Global context rapidly shapes sensory responses in V1

Area of Science:

• Neuroscience
• Sensory Processing
• Computational Neuroscience

Background:

• Contextual modulation is crucial for sensory processing in the cerebral cortex.
• Existing theories debate whether early sensory areas like V1 process only local context or also global context.

Purpose of the Study:

• To dissociate local and global contextual influences on neural responses in V1.
• To investigate the role of feedback from higher cortical areas in contextual modulation.

Main Methods:

• Utilized a global/local oddball paradigm with five-item sequences in mice.
• Employed two-photon calcium imaging and local field potential (LFP) recordings in V1.
• Manipulated stimulus identity and predictability to isolate contextual effects.

Main Results:

• Global predictability rapidly abolished context modulation in V1 after minimal exposure (<10 repetitions).
• Globally deviant stimuli, but not predictable local deviants, enhanced V1 responses.
• Feedback from the anterior cingulate area (ACa) was essential for global context modulation in V1.
• Stimulus-specific adaptation constrained global prediction error signals when a repeated stimulus was globally deviant.

Conclusions:

• V1 is rapidly shaped by global context, challenging theories of purely local processing in early sensory areas.
• Global predictions, conveyed via feedback from areas like ACa, play a critical role in V1 function.
• Both prediction error signals and stimulus-specific adaptation influence V1 responses to contextually relevant stimuli.