A gut feeling: Exploring the effects of probiotics on risk-taking behavior using TMS

Area of Science:

• Neuroscience
• Psychology
• Microbiology

Background:

• The gut-brain axis (GBA) is a bidirectional communication system linking the gut microbiota and the central nervous system.
• Understanding GBA's influence on decision-making, particularly risk-taking, is crucial for behavioral science.
• The ventromedial prefrontal cortex (VMPFC) is implicated in processing GBA signals related to risk.

Purpose of the Study:

• To investigate the impact of probiotics on risk-taking behavior via the gut-brain axis (GBA).
• To examine the role of the ventromedial prefrontal cortex (VMPFC) in mediating GBA-related risk-taking.
• To assess the combined effects of probiotics and VMPFC neuromodulation on decision-making.

Main Methods:

• A 4-week double-blinded, placebo-controlled probiotic intervention.
• The Maastricht Gambling Task (MGT) to assess risk-taking behavior.
• Transcranial magnetic stimulation (TMS), specifically continuous theta burst stimulation (cTBS), targeting the VMPFC, superior parietal lobule (SPL), and sham conditions.

Main Results:

• Probiotics significantly increased risky choices and response times in the MGT compared to placebo.
• VMPFC stimulation independently promoted riskier choices, irrespective of probiotic intake.
• No significant interaction was found between probiotics and VMPFC stimulation, suggesting the VMPFC is not a key mediator of probiotic effects on risk-taking.

Conclusions:

• Probiotics can modulate human risk-taking behavior through the gut-brain axis (GBA).
• The VMPFC may not be the primary neural substrate through which probiotics influence risk-related decisions.
• These findings highlight the complex interplay between gut microbiota and brain function in shaping decision-making processes.