Integration Of Motion And Form Cues For The Perception Of Self-motion In The Human Brain

Perception of self-motion is an indispensable ability in daily life,and optic flow is an important visual cue for perceiving heading.Studies have shown that optic flow contains motion and form cues.Generally,motion and form cues are inseparable and have same focus of expansion(FOE).The location of FOE is the direction of heading.When motion and form have different FOE,people will integrate these cues and perceive the direction of heading between the two FOEs.Although the brain regions responding to optic flow have been studied(MST,VIP,CSv),little is known about the brain mechanism of integrating motion and form cues.The current study addressed this question by using the stimuli having separable motion and form cues.In experiment 1,the location of the motion-defined FOE was fixed,and the location of form-defined FOE was changed.In experiment 2,the locations of the motion and form-defined FOEs were located on the left or right side of the display at the same time in congruent situation;the locations of the motion and form-defined FOEs were located on opposite sides of the display in incongruent situation.In both situation,the shift of motion and form-defined FOE was the same in two stimuli,but for consistent stimulus,the perceived direction of heading changed for the congruent but not the incongruent stimuli.For brain regions that integrate these two cues,the classification of congruent stimuli should be higher than that of incongruent stimuli.Multiple voxel pattern analysis(MVPA)was used to analysis the data.We found that the primary visual regions V1,V2,V3,V3 a,V3b/KO could represent the different location of motion or form-defined FOE.In addition,the classification accuracy of V3b/KO for congruent stimuli is higher than that of incongruent stimuli,suggesting that the region integrate motion and form cues in the processing of optical flow stimuli.