In order to investigate how is neuronal activity correlated with behavioral response to unapparent wide-field motion stimulus, we examined the motion perception with respect to both behavioral and neuronal activity in Drosophila melanogaster. We measured the head yaw optomotor response and horizontalsystems (HS) cell activity with in vivo whole-cell patch clamp recordings. We found that flies have high capability to discriminate the direction of motion objects even though the stimulus is very noisy. Interestingly, on the other hand, the sensitivity of behavioral response to motion stimuli proportionally decrease with the increase of noise level. These results indicate that two distinct features, which is non-linear effect of the noise on the discriminative performance and linear effect on the sensitivity, characterize the behavioral response to unapparent motion. Furthermore, we also found that HS cell activity was surprisingly correlates with these aspects of the behavioral optomotor response. Our results suggest that flies can perform the appropriate behavioral reaction to unapparent motion information in order to correctly control their flight or walking orientation, and this behavior originates from HS cells activities.