Self-initiated Sounds Research Articles

Processing of self-initiated sound motion in the human brain

Interacting with objects in our environment usually leads to audible noise. Brain responses to such self-initiated sounds have been shown to be attenuated, in particular the so-called N1 component measured with electroencephalography (EEG). This attenuation has been proposed to be the effect of an internal forward model that allows for cancellation of the sensory consequences of a motor command.In the current study we asked whether the attenuation due to self-initiation of a sound also affects a later event-related potential – the so-called motion-onset response – that arises in response to moving sounds. To this end, volunteers were instructed to move their index fingers either left or rightward which resulted in virtual movement of a sound either to the left or to the right. In Experiment 1, sound motion was induced with in-ear head-phones by shifting interaural time and intensity differences and thus shifting the intracranial sound image. We compared the motion-onset responses under two conditions: a) congruent, and b) incongruent. In the congruent condition, the sound image moved in the direction of the finger movement, while in the incongruent condition sound motion was in the opposite direction of the finger movement. Clear motion-onset responses with a negative cN1 component peaking at about 160 ms and a positive cP2 component peaking at about 230 ms after motion-onset were obtained for both the congruent and incongruent conditions. However, the motion-onset responses did not significantly differ between congruent and incongruent conditions in amplitude or latency. In Experiment 2, in which sounds were presented with loudspeakers, we observed attenuation for self-induced versus externally triggered sound motion-onset, but again, there was no difference between congruent and incongruent conditions.In sum, these two experiments suggest that the motion-onset response measured by EEG can be attenuated for self-generated sounds. However, our result did not indicate that this attenuation depended on congruency of action and sound motion direction.

Sensory attenuation of self-initiated sounds maps onto habitual associations between motor action and sound.

Sensory attenuation refers to reduced brain responses to self-initiated sensations relative to those produced by the external world, a distinction that is vital for dynamic motor control and our sense of agency. Typically, willed vocalizations elicit larger N1 reduction of the auditory evoked potential compared to indirectly evoked sounds, such as tones generated by button-presses, which is attributed to the prediction and cancellation of incoming signals enabled by speech motor commands. However, physical confounds exist, including different stimuli and the increased motor artefact associated with mouth vs. finger movements. The present study investigated N1 attenuation to physically identical sounds evoked by hand, eye, and mouth-initiated movements. Twenty-eight healthy participants had their electroencephalogram (EEG) recorded as they blew into a microphone, pressed a button, or moved their eye to generate a pure tone. We found that N1 and P2 response was most reduced in the blow initiation condition, and that both blow and button-press but not saccade initiated tones elicited significantly reduced N1 and P2 amplitude compared to external initiation. This indicates that the eliciting motor action markedly influences ERP response to auditory stimuli. Given that saccades are never associated with sounds, finger movements sometimes are, and mouth movements often are, the pattern of results suggests that N1 attenuation to self-initiated sounds may depend on existing associations between the initiating action and resultant sensation.

Attenuation of auditory evoked potentials for hand and eye-initiated sounds

Reduction of auditory event-related potentials (ERPs) to self-initiated sounds has been considered evidence for a predictive model in which copies of motor commands suppress sensory representations of incoming stimuli. However, in studies which involve arbitrary auditory stimuli evoked by sensory-unspecific motor actions, learned associations may underlie ERP differences. Here, in a new paradigm, eye motor output generated auditory sensory input, a naïve action–sensation contingency. We measured the electroencephalogram (EEG) of 40 participants exposed to pure tones, which they produced with either a button-press or volitional saccade. We found that button-press-initiated stimuli evoked reduced amplitude compared to externally initiated stimuli for both the N1 and P2 ERP components, whereas saccade-initiated stimuli evoked intermediate attenuation at N1 and no reduction at P2. These results indicate that the motor-to-sensory mapping involved in speech production may be partly generalized to other contingencies, and that learned associations also contribute to the N1 attenuation effect.

