Restorative Neurology and Neuroscience - Volume 25, issue 3-4

Authors: Jäncke, Lutz

Article Type: Editorial

Citation: Restorative Neurology and Neuroscience, vol. 25, no. 3-4, pp. 191-191, 2007

Authors: Chandrasekaran, Bharath | Gandour, Jackson T. | Krishnan, Ananthanarayan

Article Type: Research Article

Abstract: Purpose : An auditory electrophysiological study was conducted to explore the influence of language experience on the saliency of dimensions underlying cortical pitch processing. Methods : Mismatch negativity (MMN) responses to Mandarin tones were recorded in Chinese and English participants (n = 10 per group) using a passive oddball paradigm. Stimuli consisted of three tones (T1: high level; T2: high rising; T3: low falling-rising). There were three oddball conditions (standard/deviant): T1/T2, T1/T3, T2/T3. In the T1/T2 and T1/T3 conditions, each tonal pair represented a contrast between a level and a contour tone; the T2/T3 condition, a contrast between …two contour tones. Twenty dissimilarity matrices were created using the MMN mean amplitude measured from the Fz location for each condition per participant, and analyzed by an individual differences multidimensional scaling model. Results : Two pitch dimensions were revealed, interpretively labeled as ‘height’ and ‘contour’. The latter was found to be more important for Chinese than English subjects. Using individual weights on the contour dimension, a discriminant function showed that 17 out of 20 participants were correctly classified into their respective language groups. Conclusions : The MMN can serve as an index of pitch features that are differentially weighted depending on a listener’s experience with lexical tones and their acoustic correlates within a particular tone space. Show more

Keywords: Mismatch negativity, pitch, multidimensional scaling, experience-dependent plasticity, lexical tone, Mandarin Chinese

Citation: Restorative Neurology and Neuroscience, vol. 25, no. 3-4, pp. 195-210, 2007

Authors: Petit, Laurent | Simon, Grégory | Joliot, Marc | Andersson, Frédéric | Bertin, Thomas | Zago, Laure | Mellet, Emmanuel | Tzourio-Mazoyer, Nathalie

Article Type: Research Article

Abstract: Purpose : Previous neuroimaging studies of oddball tasks and other paradigms measuring attention processes support right hemisphere dominance for attentional processes. Using an auditory selective attention task, we studied the functional asymmetry of the human brain in response to attended or unattended deviant tones. Secondly, we examined whether a congruency or a discrepancy between audio-spatial and visuo-spatial cued attentional resources may influence the activity elicited by an auditory selective attention task. Methods : We used event-related functional magnetic resonance imaging (fMRI) to study healthy adults as they performed an auditory oddball task in which a spatial-cued instruction indicated the …ear to attend a monaural deviant tone. We addressed the question of congruency/discrepancy between attentional resources by using three different eye positions during the performance of the auditory oddball task. Results : Relative to standard tones, both attended and unattended deviant tones (DTs) presented to either ear elicit the activation of a widespread bilaterally distributed cortical and subcortical network. A subset of this network, essentially frontal and temporal areas, showed not only greater right than left activity but an enhancement of this rightward asymmetry in response to attended DTs. The only cortical region that showed a leftward asymmetry in response to attended DTs overlapped Heschl gyrus and planum temporale, unmasking a left hemisphere preference of both primary and secondary auditory cortex for processing simple attended monaural stimuli. Questioning the impact of eye position during auditory oddball task, we observed a lesser activity in right integrative crossmodal areas (superior temporal sulcus, opercular part of the inferior frontal gyrus, pre-SMA) when the eye positions were contralateral to detected DTs. These regions may be tuned to best respond when both visuo-spatial and audio-spatial attentional resources work together. Conclusion : These results support the assumption that the right hemisphere is preferentially engaged in processing audio-spatial attentional resources and underline the interest to study the crossmodal integration of attentional resources by the mean of the detection of DTs in different eye positions. Show more

Keywords: Auditory oddball task, eye position, spatial attention, fMRI, hemispheric specialization, functional asymmetry

