Background
Functional magnetic resonance imaging
(fMRI) is a novel method for studying the changes of brain networks due
to acupuncture treatment. In recent years, more and more studies have
focused on the brain functional connectivity network of acupuncture
stimulation.
Objective
To offer an overview of
the different influences of acupuncture on the brain functional
connectivity network from studies using resting-state fMRI.
Search strategy
The
authors performed a systematic search according to PRISMA guidelines.
The database PubMed was searched from January 1, 2006 to December 31,
2016 with restriction to human studies in English language.
Inclusion criteria
Electronic
searches were conducted in PubMed using the keywords “acupuncture” and
“neuroimaging” or “resting-state fMRI” or “functional connectivity”.
Data extraction and analysis
Selection
of included articles, data extraction and methodological quality
assessments were respectively conducted by two review authors.
Results
Forty-four
resting-state fMRI studies were included in this systematic review
according to inclusion criteria. Thirteen studies applied manual
acupuncture vs. sham, four studies applied electro-acupuncture vs. sham,
two studies also compared transcutaneous electrical acupoint
stimulation vs. sham, and nine applied sham acupoint as control.
Nineteen studies with a total number of 574 healthy subjects selected to
perform fMRI only considered healthy adult volunteers. The brain
functional connectivity of the patients had varying degrees of change.
Compared with sham acupuncture, verum acupuncture could increase default
mode network and sensorimotor network connectivity with pain-,
affective- and memory-related brain areas. It has significantly greater
connectivity of genuine acupuncture between the periaqueductal gray,
anterior cingulate cortex, left posterior cingulate cortex, right
anterior insula, limbic/paralimbic and precuneus compared with sham
acupuncture. Some research had also shown that acupuncture could adjust
the limbic-paralimbic-neocortical network, brainstem, cerebellum,
subcortical and hippocampus brain areas.
Conclusion
It
can be presumed that the functional connectivity network is closely
related to the mechanism of acupuncture, and central integration plays a
critical role in the acupuncture mechanism.