Functional Localization of the Frontal Eye Fields in the Common Marmoset Using Microstimulation

Area of Science:

• Neuroscience
• Primate Models
• Oculomotor Control

Background:

• The frontal eye field (FEF) is crucial for spatial attention.
• Macaque FEF is difficult to study due to its location within a sulcus.
• Marmosets offer a more accessible lissencephalic cortex for studying FEF.

Purpose of the Study:

• To physiologically locate and characterize the FEF in the common marmoset.
• To provide evidence for the homology between marmoset and macaque FEF.
• To validate the marmoset as a model for FEF microcircuitry research.

Main Methods:

• Intracortical microstimulation was applied to frontal cortical areas in awake, behaving marmosets.
• 96-channel Utah arrays were used for recordings and stimulation.
• Saccade responses to microstimulation were analyzed for direction and amplitude.

Main Results:

• Low-current microstimulation evoked short-latency saccades in specific marmoset frontal areas (45, 8aV, 8C, 6DR).
• A topographical organization of saccade direction and amplitude was observed, consistent with macaque and human FEF.
• Evidence supports homology between marmoset and macaque FEF.

Conclusions:

• The common marmoset possesses a physiologically identifiable FEF.
• The marmoset is a suitable primate model for investigating FEF microcircuitry.
• This research advances understanding of attention and oculomotor functions.