Brosch M, Schreiner C E
Coleman Laboratory, W.M. Keck Center for Integrative Neuroscience, Sloan Center for Theoretical Neurobiology, University of California at San Francisco, 94143-0732, USA.
Eur J Neurosci. 1999 Oct;11(10):3517-30. doi: 10.1046/j.1460-9568.1999.00770.x.
The functional role of correlated neural activity in auditory cortex for the processing of sounds was explored by investigating whether and how cross-correlation parameters are related to receptive field similarities of neurons. Multi-unit activity was recorded simultaneously from several sites of isofrequency domains in primary auditory cortex. At each site various receptive field properties were determined. From the discharges of pairs of clusters, normalized cross-correlation histograms (CCH) were calculated for extended periods of spontaneous activity and for periods with noise-burst stimulation. In both conditions, most CCHs exhibited a symmetrical positivity near the origin of the CCH, a few to several tens of milliseconds wide. Cross-correlation histograms were characterized with two parameters: the correlation strength, which was estimated from the peak correlation, and the correlation width, i.e. the time period of correlated firing, which was measured as the width of the positivity at half height. It was found that correlation strength increased and correlation width narrowed with increasing similarity of the receptive fields of two clusters. These relationships were observed both in the acoustically-driven and spontaneous conditions. Specifically, correlation strength was most strongly associated with similarity in binaural interaction and in temporal response properties such as response onset, response offset and the temporal pattern of the response. Correlation width was predominantly associated with similarity in characteristic frequency, bandwidth and intensity threshold. Results suggest that correlated activity, reflecting potential mechanisms involved in the neural computation in auditory cortex, provides a means to evaluate the properties of the functional organization of auditory cortex. Systematic relationships were found between correlation properties and the receptive field-based organization of cortical processing, suggesting that similar general mechanisms are utilized in many parts of the sensory cortex. In particular, the magnitude and/or the time period of synchronized firing of neurons is increased if the receptive field properties of the involved neurons are similar.
通过研究互相关参数是否以及如何与神经元的感受野相似性相关，探讨了听觉皮层中相关神经活动在声音处理中的功能作用。在初级听觉皮层的等频域的多个部位同时记录多单元活动。在每个部位确定各种感受野特性。从成对簇的放电中，计算了长时间自发活动以及噪声爆发刺激期间的归一化互相关直方图（CCH）。在这两种情况下，大多数CCH在CCH原点附近呈现对称的正性，宽度为几毫秒到几十毫秒。互相关直方图用两个参数表征：相关强度，由峰值相关性估计；相关宽度，即相关放电的时间段，以半高正性的宽度测量。发现随着两个簇的感受野相似性增加，相关强度增加而相关宽度变窄。在声学驱动和自发条件下均观察到了这些关系。具体而言，相关强度与双耳相互作用以及诸如反应起始、反应终止和反应时间模式等时间反应特性的相似性最密切相关。相关宽度主要与特征频率、带宽和强度阈值的相似性相关。结果表明，反映听觉皮层神经计算中潜在机制的相关活动提供了一种评估听觉皮层功能组织特性的方法。发现相关特性与基于感受野的皮层处理组织之间存在系统关系，表明在感觉皮层的许多部分利用了类似的一般机制。特别是，如果所涉及神经元的感受野特性相似，神经元同步放电的幅度和/或时间段会增加。
