偶然性，由OF集合编码得很差。因此，OF中的神经集合可能仅代表单个神经元活动中反映的部分信息。稳定的编码，只有最有用的和相关的信息的合奏可能会出现从调谐性能的单神经元的影响下，手头的任务，生产在训练有素的动物观察到的模式广泛和多样的编码由单个神经元和选择性，任务相关的编码由神经合奏在OF。
1. Neural activity was recorded from the orbitofrontal cortex (OF) of rats performing an eight-odor discrimination task that included predictable associations between particular odor pairs. A modified linear discriminant analysis was employed to characterize the population response in each trial of the task as a point in an N-dimensional activity space with the firing rate of each cell in the population represented on one of the N dimensions. The ability of the ensemble to discriminate among conditions of a variable was reflected in the tendency of population responses to cluster together in this activity space for repetitions of a given condition. We assessed coding of several variables describing the period of odor sampling, focusing on aspects of current, past, and future events reflected in single-neuron firing patterns, in ensembles composed of 22-138 cells active during the period when the rats sampled the discriminative stimulus in each trial.2. OF ensembles performed well at discriminating variables with relevance to task demands represented in single-neuron firing patterns, specifically the physical attributes and assigned reward contingency of the current odor as well as the expectation of reward in the following trial that could be inferred from the predictable associations between particular pairs of odors. OF ensembles were able to correctly identify the identity and assigned reward contingency of the current odor in up to 52% (chance = 12.5%) and 99% (chance = 50%) of all trials, respectively, such that the observed behavioral performance required a population of 5,364 odor-responsive cells in the case of odor identity and only 40 cells in the case of valence. Expectations regarding upcoming rewards based on both assigned response contingency and associations between particular pairs of odors were correctly classified in up to 67% (chance = 20%) of all trials such that the observed level of behavioral performance required a population of 3,169 cells.3. Other information represented in the single-neuron firing patterns, such as the identity and reward contingency of the preceding odor and specific odor-odor associations, was poorly encoded by OF ensembles. Thus neural ensembles in OF may represent only some of the information reflected in single-neuron activity. Stable coding of only the most useful and relevant information by the ensemble might emerge from the tuning properties of single neurons under the influence of the task at hand, producing in the well-trained animal the observed pattern of broad and diverse coding by single neurons and selective, task-relevant coding by neural ensembles in OF.