Susanne Maria Reiterer

Impact of voice on emotional judgment of faces: An event-related fMRI study

Emotional information can be conveyed by various means of communication, such as propositional content, speech intonation, facial expression, and gestures. Prior studies have demonstrated that inputs from one modality can alter perception in another modality. To evaluate the impact of emotional intonation on ratings of emotional faces, a behavioral study first was carried out. Second, functional magnetic resonance (fMRI) was used to identify brain regions that mediate crossmodal effects of emotional prosody on judgments of facial expressions. In the behavioral study, subjects rated fearful and neutral facial expressions as being more fearful when accompanied by a fearful voice as compared to the same facial expressions without concomitant auditory stimulus, whereas no such influence on rating of faces was found for happy voices. In the fMRI experiment, this shift in rating of facial expressions in presence of a fearfully spoken sentence was correlated with the hemodynamic response in the left amygdala extending into the periamygdaloid cortex, which suggests that crossmodal effects on cognitive judgments of emotional information are mediated via these neuronal structures. Furthermore, significantly stronger activations were found in the mid‐portion of the right fusiform gyrus during judgment of facial expressions in presence of fearful as compared to happy intonations, indicating that enhanced processing of faces within this region can be induced by the presence of threat‐related information perceived via the auditory modality. Presumably, these increased extrastriate activations correspond to enhanced alertness, whereas responses within the left amygdala modulate cognitive evaluation of emotional facial expressions. Hum Brain Mapp, 2006.

Voxel-based morphometry studies of personality: Issue of statistical model specification—effect of nuisance covariates

There are an increasing number of studies on the localization of personality using voxel-based morphometry. Due to the complex analytic challenge in volumetric studies, the specification and treatment of the nuisance covariate (such as age, gender, and global measures) is currently not consistent. Here, we present a study in which we conducted voxel-based morphometry with Five-Factor Model (FFM) of personality traits (extraversion, neuroticism, openness to experience, agreeableness, and conscientiousness) that aimed to test the influence of NC specification in the determination of the results. In this study, 62 healthy subjects underwent MRI investigation and completed a German version of the FFM personality questionnaire. Voxel-based morphometry was used to investigate the correlation between the FFM personality traits and subtle brain structure. Different NC combinations were used during the model specification. Significant clusters were found only under the condition of some of the NC combinations but not under the others. In addition, we use the structure equation modeling (automated specification search from AMOS) to narrow down the possible choices of NC combinations according to a set of goodness-of-fit indices to identify well-fitted statistic models. As a final step, theoretical implications of the results are discussed, before accepting the selected model.

Individual Differences in Audio-Vocal Speech Imitation Aptitude in Late Bilinguals: Functional Neuro-Imaging and Brain Morphology

An unanswered question in adult language learning or late bi and multilingualism is why individuals show marked differences in their ability to imitate foreign accents. While recent research acknowledges that more adults than previously assumed can still acquire a “native” foreign accent, very little is known about the neuro-cognitive correlates of this special ability. We investigated 140 German-speaking individuals displaying varying degrees of “mimicking” capacity, based on natural language text, sentence, and word imitations either in their second language English or in Hindi and Tamil, languages they had never been exposed to. The large subject pool was strictly controlled for previous language experience prior to magnetic resonance imaging. The late-onset (around 10 years) bilinguals showed significant individual differences as to how they employed their left-hemisphere speech areas: higher hemodynamic activation in a distinct fronto-parietal network accompanied low ability, while high ability paralleled enhanced gray matter volume in these areas concomitant with decreased hemodynamic responses. Finally and unexpectedly, males were found to be more talented foreign speech mimics.

Language aptitude for pronunciation in advanced second language (L2) Learners: Behavioural predictors and neural substrates

Individual differences in second language (L2) aptitude have been assumed to depend upon a variety of cognitive and personality factors. Especially, the cognitive factor phonological working memory has been conceptualised as language learning device. However, strong associations between phonological working memory and L2 aptitude have been previously found in early-stage learners only, not in advanced learners. The current study aimed at investigating the behavioural and neurobiological predictors of advanced L2 learning. Our behavioural results showed that phonetic coding ability and empathy, but not phonological working memory, predict L2 pronunciation aptitude in advanced learners. Second, functional neuroimaging revealed this behavioural trait to be correlated with hemodynamic responses of the cerebral network of speech motor control and auditory-perceptual areas. We suggest that the acquisition of L2 pronunciation aptitude is a dynamic process, requiring a variety of neural resources at different processing stages over time.

Impact of task difficulty on lateralization of pitch and duration discrimination.

