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Updated: May 14, 2026
09:25
Detecting Pre-Stimulus Source-Level Effects on Object Perception with Magnetoencephalography
Published on: July 26, 2019
Prestimulus oscillatory activity over motor cortex reflects perceptual expectations
Floris P de Lange1, Dobromir A Rahnev, Tobias H Donner
1Radboud University Nijmegen, Donders Institute for Brain, Cognition and Behavior, 6500 HB, Nijmegen, The Netherlands. floris.delange@donders.ru.nl
Summary
Perceptual expectations bias decision-making by altering the starting point of motor cortical activity before sensory evidence is processed. This finding reveals how prior beliefs influence neural processes underlying choice.
Area of Science:
- Neuroscience
- Cognitive Science
- Decision Science
Background:
- Motor cortical activity reflects perceptual choice dynamics by integrating sensory evidence.
- Computational models suggest expectation can alter decision-making parameters like starting point, accumulation rate, or decision bound.
Purpose of the Study:
- To investigate how prior expectation modifies choice-selective motor cortical activity.
- Specifically testing for changes in the starting point of decision-related activity.
Main Methods:
- Used magneto-encephalography (MEG) in human observers during a visual motion discrimination task.
- Measured choice-selective oscillatory activity (8-30 Hz) in motor cortex before stimulus onset.
Main Results:
- Prior expectation of motion direction biased both perceptual judgments and motor cortical activity.
- Spontaneous biases in motor cortex predicted perceptual choice and were influenced by previous trials.
- Behavioral and neural biases were correlated across subjects.
Conclusions:
- Both endogenous and explicit perceptual expectations bias the starting point of decision-related neural activity.
- This bias occurs prior to the accumulation of sensory evidence, influencing perceptual decisions.
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