Neural Computation Laboratory, Istituto Italiano di Tecnologia, Rovereto, Italy.
Centro Interdisciplinare Mente e Cervello (CIMeC), University of Trento, Rovereto, Italy.
Nat Neurosci. 2021 Jul;24(7):975-986. doi: 10.1038/s41593-021-00845-1. Epub 2021 May 13.
Noise correlations (that is, trial-to-trial covariations in neural activity for a given stimulus) limit the stimulus information encoded by neural populations, leading to the widely held prediction that they impair perceptual discrimination behaviors. However, this prediction neglects the effects of correlations on information readout. We studied how correlations affect both encoding and readout of sensory information. We analyzed calcium imaging data from mouse posterior parietal cortex during two perceptual discrimination tasks. Correlations reduced the encoded stimulus information, but, seemingly paradoxically, were higher when mice made correct rather than incorrect choices. Single-trial behavioral choices depended not only on the stimulus information encoded by the whole population, but unexpectedly also on the consistency of information across neurons and time. Because correlations increased information consistency, they enhanced the conversion of sensory information into behavioral choices, overcoming their detrimental information-limiting effects. Thus, correlations in association cortex can benefit task performance even if they decrease sensory information.
噪声相关（即，对于给定刺激，神经活动在试验间的协变）限制了神经群体编码的刺激信息，导致广泛存在的预测，即它们会损害感知辨别行为。然而，这一预测忽略了相关性对信息读出的影响。我们研究了相关性如何影响感觉信息的编码和读出。我们分析了在两个感知辨别任务期间，来自小鼠后顶叶皮层的钙成像数据。相关性降低了编码的刺激信息，但奇怪的是，当老鼠做出正确而不是错误的选择时，相关性更高。单次试验的行为选择不仅取决于整个群体编码的刺激信息，而且出乎意料的是，还取决于神经元和时间之间信息的一致性。由于相关性增加了信息一致性，因此它们增强了将感觉信息转化为行为选择的能力，克服了它们对信息限制的有害影响。因此，即使相关性降低了感觉信息，联合皮层中的相关性也可以有益于任务表现。
