Tinnitus: at a crossroad between phantom perception and sleep

Sleep Science, 2014

Based on the knowledge that sensory processing continues during sleep and that a relationship exists between sleep and learning, a new strategy for treatment of idiopathic subjective tinnitus, consisted of customized sound stimulation presented during sleep, was tested. It has been previously shown that this treatment induces a sustained decrease in tinnitus intensity; however, its effect on brain activity has not yet been studied. In this work, we compared the impact of sound stimulation in tinnitus patients in the different sleep stages. Ten patients with idiopathic tinnitus were treated with sound stimulation mimicking tinnitus during sleep. Power spectra and intra-and inter-hemispheric coherence of electroencephalographic waves from frontal and temporal electrodes were measured with and without sound stimulation for each sleep stage (stages N2 with sleep spindles; N3 with slow wave sleep and REM sleep with Rapid Eye Movements). The main results found were that the largest number of changes, considering both the power spectrum and wave's coherence, occurred in stages N2 and N3. The delta and theta bands were the most changed, with important changes also in coherence of spindles during N2. All changes were more frequent in temporal areas. The differences between the two hemispheres do not depend, at least exclusively, on the side where the tinnitus is perceived and, hence, of the stimulated side. These results demonstrate that sound stimulation during sleep in tinnitus patients' influences brain activity and open an avenue for investigating the mechanism underlying tinnitus and its treatment.

Journal of Cognitive Neuroscience, 2008

& How does the sleeping brain process external stimuli, and in particular, up to which extent does the sleeping brain detect and process modifications in its sensory environment? In order to address this issue, we investigated brain reactivity to simple auditory stimulations during sleep in young healthy subjects. Electroencephalogram signal was acquired continuously during a whole night of sleep while a classical oddball paradigm with duration deviance was applied. In all sleep stages, except Sleep Stage 4, a mismatch negativity (MMN) was unquestionably found in response to deviant tones, revealing for the first time preserved sensory memory processing during almost the whole night. Surprisingly, during Sleep Stage 2 and paradoxical sleep, both P3a-like and P3b-like components were identified after the MMN, whereas a P3a alone followed the MMN in wakefulness and in Sleep Stage 1. This totally new result suggests elaborated processing of external stimulation during sleep. We propose that the P3b-like response could be associated to an active processing of the deviant tone in the dream's consciousness. &

Neuroscience Research, 1990

Phantom auditory perception -tinnitus -is a symptom of many pathologies. Although there are a number of theories postulating certain mechanisms of its generation, none have been proven yet. This paper analyses the phenomenon of tinnitus from the point of view of general neurophysiology. Existing theories and their extrapolation are presented, together with some new potential mechanisms of tinnitus generation, encompassing the involvement of calcium an d calcium c hannels in co chlear functio n, with implications for malfunction and aging of the auditory and vestibular systems.

European Journal of Neuroscience, 2011

Tinnitus is characterized by an ongoing conscious perception of a sound in the absence of any external sound source. Chronic tinnitus is notoriously characterized by its resistance to treatment. In the present study the objective was to verify whether the neural generators and ⁄ or the neural tinnitus network, evaluated through EEG recordings, change over time as previously suggested by MEG. We therefore analyzed the source-localized EEG recordings of a very homogenous group of left-sided narrow-band noise tinnitus patients. Results indicate that the generators involved in tinnitus of recent onset seem to change over time with increased activity in several brain areas [auditory cortex, supplementary motor area and dorsal anterior cingulate cortex (dACC) plus insula], associated with a decrease in connectivity between the different auditory and nonauditory brain structures. An exception to this general connectivity decrease is an increase in gamma-band connectivity between the left primary and secondary auditory cortex and the left insula, and also between the auditory cortices and the right dorsal lateral prefrontal cortex. These networks are both connected to the left parahippocampal area. Thus acute and chronic tinnitus are related to differential activity and connectivity in a network comprising the auditory cortices, insula, dACC and premotor cortex. European Journal of Neuroscience tomography (SPECT), magnetoencephalography (MEG), EEG and voxel-based morphometry (VBM) tinnitus literature.

Loquens

It is known that auditory information is continuously processed both during wakefulness and sleep. Consistently, it has been shown that sound stimulation mimicking tinnitus during sleep decreases the intensity of tinnitus and improves the patients’ quality of life. The mechanisms underlying this effect are not known. To begin to address this question, eleven patients suffering from tinnitus were stimulated with sound mimicking tinnitus at different sleep stages; 4 were stimulated in N2, 4 in stage N3 (slow waves sleep) and 3 in REM sleep (stage with Rapid Eyes Movements). Patients’ sleep stage was monitored through polysomnography, for sound stimulation application. Tinnitus level reported by subjects were compared the days before and after stimulation and statistically analyzed (paired Student t test). All patients stimulated at stage N2 reported significantly lower tinnitus intensity the day after stimulation, while none stimulated during stage N3 and only one out of three stimula...

