Parallel mechanisms signal a hierarchy of sequence structure violations in the auditory cortex

Area of Science:

• Neuroscience
• Auditory processing
• Sensory prediction

Background:

• The brain's ability to predict regularities in sensory input is crucial for perception.
• Neuronal mechanisms underlying auditory prediction at multiple complexity levels are not fully understood.

Purpose of the Study:

• To investigate the neuronal mechanisms of auditory prediction at local and global levels.
• To differentiate cellular contributions to processing different types of regularity in sound sequences.

Main Methods:

• Monitoring auditory cortex activity in mice using the local-global paradigm.
• Analyzing neural responses to predictable and unpredictable sound sequences during different behavioral states (anesthesia vs. wakefulness).

Main Results:

• Auditory responses are enhanced upon local prediction violation, driven by adaptation and a surprise mechanism.
• VIP interneurons in wakefulness signal sequence chunking via response to omitted expected sounds.
• Global structure violation leads to increased activity in VIP and PV neurons.

Conclusions:

• Distinct cellular mechanisms in the auditory cortex predict different levels of regularity in sound sequences.
• VIP interneurons play a role in processing global sequence structure during wakefulness.
• The brain employs sophisticated strategies to predict and respond to auditory regularities.