Consecutive acupuncture stimulations lead to significantly decreased neural responses.
OBJECTIVE
Functional magnetic resonance imaging (fMRI), in combination with block design paradigms with consecutive acupuncture stimulations, has often been used to investigate the neural responses to acupuncture. In this study, we investigated whether previous acupuncture stimulations can affect brain activations of later acupuncture stimulations.


METHODS
All subjects were measured twice in the same scanning session and a block design was used.


METHODS
The study was conducted at Kyung Hee University, Seoul, Republic of Korea.


METHODS
Fifteen (15) healthy right-handed male volunteers participated in the study.


METHODS
The subjects received two acupuncture stimulations on BL62 (Shenmai) on the right foot with a time interval of 5 minutes. In addition, sham stimulations were tested with the same paradigm.


METHODS
One-sample t tests were conducted in order to map the brain activations induced by the acupuncture and sham stimulations. Moreover, paired-sample t tests were conducted to investigate the signal changes between the first and second acupuncture stimulation.


RESULTS
During the first acupuncture stimulation, in the left hemisphere, significant foci of activation were found in the hypothalamus, thalamus, claustrum, cerebellum, inferior frontal gyrus, and the superior temporal gyrus. In the right hemisphere, a significant focus of activation was found in the middle frontal gyrus. In addition, in both hemispheres, a significant focus of activation was found in the inferior parietal lobule. Interestingly, however, during the second acupuncture stimulation, the only areas that were also significantly activated were the cerebellum in the left hemisphere and the inferior parietal lobule in the right hemisphere.


CONCLUSIONS
We found that consecutive acupuncture stimulations on BL62 affected the neural responses in a significant way, resulting in decreased activations during the second acupuncture stimulation. This is an important finding, suggesting that in future fMRI studies on acupuncture, researchers should take this methodological issue more seriously.
Yeo
Sujung
S
Research Group of Pain and Neuroscience, WHO Collaborating Centre for Traditional Medicine, East-West Medical Research Institute, Kyung Hee University, Seoul, Republic of Korea.
Choe
Il-Hwan
IH
van den Noort
Maurits
M
Bosch
Peggy
P
Lim
Sabina
S
D015669:Acupuncture Points; D015670:Acupuncture Therapy; D000328:Adult; D001921:Brain / Q000502:physiology*; D001931:Brain Mapping; D005528:Foot; D006801:Humans; D008297:Male; D009424:Nervous System Physiological Phenomena; D055815:Young Adult