bioRxiv (Cold Spring Harbor Laboratory), 2021

Sleep in all species is universally defined as a reversible, homeostatically-regulated state of a reduced behavioral responsiveness, with a high arousal threshold in response to external sensory stimulation 1. However, it remains unclear whether sleep mainly gates motor output or affects responses along sensory pathways, and whether sleep primarily modulates specific aspects of the sensory response such as feedforward vs. feedback signaling 2-7. Here, we simultaneously recorded polysomnography, iEEG, microwire LFPs, and neuronal spiking activity during wakefulness and sleep in 13 epilepsy patients implanted with clinical depth electrodes, while presenting auditory stimuli (e.g. click-trains, words, music). The results revealed robust spiking and induced LFP high-gamma (80-200Hz) power responses during both NREM and REM sleep across the lateral temporal lobe. The magnitude of the responses was only moderately attenuated in sleep, most notably for late responses beyond the early auditory cortex. Nonetheless, sleep responses maintained their tight locking with soundwave envelopes and their information content was only minimally affected. In contrast, a decrease in LFP alpha-beta (10-30Hz) power responses was prevalent in wakefulness but significantly disrupted in sleep. Entrainment to 40 Hz click-trains was comparable across REM sleep and wakefulness, but reduced in NREM sleep. In conclusion, our results establish the presence of extensive and robust auditory responses during sleep while LFP alpha-beta power decrease, likely reflecting top-down processes 8-10 , is deficient. More broadly, our findings suggest that feedback signalling is key to conscious sensory processing 11-13. .

International Journal of Environmental Research and Public Health, 2023

This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY

2007

Tinnitus is defined by an auditory perception in the absence of an external source of sound. This condition provides the distinctive possibility of extracting neural coding of perceptual representation. Previously, we had established that tinnitus is characterized by enhanced magnetic slow-wave activity (ϳ4 Hz) in perisylvian or putatively auditory regions. Because of works linking high-frequency oscillations to conscious sensory perception and positive symptoms in a variety of disorders, we examined gamma band activity during brief periods of marked enhancement of slow-wave activity. These periods were extracted from 5 min of resting spontaneous magnetoencephalography activity in 26 tinnitus and 21 control subjects. Results revealed the following, particularly within a frequency range of 50-60 Hz: (1) Both groups showed significant increases in gamma band activity after onset of slow waves. (2) Gamma is more prominent in tinnitus subjects than in controls. (3) Activity at ϳ55 Hz determines the laterality of the tinnitus perception. Based on present and previous results, we have concluded that cochlear damage, or similar types of deafferentation from peripheral input, triggers reorganization in the central auditory system. This produces permanent alterations in the ongoing oscillatory dynamics at the higher layers of the auditory hierarchical stream. The change results in enhanced slow-wave activity reflecting altered corticothalamic and corticolimbic interplay. Such enhancement facilitates and sustains gamma activity as a neural code of phantom perception, in this case auditory.

Nature Neuroscience, 2022

Sleep, 2011

Processing of Near-Threshold Stimuli-Campbell and Muller-Gass The most studied of these components is a negative deflection, N1, peaking at 75-100 ms. There is now substantial evidence that the sources of this N1 component originate in or near the auditory cortex, although there may be contributions from the frontal lobe. 3 N1 is followed by a later positive deflection, P2, peaking at about 175-225 ms. Collectively, these long latency ERPs have come to be known as the "vertex" potential because they are prominent over the central (or vertex) region of the scalp. In the waking state, the amplitude of N1-P2 varies directly with the intensity of the auditory stimulus. 4,5 Several labs have reported that the N1-P2 deflection remains visible to within 5-20 dB of the subjective hearing threshold. 6-10 N1 and P2 are much altered by sleep. The amplitude of N1 declines dramatically during drowsiness and sleep onset. 11,12 During definitive NREM sleep, its amplitude does not exceed the pre-stimulus zero voltage baseline level, while during REM sleep its amplitude may only reach 15% to 30% of its waking level. Although the amplitude of N1 is difficult to observe during NREM sleep, the amplitude of P2 is usually larger compared to the waking state. 13 The large attenuation of N1 but enhancement of P2 during sleep has been explained in detail by Campbell and Colrain. 11,12 In brief, they employ the classic, elaborate Näätänen model 14 of auditory processing (see also recent revision of this model 15) to describe the changes in processing that occur between the conscious, waking state and the unconscious, sleeping state. This model emphasizes that a large N1-P2 can be elicited passively by auditory stimuli, without the need for active attention. However, when attention is directed to the auditory channel, an additional attention-related negative component, termed the processing negativity (PN), is also elicited. Its amplitude varies with the extent of attention that is directed to the channel. Importantly, this long-lasting attention-related negativity will overlap and summate with