This article introduces the method of single-neuron recording in humans to marketing and consumer researchers. First, the authors provide a general description of this methodology, discuss its advantages and disadvantages, and describe findings from previous single-neuron human research. Second, they discuss the relevance of this method for marketing and consumer behavior and, more specifically, how it can be used to gain insights into the areas of categorization, sensory discrimination, reactions to novel versus familiar stimuli, and recall of experiences. Third, they present a study designed to illustrate how single-neuron studies are conducted and how data from them are processed and analyzed. This study examines people's ability to up-regulate (i.e., enhance) the emotion of fear, which has implications for designing effective fear appeals. The study shows that the firing rates of neurons previously shown to respond selectively to fearful content increased with emotion enhancement instructions, but only for a video that did not automatically evoke substantial fear. The authors discuss how the findings help illustrate which conclusions can and cannot be drawn from single-neuron research.