Title: " Hierarchy of Direction-tuned Motion Adaptation in 1 Human Visual Cortex " 2

20 Prolonged exposure to a single direction of motion alters perception of subsequent 21 static or dynamic stimuli and induces substantial changes in behaviors of motion22 sensitive neurons, but it remains unclear about an origin of neural adaptation and 23 neural correlates of perceptual consequences of motion adaptation in human brain. 24 Using functional magnetic resonance imaging (fMRI), we measured motion 25 adaptation tuning curves in a fine scale by probing changes in cortical activity after 26 adaptation for a range of directions relative to the adapted direction. We found a clear 27 dichotomy in tuning curve shape: cortical responses in early-tier visual areas reduced 28 at around both the adapted and opposite direction, resulting in a bi-directional tuning 29 curve, whereas response reduction in high-tier areas occurred only at around the 30 adapted direction, resulting in a uni-directional tuning curve. We also found that the 31 psychophysically measured adaptation tuning curves were uni-directional and best 32 matched the cortical adaptation tuning curves in MT and MST. Our findings are 33 compatible with, but not limited to, an interpretation in which direct impacts of 34 motion adaptation occur in both uni-directional and bi-directional units in early visual 35 areas, but its perceptual consequences are manifested in the population activity in MT 36 and MST, which may inherit those direct impacts of adaptation from the directionally 37 selective units. 38 39