Citation: Restorative Neurology and Neuroscience, vol. 25, no. 3-4, pp. 211-225, 2007

Authors: Sandmann, Pascale | Eichele, Tom | Specht, Karsten | Jäncke, Lutz | Rimol, Lars Morten | Nordby, Helge | Hugdahl, Kenneth

Article Type: Research Article

Abstract: Purpose : In order to examine auditory lateralization of prelexical speech processing, a dichotic listening task was performed with concurrent EEG measurement. Methods : Subjects were tested with dichotic pairs of six consonant-vowel (CV) syllables that initially started with a voiced (/ba/, /da/, /ga/) or a voiceless stop consonant (/pa/, /ta/, /ka/). Electrophysiological correlates were analyzed by a low resolution electromagnetic tomography (LORETA) approach to estimate the sources of N1 event-related potentials (ERP) in the 3D brain. Results : Behavioral and electrophysiological measures revealed different ear advantages and ERP amplitude measures for voiced and voiceless syllables. Fronto-central N1 …amplitudes were larger for syllables with voiced than voiceless initial consonants. LORETA source estimates revealed a lateralization effect, with stronger leftward lateralization for voiced than voiceless CV syllables. Conclusions : The present study demonstrates that auditory lateralization is affected by temporal cues in CV syllables. The lateralization effect suggests that functional hemispheric differences exist at an early prelexical level of speech processing. Show more

Keywords: Speech processing, dichotic listening, voice onset time, lateralization, event-related potentials, N1

Citation: Restorative Neurology and Neuroscience, vol. 25, no. 3-4, pp. 227-240, 2007

Authors: Grimm, Sabine | Schröger, Erich

Article Type: Research Article

Abstract: Purpose : The present study aimed at further clarifying the nature of the automatic deviance detection system indexed by the mismatch negativity (MMN) component of the event-related potential (ERP). We investigated the pre-attentive detection of a transient frequency deviance occurring within a short tone at different temporal distances relative to tone onset. It was of specific interest whether these different types of deviations were categorized as distinctive events by the MMN system or not. Methods : We compared the MMN elicited by a rare frequency deviation occurring 200 ms after tone onset among frequent standard tones without frequency deviation. …In three conditions, the proportions of standards and deviants were 90-10 (90% standards, 10% frequency deviation occurring 200 ms after sound onset), 70-30 (70% standards, 30% frequency deviation), or 70-10-10-10 (70% standard, frequency deviation 10% after 100 ms, 10% after 200 ms, 10% after 300 ms). Results : We found that the MMN in the 70-10-10-10 condition resembles the MMN in the 90-10 condition, both MMNs being larger than the MMN in the 70-30 condition. In other words, although a frequency deviation in the 70-10-10-10 condition was as likely as in the 70-30 condition (i.e. 30%), it was treated as if it were as unlikely as in the 90-10 condition (i.e. 10%). Thus, the amplitude of the MMN was related to the specific temporal occurrence of the frequency deviance rather than the global probability of the frequency deviance. Conclusions : The data support the hypothesis that the MMN system was operating on the basis of a spectrotemporal representation rather than on independent feature dimensions. Results are compatible with a new theory of the MMN system according to which MMN is based on a pointwise comparison between the current sound and a model-based concrete prediction of a forthcoming sound as it evolves over time. Show more

Keywords: Mismatch negativity, pre-attentive change detection, event-related brain potentials, electrophysiology

Citation: Restorative Neurology and Neuroscience, vol. 25, no. 3-4, pp. 241-249, 2007

Authors: Zaehle, Tino | Clapp, Wesley C. | Hamm, Jeff P. | Meyer, Martin | Kirk, Ian J.

