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