Neural correlates of the multiple-object tracking deficit in amblyopia.
Deficits in multiple-object tracking have previously been reported in both the amblyopic and the clinically unaffected fellow eye of patients with amblyopia. We examined the neural correlates of this deficit using functional MRI. Attentive tracking of 1, 2 or 4 moving targets was compared to passive viewing and to baseline fixation in an amblyopic group and an age-matched control group in six regions of interest: V1, middle temporal complex (MT+), superior parietal lobule (SPL), frontal eye fields (FEF), anterior intraparietal sulcus (IPS), and posterior IPS. Activation in all regions of interest, except V1, increased with attentional load in both groups. MT+ was less active in both eyes of the amblyopic group relative to controls for passive viewing and each of the tracking conditions. Anterior IPS and FEF were less active with amblyopic eye viewing when tracking four targets. These results implicate both the low-level passive and high-level active motion systems in the multiple-object tracking deficit in amblyopia.
University of British Columbia, Department of Ophthalmology and Visual Sciences, Room A146, 4480 Oak Street, Vancouver, BC, Canada V6H 3V4. johnsecen@gmail.com
John
J
Secen
Jody
J
Culham
Cindy
C
Ho
Deborah
D
Giaschi
D000328:Adult; D000550:Amblyopia / Q000503:physiopathology*; D001288:Attention / Q000502:physiology*; D001931:Brain Mapping / Q000379:methods; D002540:Cerebral Cortex / Q000502:physiology*; D002648:Child; D005133:Eye Movements / Q000502:physiology; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D009039:Motion Perception / Q000502:physiology*; D010775:Photic Stimulation / Q000379:methods; D011601:Psychophysics; D055815:Young Adult