Neuronal connectivity and interactions between the auditory and limbic systems. Effects of noise and tinnitus

Effects of environmental noise exposure on DNA methylation in the brain and metabolic health

“…Studies elsewhere have reported that chronic environmental noise exposure is associated with disrupted function of the hippocampus, an extra-auditory structure of the central nervous system, thereby inducing memory deficit and cognition impairment (Cheng et al, 2011;Chengzhi et al, 2011;Manikandan et al, 2006;Uran et al, 2012Uran et al, , 2010Cui et al, 2012Cui et al, , 2013. Indeed, Jáuregui-Huerta et al showed that chronic exposure to environmental noise in the early stages of life produces a long-lasting reduction in cell proliferation in the hippocampus in the neurogenic and non-neurogenic hippocampal regions (Kraus and Canlon, 2012). Further studies are required to determine whether chronic nocturnal environmental noise exposure-induced Mc2r hypomethylation in the hippocampus is associated with memory deficit and cognition impairment.…”

Associations of Organizational Justice with Tinnitus and the Mediating Role of Depressive Symptoms and Burnout—Findings from a Cross-Sectional Study

“…Several mechanisms have been proposed to explain the association of stress with tinnitus and hearing problems [41][42][43][44][45]. Stress hormones are proposed to influence the auditory function and the inner ear is thought to be exposed to and to be highly sensitive to the activity of the sympathetic and neuroendocrine stress systems [41,42,46,47].…”

“…Empirical evidence revealed that individuals with tinnitus have elevated stress-related hormones and display a blunted cortisol response to psychosocial stress compared to healthy controls, indicative for a dysregulated hypothalamus-pituitary-adrenal (HPA) axis [48,49]. Stimulation of the HPA axis is suggested to affect neuronal plasticity, connecting stress to the auditory system, and neuronal associations exist between the limbic and the auditory system (for details [41][42][43]). However, overall, the exact mechanism by which psychosocial stress affects tinnitus is not fully understood and further research is needed.…”

Cerebral Processing of Emotionally Loaded Acoustic Signals by Tinnitus Patients

“…The hypothetical existence of an extended tinnitus-specific distress network has been discussed by various authors [Husain et al, 2014;Kraus and Canlon, 2012;Pattyn et al, 2015] and is defined as a linkage between tinnitus percept in the auditory cortex and the limbic, prefrontal and association brain areas. In this hypothetical network, amplification of the tinnitus percept is modeled as a con- sequence of emotional distress whereas at the same time, the tinnitus percept can intensify the emotional distress.…”

“…The differences in the network activation pattern that involve the limbic system, frontal and striatal areas and acoustic association cortices could reflect connectivity between altered emotional processing of an acoustic signal and an emotional evaluation of tinnitus tone. Tinnitus distress and changing filter symptoms may be manifested by dysfunctional connectivity between the auditory, attention and emotional brain areas [Georgiewa et al, 2012;Kaltenbach, 2011;Kraus and Canlon, 2012;Leaver et al, 2011]. Application of new technologies, extending the sample number as well as using control subjects distressed by different means than tinnitus, but to the same degree as the tinnitus patients, should yield more evidence to clarify the existence of the tinnitus-specific cerebral network.…”