FIGURE 5.

Noise and the microbiome. The gastro-intestinal microbiome is connected to neuropsychiatric processes via the gut-brain axis and thereby affects neuropsychiatric disorders, whereas mood and neuropsychiatric health may affect intestinal inflammatory disease (Collins et al., 2012; Cryan and Dinan, 2012). Noise causes neuronal activation with subsequent stress hormone release and is associated with annoyance, depression and dementia. Accordingly, noise triggers alterations of the gut-brain axis leading to a shift to harmful bacteria in the intestine associated with cognitive impairment and Aβ accumulation in a murine model of Alzheimer’s disease (Cui et al., 2018). Noise also disrupts the equilibrium of intestinal pro-oxidative and antioxidant mechanisms in association with low-grade systemic inflammation in mice (Chi et al., 2021) and generally causes an imbalance of health-compromising versus -promoting bacteria together with impaired mental health. As a proof-of-concept these adverse health effects of noise where mostly corrected by probiotic therapy (Hadizadeh et al., 2019), whereas feces transplantation from noise-exposed to unexposed mice induced the above mentioned health complications (Cui et al., 2018). Image was created using Biorender.com by modifying the central scheme from https://de.freepik.com/vektoren-premium/menschlicher-doppelpunktvektor-der-guten-bacterial-flora-illustration_3804027.htm.