Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, United Kingdom.
J Neurophysiol. 2021 Jul 1;126(1):275-303. doi: 10.1152/jn.00667.2020. Epub 2021 May 12.
Variability in cortical neural activity potentially limits sensory discriminations. Theoretical work shows that information required to discriminate two similar stimuli is limited by the correlation structure of cortical variability. We investigated these information-limiting correlations by recording simultaneously from visual cortical areas primary visual cortex (V1) and extrastriate area V4 in macaque monkeys performing a binocular, stereo depth discrimination task. Within both areas, noise correlations on a rapid temporal scale (20-30 ms) were stronger for neuron pairs with similar selectivity for binocular depth, meaning that these correlations potentially limit information for making the discrimination. Between-area correlations (V1 to V4) were different, being weaker for neuron pairs with similar tuning and having a slower temporal scale (100+ ms). Fluctuations in these information-limiting correlations just prior to the detection event were associated with changes in behavioral accuracy. Although these correlations limit the recovery of information about sensory targets, their impact may be curtailed by integrative processing of signals across multiple brain areas. Correlated noise reduces the stimulus information in visual cortical neurons during experimental performance of binocular depth discriminations. The temporal scale of these correlations is important. Rapid (20-30 ms) correlations reduce information within and between areas V1 and V4, whereas slow (>100 ms) correlations between areas do not. Separate cortical areas appear to act together to maintain signal fidelity. Rapid correlations reduce the neuronal signal difference between stimuli and adversely affect perceptual discrimination.
皮质神经活动的可变性可能限制了感觉辨别。理论工作表明，辨别两个相似刺激所需的信息受到皮质可变性相关结构的限制。我们通过在执行双眼立体深度辨别任务的猕猴的初级视觉皮层 (V1) 和外纹状区 V4 同时进行记录，研究了这些信息限制相关的相关性。在这两个区域中，对于对双眼深度具有相似选择性的神经元对，快速时间尺度（20-30 毫秒）的噪声相关性更强，这意味着这些相关性可能限制了做出辨别所需的信息。区间相关性（V1 到 V4）不同，对于具有相似调谐且具有较慢时间尺度（100+ 毫秒）的神经元对较弱。在检测事件之前，这些信息限制相关性的波动与行为准确性的变化有关。虽然这些相关性限制了关于感觉目标的信息的恢复，但它们的影响可能会被多个大脑区域的信号整合处理所削弱。在进行双眼深度辨别实验时，相关噪声会降低视觉皮层神经元中的刺激信息。这些相关性的时间尺度很重要。快速（20-30 毫秒）相关性降低了 V1 和 V4 内和之间的信息，而区域之间的缓慢（>100 毫秒）相关性则没有。单独的皮质区域似乎共同作用以维持信号保真度。快速相关性降低了刺激之间的神经元信号差异，并对感知辨别产生不利影响。
