Motor cortex latent dynamics encode spatial and temporal arm movement parameters independently.

Area of Science:

• Neuroscience
• Motor Control
• Computational Neuroscience

Background:

• Arm movement requires precise spatiotemporal control.
• The motor cortex is hypothesized to generate movements via collective neural dynamics.
• A key prediction is that independent movement parameters map to independent neural dynamics.

Approach:

• Monkeys performed reaching movements to random targets.
• Analyzed low-dimensional population activity in motor cortex.
• Utilized recurrent neural network models to interpret coding schemes.

Key Points:

• Spatial (direction) and temporal (speed) parameters of arm movements are independently encoded in motor cortex neural activity.
• Movement direction maps to distinct neural trajectories, while speed relates to traversal time.
• Recurrent neural networks demonstrate how separate network parameters can control these independent movement features.

Conclusions:

• Results support the dynamical systems view of motor cortex function.
• Independent encoding of movement parameters in neural trajectories is demonstrated.
• Not all movement parameters are necessarily represented by distinct population activity trajectories.