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Table 1 List of studies included in the ALE meta-analyses

From: Subliminal versus supraliminal stimuli activate neural responses in anterior cingulate cortex, fusiform gyrus and insula: a meta-analysis of fMRI studies

Study name Type of subject, gender, mean age Subliminal condition Supraliminal condition n Foci fMRI analysis Activation threshold
a) Subliminal activation greater than supraliminal activation  
Diekhof et al. 2009 Healthy: 4 male, 5 female, 24.4 years (S.D. 2.2) Subtle changes in audio frequency Detectable changes in audio frequency 9 1 WBe p < 0.001
Lawal et al. 2006 Irritable Bowel Syndrome: 10 female, Healthy: 10 female. 19–38 years Rectal stimulation (bag inflated below perception threshold) Rectal stimulation (bag inflated above perception threshold) 18 17 WBb p < 0.05
Phillips et al. 2004 Healthy: 5 males (grp.1), 29.5 years (S.D. 4.7) 5 male (grp. 2) 28.4 years (S.D. 6.2) Covert angry and disgusted faces Overt angry and disgusted faces 8 23 WBb p < 0.005
Prochnow et al. 2013 Healthy: 5 men, 7 women, 23.8 years (S.D. 3.0) Covert facial expressions of happiness, anger, sadness Overt facial expressions of happiness, anger, sadness 12 11 WBe p < 0.05 (2 foci at p < 0.01)
Sidhu et al. 2004 Irritable Bowel Syndrome: 8 female, Healthy: 8 female, 19–38 years Rectal stimulation (bag inflated below perception) Rectal stimulation (bag inflated at perception and above perception) 16 64 WBb p < 0.05
Only subliminal stimulation  
Duan et al. 2010 Healthy: 5 males, 13 females, 23.6 years (S.D. 1.3) Covert surprised faces   18 41 WBb p < 0.001
Kouider et al. 2009 Healthy: 8 males, 8 female, 23 years (S.D. 2) Covert famous faces   16 9 WBe p < 0.001
Smith et al. 2011 Healthy female, 29 years (range 19–53) Rectal stimulation (bag inflated below perception)   14 13 WBb p < 0.001
Song et al. 2006 Irritable Bowel Syndrome: 12 female, Healthy: 12 female. 23 years (S.D. 0.3/S.D. 0.92) Rectal stimulation (bag inflated below perception)   24 13 WBb p < 0.001
     135 192   
b) Supraliminal activation greater than subliminal activation  
Diekhof et al. 2009 Healthy: 4 male, 5 female, 24.4 years (S.D. 2.2) Subtle changes in audio frequency Changes in audio frequency 9 27 WBe p < 0.001
Gillath & Canterberry, 2011 Healthy: 19 male. 20 female, 19.65 years (no avail S.D.) Masked sexual images presented at 23 ms Supraliminal masked sexual images presented at 524 ms 39 21 WBe p < 0.001
Lawal et al. 2006 Irritable Bowel Syndrome: 10 female, Healthy: 10 female. 19–38 years Rectal stimulation (bag inflated below perception threshold) Rectal stimulation (bag inflated above perception threshold) 18 25 WBb p < 0.05
Phillips et al. 2004 Healthy: 5 male (grp.1), 29.5 years (S.D. 4.7) 5 male (grp. 2) 28.4 years (S.D. 6.2) Covert angry and disgusted faces Overt angry and disgusted faces 8 32 WBb p < 0.005
Prochnow et al. 2013 Healthy: 5 men, 7 women, 23.8 years (S.D. 3.0) Covert facial expressions of happiness, anger, sadness Overt facial expressions of happiness, anger, sadness 12 11 WBe p < 0.05 (2 foci at p < 0.01)
Sidhu et al. 2004 Irritable Bowel Syndrome: 8 female, Healthy: 8 female, 19–38 years Rectal stimulation (bag inflated below perception) Rectal stimulation (bag inflated at perception and above perception) 16 136 WBb p < 0.05
Only supraliminal stimulation  
Hall et al. 2010 Irritable Bowel Syndrome: 7 female, Healthy: 6 female, 30–40 years   Rectal stimulation (bag inflated above pain perception) 13 26 WBe p < 0.001
Kouider et al. 2009 Healthy: 8 males, 8 female, 23 years (S.D. 2)   Overt famous faces 16 8 WBe p < 0.001
Smith et al. 2011 Healthy female, 29 years (range 19–53)   Rectal stimulation (bag inflated above pain perception) 14 9 WBb p < 0.001
Song et al. 2006 Irritable Bowel Syndrome: 12 female, Healthy: 12 female. 23 years (S.D. 0.3/S.D. 0.92)   Rectal stimulation (bag inflated above pain perception) 24 20 WBb p < 0.001
     169 315   
    Grand Total: 304 507   
  1. bBlock design fMRI, eEvent-related fMRI, n = number of participants, foci = number of separate Talairach coordinates contributing to the meta-analysis, n = number of participants, WB = Whole Brain Analysis, S.D. = Standard deviation. Note: all participants had no psychiatric comorbidities.