Reward-timing-dependent bidirectional modulation of cortical microcircuits during optical single-neuron operant...

Area of Science:

• Neuroscience
• Computational Neuroscience
• Systems Neuroscience

Background:

• Animals exhibit remarkable adaptability to environmental shifts.
• Understanding the neural mechanisms of rapid adaptation is crucial for neuroscience.
• Cortical microcircuits play a key role in behavioral flexibility.

Purpose of the Study:

• To investigate how cortical microcircuits reorganize during the recognition of novel reward contingencies.
• To elucidate the role of specific neuronal activity reinforcement in motor cortex adaptation.

Main Methods:

• Two-photon calcium imaging of layer 2/3 motor cortex neurons in mice.
• Simultaneous reinforcement of single cortical neuron activity with water delivery.
• Operant conditioning paradigms to assess behavioral changes and neural activity.

Main Results:

• Mice increased target neuron activity and reward acquisition during operant conditioning without altering forelimb movements.
• Reinforcement bidirectionally modulated activity in non-target neurons, irrespective of their distance from the target neuron.
• This modulation was dependent on the precise timing between reward delivery and neuronal activity, and could be replicated by optogenetic pairing.

Conclusions:

• Reward-timing-dependent bidirectional modulation is a fundamental process in rapid microcircuit reorganization.
• This mechanism underlies adaptive changes in neural circuits in response to environmental learning.
• The findings provide insights into the neural basis of behavioral adaptation and learning.