Maladaptive auditory cortex reorganization may contribute to the generation and maintenance of tinnitus. Because cortical organization can be modified by behavioral training, we attempted to reduce tinnitus loudness by exposing chronic tinnitus patients to self-chosen, enjoyable music, which was modified ("notched") to contain no energy in the frequency range surrounding the individual tinnitus frequency. After 12 months of regular listening, the target patient group (n = 8) showed significantly reduced subjective tinnitus loudness and concomitantly exhibited reduced evoked activity in auditory cortex areas corresponding to the tinnitus frequency compared to patients who had received an analogous placebo notched music treatment (n = 8). These findings indicate that tinnitus loudness can be significantly diminished by an enjoyable, low-cost, customtailored notched music treatment, potentially via reversing maladaptive auditory cortex reorganization.cortical plasticity | human auditory cortex | lateral inhibition | magnetoencephalography | MEG S ubjective tinnitus (1) is among the most prevalent symptoms of hearing disorders in industrialized countries (2, 3). Tinnitus loudness can be considered as the most tangible tinnitus characteristic. In 1-3% of the general population, the tinnitus sensation is loud enough to affect the quality of life (4). Causal treatment strategies for tinnitus are not yet available.The lack of treatment strategies is due to incomplete knowledge concerning the mechanisms of tinnitus generation and maintenance. However, recent neurophysiological studies have shown that tinnitus is presumably caused by maladaptive auditory cortex reorganization (4-6) (similar phenomena were observed also in somatosensory cortex; refs. 7-9). For instance, magnetoencephalography (MEG) studies have demonstrated that auditory cortical map areas corresponding to the tinnitus frequency were distorted; the amount of distortion correlated positively with perceived tinnitus strength (10). Moreover, auditory cortex activity corresponding to the tinnitus frequency was shown to be enhanced and related to perceived tinnitus intrusiveness (11).To date, widely used tinnitus treatment strategies (e.g., tinnitus retraining therapy; ref. 12) are merely symptom management approaches. Therefore, there is a great demand for causal treatment approaches targeting the tinnitus percept more directly. Recent neurophysiological studies indicate that behavioral training can be a powerful means to reverse maladaptive cortical reorganization (7, 13).A previous study (14) demonstrated that listening to spectrally "notched" music can reduce cortical activity corresponding to the notch center frequency, possibly through lateral inhibition. Motivated by this finding, we developed an innovative tinnitus treatment strategy aimed at reducing tinnitus loudness. The treatment regimen consists of regular listening to enjoyable, custom-tailored notched music. Here, we evaluate and report results of the treatment from a longitudinal double-blinded ...

Attention improves auditory performance in noisy environments by either enhancing the processing of task-relevant stimuli ("gain"), suppressing task-irrelevant information ("sharpening"), or both. In the present study, we investigated the effect of focused auditory attention on the population-level frequency tuning in human auditory cortex by means of magnetoencephalography. Using complex stimuli consisting of a test tone superimposed on different band-eliminated noises during active listening or distracted listening conditions, we observed that focused auditory attention caused not only gain, but also sharpening of frequency tuning in human auditory cortex as reflected by the N1m auditory evoked response. This combination of gain and sharpening in the auditory cortex may contribute to better auditory performance during focused auditory attention.

The goal of this study was to compare the lateral inhibition and the habituation in the human auditory cortex, two important physiological effects during auditory processing that can be reliably measured by means of magnetoencephalography when recording auditory evoked fields. Applying 40-Hz amplitude-modulated stimuli allowed us to record simultaneously the slow transient evoked and the steady-state fields and thus to characterize the lateral inhibition and the habituation effect in primary and non-primary auditory cortical structures. The main finding of the study is that the lateral inhibition effect of non-primary auditory areas as measured on the major component of the slow transient auditory evoked field (N1) is significantly stronger than the corresponding habituation effect. By contrast, this effect was not observed for the 40-Hz steady-state fields, characterizing the activation of the primary auditory cortex in humans. The results might be interpreted as (i) evidence that the inhibition mediated by lateral connections is stronger than the habituation of excitatory neurons in the non-primary auditory cortex and (ii) the processing hierarchy in the human auditory cortex is demonstrated by the different behaviour of lateral inhibition and habituation in primary and non-primary auditory cortical structures.