Saccades in pursuit eye tracking reflect motor attention processes

Area of Science:

• Neuroscience
• Psychiatry
• Cognitive Science

Background:

• Pursuit eye tracking (PET) dysfunction is common in psychiatric patients, but its underlying cause remains unclear.
• Speculation suggests pathological disinhibition of saccades contributes to this deficit.
• Significant variability in tracking performance exists even among healthy individuals.

Purpose of the Study:

• To investigate the cause of pursuit eye tracking dysfunction in psychiatric patients.
• To explore the impact of cognitive analysis on tracking performance.
• To determine if improved tracking reflects an automatic, preferred mode of function.

Main Methods:

• Nine healthy subjects performed a pursuit eye tracking task.
• Subjects were instructed to analyze the tracking target, specifically counting saccades and their amplitudes.
• Root-mean-square (RMS) error was used to measure overall tracking performance.

Main Results:

• Tracking performance varied significantly among normal subjects.
• Instructing subjects to analyze the tracking target led to decreased saccade counts and amplitudes.
• A reduction in RMS error was observed, indicating improved tracking quality.
• Performance improvements were sustained throughout the analysis period.

Conclusions:

• The improvement in tracking suggests a preferred, automatic mode of tracking engaged during cognitive analysis.
• This automatic tracking mode, characterized by anticipatory saccades, reflects frontal lobe function.
• Such saccade characteristics can potentially be used for the diagnostic classification of attentional dysfunction.