Information content of electrophysiological responses elicited by omissions of self-initiated sounds

Event Abstract Back to Event Information content of electrophysiological responses elicited by omissions of self-initiated sounds Iria SanMiguel1* and Erich Schröger1 1 Leipzig University, BioCog, Institute for Psychology, Germany Prediction plays a fundamental role in sensory processing and perception. However, the neural representation code of sensory predictions is still unknown. In previous studies, (SanMiguel et al., 2013 J Neurosci; SanMiguel, Saupe & Schröger 2013, Front Hum Neurosci) we have been able to unmask neural activity representing sensory predictions inserting sound omissions in a paradigm where participants self-initiate sounds by pressing a button. Here, we aimed at clarifying to which degree prediction-related activity unmasked in this paradigm reflects the physical characteristics of the predicted stimulus. Our main hypothesis is that sensory predictions are represented with sensory templates; hence omissions of self-initiated sounds should mimic the behaviour of exogenous responses when the physical characteristics of the self-initiated sounds are predictable. We manipulated two physical characteristics of the self-initiated sounds which are known to affect the morphology of scalp-recorded auditory ERPs: sound frequency and presentation ear. Participants chose on a trial-by-trial basis to generate a high- or a low-frequency sound by pressing either one of two buttons. Presentation ear was manipulated block-wise. Self-initiated sounds were omitted in 12.5% of the trials. Morphological differences were observed between the auditory responses of high- and low-frequency and left and right ear sounds. Interestingly, these differences were mimicked in the electrophysiological responses elicited by the unexpected omissions of the same sounds. We will present results from a pattern classification analysis, performed to assess the information content of the omission responses. In this analysis, we investigate whether a classifier trained on the basis of sound responses is able to correctly classify omission responses according to the expected frequency and presentation ear of the omitted sound. Keywords: Prediction error, Pattern Classification, self-generation, Omissions, auditory ERPs Conference: XII International Conference on Cognitive Neuroscience (ICON-XII), Brisbane, Queensland, Australia, 27 Jul - 31 Jul, 2014. Presentation Type: Poster Topic: Sensation and Perception Citation: SanMiguel I and Schröger E (2015). Information content of electrophysiological responses elicited by omissions of self-initiated sounds. Conference Abstract: XII International Conference on Cognitive Neuroscience (ICON-XII). doi: 10.3389/conf.fnhum.2015.217.00383 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 19 Feb 2015; Published Online: 24 Apr 2015. * Correspondence: Dr. Iria SanMiguel, Leipzig University, BioCog, Institute for Psychology, Leipzig, Germany, isanmiguel@ub.edu Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Iria SanMiguel Erich Schröger Google Iria SanMiguel Erich Schröger Google Scholar Iria SanMiguel Erich Schröger PubMed Iria SanMiguel Erich Schröger Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.

Motor Intention Determines Sensory Attenuation of Brain Responses to Self-initiated Sounds

One of the functions of the brain is to predict sensory consequences of our own actions. In auditory processing, self-initiated sounds evoke a smaller brain response than passive sound exposure of the same sound sequence. Previous work suggests that this response attenuation reflects a predictive mechanism to differentiate the sensory consequences of one's own actions from other sensory input, which seems to form the basis for the sense of agency (recognizing oneself as the agent of the movement). This study addresses the question whether attenuation of brain responses to self-initiated sounds can be explained by brain activity involved in movement planning rather than movement execution. We recorded ERPs in response to sounds initiated by button presses. In one condition, participants moved a finger to press the button voluntarily, whereas in another condition, we initiated a similar, but involuntary, finger movement by stimulating the corresponding region of the primary motor cortex with TMS. For involuntary movements, no movement intention (and no feeling of agency) could be formed; thus, no motor plans were available to the forward model. A portion of the brain response evoked by the sounds, the N1-P2 complex, was reduced in amplitude following voluntary, self-initiated movements, but not following movements initiated by motor cortex stimulation. Our findings demonstrate that movement intention and the corresponding feeling of agency determine sensory attenuation of brain responses to self-initiated sounds. The present results support the assumptions of a predictive internal forward model account operating before primary motor cortex activation.

