We searched the original articles published during 1995 to 2014 on PubMed (http://www.ncbi.nlm.nih.gov/pubmed/) using the following MeSH terms and search strategies: ((“Acupuncture” [Mesh] OR “Acupuncture Therapy” [Mesh] OR “Acupuncture, Ear” [Mesh] OR “Acupuncture Points” [Mesh] OR “Acupuncture Analgesia” [Mesh])) AND ((“Neuroimaging” [Mesh] OR “Functional Neuroimaging” [Mesh] OR “Functional MRI” [Mesh] OR “PET” [Mesh] OR “EEG” [Mesh])).