Article Type: Research Article

Abstract: Purpose : Previously we have shown that rapid sensory stimulation, in this case, auditory tone pips, can induce long-lasting plastic changes akin to Long Term Potentiation (LTP) within adult human sensory cortex. In a previous study, auditory LTP was reflected as an increase in the amplitude of the N1 component of the auditory event-related potential as measured by EEG. The goal of the present study was to investigate potential effects of LTP-like changes on the hemodynamic response of the human auditory cortex. Methods : Silent sparse-sampled fMRI recordings were obtained while subjects passively listened to tone-pips both before and …after a short block of rapidly presented auditory tone-pips (auditory tetanus) was delivered. Results : The BOLD response within the primary auditory cortex was significantly enhanced after the auditory tetanus. Conclusion : This is the first study demonstrating LTP-like changes of the hemodynamic response in the auditory system, and thus supports the growing literature demonstrating LTP can be induced in adult human cortex. These results have implications in the fields of perceptual learning and rehabilitation. Show more

Keywords: LTP, human, auditory, fMRI, plasticity

Citation: Restorative Neurology and Neuroscience, vol. 25, no. 3-4, pp. 251-259, 2007

Authors: Lakshminarayanan, Kala | Tallal, Paula

Article Type: Research Article

Abstract: Purpose : The generalization of non-linguistic auditory perceptual training to syllable discrimination was investigated in two experiments. Methods : Participants were divided into a control and training group. Both groups came for pre and post-testing sessions spaced ten days apart. Following pre- testing, the training group also participated for five consecutive days in non-linguistic auditory perceptual training. Training was adaptive and involved active sequencing of rising and falling frequency modulated sweeps for 30 minutes per day. Sweeps were passively varied in onset frequency, duration and rate of presentation. A syllable discrimination threshold (SDT) task was used as the pre …and post-test measure. In experiment 1, a /ba/-/da/ syllable continuum was used. In experiment 2, the pre-test battery was expanded to include /ba/-/da/, /ba/-/wa/, and /sa/-/sta/ syllable continua and a tone sequencing task that mimicked other parameters of training. Results : Results of experiment 1 revealed that the training group had a significantly lowered (better) SDT following training as compared to the control group. The extent of training-driven perceptual gain was significantly correlated with pre-training performance. In experiment 2, training resulted in a significantly lowered SDT for /ba/-/da/, but not for the other syllables or the tone sequencing task. Conclusions : Results showed that task-specific attention drives generalization of auditory perceptual training from non-linguistic to linguistic contexts. Furthermore, individual differences in initial perceptual performance affect the degree of generalization following training. Show more

Keywords: Discrimination training, generalization, perceptual learning, auditory plasticity, syllable discrimination

Citation: Restorative Neurology and Neuroscience, vol. 25, no. 3-4, pp. 263-272, 2007

Authors: Kotz, Sonja A. | Opitz, Bertram | Friederici, Angela D.

Article Type: Research Article

Abstract: Purpose : The contribution of the anterior temporal lobe to the processing of environmental sounds was investigated in patients with primary lesions in the anterior portion of the left (ATL) and right (ATR) temporal lobe in comparison to healthy controls. Two controversial questions were addressed: (1) whether environmental sounds are processed similarly for meaning as language, and (2) whether task-dependent lateralized semantic and perceptual effects observed in earlier studies persist when testing environmental sounds independent of task. Methods : In an event-related brain potential (ERP) experiment we examined the effect of meaningful and non-meaningful novel sound processing in a …novelty oddball paradigm. Results : Healthy controls and both patient groups displayed a normal target P3b as well as a novelty P3a. In addition, while healthy controls differentiated non-meaningful and meaningful novel sounds in the novelty P3a at posterior lateral and midline electrode-sites, all patients showed this effect only at midline sites. Lastly, the P3a effect was followed by a larger N400 amplitude rise for meaningful compared to non-meaningful novel sounds in healthy controls, but not in either patient group. Conclusion : The present data indicate that independent of task both the left and right anterior temporal lobe is crucial for lexical-semantic processing of novel sounds. Show more

Keywords: Auditory novel sound processing, anterior temporal lobe, hemispheric asymmetry, ERPs, novelty P3, N400

Citation: Restorative Neurology and Neuroscience, vol. 25, no. 3-4, pp. 273-284, 2007

