Speed-accuracy tradeoff (SAT) is a well-documented phenomenon in the decision-making of humans and animals, but its underlying neuronal mechanism remains unclear. While modeling approaches conceptualize SAT through the threshold-tuning hypothesis as adjustments to the decision threshold, the leading neurophysiological perspective is the gain modulation hypothesis which postulates that the SAT mechanism is implemented through the baseline firing rate and the speed of evidence integration. In this paper, I investigate alternative computational mechanisms of SAT and show that while the threshold-tuning hypothesis is qualitatively consistent with behavioral data, the gain modulation hypothesis is inconsistent with the data. In order to reconcile the threshold-tuning hypothesis with the neurophysiological observations, I consider the interference of alpha oscillations with the decision process and show that the desynchronization of alpha oscillations results in an increase of the baseline firing rate and the speed of evidence integration. While alpha oscillations increase the discriminatory power of the decision system, they slow down the decision process. This suggests that alpha oscillations interact with the SAT mechanism and this interaction provides an alternative explanation of why the increase of the baseline firing rate and the speed of evidence integration is observed during the speed condition.