Reliable Sensory Processing in Mouse Visual Cortex through Cooperative Interactions between Somatostatin and...

Area of Science:

• Neuroscience
• Computational Neuroscience
• Sensory Processing

Background:

• Neuronal variability in the primary visual cortex (V1) limits information encoding.
• Understanding circuit mechanisms that dynamically modulate intertrial variability is crucial.
• The roles of specific inhibitory interneurons in reliable neural coding are not fully understood.

Purpose of the Study:

• To elucidate the role of somatostatin-expressing interneurons (SST-INs) and parvalbumin-expressing interneurons (PV-INs) in reliable coding in mouse V1.
• To investigate the functional interactions within the inhibitory SST→PV circuit.
• To determine how this circuit modulates pyramidal neuron reliability during visual processing.

Main Methods:

• Simultaneous dual-color calcium imaging of SST-INs and PV-INs in awake mice viewing natural movies.
• Temporally limited optogenetic activation and inactivation of SST and PV interneurons.
• Rate-based computational modeling to support experimental findings.

Main Results:

• SST neurons were active during reliable pyramidal neuron firing epochs, while PV neurons were active during unreliable epochs.
• SST neuron activity lagged PV neuron activity, suggesting a feedback inhibitory SST→PV circuit.
• Optogenetic activation of SST neurons increased pyramidal neuron reliability by suppressing PV neurons.

Conclusions:

• The SST→PV circuit plays a cooperative role in modulating pyramidal neuron activity reliability.
• This inhibitory circuit enhances the fidelity of neural coding in V1.
• Findings reveal a novel mechanism for regulating sensory information processing critical for visual perception.