Flexible sensitivity to inputs during skilled tongue movements

Area of Science:

• Neuroscience
• Motor Control
• Sensory Integration

Background:

• Complex goal-directed movements require rapid motor program switching based on sensory input and action context.
• The neural mechanisms underlying this flexible motor control remain largely unknown.

Purpose of the Study:

• To investigate a network mechanism for adjusting motor execution sensitivity to external inputs within varying sensorimotor contexts.
• To provide causal evidence for integrating external inputs with internal context for flexible motor control.

Main Methods:

• Mice were trained on a licking task involving sequences directed at a moving target.
• Optogenetic stimulation targeted somatosensory cortical inputs to the tongue premotor cortex (ALM) during specific motor switching points.
• Sessions were divided into blocks where sensory-driven backtracking was either required or not required.

Main Results:

• Optogenetic stimulation reliably induced backtracking-like licking movements, particularly during blocks requiring sensory-driven backtracking.
• Optically evoked neural activity deviations were larger during these conditions.
• Population neural activity separated along a latent axis that correlated with stimulation impact and influenced motor switching speed.

Conclusions:

• A neural network mechanism enables flexible adjustment of motor execution sensitivity to external inputs based on context.
• External sensory inputs are integrated with internal context signals to achieve adaptable, goal-directed motor control.
• This provides causal evidence for context-dependent sensory integration in motor flexibility.