Cross correlation can be used to relate stimulus or behavioral variables to individual voxel responses. Here, responses are related to the animal's swimming behavior. To capture the fact that the relationships may depend on the relative timing between predictor and response, the analysis examines multiple time lags (with the predictor preceding or following the response), and then uses dimensionality reduction to capture the most common temporal relationships. In the visualization, color represents the sign and temporal profile relating neural responsea and swimming, and brightness represents strength of response.