Investigating functional changes in the brain to intermittently induced auditory illusions and its relevance to chronic tinnitus

Abstract

Several studies have demonstrated the neural correlates of chronic tinnitus. However, we still do not understand what happens in the acute phase. Past studies have established Zwicker tone (ZT) illusions as a good human model for acute tinnitus. ZT illusions are perceived following the presentation of a notched noise stimulus, that is, broadband noise with a narrow band‐stop filter (notch). In the current study, we compared the neural correlates of the reliable perception of a ZT illusion to that which is not. We observed changes in evoked and total theta power in wide‐spread regions of the brain particularly in the temporal‐parietal junction, pregenual anterior cingulate cortex/ventromedial prefrontal cortex (pgACC/vmPFC), parahippocampus during perception of the ZT illusion. Furthermore, we observe that increased theta power significantly predicts a gradual positive change in the intensity of the ZT illusion. Such changes may suggest a malfunction of the sensory gating system that enables habituation to redundant stimuli and suppresses hyperactivity. It could also suggest a successful retrieval of the memory of the missing frequencies, resulting in their conscious perception indicating the role of higher‐order processing in the mechanism of action of ZT illusions. To establish a more concrete relationship between ZT illusion and chronic tinnitus, future longitudinal studies following up a much larger sample of participants who reliably perceive a ZT illusion to see if they develop tinnitus at a later stage is essential. This could inform us if the ZT illusion may be a precursor to chronic tinnitus.

The Stochastic Resonance model of auditory perception: A unified explanation of tinnitus development, Zwicker tone illusion, and residual inhibition

“…It has previously been proposed that the Zwicker tone and tinnitus and thus also the neural mechanisms of these two auditory phantom perceptions are closely connected (Lummis andGuttmann, 1972, Hoke &Hoke, 1996;Mohan et al, 2020,), and a number of findings support this assumption: For example, Parra and Pearlmutter were able to show that people with a tinnitus percept are also more likely to perceive a Zwicker tone percept (Parra & Pearlmutter, 2007). Additionally, Wiegrebe and coworkers showed that the presence of a Zwicker tone leads to decreased auditory thresholds of 13 dB even in normal hearing subjects (Wiegrebe et al, Norena et al 1999), a finding which may easily be explained within our above described model of SR, since a similar effect can be observed in tinnitus patients , Krauss et al 2016) who have improved hearing thresholds in comparison to patients without tinnitus, at least within frequency ranges below 3 kHz.…”

The stochastic resonance model of auditory perception: A unified explanation of tinnitus development, Zwicker tone illusion, and residual inhibition

“…It has previously been proposed that the Zwicker tone and tinnitus and thus also the neural mechanisms of these two auditory phantom perceptions are closely connected (Hoke et al, 1996;Lummis and Guttmann, 1972;Mohan et al, 2020), and a number of findings support this assumption: For example, Parra and Pearlmutter were able to show that people with a tinnitus percept are also more likely to perceive a Zwicker tone percept (Parra & Pearlmutter, 2007). Additionally, Wiegrebe and coworkers showed that the presence of a Zwicker tone leads to decreased auditory thresholds of 13 dB even in normal hearing subjects (Norena et al 1999;Wiegrebe et al, 1996), a finding which may easily be explained within our above described model of SR, since a similar effect can be observed in tinnitus patients (Gollnast et al, 2017;Krauss et al 2016) who have improved hearing thresholds in comparison to patients without tinnitus, at least within frequency ranges below 3 kHz.…”

Auditory thalamus dysfunction and pathophysiology in tinnitus: a predictive network hypothesis

“…Support for dysfunctional sensory gating mechanisms in the thalamus in persons with tinnitus was recently provided by Lin et al ( 2020 ), showing in a graph-theoretical approach that the thalamus hub was only present in the control group and not in persons with tinnitus. Eliciting tinnitus-like symptoms using an auditory illusion in healthy young adults without hearing loss, resulted in enhanced total theta power in the parahippocampus, pregenual ACC, the ventro-medial PFC and OFC, further supporting inadequate sensory gating even in healthy participants (Mohan et al 2020 ). The concept of sensory gating allows linking the intrinsic firing modes of the thalamus, the top–down noise-cancellation approach (Rauschecker et al 2010 ) and the bottom–up thalamo-cortical dysrhythmia approach (De Ridder et al 2015 ; Llinas et al 1999 ) into a common theoretical framework for predictive adaptation.…”