Temporal integration in human auditory cortex is predominantly yoked to absolute time.

Area of Science:

• Neuroscience
• Auditory Perception
• Computational Linguistics

Background:

• Neural integration in auditory processing is modeled based on either absolute time or linguistic structure.
• The relative contribution of time versus structure to neural integration remains unclear.
• Speech structures like phonemes and words have variable durations, posing challenges for temporal processing.

Purpose of the Study:

• To investigate whether neural integration in the human auditory cortex is primarily driven by absolute time or by the duration of sound structures.
• To determine the extent to which cortical computations reflect temporal versus structural processing during speech perception.

Main Methods:

• Utilized time stretching and compression to manipulate speech structure durations.
• Employed a novel experimental and computational method with spatiotemporally precise intracranial recordings in humans.
• Measured auditory cortex integration windows under altered speech durations.

Main Results:

• Integration windows showed a slight increase (~5%) for time-stretched speech compared to duration changes.
• This temporal effect was observed even in non-primary auditory regions associated with speech processing.
• Findings indicate that time-yoked computations are dominant across the auditory cortex.

Conclusions:

• Neural computations in the human auditory cortex are predominantly governed by time, not the duration of speech structures.
• These results constrain neurocomputational models of auditory and speech processing.
• The auditory cortex prioritizes temporal processing, even when faced with altered structural durations.