P 144. Activity prior to motor cortex and the sensation of agency modulate brain responses to self-initiated sounds

One of the functions of the brain is to predict sensory consequences of our own actions. In auditory processing self-initiated sounds evoke a smaller auditory brain response than passive sound exposure of the same sound sequence [1] . Previous work suggests that this response attenuation reflects a predictive mechanism to differentiate the sensory consequences of one’s own actions from other sensory input [2] . On a psychological level correctly predicted sensory feedback has been linked to a pre-reflective sensation of self-agency (feeling of coherence in action processing) [3] which is formed in premotor areas involved in movement planning [4] . We addresses the question whether attenuation of brain responses to self-initiated sounds can be explained by brain activity leading up to, but not including, the motor cortex. Moreover, the relation between attenuated auditory brain responses to self-initiated sounds and the pre-reflective sensation of agency was investigated. Event-related brain potentials (ERPs) from the human scalp of 17 participants were recorded in response to sounds initiated by a button press. In one experimental condition, participants moved a finger to press the button voluntarily, whereas, in another condition, we initiated a similar finger movement involuntarily by stimulating the corresponding region of the primary motor cortex with transcranial magnetic stimulation (TMS). No sensation of agency was experienced for involuntary movements as no motor plans were available. A portion of the brain response evoked by the sounds, the N1–P2 complex, was reduced in amplitude only following a voluntary, self-initiated, movement, but not following a movement initiated by motor cortex stimulation. Our findings demonstrate that sensory attenuation of brain responses to self-initiated sounds depends on a pre-reflective sensation of agency and on predictive mechanisms that operate prior to the activation of the primary motor cortex. The present results support the assumptions of an internal forward-model account [2] . This work was supported by the Erasmus Mundus Student Exchange Network in Auditory Cognitive Neuroscience and a Reinhart-Koselleck Grant of the German Research Foundation (Deutsche Forschungsgemeinschaft, DFG, Project 375/20-1).

Sensory suppression effects to self‐initiated sounds reflect the attenuation of the unspecific N1 component of the auditory ERP

The suppression of the auditory N1 event-related potential (ERP) to self-initiated sounds became a popular tool to tap into sensory-specific forward modeling. It is assumed that processing in the auditory cortex is attenuated due to a match between sensory stimulation and a specific sensory prediction afforded by a forward model of the motor command. The present study shows that N1 suppression was dramatically increased with long (≈ 3 s) stimulus onset asynchronies (SOA), whereas P2 suppression was equal in all SOA conditions (0.8, 1.6, 3.2 s). Thus, the P2 was found to be more sensitive to self-initiation effects than the N1 with short SOAs. Moreover, only the unspecific but not the sensory-specific N1 components were suppressed for self-initiated sounds suggesting that N1-suppression effects mainly reflect an attenuated orienting response. We argue that the N1-suppression effect is a rather indirect measure of sensory-specific forward models.

The N1-suppression effect for self-initiated sounds is independent of attention.

BackgroundIf we initiate a sound by our own motor behavior, the N1 component of the auditory event-related brain potential (ERP) that the sound elicits is attenuated compared to the N1 elicited by the same sound when it is initiated externally. It has been suggested that this N1 suppression results from an internal predictive mechanism that is in the service of discriminating the sensory consequences of one’s own actions from other sensory input. As the N1-suppression effect is becoming a popular approach to investigate predictive processing in cognitive and social neuroscience, it is important to exclude an alternative interpretation not related to prediction. According to the attentional account, the N1 suppression is due to a difference in the allocation of attention between self- and externally-initiated sounds. To test this hypothesis, we manipulated the allocation of attention to the sounds in different blocks: Attention was directed either to the sounds, to the own motor acts or to visual stimuli. If attention causes the N1-suppression effect, then manipulating attention should affect the effect for self-initiated sounds.ResultsWe found N1 suppression in all conditions. The N1 per se was affected by attention, but there was no interaction between attention and self-initiation effects. This implies that self-initiation N1 effects are not caused by attention.ConclusionsThe present results support the assumption that the N1-suppression effect for self-initiated sounds indicates the operation of an internal predictive mechanism. Furthermore, while attention had an influence on the N1a, N1b, and N1c components, the N1-suppression effect was confined to the N1b and N1c subcomponents suggesting that the major contribution to the auditory N1-suppression effect is circumscribed to late N1 components.

