Layer 6 ensembles can selectively regulate the behavioral impact and layer-specific representation of sensory...

Area of Science:

• Neuroscience
• Computational Neuroscience
• Sensory Processing

Background:

• Predictive models are essential for processing novel sensory information.
• Layer 6 (L6) neurons in the neocortex are hypothesized to play a role in predictive model formation.
• Understanding the function of specific neuronal layers is key to deciphering brain computations.

Purpose of the Study:

• To investigate the role of L6 neurons in neocortical predictive processing.
• To determine if L6 neurons are necessary for behavioral enhancements driven by deviant stimuli.
• To elucidate the impact of L6 activity modulation on neural encoding in other cortical layers.

Main Methods:

• Utilized a combination of behavioral assays, electrophysiology, and in vivo imaging in mouse primary somatosensory cortex.
• Employed optogenetics to selectively modulate the activity of L6 neurons.
• Analyzed neural responses in L2/3 and L6, alongside behavioral sensitivity to tactile stimuli.

Main Results:

• Deviant tactile stimuli improved detection and were encoded in L2/3 neural tuning.
• Weak optogenetic stimulation of L6 neurons selectively impaired behavioral sensitivity to deviant stimuli, not baseline performance.
• This L6 modulation abolished deviance encoding in L2/3 without affecting basic stimulus responses across layers.
• Stronger L6 inhibition suppressed overall sensory function.

Conclusions:

• Specific, stimulus-driven L6 neuronal ensembles are critical for generating neocortical predictions.
• These L6 ensembles are necessary for translating predictive models into behavioral benefits, specifically for detecting unexpected events.
• The findings highlight a specialized role for L6 neurons in predictive coding within the somatosensory cortex.