Figure 4. Experiment 3. MT+ responds to a range of auditory motion strengths.

(A) For ITD motion, inter-aural temporal differences were linearly ramped from positive to negative (e.g. leading in left ear to leading in right ear, or vice versa). The slope of the ITD ramp was parametrically varied using even increments. The 0% condition (stationary percept, no temporal lags) and the 100% condition (temporal lag ramped from +1ms to −1ms during the stimulus duration of 1s) were equivalent to the stationary and moving conditions of Exp. 2. (B) MT+ responses (% fMRI signal change) to each motion condition are relative to the response to the 0% (stationary) condition for sight-recovery subjects (n=2) and controls (n=2). MT+ responded to all ITD motion strengths within sight-recovery subjects, but not controls. (C) For ILD motion, inter-aural level (volume) differences were linearly ramped from positive to negative (e.g. louder in left ear to louder in right ear, or vice versa), with the slope again varying between 0% (stationary) and 100% (volume difference ramped from +max to −max value). (D) MT+ responses to each motion condition are plotted relative to the 0% (stationary) condition. MT+ responses increased linearly (R²=0.97) with ILD motion strength within sight-recovery subjects, but not controls. Error bars denote s.e.m. Stars denote significant differences from zero (*p<0.05, ** p<0.01).