To determine if the mice spent a greater percentage of running distance arriving at rewarding targets after advanced training, we computed the percent of total distance that was used for receiving rewards during different phases. This distance was increased from 35.7±6% during the Baseline phase to 73.4±6% during the Data Acquisition phase (Fig 3F). A paired Student t-test shows that the difference between these two groups is statistically significant (df = 22, t = 4.69, P<0.001). The increased total running distance per session was accompanied by a reduced time required to arrive at each reward (Fig 3G). In average, mice spent 100.00±6.8 seconds (sec) to reach a reward during the Baseline phase. However, the time required for each reward was decreased to 75.07±5.9 sec per reward during the Data Acquisition phase (Fig 3G). A paired Student t-test shows that the difference between these two groups is statistically significant (df = 18, t = 2.24, P<0.05). All together, these results suggest that the training of the VR behavioral test seems to have two components, the training for visual recognition, and the training for maneuvering the treadmill. The training for the visual recognition is fast (9 days), but the training for controlling the treadmill requires more time and effort.