Neural representations of visual motion for perception and interception

Eye movements are critical for guiding interactions with moving objects according to a behavioral goal, such as tracking an object to perceive its speed or to intercept it with the hand. There are overlapping brain areas involved in motion perception, eye movements, and visually-guided reaching, yet little is known about how these brain areas govern eye-hand interactions with moving objects in different behavioral contexts. Here, we used functional magnetic resonance imaging (fMRI) to investigate how the task goal (perceive/act) and eye movement (fixation/pursuit) modulate neural representations of visual motion. Participants (N = 20) either passively observed (View) or actively intercepted (Intercept-Go) a target moving at a constant rightward or leftward velocity toward an interception zone while their right-hand position and force were recorded on an MR-compatible tablet. On some interception trials, the target changed color prior to movement initiation, indicating that participants should inhibit their planned interception (Intercept-NoGo). Across trials, participants fixated their eyes on the interception zone (Fixate) or smoothly pursued the moving target (Pursue). In-scanner tablet recordings of hand movements and posthoc decoding of eye movements from the MR signal confirmed adherence to the task conditions. Bayesian variational representational similarity analyses of the fMRI data showed that during the initial target motion phase, neural activity patterns in primary visual cortex and human middle temporal area were specific to the eye movement (Fixate vs. Pursue) and motion direction (Right vs. Left), whereas patterns in motor, premotor, and parietal regions were most sensitive to the task goal (View vs. Intercept-NoGo). Analysis of the execution phase of the Intercept-Go trials showed neural activity patterns in primary visual and motor cortices were strongly sensitive to the direction of the target and hand movement. Together, these results reveal distinct eye- and goal-dependent representations for processing visual motion along the sensorimotor hierarchy.