Pre-stimulus beta power mediates explicit and implicit perceptual biases in distinct cortical areas

Area of Science:

• Neuroscience
• Cognitive Science
• Psychology

Background:

• Perception is influenced by prior expectations and actions.
• Pre-stimulus brain oscillations are hypothesized to implement these biases.
• Understanding neural correlates of bias is crucial for cognitive neuroscience.

Purpose of the Study:

• Investigate pre-stimulus neural correlates of implicit (previous choice) and explicit biases in somatosensory detection.
• Examine the role of pre-stimulus oscillations in mediating these biases.
• Differentiate neural mechanisms for explicit versus implicit biases.

Main Methods:

• Two electroencephalography (EEG) studies with 43 and 39 participants.
• Somatosensory near-threshold detection task.
• Manipulation of explicit bias using cued stimulus probabilities (volatile and stable contexts) and implicit bias via previous choices.

Main Results:

• Behavioral analysis confirmed adjustments in decision criteria and confidence ratings based on cued probabilities and prior choices.
• Pre-stimulus beta power in distinct cortical areas (sensory and higher-order) predicted explicit and implicit biases, respectively.
• Beta oscillations partially mediated the influence of previous choice and stimulus probability on detection responses.

Conclusions:

• Pre-stimulus beta oscillations in specific brain regions serve as neural correlates for both explicit and implicit biases in somatosensory perception.
• Distinct neural sources of beta power underlie different types of perceptual bias.
• This finding provides insight into the neural mechanisms of expectation-driven perception.