Theta-gamma dysrhythmia and auditory phantom perception

Abstract

Tinnitus is considered an auditory phantom percept analogous to phantom pain. Thalamocortical dysrhythmia has been proposed as a possible pathophysiological mechanism for both tinnitus and pain. Thalamocortical dysrhythmia refers to a persistent pathological resting state theta-gamma coupling that is spatially localized at an area where normally alpha oscillations predominate. Auditory cortex stimulation via implanted electrodes has been developed to treat tinnitus, targeting an area of activation on functional MR imaging elicited by tinnitus-matched sound presentation. The authors describe a case in which clinical improvement was correlated with changes in intracranial recordings. Maximal tinnitus suppression was obtained by current delivery exactly at the blood oxygen level-dependent activation hotspot, which colocalizes with increased gamma and theta activity, in contrast to the other electrode poles, which demonstrated a normal alpha peak. These spectral changes normalized when stimulation induced tinnitus suppression, both on electrode and source-localized electroencephalography recordings. These data suggest that thetagamma coupling as proposed by the thalamocortical dysrhythmia model might be causally related to a conscious auditory phantom percept.

Unlearning tinnitus-related cerebral synchrony with acoustic coordinated reset stimulation: theoretical concept and modelling

“…Illustrated by numerical simulations of the above model, we sketched a novel, non-invasive approach, acoustic CR stimulation, to counteract pathological synchrony and connectivity in the central auditory system underlying subjective tonal tinnitus Kahlbrock and Weisz 2008;De Ridder et al 2011). Previously, it was shown that electrical CR stimulation robustly causes an anti-kindling in different networks with and without inhibition, but without afferent input (Tass and Majtanik 2006;Hauptmann 2007, 2009;Hauptmann and Tass 2007).…”

“…Pathologically enhanced delta activity emerges in cortical regions deprived of afferent input (Steriade 2006). There is a tight relationship between tinnitus loudness, on the one hand, and delta power in temporal regions Kahlbrock and Weisz 2008) or theta power extradurally recorded from the secondary auditory cortex (De Ridder et al 2011). While the cortical reorganization evolves on a slow time scale within several days or weeks (Robertson and Irvine 1989), the tinnitus percept and the related neuronal synchronization follow a noise trauma typically immediately (Norena and Eggermont 2003;Ortmann et al 2011).…”

“…While the cortical reorganization evolves on a slow time scale within several days or weeks (Robertson and Irvine 1989), the tinnitus percept and the related neuronal synchronization follow a noise trauma typically immediately (Norena and Eggermont 2003;Ortmann et al 2011). As pathological neuronal synchronization processes are considered to be the correlate of the tinnitus percept Kahlbrock and Weisz 2008;De Ridder et al 2011), in a first step, we here focus on the control of tinnitus-related pathological synchrony.…”

Phantom percepts: Tinnitus and pain as persisting aversive memory networks

“…This coupled θ-γ activity coordinates activity in distributed cortical areas, providing a mechanism for effective communication between these distributed areas (33). The θ-γ coupling has also been shown on intracranial recordings in a patient with tinnitus, which disappears when tinnitus is suppressed by electrical stimulation of the auditory cortex (34). The thalamocortical dysrhythmia model provides an explanation for the emergence and persistence of such a pattern as a consequence of sensory deafferentiation (27).…”

A Preliminary Diffusion Tensor Imaging Study: Analysis of Whole Brain according to the Affected Side in Tinnitus

“…Resting-state functional connectivity studies take advantage of such state changing focus from a core region to a network, to study the pathophysiology of the disease. Therefore, multi-sensory association areas such as the cortico-cortical connections or sub-cortical connections through the thalamus probably play an important role supporting a model of thalamocortical dysrhythmia, in which the thalamus generates faulty signals resulting in altered cortical activity, could not be ruled out 10 . Thalamus is connected to the anterior cingulate gyrus through the anterior thalamic radiation, which corresponds to the findings of this study with decreased FA and AD values in right-sided tinnitus patients while MO in the left.…”