Looking at human eyes affects contralesional stimulus processing after right hemispheric stroke

Area of Science:

• Neuroscience
• Ophthalmology
• Cognitive Psychology

Background:

• Human eyes serve as a potent social cue, automatically capturing observer attention.
• Visual extinction is a condition where patients fail to perceive stimuli in the visual field contralateral to a brain lesion, particularly when stimuli are presented bilaterally.

Purpose of the Study:

• To investigate if viewing open human eyes influences contralesional errors in patients with right brain damage and visual extinction.
• To determine the effect of central eye stimuli on the detection of peripheral targets in affected visual fields.

Main Methods:

• Right brain-damaged patients with visual extinction performed a shape-target discrimination task with peripheral stimuli (left, right, or bilateral).
• A central task-irrelevant stimulus of a human eye (open or closed) was presented concurrently with peripheral targets.
• Contralesional errors were analyzed based on the state of the central eye stimulus.

Main Results:

• Central presentation of open eyes, compared to closed eyes, significantly increased errors for contralesional peripheral targets.
• This effect was particularly pronounced during bilateral stimulation trials.
• Results indicate that open eyes in central vision capture attentional resources, diminishing peripheral attention, especially on the affected side.

Conclusions:

• The visual gaze of an examiner may influence the outcomes of clinical confrontation testing.
• Attentional capture by open eyes could explain the effectiveness of certain clinical procedures in assessing visual field deficits.