SMOOTH-PURSUIT IN 1 TO 4-MONTH-OLD HUMAN INFANTS

The ability of human infants less than or equal to 4 months of age to pursue objects smoothly with their eyes was assessed by presenting sma ll target spots moving with hold-ramp-hold trajectories at ramp veloci ties of 4-32 deg/sec, Infants as young as 1 month old followed such ta rget motions with a combination of smooth-pursuit and saccadic eye mov ements interrupted occasionally by periods when the eyes remained stat ionary. The slowest targets produced variable performance, but targets moving 8-32 deg/sec produced consistent pursuit behavior, even in the youngest infants, By the fourth month, eye-movement latency decreased and smooth-pursuit gain and the percentage of smooth pursuit per tria l increased for all target velocities, though these measures had not y et reached adult levels, (C) 1997 Elsevier Science Ltd.