Rhythmic Temporal Expectation Boosts Neural Activity by Increasing Neural Gain.

Area of Science:

• Auditory neuroscience
• Cognitive neuroscience
• Sensory processing

Background:

• Temporal orienting enhances sensory processing via top-down biases.
• It remains unclear if these benefits involve general neural gain or specific tuning.
• The selectivity and trade-offs of temporal expectations in perception are not well understood.

Purpose of the Study:

• To investigate if rhythmic temporal expectations modulate neural gain and tuning in auditory frequency processing.
• To determine if these modulations are specific to task-relevant time points.
• To explore the impact of temporal expectations on processing both targets and distractors.

Main Methods:

• Magnetoencephalography/electroencephalography (M/EEG) recorded brain activity in 23 healthy participants.
• Participants performed an auditory discrimination task with rhythmic or jittered stimulus sequences.
• Neural decoding and quantitative modeling of tuning curves (gain and sharpness) were used.

Main Results:

• Rhythmic expectation improved behavioral accuracy and M/EEG-based decoding of both targets and preceding distractors.
• Decoding improvements for distractors were primarily linked to increased neural gain, not sharpened tuning.
• The effect of rhythmic expectation was associated with nonspecific gain increases, enhancing sensitivity at expected times.

Conclusions:

• Rhythmic temporal expectations increase neural gain, enhancing sensitivity to auditory stimuli at expected time points.
• This gain increase is nonspecific, benefiting both task-relevant targets and irrelevant distractors.
• Temporal expectations improve auditory processing without competitively impairing perception at unexpected time points.