Authors: Rey, Beatrice | Frischknecht, Rolf | Maeder, Philippe | Clarke, Stephanie

Article Type: Research Article

Abstract: Purpose : Cognitive deficits that are present in the acute stage of a focal hemispheric lesion tend to be greater and more general than residual deficits, which persist into the chronic stage. We have investigated the patterns of recovery and the relationship between deficits and damage to specialized networks taking as model auditory cognitive functions. Evidence from human psychophysical, activation and neuropsychological studies suggests that sound recognition and sound localization are processed in anatomically and functionally distinct cortical networks, the auditory “What” and “Where” processing streams, that are each present in both hemispheres. Focal left or right hemispheric lesions centred …on these networks were found to be associated, in the chronic stage, with the corresponding deficits in sound recognition and/or sound localization. Methods : We report here on recovery patterns in 24 patients who sustained focal hemispheric lesions and were deficient in sound recognition, sound localization and/or sound motion perception at a first evaluation in the acute (n = 9), subacute (n = 6) or early chronic stages (n = 9). Results : All 24 patients had initially a deficit in sound localization and/or sound motion perception. In the acute stage this deficit occurred without damage to the auditory “Where” stream in almost half of the patients, a situation which was never observed in the early chronic stage. Lack of recovery tended to be associated with damage to the specialized stream plus the persistence of deficits beyond the acute stage, and was only loosely related to the size of the lesion and to the extent of damage to a specialized network. Conclusions : Our results suggest that different mechanisms underlie deficits and recovery at different time points. Show more

Keywords: Auditory cortex, acute stage, subacute stage, chronic stage, plasticity, “What” and “Where”

Citation: Restorative Neurology and Neuroscience, vol. 25, no. 3-4, pp. 285-294, 2007

Authors: Gaab, N. | Gabrieli, J.D.E. | Deutsch, G.K. | Tallal, P. | Temple, E.

Article Type: Research Article

Abstract: Purpose : Developmental dyslexia, characterized by unexpected difficulty in reading, may involve a fundamental deficit in processing rapid acoustic stimuli. Using functional magnetic resonance imaging (fMRI) we previously reported that adults with developmental dyslexia have a disruption in neural response to rapid acoustic stimuli in left prefrontal cortex. Here we examined the neural correlates of rapid auditory processing in children. Methods : Whole-brain fMRI was performed on twenty-two children with developmental dyslexia and twenty-three typical-reading children while they listened to nonlinguistic acoustic stimuli, with either rapid or slow transitions, designed to mimic the spectro-temporal structure of consonant-vowel-consonant speech syllables. …Results : Typical-reading children showed activation for rapid compared to slow transitions in left prefrontal cortex. Children with developmental dyslexia did not show any differential response in these regions to rapid versus slow transitions. After eight weeks of remediation focused primarily on rapid auditory processing, phonological and linguistic training the children with developmental dyslexia showed significant improvements in language and reading skills, and exhibited activation for rapid relative to slow transitions in left prefrontal cortex. Conclusion : The presence of a disruption in the neural response to rapid stimuli in children with developmental dyslexia prior to remediation, coupled with significant improvement in language and reading scores and increased brain activation after remediation, gives further support to the importance of rapid auditory processing in reading development and disorders. Show more

Keywords: Developmental dyslexia, fMRI, rapid auditory processing, remediation, training, children

Citation: Restorative Neurology and Neuroscience, vol. 25, no. 3-4, pp. 295-310, 2007