Cerebellar contribution to the prediction of self-initiated sounds

In everyday life we frequently make the fundamental distinction between sensory input resulting from our own actions and sensory input that is externally-produced. It has been speculated that making this distinction involves the use of an internal forward-model, which enables the brain to adjust its response to self-produced sensory input. In the auditory domain, this idea has been supported by event-related potential and evoked-magnetic field studies revealing that self-initiated sounds elicit a suppressed N100/M100 brain response compared to externally-produced sounds. Moreover, a recent study reveals that patients with cerebellar lesions do not show a significant N100-suppression effect. This result supports the theory that the cerebellum is essential for generating internal forward predictions. However, all except one study compared self-initiated and externally-produced auditory stimuli in separate conditions. Such a setup prevents an unambiguous interpretation of the N100-suppression effect when distinguishing self- and externally-produced sensory stimuli: the N100-suppression can also be explained by differences in the allocation of attention in different conditions. In the current electroencephalography (EEG)-study we investigated the N100-suppression effect in an altered design comparing (i) self-initiated sounds to externally-produced sounds that occurred intermixed with these self-initiated sounds (i.e., both sound types occurred in the same condition) or (ii) self-initiated sounds to externally-produced sounds that occurred in separate conditions. Results reveal that the cerebellum generates selective predictions in response to self-initiated sounds independent of condition type: cerebellar patients, in contrast to healthy controls, do not display an N100-suppression effect in response to self-initiated sounds when intermixed with externally-produced sounds. Furthermore, the effect is not influenced by the temporal proximity of externally-produced sounds to self-produced sounds. Controls and patients showed a P200-reduction in response to self-initiated sounds. This suggests the existence of an additional and probably more conscious mechanism for identifying self-generated sounds that does not functionally depend on the cerebellum.

The Cerebellum Generates Motor-to-Auditory Predictions: ERP Lesion Evidence

Forward predictions are crucial in motor action (e.g., catching a ball, or being tickled) but may also apply to sensory or cognitive processes (e.g., listening to distorted speech or to a foreign accent). According to the "internal forward model," the cerebellum generates predictions about somatosensory consequences of movements. These predictions simulate motor processes and prepare respective cortical areas for anticipated sensory input. Currently, there is very little evidence that a cerebellar forward model also applies to other sensory domains. In the current study, we address this question by examining the role of the cerebellum when auditory stimuli are anticipated as a consequence of a motor act. We applied an N100 suppression paradigm and compared the ERP in response to self-initiated with the ERP response to externally produced sounds. We hypothesized that sensory consequences of self-initiated sounds are precisely predicted and should lead to an N100 suppression compared with externally produced sounds. Moreover, if the cerebellum is involved in the generation of a motor-to-auditory forward model, patients with focal cerebellar lesions should not display an N100 suppression effect. Compared with healthy controls, patients showed a largely attenuated N100 suppression effect. The current results suggest that the cerebellum forms not only motor-to-somatosensory predictions but also motor-to-auditory predictions. This extends the cerebellar forward model to other sensory domains such as audition.

