Table 4 Tasks performed during functional magnetic resonance imaging (fMRI) and reported probiotic effects
Study | fMRI paradigm | Measured parameter and direction of effect | Localisation of effect |
|---|---|---|---|
Tillisch et al.31 | Emotional faces attention task (angry and fearful faces (ME), control: geometric forms (MF)) | Brain activity, Probiotics < placebo | ME > MF: primary viscerosensory, somatosensory cortex (posterior and mid insula) (with a priori-defined region of interest analysis based on a network with altered connectivity, while no effect with a whole-brain analysis) |
Task-related functional connectivity, sig. differences post vs pre across all groups, post hoc: Probiotics 4 weeks < baseline, (placebo 4 weeks = baseline) | PLS of all ME > MF: Widely distributed network of primary interoceptive and somatosensory regions, midbrain cluster centred around periaqueductal grey, prefrontal cortex, precuneus, basal ganglia, parahippocampal gyrus | ||
Pinto-Sanchez et al.50 | Fearful face backward masking paradigm (fearful and neutral faces, control: fixation cross) Whole-brain & a priori selected regions of interest: bilateral amygdala | Brain activity, Probiotics vs placebo | No significant difference between fearful and neutral faces. |
Brain activity, Probiotics < placebo | Fearful faces vs fixation cross: amygdala and frontal and temporal cortices | ||
Brain activity, Probiotics > placebo | Fearful faces vs fixation cross: occipital regions | ||
Bagga et al.37 | Emotional-decision making task (neutral (N), unpleasant (U), control: geometric (B) pictures) | Brain activity, Probiotics < placebo | N > B: no sig differences, U > B: precuneus, mid cingulum, parahippocampal gyrus |
Emotional recognition memory task (neutral (N), unpleasant (U), control: geometric (B) pictures) | Brain activity, Probiotics < placebo | N > B: anterior cingulum; U > B: posterior cingulum | |
Papalini et al.32 | Emotional face-matching paradigm (angry and fearful faces, control: geometric shapes) | Brain activity, Probiotics vs placebo | No effect |
Emotional face-word stroop paradigm (happy and fearful) | Brain activity, Probiotics vs placebo | No effect | |
Classical colour-word Stroop task | Brain activity, Probiotics vs placebo | No effect | |
Edebol-Carlman et al.41 | Montreal Imaging Stress Task (stress, control, baseline condition) | Brain activity, Probiotics > placebo | Stress>control*: A40rv, rostroventral area 40, A37dl, dorsolateral area 37 (*not significant after Bonferroni or FDR correction) |
Task-related functional connectivity, Probiotics > placebo | RRC of all stress>control: A4ul, area 4 (upper limbregion) with A37mv, medioventral area37 | ||
Rode et al.42 | Emotional Attention Task (angry and fearful faces (ME), control: geometric shapes (MS)) | Brain activity, Probiotics > placebo | ME > MS*: medial area 10, orbital gyrus – orbital area 12/47, lateral area 12/47 (*not significant after Bonferroni or FDR correction) |
Task-related functional connectivity, Probiotics < placebo | RRC of all ME > MS: frontal pole with caudal area 45, Caudal ventrolateral area 6 with occipital polar cortex, frontal pole with inferior frontal junction and sulcus, left with right caudoposterior superior temporal sulcus | ||
Schaub et al.53 | Emotional task to indicate gender (neutral, semi-fearful, fearful faces, control: fixation cross) | Brain activity, Probiotics vs placebo | No effect |
Brain activity, Probiotics: 31 days < baseline, placebo: no change compared to baseline | Neutral faces vs control: bilateral putamen (Semi-)fearful faces vs control: no effect | ||
Schneider et al.55 | Working memory task (n-back) | Brain activity, sig. intervention group*time interaction, post hoc Probiotics: 31 days < baseline, placebo: 31 days > baseline | 0-back, 2-back: left hippocampus, 1-back: no effect (with a priori-defined region of interest analysis, while no effect with a whole-brain analysis) |
