Cortical ensembles selective for context

Area of Science:

• Neuroscience
• Computational Neuroscience
• Sensory Processing

Background:

• Neural processing is context-dependent, with responses varying for predictable versus novel stimuli.
• Understanding how cortical circuits achieve this contextual modulation is key for explaining attention, learning, and behavior.

Purpose of the Study:

• To investigate the neural mechanisms underlying context-dependent modulation of sensory responses in the primary visual cortex (V1).
• To identify neuronal populations responsible for detecting stimulus deviance and their circuit basis.

Main Methods:

• Utilized in vivo two-photon calcium imaging and local field potential recordings in awake mice.
• Employed visual oddball paradigms to present predictable and deviant stimuli.
• Used optogenetics to manipulate prefrontal inputs to V1.

Main Results:

• Identified stimulus-evoked response reductions to redundant stimuli and augmentations to deviant stimuli in V1.
• Discovered a specific subset of supragranular neurons ('deviance-detecting cells') exhibiting augmented responses.
• Showed that optogenetic suppression of prefrontal inputs impaired the contextual selectivity of these deviance-detecting ensembles.

Conclusions:

• Specialized, context-selective neuronal ensembles exist in primary sensory cortex.
• Top-down prefrontal inputs causally modulate the contextual selectivity of these ensembles.
• These findings provide a circuit basis for prediction error signaling, vital for survival and implicated in psychiatric disorders.