Authors: Röder, Brigitte | Krämer, Ulrike M. | Lange, Kathrin

Article Type: Research Article

Abstract: Purpose : Superior temporal processing skills, both in the auditory and tactile system have been reported in blind as compared to sighted humans. The present experiment tested whether blind people prefer, as a possible consequence, temporal rather than spatial stimulus selection strategies. Methods : Eight congenitally blind adults were tested in a selective attention experiment that simultaneously manipulated spatial and temporal attention. Participants had to attend to an auditory offset stimulus demarcating the end of a short (600 ms) or long (1200 ms) interval. They had to detect slightly less intense offset markers at the attended point in time …presented in the left (half of the trials) or right (other half of the trials) hemifield. Event-related potentials (ERPs) were recorded throughout the experiment. Results : Whereas the N1 was significantly enhanced by both spatial and temporal attention in the sighted (see Lange, Kramer, & Röder, 2006), only a temporal attention effect was found in the blind. Moreover, in both groups a second, longer lasting negativity was observed for offset markers presented at the attended as compared to the unattended spatial location. This negativity was modulated by temporal attention only in the blind. Conclusion : These results are consistent with the assumption of a higher priority of time for stimulus selection in the absence of vision from birth. Show more

Keywords: Neuroplasticity, blindness, temporal attention, spatial attention, auditory event-related potential

Citation: Restorative Neurology and Neuroscience, vol. 25, no. 3-4, pp. 311-322, 2007

Authors: Mandell, Jake | Schulze, Katrin | Schlaug, Gottfried

Article Type: Research Article

Abstract: Purpose : Congenital amusia (tone deafness ) is a disorder in which those affected typically complain of or are identified by their inability to sing in tune. A psychophysical and possibly surrogate marker of this condition is the inability to recognize deviations in pitch that are one semitone (100 cents) or less. The aim of our study was to identify candidate brain regions that might be associated with this disorder. Methods : We used Voxel-Based-Morphometry (VBM) to correlate performance on a commonly used assessment tool, the Montreal Battery for the Evaluation of Amusia (MBEA), with local inter-individual variations in …gray matter volumes across a large group of individuals (n = 51) to identify brain regions potentially involved in the expression of this disorder. Results : The analysis across the entire brain space revealed significant covariations between performance on the MBEA and inter-individual gray matter volume variations in the left superior temporal sulcus (BA 22) and the left inferior frontal gyrus (BA 47). The regression analyses identified subregions within the inferior frontal gyrus, and inferior portion of BA47 that correlated with performance on melodic subtests, while gray matter volume variations in a more superior subregion of BA47 correlated with performance on rhythmic subtests. Conclusions : Our analyses demonstrate the existence of a left fronto-temporal network that appears to be involved in the melodic and rhythmic discrimination skills measured by the MBEA battery. These regions could also be part of a network that enable subjects to map motor actions to sounds including a feedback loop that allows for correction of motor actions (i.e., singing) based on perceptual feedback. Thus, it is conceivable that individuals with congenital amusia, or the inability to sing in tune, may actually have an impairment of the auditory-motor feedback loop and/or auditory-motor mapping system. Show more

Keywords: Congenital amusia, tone deafness, voxel-based-morphometry (VBM), BA 22, BA 47, auditory-motor mapping, auditory-motor feedback loop

Citation: Restorative Neurology and Neuroscience, vol. 25, no. 3-4, pp. 323-334, 2007

Authors: Meyer, Martin | Toepel, Ulrike | Keller, Joerg | Nussbaumer, Daniela | Zysset, Stefan | Friederici, Angela D.

Article Type: Research Article

Abstract: Purpose : The present study was designed to investigate the neural correlates of German Sign Language (Deutsche Gebärdensprache; DGS) processing. In particular, was expected the impact of the visuo-spatial mode in sign language on underlying neural networks compared to the impact of the interpretation of linguistic information. Methods : For this purpose, two groups of participants took part in a functional MRI study at 3 Tesla. One group consisted of prelingually deafened users of DGS, the other group of hearing non-signers naïve to sign language. The two groups were presented with identical video sequences comprising DGS sentences in form …of dialoges. To account for substantial interindividual anatomical variability observed in the group of deaf participants, the brain responses in the two groups of subjects were analyzed with two different procedures. Results : Results from a multi-subject averaging approach were contrasted with an analysis, which can account for the considerable inter-individual variability of gross anatomical landmarks. The anatomy-based approach indicated that individuals’ responses to proper DGS processing was tied up with a leftward asymmetry in the dorsolateral prefrontal cortex, anterior and middle temporal gyrus, and visual association cortices. In contrast, standard multi-subject averaging of deaf individuals during DGS perception revealed a less lateralized peri- and extrasylvian network. Furthermore, voxel-based analyses of the brains’ morphometry evidenced a white-matter deficit in the left posterior longitudinal and inferior uncinate fasciculi and a steeper slope of the posterior part of the left Sylvian Fissure (SF) in the deaf individuals. Conclusion : These findings may imply that the cerebral anatomy of deaf individuals has undergone structural changes as a function of monomodal visual sign language perception during childhood and adolescence. Show more

