Andrew C. N. Chen

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Eyes-closed (EC) and eyes-open (EO) are essential behaviors in mammalians, including man. At resting EC-EO state, brain activity in the default mode devoid of task-demand has recently been established in fMRI. However, the corresponding comprehensive electrophysiological conditions are little known even though EEG has been recorded in humans for nearly 80(More)
UNLABELLED This high-resolution electroencephalography (EEG) study tested the hypothesis that the suppression of rolandic alpha power before predictable painful stimulation affects the subject's subsequent evaluation of pain intensity, as a reflection of the influence of expectancy processes on painful stimulus processing. High-resolution EEG data were(More)
Two- or 100-Hz electrical acupoint stimulation (EAS) can induce analgesia via distinct central mechanisms. It has long been known that the extent of EAS analgesia showed tremendous difference among subjects. Functional MRI (fMRI) studies were performed to allocate the possible mechanisms underlying the frequency specificity as well as individual variability(More)
To explore the effects of tonic cold pain in man, the pain rating (intensity and distress), skin temperature, and continuous EEG recording were conducted before, during, and after cold pressor test (CPT) in 15 young healthy males. The acquired electroencephalogram (EEG) data was analysed in four ways: (1) comparison of EEG topographic patterns and power(More)
OBJECTIVE: To develop a reliable and repeatable way to monitor changes in the flexion relaxation phenomenon of the lumbar paraspinal muscles during forward flexion by the development of a flexion relaxation ratio and observation of the sEMG activity in standing and during forward flexion in patients with chronic low back pain (CLBP) and healthy controls.(More)
Contact heat evoked potentials (CHEPs) have been difficult to elicit due to slow temperature rise times. A recently developed heat-foil technology was used to elicit pain and CHEPs. Two groups of subjects were separately stimulated at the left arm with contact heat via one fast-acting (70 degrees C/s) heat-foil thermode. A set of CHEPs was recorded, each at(More)
Although pathological muscle pain involves a significantly larger population than any other pain condition, the central mechanisms are less explored than those of cutaneous pain. The aims of the study were to establish the pain matrix for muscle pain in the full head volume and, further, to explore the possibility of a functional segregation to nonpainful(More)
Little is known about somatosensory evoked potentials (SEPs) from muscle stimulation compared to that from skin stimulation. The current study examined this issue in the full SEP spectrum (0 - 440 ms). The aims of the study were to (1) establish the dynamics of early to late latency SEPs from intramuscular stimulation in contrast to surface stimulation, (2)(More)
Previous electroencephalographic (EEG) evidence has shown event-related desynchronization (ERD) of alpha rhythms before predictable painful stimuli, as a possible neural concomitant of attentional preparatory processes (Babiloni, C., Brancucci, A., Babiloni, F., Capotosto, P., Carducci, F., Cincotti, F., Arendt-Nielsen, L., Chen, A.C., Rossini, P.M., 2003.(More)
To clarify the specific effects of muscle pain on electroencephalogram (EEG) activation in man, painful and non-painful sensations were produced by intramuscular injections of capsaicin and vehicle solution in the left brachioradialis muscle, with identical procedures in 15 male volunteers. Thirty-one channel EEG data acquired before, during and after the(More)