Evidence for interactions between target selection and visual fixation for saccade generation in humans

Area of Science:

• Neuroscience
• Ophthalmology
• Cognitive Psychology

Background:

• Saccadic eye movements are crucial for visual exploration.
• Initiating a saccade requires disengaging fixation and selecting a new target.
• The interplay between these processes is not fully understood.

Purpose of the Study:

• To investigate whether the neural processes of disengaging fixation and selecting saccade targets operate independently or interactively.
• To explore the relationship between fixation disengagement, target selection, and saccadic reaction times.

Main Methods:

• A multimodal choice reaction task was employed.
• Participants performed a saccade away from a central fixation target to an eccentric visual target.
• An auditory distractor was presented simultaneously to assess interference.

Main Results:

• Difficulty suppressing incorrect saccades toward a distractor increased when the fixation target was extinguished before the eccentric target appeared.
• Faster saccadic reaction times correlated with a higher number of incorrect movements.
• These findings suggest an interaction between fixation disengagement and target selection.

Conclusions:

• The processes of disengaging visual fixation and selecting a new saccade target are interrelated.
• This interaction likely involves neural activity changes within the superior colliculus.
• Understanding this interplay is key to comprehending selective orientation and saccadic control.