Keywords: fMRI, German sign language, plasticity, Sylvian fissure, arcuate fasciculus, uncinate fasciculus, voxel-based morphometry, auditory cortex

Citation: Restorative Neurology and Neuroscience, vol. 25, no. 3-4, pp. 335-351, 2007

Authors: Kast, Monika | Meyer, Martin | Vögeli, Christian | Gross, Markus | Jäncke, Lutz

Article Type: Research Article

Abstract: Purpose : Several attempts have been made to remediate developmental dyslexia using various training environments. Based on the well-known retrieval structure model , the memory strength of phonemes and graphemes should be strengthened by visual and auditory associations between graphemes and phonemes. Using specifically designed training software, we examined whether establishing a multitude of visuo-auditory associations might help to mitigate writing errors in children with developmental dyslexia. Methods : Forty-three children with developmental dyslexia and 37 carefully matched normal reading children performed a computer-based writing training (15–20 minutes 4 days a week) for three months with the aim to …recode a sequential textual input string into a multi-sensory representation comprising visual and auditory codes (including musical tones). The study included four matched groups: a group of children with developmental dyslexia (n = 20) and a control group (n = 18) practiced with the training software in the first period (3 months, 15–20 minutes 4 days a week), while a second group of children with developmental dyslexia (n = 23) (waiting group) and a second control group (n = 19) received no training during the first period. In the second period the children with developmental dyslexia and controls who did not receive training during the first period now took part in the training. Results : Children with developmental dyslexia who did not perform computer-based training during the first period hardly improved their writing skills (post-pre improvement of 0–9%), the dyslexic children receiving training strongly improved their writing skills (post-pre improvement of 19–35%). The group who did the training during the second period also revealed improvement of writing skills (post-pre improvement of 27–35%). Interestingly, we noticed a strong transfer from trained to non-trained words in that the children who underwent the training were also better able to write words correctly that were not part of the training software. In addition, even non-impaired readers and writers (controls) benefited from this training. Conclusion : Three-month of visual-auditory multimedia training strongly improved writing skills in children with developmental dyslexia and non-dyslexic children. Thus, according to the retrieval structure model, multi-sensory training using visual and auditory cues enhances writing performance in children with developmental dyslexia and non-dyslexic children. Show more

Keywords: Developmental dyslexia, multisensory learning, computer- based training

Citation: Restorative Neurology and Neuroscience, vol. 25, no. 3-4, pp. 355-369, 2007

Authors: Dohrmann, Katalin | Elbert, Thomas | Schlee, Winfried | Weisz, Nathan

Article Type: Research Article

Abstract: Purpose : Tinnitus, the perception of sound without the presence of a physical stimulus, provides the opportunity to study neural codes of percepts without simultaneous processing of stimuli. Previously, we have found that tinnitus is associated with enhanced delta- and reduced tau-power in temporal brain regions. By operantly modifying corresponding aspects of spontaneous EEG activity, the aim of the present study was to corroborate the assumption that tinnitus should be reduced if patterns of ongoing synchronous brain activity are normalised. Methods : In response to different variants of neurofeedback, a total of twenty-one patients produced significant changes in EEG …frequency bands. Results : Simultaneous alteration of both frequency bands was strongly related to changes in tinnitus intensity matched before and after the intervention (r = −0.74). In those two patients with the greatest modulatory success, the tinnitus sensation resided completely in response to the treatment. Comparing the neurofeedback-treated patients with a group of patients trained with a frequency discrimination task (n = 27), the tinnitus relief in the neurofeedback group was significantly stronger. Conclusions : This study supports the notion that altered patterns of intrinsic ongoing brain activity lead to phantom percepts and offer new routes to the treatment of tinnitus. Show more

