Neuroscience letters
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Neuroscience letters · Apr 2003
Comparative StudyThe influence of semantic priming on event-related potentials to painful laser-heat stimuli in migraine patients.
We investigated the effects of different semantic primes on the processing of painful stimuli in migraine patients. For prime stimuli, descriptors of three categories were used: somatosensory pain-related, affective pain-related, and neutral adjectives. While migraine patients (n = 17) processed these primes, a painful laser-heat stimulus was applied to the dorsum of the left hand. ⋯ Within the group of migraine patients, LEP amplitudes at 300 ms post laser stimulus and N2-P2 peak-to-peak amplitudes were significantly enlarged when applied while subjects processed pain-related as compared to non-pain-related primes, i.e. patients showed a pattern of priming effect similar to that of the control group. Additionally, patients recognised more affective words than control subjects, and affective pain-related primes tended to enhance the P2 amplitude of LEP more than somatosensory pain-related primes. It is suggested that pain-related semantic primes might pre-activate neural networks subserving pain memory and pain processing.
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Neuroscience letters · Apr 2003
Subjective sleepiness correlates negatively with global alpha (8-12 Hz) and positively with central frontal theta (4-8 Hz) frequencies in the human resting awake electroencephalogram.
Subjective sleepiness is part of the system controlling the decision to go to sleep in humans. Extended periods of waking lead to increased sleepiness, as well as to changes in cortical electroencephalogram (EEG) during waking. ⋯ We found: (1). strong negative correlations of alpha (8-12 Hz) power with subjective sleepiness at all scalp locations, suggesting a negative association between sleepiness and general cortical activation; and (2). positive correlations of theta (4-8 Hz) power with subjective sleepiness with a focus on frontal locations, suggesting additional location specific associations between sleepiness and cortical activation. These findings support the notion that sleepiness is directly represented in the awake EEG.