Figure 1.
A. The paradigm consisted of 3-minute event-related stimulation (STIM, 3-second stimulation, ISI mean = 19.5 sec) surrounded by two 2-minute rest sessions (BASE and POST). B. Acupuncture stimulation location (PC6). C. Experimental setup for REAL and PHNT sessions. n.b. Figure in B. was modified from an image in ‘WHO Regional Office for the Western Pacific, 2008, WHO Standard Acupuncture Point Locations in the Western Pacific Region, Manila’.
Figure 2.
Among twenty healthy subjects, ten received real acupuncture (REAL) first, while the rest received phantom acupuncture (PHNT) first, and they were re-classified into phantom credible (PHNTc) and phantom non-credible (PHNTnc) according to the needling credibility in phantom acupuncture (PHNT).
Figure 3.
Influence of credibility on autonomic response modulation to phantom acupuncture.
Phasic and tonic responses for heart rate (A and D), skin conductance (B and E), and pupil size (C and F) were contrasted between credible (PHNTc) and non-credible (PHNTnc) phantom acupuncture. n.b. *<0.05, **<0.01. Error bars represent standard error of the mean.
Figure 4.
Influence of credibility on acupuncture sensations to phantom acupuncture.
PHNTc reported significantly greater sensation intensity for numbness and dull pain (i.e. deqi sensations). n.b. *<0.05, **<0.01, ***<0.001. Error bars represent standard error of the mean.
Figure 5.
Influence of somatosensory needling on autonomic response modulation to real and phantom acupuncture.
Phasic and tonic responses for heart rate (A and D), skin conductance (B and E), and pupil size (C and F) were contrasted between real (REAL) and credible (PHNTc) phantom acupuncture. Comparisons between REAL and PHNTc were based on the data collected only from subjects who regarded phantom acupuncture as real (i.e. PHNTc) and was done using paired t-tests. n.b. *<0.05, **<0.01. Error bars represent standard error of the mean.
Figure 6.
Influence of somatosensory needling on acupuncture sensations to real (REAL) and credible (PHNTc) phantom acupuncture.
PHNTc reported similar sensation intensity as REAL for several deqi-related sensations (e.g., deep pressure, heaviness, fullness, numbness, dull pain). REAL produced greater sensation intensity for soreness, tingling, and sharp pain, as well as overall deqi sensation (i.e. MI). Comparisons between REAL and PHNTc were based on the data collected only from subjects who regarded phantom acupuncture as real (i.e. PHNTc) and was done using paired t-tests. n.b. *<0.05, **<0.01, ***<0.001. Error bars represent standard error of the mean.
Figure 7.
Temporal evolution of autonomic response to real (REAL) and phantom (credible, PHNTc; non-credible, PHNTnc) acupuncture.
Needle insertion, whether real or phantom, produced significantly greater (A) HR decrease, (B) SC increase and (C) PS increase, compared to needle manipulation. ANS response to needle manipulation was relatively stable over all 8 manipulations for REAL (n = 20), PHNTc (n = 11), and PHNTnc (n = 9). SC increase was greater for REAL compared to PHNTc and especially PHNTnc, consistently over all stimuli. Error bars represent standard error of the mean.
Table 1.
Summarization of the physiological responses to real and phantom acupuncture stimulation.