Keywords: Tinnitus, EEG, neurofeedback, perceptual coding

Citation: Restorative Neurology and Neuroscience, vol. 25, no. 3-4, pp. 371-378, 2007

Authors: Giraud, Anne-Lise | Lee, Hyo-Jeong

Article Type: Research Article

Abstract: Purpose : Cochlear implantation is an effective technique for restoring hearing in the profoundly deaf. Although cochlear implants are a therapeutical success, huge performance variability in speech comprehension is observed after implantation. The reason for this remains incompletely understood after 20 years of clinical practice and basic research. Which patients are going to respond well and why is an unresolved question. The duration of auditory deprivation plays an important role, and currently is the main predictor of implantation success in children; basically, the earlier the better. However, among patients with identical duration of deafness, performance remains highly variable, suggesting there …are other more fundamental factors that determine clinical outcome. Methods : To delineate the cognitive factors that could influence the clinical outcome of cochlear implantation, we correlated resting metabolism PET images acquired before implantation in congenitally deaf children with speech perception behavioural scores measured three years after implantation. Results : Using this paradigm, we showed distinct brain organisation patterns in the deaf brain, which predict good and bad speech perception outcome after cochlear implantation. Conclusions : These data show that brain organisation assessed immediately before cochlear implantation can efficiently predict subsequent speech outcome. Show more

Citation: Restorative Neurology and Neuroscience, vol. 25, no. 3-4, pp. 381-390, 2007

Authors: Nager, W. | Münte, T.F. | Bohrer, I. | Lenarz, T. | Dengler, R. | Möbes, J. | Schröder, C. | Lesinski-Schiedat, A.

Article Type: Research Article

Abstract: Purpose : Processing auditory scenes requires the automatic detection of unexpected acoustic irregularities which allows to reorient the attentional focus for further in-depth analysis. Even if cochlea implants (CI) may partly restore hearing capabilities in patients suffering from profound peripheral deafness, CI users complain about difficulties in identifying novel and unexpected acoustic events. To assess whether this impairment is attributable to preattentive auditory deficits, impaired automatic orienting to novel events and/or to deficits in attentional processing we recorded event-related potentials (ERPs) in an auditory novelty oddball paradigm. Methods : ERPs were obtained in 7 postlingually deafened CI patients and …their age-matched controls in passive and active listening conditions. Subjects had to press a button for infrequent novel sounds but not for frequent standard sounds in the active condition. Results : In the active condition patients and controls did not differ with regard to hit-rates and reaction times. ERPs to novel stimuli in the active condition were characterized by enhanced N2b and P3b components that did not differ between groups. By contrast, the P3a component to novel sounds in the passive condition, an index of automatic orienting of attention, was greatly attenuated in the CI users. Conclusions : CI-users are impaired in the preattentive registration of novel auditory events while attentive processing of a designated auditory stream appears intact. Show more

Keywords: Cochlear implant, event-related potentials, novelty detection, MMN, P3a, P3b

Citation: Restorative Neurology and Neuroscience, vol. 25, no. 3-4, pp. 391-396, 2007

Authors: Besson, Mireille | Schön, Daniele | Moreno, Sylvain | Santos, Andréia | Magne, Cyrille

Article Type: Research Article

Abstract: Purpose : We review a series of experiments aimed at studying pitch processing in music and speech. These studies were conducted with musician and non musician adults and children. We found that musical expertise improved pitch processing not only in music but also in speech. Demonstrating transfer of training between music and language has interesting applications for second language learning. We also addressed the issue of whether the positive effects of musical expertise are linked with specific predispositions for music or with extensive musical practice. Results of longitudinal studies argue for the later. Finally, we also examined pitch processing in …dyslexic children and found that they had difficulties discriminating strong pitch changes that are easily discriminate by normal readers. These results argue for a strong link between basic auditory perception abilities and reading abilities. Methods : We used conjointly the behavioral method (Reaction Times and error rates) and the electrophysiological method (recording of the changes in brain electrical activity time-locked to stimulus presentation, Event-Related brain Potentials or ERPs). Results : A set of common processes may be responsible for pitch processing in music and in speech and these processes are shaped by musical practice. Conclusion : These data add evidence in favor of brain plasticity and open interesting perspectives for the remediation of dyslexia using musical training. Show more

