Visual cortical neurons show variability in their responses to repeated presentations of a stimulus and a portion of this variability is shared across neurons. Attention may enhance visual perception by reducing shared spiking variability. However, shared variability and its attentional modulation are not consistent within or across cortical areas, and depend on additional factors such as neuronal type. A critical factor that has not been tested is actual anatomical connectivity. We measured spike count correlations among pairs of simultaneously recorded neurons in the primary visual cortex (V1) for which anatomical connectivity was inferred from spiking cross-correlations. Neurons were recorded in monkeys performing a contrast-change discrimination task requiring covert shifts in visual spatial attention. Accordingly, spike count correlations were compared across trials in which attention was directed toward or away from the visual stimulus overlapping recorded neuronal receptive fields. Consistent with prior findings, attention did not significantly alter spike count correlations among random pairings of unconnected V1 neurons. However, V1 neurons connected via excitatory synapses showed a significant reduction in spike count correlations with attention. Interestingly, V1 neurons connected via inhibitory synapses demonstrated high spike count correlations overall that were not modulated by attention. Correlated variability in excitatory circuits also depended upon neuronal tuning for contrast, the task-relevant stimulus feature. These results indicate that shared variability depends on the type of connectivity in neuronal circuits. Also, attention significantly reduces shared variability in excitatory circuits, even when attention effects on randomly sampled neurons within the same area are weak.

中文翻译：

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相关变异性及其注意力调节取决于解剖连接性


视觉皮层神经元对重复出现的刺激的反应表现出可变性，并且这种可变性的一部分在神经元之间共享。注意力可以通过减少共享的尖峰变异性来增强视觉感知。然而，共享的变异性及其注意力调节在皮质区域内或之间并不一致，并且取决于神经元类型等其他因素。尚未经过测试的一个关键因素是实际的解剖连接性。我们测量了初级视觉皮层（V1）中同时记录的神经元对之间的尖峰计数相关性，其解剖学连接性是根据尖峰互相关性推断的。猴子的神经元被记录下来，执行对比度变化辨别任务，需要视觉空间注意力的隐蔽转移。因此，在注意力集中或远离与记录的神经元感受野重叠的视觉刺激的试验中，比较了尖峰计数的相关性。与之前的发现一致，注意力并没有显着改变未连接的 V1 神经元随机配对之间的尖峰计数相关性。然而，通过兴奋性突触连接的 V1 神经元显示，尖峰计数与注意力的相关性显着降低。有趣的是，通过抑制性突触连接的 V1 神经元总体上表现出较高的尖峰计数相关性，而不受注意力的调节。兴奋回路的相关变异还取决于神经元对对比度的调节，即与任务相关的刺激特征。这些结果表明，共同的变异性取决于神经元回路的连接类型。 此外，即使注意力对同一区域内随机采样的神经元的影响很弱，注意力也会显着减少兴奋回路的共同变异性。