Rapid rebalancing of co-tuned ensemble activity in the auditory cortex

Area of Science:

• Neuroscience
• Auditory Neuroscience
• Computational Neuroscience

Background:

• Sensory information is processed by neuronal ensembles in the cortex.
• Auditory cortex (AC) exhibits high trial-by-trial variability in neuronal ensemble activity despite consistent sound perception.
• Efficient acoustic processing relies on interactions within sparsely distributed neuronal ensembles.

Purpose of the Study:

• To investigate interactions within and across neuronal ensembles in the auditory cortex.
• To determine how stimulating single cells affects the broader cortical network dynamics.
• To understand the role of neuronal ensemble interactions in maintaining perceptual constancy.

Main Methods:

• In vivo two-photon calcium imaging in awake mice.
• Holographic optogenetic stimulation to activate specific neuronal populations.
• Simultaneous presentation of pure tones and targeted neuronal stimulation.

Main Results:

• Non-stimulated, co-tuned neurons in the AC decreased their tone-evoked activity when the presented pure tone frequency matched their tuning.
• This activity decrease was more pronounced in co-tuned neurons with higher frequency selectivity.
• Non-co-tuned neurons remained unaffected, and co-tuned and non-co-tuned neurons were spatially intermingled.
• Stimulation led to balanced total network activity, which remained constant.

Conclusions:

• Co-tuned neuronal ensembles in the auditory cortex communicate and actively rebalance network activity.
• This rapid rebalancing mechanism helps maintain consistent encoding of network dynamics.
• The rebalanced network activity is persistent, suggesting a stable mechanism for perceptual constancy.