Only coherent spiking in posterior parietal cortex coordinates looking and reaching

Area of Science:

• Neuroscience
• Motor Control
• Cognitive Neuroscience

Background:

• The posterior parietal cortex (PPC) is implicated in sensorimotor transformations.
• Understanding how the brain coordinates distinct movements like looking and reaching is crucial for motor control research.

Purpose of the Study:

• To investigate the neural mechanisms underlying the coordination of looking and reaching movements.
• To identify specific neural activity patterns in the PPC that correlate with coordinated movement timing.

Main Methods:

• Utilized a spike-field approach to analyze neural activity in the PPC.
• Recorded local field potential (LFP) activity and single-unit spiking in the parietal area LIP.
• Correlated neural firing patterns with reaction times (RTs) for different movement tasks.

Main Results:

• Identified a population of parietal area LIP neurons firing spikes coherently with 15 Hz beta-frequency LFP activity.
• The firing rate of these coherently active neurons predicted RTs for coordinated reach-saccade movements.
• Non-coherently active LIP neurons and activity in visual area V3d did not predict movement RTs.

Conclusions:

• Temporally patterned, coherent spiking activity in the PPC coordinates the timing of looking and reaching.
• This suggests a shared neural representation within the PPC for controlling combined movements.
• The findings propose a neural mechanism where coherent activity modulates movement speed for coordinated actions.