Development of Visual Motion Perception for Prospective Control: Brain and Behavioral Studies in Infants

Abstract

During infancy, smart perceptual mechanisms develop allowing infants to judge time-space motion dynamics more efficiently with age and locomotor experience. This emerging capacity may be vital to enable preparedness for upcoming events and to be able to navigate in a changing environment. Little is known about brain changes that support the development of prospective control and about processes, such as preterm birth, that may compromise it. As a function of perception of visual motion, this paper will describe behavioral and brain studies with young infants investigating the development of visual perception for prospective control. By means of the three visual motion paradigms of occlusion, looming, and optic flow, our research shows the importance of including behavioral data when studying the neural correlates of prospective control.

Keywords: brain and behavioral development; optic flow processing; perceptual information for action; prospective control; visual motion perception.

Figure 1

Occlusion experimental set-up (A), and gaze data (↑ position and → time) for a typical slow deceleration in a 4-month-old infant (B) and a 12-month-old infant (C). (A) The car traveled horizontally on a rectangular path under one of three deceleration conditions, fast (10% deceleration), medium (50% deceleration), and slow (90% deceleration). The two green boxes temporarily occluded the car from its path of travel. (B,C) The black bar represents the occluder, and the green squares represent the car motion, while the red and blue dots represent the right and the left eye, respectively. Yellow dots are missing data. The left markers in each graph represent the catch up event (the moment at which the horizontal eye velocity equals the speed of the car for the first time), while the right markers represent the point in time at which the car starts to reappear from behind the occluder. The 4-month-old infant shows typical saccadic tracking to keep up with the target motion (B), whereas the 12-month-old infant follows the car with smooth pursuit (C). The 12-month-old infant shows an anticipatory saccade to the end of the occluder before car reappearance, while the 4-month-old infant shows no such prospective eye movement.

Figure 2

Looming experimental setup (A), and averaged looming-related VEP peak responses (with SDs) in full-term and preterm infants (B). (A) Infants were shown a flat 2-dimensional circle filled with four smaller colored circles. The looming stimuli simulated an object approaching from a distance on a direct collision course under constant accelerations of −21.1, −9.4, −5.3 ms⁻² for fast loom (2 s), medium loom (3 s), and slow loom (4 s), respectively. The bottom left equation describes the growth of the visual loom. The looming stimuli approached the infant as the image on the screen grew symmetrically and stopped when the image filled the entire screen. (B) With increasing age, the full-term infants responded significantly closer to the loom's time-to-collision compared to the pre-term infants. Only the older full-term infants responded at a fixed time-to-collision irrespective of loom speed, an indication that only the full-term infants at 12 months had switched from a visual angle strategy to the more sophisticated time strategy when timing their looming-related VEP peak responses.

Figure 3

Grand average motion VEPs in full-term infants at 3–4 months (A) and 11–12 months (B), and in preterm infants at 3–4 months (C) and 11–12 months (D). Amplitudes are on the y-axis and latencies on the x-axis. The actual N2 peak latencies for forwards optic flow are indicated at PO4 in full-term infants and POz in preterm infants. Differences in N2 peak latencies for the three motion conditions were observed only in full-term infants at 12 months where latency increased from forwards optic flow to reversed optic flow and random motion.

Figure 4

TSE plots across brain regions of interest (VClL, visual cortex lateral left; PM, parietal midline; VClR, visual cortex lateral right) when the motion conditions were compared with the static non-flow condition in a typical full-term infant at 4 months (A) and 12 months (B), and in a typical preterm infant at 4 months (C) and 12 months (D). Induced synchronized and desynchronized activities appear in red and blue colored contours, respectively. Induced theta-band desynchronized activities were observed in all the visual areas of interest in the full-term and preterm infants at both ages, with induced alpha-beta band synchronized activities observed in two or more visual areas only in the full-term infants at 12 months. Stimulus onset is the vertical red line at 0 ms, with epoch from −200 to 800 ms.