Preparing to move increases the sensitivity of superior colliculus neurons

Area of Science:

• Neuroscience
• Systems Neuroscience
• Sensory Processing

Background:

• The neural mechanisms underlying goal-directed movement selection are not fully understood.
• The superior colliculus (SC) is implicated in controlling rapid eye movements (saccades).

Purpose of the Study:

• To investigate how preparing a saccade influences sensory signal processing within the SC.
• To determine if movement commands modulate neuronal responses to visual stimuli.

Main Methods:

• Trained monkeys performed a saccade task involving visual targets of varying luminance contrast.
• Recorded activity of superior colliculus (SC) neurons.
• Analyzed neuronal contrast responses under conditions of saccade preparation, withholding saccades, and fixation.

Main Results:

• SC neurons showed increased visual responses with higher stimulus contrast.
• Neuronal sensitivity to contrast was enhanced when preparing a saccade compared to fixation.
• The SC's motor circuitry demonstrated increased contrast sensitivity during saccade preparation.

Conclusions:

• Movement commands, specifically for saccades, actively influence sensory responses in the SC.
• This modulation of sensory processing by motor preparation in the SC is analogous to attention-driven effects in other brain areas.