Average is optimal: an inverted-U relationship between trial-to-trial brain activity and behavioral performance

Area of Science:

• Neuroscience
• Cognitive Science

Background:

• Trial-to-trial variability in brain activity and behavior is significant.
• Previous studies primarily examined monotonic relationships between brain activity fluctuations and performance.
• Recent findings suggest non-monotonic (U-shaped) relationships between across-trial brain variability and behavior.

Purpose of the Study:

• To investigate the relationship between trial-to-trial brain activity fluctuations and behavioral performance.
• To test for a U- or inverted-U-shaped relationship between brain variability and behavior.
• To determine if this relationship extends to pre-stimulus spontaneous brain activity.

Main Methods:

• Utilized a visual stimulus detection task.
• Recorded human electrocorticography (ECoG) data.
• Analyzed broadband ECoG activity fluctuations in relation to hit rates and reaction times.

Main Results:

• Evidence for an inverted-U brain-behavior relationship was found.
• Lower trial-to-trial variability in ECoG activity was associated with higher hit rates and faster reaction times.
• This relationship was observed in both post-stimulus task-evoked and pre-stimulus spontaneous brain activity.

Conclusions:

• Brain activity variability, not just average activity, is crucial for performance.
• The findings support the role of stochastic noise and attractor network theories in brain function.
• Anticipatory brain dynamics, reflected in pre-stimulus activity, influence task performance.