Cortical determinants of loudness perception and auditory hypersensitivity

Area of Science:

• Neuroscience
• Auditory Neuroscience
• Cortical Circuits

Background:

• Parvalbumin-expressing neurons (PVNs) are crucial for stabilizing cortical activity, generating gamma rhythms, and modulating plasticity.
• PVNs play a key role in regulating sensory processing and perception.

Purpose of the Study:

• To investigate the role of PVNs in modulating sound level perception in the auditory cortex (ACtx).
• To determine if 40Hz PVN stimulation can persistently desensitize hypersensitive auditory circuits, particularly in models of cochlear damage.

Main Methods:

• Utilized optogenetic activation and inactivation of PVNs in the mouse auditory cortex.
• Measured neural and behavioral responses to sound levels.
• Administered a single 16-minute bout of 40Hz PVN stimulation.
• Assessed loudness perception and auditory cortex responsiveness before and after stimulation.

Main Results:

• PVN activation/inactivation modulated neural and behavioral classification of sound levels over a 20dB range.
• A single 40Hz PVN stimulation session sustainably suppressed ACtx sound responsiveness and potentiated feedforward inhibition.
• This stimulation behaviorally desensitized mice to loudness and restored normal loudness perception for one week in a model of cochlear sensorineural damage.

Conclusions:

• PVN activity functions as a "volume knob" for sound processing in the auditory cortex.
• Targeted 40Hz PVN stimulation offers a potential therapeutic strategy for persistent sensory hypersensitivity, including loudness hypersensitivity resulting from peripheral injury.