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Updated: Jul 13, 2026
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Detecting Pre-Stimulus Source-Level Effects on Object Perception with Magnetoencephalography
Published on: July 26, 2019
Baseline brain activity fluctuations predict somatosensory perception in humans
M Boly1, E Balteau, C Schnakers
1Coma Science Group, Cyclotron Research Center, B30, Allée du 6 Août, Sart Tilman, University of Liège, B-4000 Liège, Belgium. mboly@student.ulg.ac.be
Summary
Brain activity before a stimulus influences conscious perception. Higher baseline activity in certain brain areas enhances perception, while activity in others decreases it, affecting how we experience the world.
Area of Science:
- Neuroscience
- Cognitive Science
- Perception Research
Background:
- Variability in conscious perception of identical stimuli is a known phenomenon.
- The underlying neural mechanisms linking prestimulus brain activity to perceptual fluctuations are not fully understood.
Purpose of the Study:
- To investigate the relationship between prestimulus, baseline brain activity and perceptual variability.
- To determine how fluctuations in baseline neural activity modulate the conscious perception of somatosensory stimuli.
Main Methods:
- Utilized thulium-yttrium/aluminum-garnet laser for stimulus delivery.
- Employed event-related functional magnetic resonance imaging (fMRI) to measure brain activity.
- Analyzed prestimulus, baseline brain activity in relation to conscious perception reports.
Main Results:
- Positive correlation found between conscious perception of low-intensity stimuli and baseline activity in medial thalamus and frontoparietal network (vigilance, external monitoring).
- Negative correlation observed between conscious perception and baseline activity in posterior cingulate/precuneus and temporoparietal cortices (introspection, self-oriented processes).
- Pain intensity ratings positively correlated with baseline activity in anterior cingulate cortex for nociceptive stimulation.
Conclusions:
- Prestimulus brain activity significantly modulates conscious perception.
- Different neural networks are involved in modulating perception based on stimulus intensity and processing (external vs. internal focus).
- Baseline neural fluctuations play a critical role in shaping our subjective experience of the external world.
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01:11Sensory Perception: Organization of the Somatosensory System
The somatosensory system is the central and peripheral nervous system component that senses and processes touch, pressure, pain, temperature, and body position or proprioception. The process of sensation takes place at three levels:
The receptor level:
The receptor level is the first stage of sensation. It involves the detection of a stimulus by specialized sensory receptors. The stimulus must arrive within the receptor's receptive field. Next, the receptor converts the energy of the stimulus...
The receptor level:
The receptor level is the first stage of sensation. It involves the detection of a stimulus by specialized sensory receptors. The stimulus must arrive within the receptor's receptive field. Next, the receptor converts the energy of the stimulus...