Manipulation of object choice by electrical microstimulation in macaque frontal eye fields

Area of Science:

• Neuroscience
• Cognitive Science
• Ophthalmology

Background:

• Eye movements, specifically saccades, involve selecting a target and directing gaze.
• The frontal eye fields (FEF) are implicated in both visual selection and saccade generation.
• Evidence suggests distinct neuronal populations within the FEF may govern these two processes.

Purpose of the Study:

• To investigate the causal role of the frontal eye fields (FEF) in dissociating visual object selection from saccade selection.
• To determine if FEF activity influences visual object choice independently of saccade endpoint determination.

Main Methods:

• Utilized a covert object-tracking paradigm with randomly moving identical objects in monkeys.
• Applied electrical microstimulation to the FEF at different time points during object motion.
• Monitored saccade behavior and object selection following FEF stimulation.

Main Results:

• Microstimulation of the FEF at motion onset biased object selection towards specific locations, dependent on stimulation site.
• The same FEF stimulation delivered at the end of object motion did not alter saccade endpoints.
• FEF manipulation successfully changed visual object selection without affecting saccade goals.

Conclusions:

• These findings suggest the existence of neurons within the FEF that are solely responsible for visual selection.
• Demonstrates a functional dissociation between visual selection and saccade planning mediated by the FEF.
• Highlights the complex role of the FEF in guiding behavior through distinct neural mechanisms.