Stimulus encoding by specific inactivation of cortical neurons.

Area of Science:

• Neuroscience
• Computational Neuroscience
• Systems Neuroscience

Background:

• Neuronal ensembles, groups of neurons with correlated activity, are fundamental to sensory, motor, and behavioral functions.
• Understanding how these ensembles encode information is crucial for deciphering brain function.

Purpose of the Study:

• To investigate the role of neuronal ensembles in visual information encoding.
• To identify and characterize both activated and inactivated neuronal populations during visual stimulation.

Main Methods:

• Utilized volumetric two-photon calcium imaging in awake mice during visual stimulation.
• Employed an unsupervised, model-free algorithm to identify neuronal ensembles.
• Analyzed neuronal activity, including calcium decay dynamics, orientation selectivity, and trial-to-trial variability.

Main Results:

• Identified both activated ('onsemble') and inactivated ('offsemble') neuronal ensembles.
• Observed faster calcium decay in offsemble neurons, suggesting selective inhibition.
• Demonstrated that ensembles exhibit low trial-to-trial variability and high orientation selectivity.
• Showed that ensembles' predictive accuracy for stimulus orientation surpasses the sum of individual neuron activities.

Conclusions:

• The coordinated activation and inactivation of cortical neurons form an emergent and distributed neural code.
• This selective neural modulation significantly enhances visual encoding efficiency and accuracy.