Vol. 282, Issue 2, G332-G337, February 2002
Patterns of excitability in human esophageal sensorimotor
cortex to painful and nonpainful visceral stimulation
Shaheen
Hamdy1,2,
John
C.
Rothwell2,
Chris
Fraser1,
Maxine
Power1,
David
Gow1, and
David G.
Thompson1
1 Department of Gastrointestinal Science, University of
Manchester, Hope Hospital, Salford M6 8HD; and 2 Sobell
Department of Neurophysiology, University College London, National
Hospital for Neurology and Neurosurgery, London WC1N 3BG, United
Kingdom
To
better understand the relationship between cortical plasticity and
visceral pain, we developed a pain-induced model of altered esophageal
corticobulbar excitability. In eight healthy volunteers,
corticoesophageal electromyographic responses were recorded via an
intraluminal catheter, following magnetic stimulation of the right
sensorimotor cortex using perithreshold intensities. Corticothenar
responses were used as control. Responses were assessed both before and
for up to 1 h after either painful or nonpainful balloon
distension of the esophagus (frequency = 1 Hz, dwell time = 200 ms, duration = 10 min), each being delivered to each subject in random order. Painful esophageal distension (mean volume = 11 ± 3 ml) induced a profound increase in esophageal responses compared with baseline levels (at 30 min: 141 ± 12 vs. 101 ± 9 µV, P < 0.01), whereas nonpainful esophageal
distension (mean volume = 4 ± 2 ml) showed a decrease (at 30 min: 72 ± 8 vs. 88 ± 12 µV, P < 0.03).
Thenar responses were unaffected. The results show that painful and
nonpainful stimuli induce different patterns of esophageal
corticobulbar excitability, suggesting a physiological link between
cortical plasticity and visceral pain.
esophagus; magnetic stimulation; neuroplasticity