NEURAL ENSEMBLE CODING IN INFERIOR TEMPORAL CORTEX
NEURAL ENSEMBLE CODING IN INFERIOR TEMPORAL CORTEX
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DOI：
10.1152/jn.1994.71.6.2325
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发表时间：
1994-06-01
影响因子：
2.5
通讯作者：
GROSS, CG
中科院分区：
文献类型：
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作者：
GOCHIN, PM;COLOMBO, M;GROSS, CG
1.在两只猕猴（n = 58和n = 41个神经元）的下颞叶皮层（IT）的TE区连续记录孤立的单神经元细胞外电位。数据是在动物执行配对关联任务时获得的。该任务使用五个刺激和八个刺激配对（4个正确和4个不正确）。数据进行了评估，平均穗率在实验时期的100或400毫秒。单单位和人口的特点进行了测量，使用线性判别分析和信息理论的措施。为了评估群体代码测量的协方差的显著性，从被动观察视觉刺激的第三只猕猴获得了由少于或等于8个分离神经元（n = 37）的同时记录组成的额外数据。平均而言，43%的IT神经元被所使用的任何刺激激活（如果包括那些被抑制的神经元，则为60%）。然而，在测试集中，神经元对每种刺激的反应的相对大小是相当独特的。这些结果表明，信息可以表示在IT跨神经元的活动模式，并表示不是稀疏编码。进一步建议，该表示方案可能与DNA或计算机代码具有相似性，其中编码元素不是局部参数描述符。这与V1表示不同，V1表示似乎是局部的和参数化的。它也不同于IT表示理论，建议一个建设性的基础集或“字母表”。从这一观点来看，IT中刺激辨别能力的测定应该通过测量群体活动模式来评估。在固定任务期间获得的同时记录的神经元的小团体的评价表明，在IT活动的协方差传递的信息很少的视觉刺激时，在本研究中使用的时间尺度为100毫秒。这一发现与Gochin等人的先前报告一致，其使用了1毫秒的时间恐慌，并且未能发现依赖于刺激的神经活动一致性或振荡。群体-刺激-辨别能力测量受神经元数量的影响，并在一定程度上受刺激的数量和类型的影响.单个神经元传递的信息（互信息）平均为0.26比特。信息值的分布是单峰的，因此与分布式编码方案比与本地编码方案更一致。神经元群体传递的信息比个体的总和少，
1. Isolated, single-neuron extracellular potentials were recorded sequentially in area TE of the inferior temporal cortex (IT) of two macaque monkeys (n = 58 and n = 41 neurons). Data were obtained while the animals were performing a paired-associate task. The task utilized five stimuli and eight stimulus pairings (4 correct and 4 incorrect). Data were evaluated as average spike rate during experimental epochs of 100 or 400 ms. Single-unit and population characteristics were measured using a form of linear discriminant analysis and information theoretic measures. To evaluate the significance of covariance on population code measures, additional data consisting of simultaneous recordings from less than or equal to 8 isolated neurons(n = 37) were obtained from a third macaque monkey that was passively viewing visual stimuli.2. On average, 43% of IT neurons were activated by any of the stimuli used (60% if those inhibited also are included). Yet the neurons were rather unique in the relative magnitude of their responses to each stimulus in the test set. These results suggest that information may be represented in IT by the pattern of activity across neurons and that the representation is not sparsely coded. It is further suggested that the representation scheme may have similarities to DNA or computer codes wherein a coding element is not a local parametric descriptor. This is a departure from the V1 representation, which appears to be both local and parametric. It is also different from theories of IT representation that suggest a constructive basis set or ''alphabet''. From this view, determination of stimurus discrimination capacity in IT should be evaluated by measures of population activity patterns.3. Evaluation of small groups of simultaneously recorded neurons obtained during a fixation task suggests that little information about visual stimuli is conveyed by covariance of activity in IT when a 100-ms time scale is used as in this study. This finding is consistent with a prior report, by Gochin et al., which used a I-ms time scare and failed to find neural activity coherence or oscillations dependent on stimuli.4. Population-stimulus-discrimination capacity measures were influenced by the number of neurons and to some extent the number and type of stimuli.5. Information conveyed by individual neurons (mutual information) averaged 0.26 bits. The distribution of information values was uni-modal and is therefore more consistent with a distributed than a local coding scheme. Populations of neurons conveyed less information than the sum of the individuals, reaching