Selective suppression of self‐initiated sounds in an auditory stream: An ERP study

Numerous studies have shown that the N1 event-related potential (ERP) response is attenuated when it is elicited by self-initiated sounds. This N1 suppression effect is generally interpreted to reflect an internal prediction mechanism, which enables the discrimination of the sensory consequences of our own actions and those of others. The blocked design used in the forerunner studies (i.e., self- and externally initiated sounds presented in different blocks) seriously limits the relevance of these findings, because the N1 effect can simply be explained by contextual task differences. In the present study, self- and externally initiated sounds were mixed within blocks. N1 suppression was found, and its magnitude was even larger than that observed in a traditional blocked condition. This result supports the involvement of an internal prediction mechanism in the discrimination of the sensory consequences of one's own actions and those of others.

Attenuated human auditory middle latency response and evoked 40‐Hz response to self‐initiated sounds

For several modalities, it has been shown that the processing of sensory information generated by our own actions is attenuated relative to the processing of sensory information of externally generated stimuli. It has been proposed that the underlying mechanism builds predictions about the forthcoming sensory input and forwards them to the respective sensory processing levels. The present study investigated whether early auditory processing is suppressed by the top-down influences of such an internal forward model mechanism. To this end, we compared auditory middle latency responses (MLRs) and evoked 40-Hz responses elicited by self-initiated sounds with those elicited by externally initiated but otherwise identical sounds. In the self-initiated condition, the amplitudes of the Pa (27-33 ms relative to sound onset) and Nb (40-46 ms) components of the MLRs were significantly attenuated when compared to the responses elicited by click sounds presented in the externally initiated condition. Similarly, the evoked activity in the 40-Hz and adjacent frequency bands was attenuated. Considering that previous research revealed subcortical and auditory cortex contributions to MLRs and 40-Hz responses, our results support the existence of auditory suppression effects with self-initiated sounds on temporally and structurally early auditory processing levels. This attenuation in the processing of self-initiated sounds most probably contributes to the optimal processing of concurrent external acoustic events.

The processing of self-initiated but unexpected sounds: Evidence for an internal prediction mechanism

Event Abstract Back to Event The processing of self-initiated but unexpected sounds: Evidence for an internal prediction mechanism Pamela Baess1*, A. Schimming2, P. E. Keller2 and E. Schröger1 1 University of Leipzig, Institute of Psychology, BioCog - Cognitive including biological psychology, Germany 2 Max-Planck-Institute for human cognitive and brain sciences, Germany How can we accurately discriminate between the sensory consequences of our own actions and from those of others? With internal prediction mechanisms, the sensory consequences of one’s own actions can be predicted, in contrast to those of others, which can not be predicted. In human EEG studies, it has been shown that self-initiated sounds elicited a smaller N1 response than did externally-initiated sounds. In previous studies, the self-initiated sounds were, at least partially, expected. Here, we tested whether self-initiated but unexpected sounds would also elicit an attenuated N1 response, as did self-initiated but expected sounds compared to externally-initiated sounds. The participants were asked to press one of two buttons equally often in a self-paced interval that triggered the presentation of either a high or low piano sound. A different, unexpected piano sound randomly followed one of the two button presses. Identical sound sequences were played back as externally-initiated sounds. Diminished N1 responses were observed for the self-initiated expected sounds compared to the externally-initiated replayed sounds. The N1 amplitudes for self-initiated unexpected sounds were also attenuated. Further, the unexpected sounds elicited another negativity around 200 ms (similar to an N2b component) which was not seen with self-initiated expected sounds or externally-initiated replayed sounds. Thus, the internal prediction mechanism presumably tolerates unexpected but self-initiated sounds. In addition, the late negativity observed for the processing of unexpected sounds points towards the involvement of a ‘target detection system’ since a sound was produced which was not intended. Conference: MMN 09 Fifth Conference on Mismatch Negativity (MMN) and its Clinical and Scientific Applications, Budapest, Hungary, 4 Apr - 7 Apr, 2009. Presentation Type: Poster Presentation Topic: Poster Presentations Citation: Baess P, Schimming A, Keller PE and Schröger E (2009). The processing of self-initiated but unexpected sounds: Evidence for an internal prediction mechanism. Conference Abstract: MMN 09 Fifth Conference on Mismatch Negativity (MMN) and its Clinical and Scientific Applications. doi: 10.3389/conf.neuro.09.2009.05.062 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 24 Mar 2009; Published Online: 24 Mar 2009. * Correspondence: Pamela Baess, University of Leipzig, Institute of Psychology, BioCog - Cognitive including biological psychology, Leipzig, Germany, baess@uni-leipzig.de Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Pamela Baess A. Schimming P. E Keller E. Schröger Google Pamela Baess A. Schimming P. E Keller E. Schröger Google Scholar Pamela Baess A. Schimming P. E Keller E. Schröger PubMed Pamela Baess A. Schimming P. E Keller E. Schröger Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.

