Gaze-centered updating of visual space in human parietal cortex

Area of Science:

• Neuroscience
• Cognitive Neuroscience
• Human Brain Imaging

Background:

• The posterior parietal cortex (PPC) is known to represent visual space.
• Previous studies in monkeys identified a PPC region crucial for gaze-centered spatial representation and updating.
• The precise human homologue and its dynamic updating capabilities remained less understood.

Purpose of the Study:

• To identify and characterize a human PPC region analogous to the monkey's gaze-centered spatial representation area.
• To investigate whether this human PPC region dynamically updates spatial information for action guidance.
• To explore the contralateral topography of this region for both eye and arm movements.

Main Methods:

• Event-related functional magnetic resonance imaging (fMRI) was employed in human participants.
• Participants performed memory-guided eye movements and arm movements.
• Activity patterns were analyzed in relation to target location, gaze fixation, and movement direction.

Main Results:

• An analogous bilateral region in the human PPC was identified.
• This human PPC region exhibited contralateral topography for both memory-guided eye and arm movements.
• Reversing the remembered target location relative to gaze caused a shift in activity across PPC cortical lobules, indicating dynamic updating.

Conclusions:

• The human PPC contains a bilateral region analogous to the monkey's gaze-centered spatial representation area.
• This human PPC region dynamically updates spatial goals for action in a gaze-centered reference frame.
• The findings highlight the role of the human PPC in integrating visual information and action planning based on gaze direction.