Tone frequency representation beyond the tonotopic map: Cross-correlation between ongoing activity in the rat...

Area of Science:

• Neuroscience
• Auditory Neuroscience
• Computational Neuroscience

Background:

• Sensory cortices rely on functional maps for neural representation, but representations can extend beyond these maps.
• Auditory cortex shows initial tonotopic activation to tones, followed by signal decay and sustained activity in a subset of neurons, suggesting involvement of cortical states.

Purpose of the Study:

• To investigate if neural correlations within the auditory cortex (AC) reflect the cortical state underlying sustained ongoing neural activity.
• To determine if local field potential (LFP) cross-correlations can serve as a measure of this cortical state.

Main Methods:

• Dense mapping of the rat auditory cortex.
• Analysis of cross-correlation patterns of ongoing local field potential (LFP) activity.
• Assessment of tonotopic representation and LFP correlations before and after acoustic trauma.

Main Results:

• Cross-correlation patterns of ongoing AC activity were highly decodable, with informative features distributed across the cortex and frequency bands.
• Acoustic trauma disrupted initial tonotopic representation but did not affect neural representations based on LFP correlations.
• These findings suggest LFP cross-correlations represent sustained auditory stimulus frequencies beyond initial tonotopic activation.

Conclusions:

• Neural cross-correlations of LFPs within the auditory cortex serve as a measure of cortical state for ongoing activity.
• This representation mechanism is robust to acoustic trauma, indicating a distinct pathway for sustained auditory information processing.