Drifting population dynamics with transient resets characterize sensorimotor transformation in the monkey superior...

Area of Science:

• Neuroscience
• Systems Neuroscience
• Motor Control

Background:

• Sensorimotor transformation is crucial for goal-directed movements, translating sensory information into motor commands.
• The superior colliculus (SC) plays a key role in sensorimotor processing, particularly in generating eye movements like saccades.
• Understanding the neural dynamics of sensorimotor transformation is essential for deciphering movement preparation.

Purpose of the Study:

• To investigate the neural mechanisms underlying sensorimotor transformation in the superior colliculus during saccade generation.
• To characterize the dynamic evolution of neural activity from sensory to motor representations within the SC population.
• To explore the relationship between neural activity dynamics and movement preparation time.

Main Methods:

• Simultaneous recording of superior colliculus (SC) neuronal activity in three male monkeys performing visually guided saccades.
• Application of dimensionality reduction techniques to analyze the SC population response during the delay period.
• Development and utilization of a proximity index to quantify the shift from visual- to motor-dominant neural representations.

Main Results:

• Sensorimotor transformation is characterized by a gradual drift in SC population activity from a visual-like to a motor-like representation during the movement delay period.
• Transient visual resets in SC activity were observed following microsaccades.
• The proximity index, reflecting the degree of motor representation, correlated with reaction time, indicating its role in movement preparation.

Conclusions:

• The superior colliculus implements sensorimotor transformation through a dynamic shift in population activity, transitioning from sensory to motor domains.
• This dynamic process in the SC is closely linked to the preparation of voluntary movements.
• The findings suggest a conserved movement preparation mechanism across different motor systems, including oculomotor and skeletomotor control.