Abstract:

Purpose: To compare psychophysical performance and brain activation during a motion salience task and voluntary saccadesin adult strabismicamblyopes and controls.
Methods: The motion salience task involved discrimination and detection of a target of coherently moving dots. The second task required voluntary saccades to horizontal stimulus position changes. fMRI activation and functional connectivity between parieto-frontal attention network ROIs, and V1 and V5 were compared for the two tasks.
Results: Behavioural thresholds were higher for detection ofthe moving stimuli by the strabismic amblyopic eye compared to the fellow eye or control eyes. BOLD activation in IPS, FEF and V5 for both tasks, through the amblyopic eye was weaker than that to fellow eye or control subject eyes though no di?erence was seen in V1 activation to the motion task under any eye-viewing condition. Correlational connections between key nodes of the visual attention network activated by the amblyopic eye were abnormal in the motion task, with the FEF ipsilateral to the amblyopic eye the most isolated node.By contrast, the functional connections of this network were relatively normal for the voluntary saccade task.
Conclusions: Amblyopic eyes require slower speed and longer exposure for the detection of moving targets.Overall our results suggest that strabismic amblyopia is associated with reduced attention network activation during motion-driven attention tasks independent of V1.

Key words: Strabismic amblyopia;Visual attention, fMRI, Psychophysics