by Yueyue Sapphire Hou, Pooya Laamerad, Liu D. Liu, Christopher C. Pack Fluctuations in single-neuron activity in the sensory cortex often correlate with perceptual decisions. This kind of correlation is often hypothesized to reflect a causal influence of sensory signals on decisions, but it can be attributed to various noncausal factors as well. To disentangle these different possibilities, we have examined local field potentials (LFPs) recorded from the middle temporal (MT) area and area V4 of nonhuman primates ( Macaca mulatta ) while they performed two different perceptual decision-making tasks. Compared to single-neuron spiking, LFPs have the advantage of being decomposable into frequency bands that are associated with different anatomical sources of input. More importantly, they persist when spiking activity is inactivated, which precludes a causal influence of the corresponding neural activity on behavior. We found that high-gamma frequency (70–150 Hz) LFP power was correlated w