To investigate lateralization of duration and pitch discrimination processing with emphasis on the influences of task difficulty, we used event-related functional magnetic resonance imaging. Seventeen healthy volunteers performed paired auditory discrimination tasks at varying levels of difficulty. Analysis of lateralization effects revealed leftward lateralization within the insular and the temporal cortex under both conditions. Moreover, parametric analysis of haemodynamic responses showed increasing activation within the right temporal cortex correlated to increasing accuracy of stimulus discrimination. Thus, highly differential acoustic stimuli seem to be predominantly processed within the right hemisphere, whereas the detection of slight signal differences might be linked to the left hemisphere. In conclusion, we found evidence for preferential involvement of the right hemisphere in holistic feature processing within the auditory domain.

Song and speech: examining the link between singing talent and speech imitation ability

In previous research on speech imitation, musicality, and an ability to sing were isolated as the strongest indicators of good pronunciation skills in foreign languages. We, therefore, wanted to take a closer look at the nature of the ability to sing, which shares a common ground with the ability to imitate speech. This study focuses on whether good singing performance predicts good speech imitation. Forty-one singers of different levels of proficiency were selected for the study and their ability to sing, to imitate speech, their musical talent and working memory were tested. Results indicated that singing performance is a better indicator of the ability to imitate speech than the playing of a musical instrument. A multiple regression revealed that 64% of the speech imitation score variance could be explained by working memory together with educational background and singing performance. A second multiple regression showed that 66% of the speech imitation variance of completely unintelligible and unfamiliar language stimuli (Hindi) could be explained by working memory together with a singers sense of rhythm and quality of voice. This supports the idea that both vocal behaviors have a common grounding in terms of vocal and motor flexibility, ontogenetic and phylogenetic development, neural orchestration and auditory memory with singing fitting better into the category of “speech” on the productive level and “music” on the acoustic level. As a result, good singers benefit from vocal and motor flexibility, productively and cognitively, in three ways. (1) Motor flexibility and the ability to sing improve language and musical function. (2) Good singers retain a certain plasticity and are open to new and unusual sound combinations during adulthood both perceptually and productively. (3) The ability to sing improves the memory span of the auditory working memory.

Language talent and brain activity

This book describes and assesses pronunciation talent in its various dimensions, such as production and perception or the segmental and suprasegmental levels of speech. Special focus is put on the psychological and neural correlates of phonetic performance. Behavioral influences such as empathy or motivation are investigated. The resulting classification of proficiency and talent level is used to select subjects for neuroimaging studies in which differences in brain activity between talented and untalented individuals are observed. Key features indispensible contribution to research in the neurolinguistic analysis of pronunciation talent interesting case studies in language learning suitable reading for students of linguistics andforeign languages

Thalamus segmentation based on the local diffusion direction: A group study

Fast and accurate segmentation of deep gray matter regions in the brain is important for clinical applications such as surgical planning for the placement of deep brain stimulation implants. Mapping anatomy from stereotactic atlases to patient data is problematic because of individual differences in subject anatomy that are not accounted for by commonly used atlases. We present a segmentation method for individual subject diffusion tensor MR data that is based on local diffusion information to identify subregions of the thalamus. We show the correspondence of our segmentation results to anatomy by comparison with stereotactic atlas data. Importantly, we verify the consistency of our segmentation by evaluating the method on 63 healthy volunteers. Our method is fast, reliable, and independent of any segmentation before the classification of regions within the thalamus. It should, therefore, be useful in clinical applications. Magn Reson Med, 2011.

Decreased EEG coherence between prefrontal electrodes: a correlate of high language proficiency?

To investigate the influence of proficiency level on the cortical organization of foreign language processing, two groups of German speaking students, differing only in their proficiency in English as a second language, were subjected to EEG coherence analysis during foreign and native language processing (news reports, alpha1 frequency band). In the group with minor experience with English, coherence increase was observed with all electrode combinations, with left hemisphere (LH) predominance. In the high proficiency group, coherence increase was limited to temporal electrodes over LH. In the latter group only, coherence between prefrontal electrodes was significantly lower during the language tasks than during the baseline task (silence, noisy screen). Both results were obtained with foreign as well as native language processing. We suggest that reduced EEG coherence in highly proficient foreign language speakers reflects a more efficient operating strategy not only for their second, but also for their native language.

Multivariate tests for the evaluation of high-dimensional EEG data.

In this paper several multivariate tests are presented, in particular permutation tests, which can be used in multiple endpoint problems as for example in comparisons of high-dimensional vectors of EEG data. We have investigated the power of these tests using artificial data in simulations and real EEG data. It is obvious that no one multivariate test is uniformly most powerful. The power of the different methods depends in different ways on the correlation between the endpoints, on the number of endpoints for which differences exist and on other factors. Based on our findings, we have derived rules of thumb regarding under which configurations a particular test should be used. In order to demonstrate the properties of different multivariate tests we applied them to EEG coherence data. As an example for the paired samples case, we compared the 171-dimensional coherence vectors observed for the alpha1-band while processing either concrete or abstract nouns and obtained significant global differences for some sections of time. As an example for the unpaired samples case, we compared the coherence vectors observed for language students and non-language students who processed an English text and found a significant global difference.