Citation: Restorative Neurology and Neuroscience, vol. 25, no. 3-4, pp. 399-410, 2007

Authors: Meyer, Martin | Elmer, Stefan | Baumann, Simon | Jancke, Lutz

Article Type: Research Article

Abstract: Purpose : In this EEG study we sought to examine the neuronal underpinnings of short-term plasticity as a top-down guided auditory learning process. We hypothesized, that (i) auditory imagery should elicit proper auditory evoked effects (N1/P2 complex) and a late positive component (LPC). Generally, based on recent human brain mapping studies we expected (ii) to observe the involvement of different temporal and parietal lobe areas in imagery and in perception of acoustic stimuli. Furthermore we predicted (iii) that temporal regions show an asymmetric trend due to the different specialization of the temporal lobes in processing speech and non-speech sounds. Finally …we sought evidence supporting the notion that short-term training is sufficient to drive top-down activity in brain regions that are not normally recruited by sensory induced bottom up processing. Methods : 18 non-musicians partook in a 30 channels based EEG session that investigated spatio-temporal dynamics of auditory imagery of “consonant-vowel” (CV) syllables and piano triads. To control for conditioning effects, we split the volunteers in two matched groups comprising the same conditions (visual, auditory or bimodal stimulation) presented in a slightly different serial order. Furthermore the study presents electromagnetic source localization (LORETA) of perception and imagery of CV- and piano stimuli. Results : Our results imply that auditory imagery elicited similar electrophysiological effects at an early stage (N1/P2) as auditory stimulation. However, we found an additional LPC following the N1/P2 for auditory imagery only. Source estimation evinced bilateral engagement of anterior temporal cortex, which was generally stronger for imagery of music relative to imagery of speech. While we did not observe lateralized activity for the imagery of syllables we noted significantly increased rightward activation over the anterior supratemporal plane for musical imagery. Conclusions : Thus, we conclude that short-term top-down training based auditory imagery of music and speech prompts involvement of distinct neural circuits residing in the perisylvian cortex. Show more

Keywords: EEG, LORETA, auditory imagery, auditory plasticity, auditory cortex

Citation: Restorative Neurology and Neuroscience, vol. 25, no. 3-4, pp. 411-431, 2007

Authors: Thiel, Christiane M.

Article Type: Research Article

Abstract: Purpose : Converging evidence from animals and humans indicate that the primary auditory cortex is continuously reshaped in an experience-dependent way. Reorganisation in primary auditory cortex can be observed at the level of receptive fields, topographic maps and brain activations measured with neuroimaging methods. Several neuromodulatory systems were shown to contribute to such an experience-dependent reorganization. Methods : This paper reviews evidence addressing the cholinergic, noradrenergic, dopaminergic and serotonergic modulation of learning-, experience-, and injury-induced plasticity in the auditory cortex. Results : Regarding learning-induced plasticity in the auditory cortex most studies have investigated the role of the cholinergic …system and shown that ACh is essential for this form of rapid plasticity. Nevertheless there is also evidence that the catecholamines dopamine and noradrenaline might contribute to learning- and experience-induced changes in the auditory cortex. Conclusions : I suggest, that the available experimental data on cholinergic and noradrenergic modulation of plasticity offers a promising basis for potential pharmacological interventions to aid recovery of aural functions. Show more

Keywords: Plasticity, psychopharmacology, auditory cortex, drug, experience

Citation: Restorative Neurology and Neuroscience, vol. 25, no. 3-4, pp. 435-443, 2007