-The evolution of a visually guided perceptual decision results from multiple neural processes, and recent work suggests that signals with different neural origins are reflected in separate frequency bands of the cortical local field potential (LFP). Spike activity and LFPs in the middle temporal area (MT) have a functional link with the perception of motion stimuli (referred to as neural-behavioral correlation). To cast light on the different neural origins that underlie this functional link, we compared the temporal dynamics of the neural-behavioral correlations of MT spikes and LFPs. Wide-band activity was simultaneously recorded from two locations of MT from monkeys performing a threshold, two-stimuli, motion pulse detection task. Shortly after the motion pulse occurred, we found that high-gamma (100 -200 Hz) LFPs had a fast, positive correlation with detection performance that was similar to that of the spike response. Beta (10 -30 Hz) LFPs were negatively correlated with detection performance, but their dynamics were much slower, peaked late, and did not depend on stimulus configuration or reaction time. A late change in the correlation of all LFPs across the two recording electrodes suggests that a common input arrived at both MT locations prior to the behavioral response. Our results support a framework in which early high-gamma LFPs likely reflected fast, bottom-up, sensory processing that was causally linked to perception of the motion pulse. In comparison, late-arriving beta and highgamma LFPs likely reflected slower, top-down, sources of neuralbehavioral correlation that originated after the perception of the motion pulse.behavior; cortex; local field potential; MT; vision VISUALLY GUIDED DECISIONS involve multiple neural components, such as sensory and evaluative stages (Gold and Shadlen 2007). But when and how do different neural components make their contribution? This question is typically studied by measuring the trial-by-trial correlation between cortical spiking and perceptual behavior (Parker and Newsome 1998). Interpreting these neural-behavioral correlations, however, is difficult because they do not tell us whether fluctuations in neural activity directly produced fluctuations in perception. Thus additional data are needed to better understand and model the causality behind observed neural-behavioral correlations.Recent efforts have focused on the local field potential (LFP) and suggest that distinct neurophysiological processes can be measured from different LFP frequency bands (Bastos et al. 2015;Katzner et al. 2009;Kopell et al. 2010;Siegel et al. 2012). Gamma-band LFPs are thought to carry stimulus information (Belitski et al. 2010) and reflect the synaptic inputs from earlier stages (Khawaja et al. 2009) and the activity of local neurons (Ray and Maunsell 2011a), while beta-band LFPs may reflect intercortical feedback (Saalmann et al. 2007). Correspondingly, attention increases gamma LFP power in a manner similar to that of local spiking activity, while beta power is attenuated (Khaya...