Selective suppression of self-initiated sounds in an auditory stream. An EEG-study

Event Abstract Back to Event Selective suppression of self-initiated sounds in an auditory stream. An EEG-study Pamela Baess1*, J. Horváth1, T. Jacobsen1 and E. Schröger1 1 University of Leipzig, Germany One of the most important human cognitive functions is the ability to discriminate the sensory consequences of one’s own actions from sensory events originating from other sources. One way to explain how this is realized in the brain is through the concept of the internal forward model (see e.g., Wolpert & Ghahramani, 2000). According to this model, for each action, a prediction about its sensory consequences is generated. If the re-afferent sensory information matches the prediction, the impact of the sensory information is attenuated or even completely eliminated. In the auditory domain, the existence of such a mechanism is supported by a number of psychophysiological studies, which found attenuated cortical brain responses to self-initiated sounds compared to externally initiated sounds around 100 ms after sound onset (Bäß et al, in revision; Martikainen et al, 2005; McCarthy & Donchin, 1976; Schäfer & Marcus, 1973). In these studies, brain responses to tones were recorded in 1) a condition where participants self-initiated the presentation of each tone (controlled solely for motor activity) and 2) the exact replay of the auditory stimulation from the self-initiated sequence, without any motor task. However, because of the blocked design, it remained unclear whether the attenuated brain responses to self-initiated sounds were attributable to self-initiation, or to some other difference (e.g. task-demands) between the different conditions. Therefore, in the present study, we recorded human EEG in a condition in which self-initiated and external sounds were mixed (“mixed” condition). A condition in which participants self-initiated the presentation of each tone was also added (“completely self-initiated” condition), similarly to the previous studies mentioned above. Our results showed that in the mixed condition, only the self-initiated sounds but not the external sounds were attenuated. Further, the brain responses were more attenuated in the “mixed”, than in the “completely self-initiated” condition. This is in line with the internal forward model assumptions. In a stream of sounds with different origin, the comparison process has to be more accurate. In contrast, in the “completely self-initiated” condition, the underlying comparison-process needs to be less accurate for the self-initiated sounds. Thus, the internal forward model mechanism in auditory perception seems to be flexible in regard to the environmental context. Conference: 10th International Conference on Cognitive Neuroscience, Bodrum, Türkiye, 1 Sep - 5 Sep, 2008. Presentation Type: Poster Presentation Topic: Attention Citation: Baess P, Horváth J, Jacobsen T and Schröger E (2008). Selective suppression of self-initiated sounds in an auditory stream. An EEG-study. Conference Abstract: 10th International Conference on Cognitive Neuroscience. doi: 10.3389/conf.neuro.09.2009.01.095 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 02 Dec 2008; Published Online: 02 Dec 2008. * Correspondence: Pamela Baess, University of Leipzig, Leipzig, Germany, baess@uni-leipzig.de Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Pamela Baess J. Horváth T. Jacobsen E. Schröger Google Pamela Baess J. Horváth T. Jacobsen E. Schröger Google Scholar Pamela Baess J. Horváth T. Jacobsen E. Schröger PubMed Pamela Baess J. Horváth T. Jacobsen E. Schröger Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.