Modulation in cortical excitability disrupts information transfer in perceptual-level stimulus processing

Area of Science:

• Neuroscience
• Cognitive Neuroscience
• Auditory Perception

Background:

• Understanding behavioral variability is crucial, yet the cortical mechanisms behind failing to respond to subtle stimuli remain unclear.
• Previous research highlights the importance of neural underpinnings but lacks detail on how cortical activity translates to behavioral output for near-threshold stimuli.

Purpose of the Study:

• To investigate the cortical mechanisms responsible for the failure to respond to perceptual-level auditory stimuli.
• To test the hypothesis that moment-to-moment fluctuations in cortical excitability influence the success of sensory-to-motor pathway activation.

Main Methods:

• Utilized electrocorticography (ECoG) recordings in six human subjects.
• Tracked the propagation of cortical activity following perceptual-level auditory stimuli.
• Quantified cortical excitability using instantaneous voltage preceding cortical activity onset.

Main Results:

• When stimuli did not elicit a behavioral response, cortical activity propagation decreased from auditory to motor cortex.
• Reduced local cortical excitability was significantly correlated with the absence of a behavioral response.
• These findings indicate that fluctuations in cortical excitability directly impact the sensory-motor pathway's ability to generate a response.

Conclusions:

• Moment-to-moment variations in cortical excitability are critical determinants of behavioral responses to near-threshold auditory stimuli.
• Successful sensory-to-motor integration, leading to a behavioral output, depends on sufficient cortical excitability at the time of stimulation.
• This study elucidates a key neural mechanism underlying behavioral variability in response to subtle sensory input.