22 research outputs found
Attentional Modulation of Auditory Signal-in-Noise Processing
Trotz der offensichtlichen Relevanz von auditorischer Aufmerksamkeit für die Verarbeitung von akustischen Signalen in Rauschen sind die Effekte und Mechanismen von Aufmerksamkeit auf neuronaler Ebene bislang weitgehend ungeklärt. Die Ergebnisse der drei vorliegenden Magnetenzephalographie-Studien legen diesbezüglich unter Berücksichtigung des aktuellen Forschungsstandes folgende Schlussfolgerungen nahe: (i) der beobachtete schärfende Effekt von auditorischer Aufmerksamkeit spiegelt eine aktive Unterdrückung nichtrelevanter neuronaler Aktivität wider, welche über efferente, inhibitorische Verbindungen vermittelt wird. (ii) Es existiert vermutlich eine grundlegende funktionelle Dominanz der linken Hemisphäre für die Verarbeitung von akustischen Signalen in Rauschen. (iii) Diese generelle funktionelle Dominanz der linken Hemisphäre für die Verarbeitung von akustischen Signalen in Rauschen kann unter ganz bestimmten Bedingungen durch Aufmerksamkeitsprozesse moduliert werden
Left hemispheric dominance during auditory processing in a noisy environment
<p>Abstract</p> <p>Background</p> <p>In daily life, we are exposed to different sound inputs simultaneously. During neural encoding in the auditory pathway, neural activities elicited by these different sounds interact with each other. In the present study, we investigated neural interactions elicited by masker and amplitude-modulated test stimulus in primary and non-primary human auditory cortex during ipsi-lateral and contra-lateral masking by means of magnetoencephalography (MEG).</p> <p>Results</p> <p>We observed significant decrements of auditory evoked responses and a significant inter-hemispheric difference for the N1m response during both ipsi- and contra-lateral masking.</p> <p>Conclusion</p> <p>The decrements of auditory evoked neural activities during simultaneous masking can be explained by neural interactions evoked by masker and test stimulus in peripheral and central auditory systems. The inter-hemispheric differences of N1m decrements during ipsi- and contra-lateral masking reflect a basic hemispheric specialization contributing to the processing of complex auditory stimuli such as speech signals in noisy environments.</p
Short and Intense Tailor-Made Notched Music Training against Tinnitus: The Tinnitus Frequency Matters
Tinnitus is one of the most common diseases in industrialized countries. Here, we developed and evaluated a short-term (5 subsequent days) and intensive (6 hours/day) tailor-made notched music training (TMNMT) for patients suffering from chronic, tonal tinnitus. We evaluated (i) the TMNMT efficacy in terms of behavioral and magnetoencephalographic outcome measures for two matched patient groups with either low (≤8 kHz, N = 10) or high (>8 kHz, N = 10) tinnitus frequencies, and the (ii) persistency of the TMNMT effects over the course of a four weeks post-training phase. The results indicated that the short-term intensive TMNMT took effect in patients with tinnitus frequencies ≤8 kHz: subjective tinnitus loudness, tinnitus-related distress, and tinnitus-related auditory cortex evoked activity were significantly reduced after TMNMT completion. However, in the patients with tinnitus frequencies >8 kHz, significant changes were not observed. Interpreted in their entirety, the results also indicated that the induced changes in auditory cortex evoked neuronal activity and tinnitus loudness were not persistent, encouraging the application of the TMNMT as a longer-term training. The findings are essential in guiding the intended transfer of this neuro-scientific treatment approach into routine clinical practice
Left hemispheric dominance during auditory processing in a noisy environment-0
<p><b>Copyright information:</b></p><p>Taken from "Left hemispheric dominance during auditory processing in a noisy environment"</p><p>http://www.biomedcentral.com/1741-7007/5/52</p><p>BMC Biology 2007;5():52-52.</p><p>Published online 15 Nov 2007</p><p>PMCID:PMC2194668.</p><p></p>t to the subject's ear. (A) Spectrum of the masker (comb-filtered noise; CFN). The distance between neighboring centers of pass-band sections is half an octave in the frequency range between 0.5 and 2.8 kHz. (B) Spectrum of the pass-band stimulus (PB) composed of five spectral components corresponding to the center frequencies of the pass-band sections of the CFN. Due to the 40 Hz amplitude modulation, each component shows spectral peaks at its carrier frequency and at two sideband frequencies 40 Hz below and above. (C) Spectrum of the complex sound stimulus characterized by frequency components corresponding to the stop-band sections (SB) of the comb-filtered noise. All acoustical spectra reflect the low pass characteristic of the sound transmission system. Masking conditions. (D) Contra-lateral masking condition: TS and CFN were presented to different ears. (E) Ipsi-lateral masking condition: TS and CFN were presented to the same ear. (F) Control condition: Only the TS was presented to one ear, no masker was presented. Design of the experiment. (G) One session consisted of four blocks with three sub-blocks. Each sub-block consisted of either the contra-lateral, the ipsi-lateral, or the control condition. Within one session, the TS was presented only to the right or to the left ear
Left hemispheric dominance during auditory processing in a noisy environment-2
<p><b>Copyright information:</b></p><p>Taken from "Left hemispheric dominance during auditory processing in a noisy environment"</p><p>http://www.biomedcentral.com/1741-7007/5/52</p><p>BMC Biology 2007;5():52-52.</p><p>Published online 15 Nov 2007</p><p>PMCID:PMC2194668.</p><p></p>tes the threshold shift during ipsi-lateral masking, the right graph denotes the shift during contra-lateral masking. The error bars represent the 95% confidence limits for the mean threshold shifts (the scale of the y-axis of the left graph is multiplied by a factor of 10 compared to the right graph)
Left hemispheric dominance during auditory processing in a noisy environment-3
<p><b>Copyright information:</b></p><p>Taken from "Left hemispheric dominance during auditory processing in a noisy environment"</p><p>http://www.biomedcentral.com/1741-7007/5/52</p><p>BMC Biology 2007;5():52-52.</p><p>Published online 15 Nov 2007</p><p>PMCID:PMC2194668.</p><p></p>tion (normalized decrement = (source strength-source strength)/source strength) representing the masking effects between 0 (no masking) and 1 (complete extinction). The upper graphs denote the normalized N1m decrements and the lower graphs denote the normalized ASSR decrements for the left and the right hemisphere during left (left column) or right ear (right column) stimulation. The error bars denote the 95% confidence limits
Left hemispheric dominance during auditory processing in a noisy environment-1
<p><b>Copyright information:</b></p><p>Taken from "Left hemispheric dominance during auditory processing in a noisy environment"</p><p>http://www.biomedcentral.com/1741-7007/5/52</p><p>BMC Biology 2007;5():52-52.</p><p>Published online 15 Nov 2007</p><p>PMCID:PMC2194668.</p><p></p> (graphs are assorted according to Figure 5)