Neuromagnetic representation of musical roundness in chord progressions.

Introduction: Musical roundness perception relies on consonance/dissonance within a rule-based harmonic context, but also on individual characteristics of the listener. The present work tackles these aspects in a combined psychoacoustic and neurophysiological study, taking into account participant's musical aptitude. Methods: Our paradigm employed cadence-like four-chord progressions, based on Western music theory. Chord progressions comprised naturalistic and artificial sounds; moreover, their single chords varied regarding consonance/dissonance and harmonic function. Thirty participants listened to the chord progressions while their cortical activity was measured with magnetoencephalography; afterwards, they rated the individual chord progressions with respect to their perceived roundness. Results: Roundness ratings differed according to the degree of dissonance in the dominant chord at the progression's third position; this effect was pronounced in listeners with high musical aptitude. Interestingly, a corresponding pattern occurred in the neuromagnetic N1m response to the fourth chord (i.e., at the progression's resolution), again with somewhat stronger differentiation among musical listeners. The N1m magnitude seemed to increase during chord progressions that were considered particularly round, with the maximum difference after the final chord; here, however, the musical aptitude effect just missed significance. Discussion: The roundness of chord progressions is reflected in participant's psychoacoustic ratings and in their transient cortical activity, with stronger differentiation among listeners with high musical aptitude. The concept of roundness might help to reframe consonance/dissonance to a more holistic, gestalt-like understanding that covers chord relations in Western music.

Altered binaural hearing in pre-ataxic and ataxic mutation carriers of spinocerebellar ataxia type 3.

Brainstem degeneration is a prominent feature of spinocerebellar ataxia type 3 (SCA3), involving structures that execute binaural synchronization with microsecond precision. As a consequence, auditory processing may deteriorate during the course of disease. We tested whether the binaural "Huggins pitch" effect is suitable to study the temporal precision of brainstem functioning in SCA3 mutation carriers. We expected that they would have difficulties perceiving Huggins pitch at high frequencies, and that they would show attenuated neuromagnetic responses to Huggins pitch. The upper limit of Huggins pitch perception was psychoacoustically determined in 18 pre-ataxic and ataxic SCA3 mutation carriers and in 18 age-matched healthy controls. Moreover, the cortical N100 response following Huggins pitch onset was acquired by means of magnetoencephalography (MEG). MEG recordings were analyzed using dipole source modeling and comprised a monaural pitch condition and a no-pitch condition with simple binaural correlation changes. Compared with age-matched controls, ataxic but not pre-ataxic SCA3 mutation carriers had significantly lower frequency limits up to which Huggins pitch could be heard. Listeners with lower frequency limits also showed diminished MEG responses to Huggins pitch, but not in the two control conditions. Huggins pitch is a promising tool to assess brainstem functioning in ataxic SCA3 patients. Future studies should refine the psychophysiological setup to capture possible performance decrements also in pre-ataxic mutation carriers. Longitudinal observations will be needed to prove the potential of the assessment of Huggins pitch as a biomarker to track brainstem functioning during the disease course in SCA3.

Coping Strategies and Posttraumatic Growth Following Transient Ischemic Attack: A Qualitative Study.

A transient ischemic attack (TIA) is defined as a temporary neurological dysfunction due to focal brain ischemia. We aimed to identify common coping strategies and the possible occurrence of posttraumatic growth in TIA patients. Semistructured interviews were conducted with TIA patients three months after TIA. We asked the participants about possible changes in the aftermath of their TIA and their way of coping with said changes. All interviews were tape-recorded and subsequently transcribed verbatim. Thematic content analysis was performed to identify main categories and themes. Seventeen patients with a median age of 66 years completed the semistructured interviews. Qualitative content analysis revealed 332 single codes, from which the three main categories "impairments as a consequence of TIA", "coping strategies" and "posttraumatic growth" were generated. The main categories were further subdivided into seven categories and thirty-six themes. TIA patients may suffer from various physical impairments, which also involve medication side effects. Activating resources on the one hand, and avoiding negative thoughts and feelings on the other hand, were identified to be the relevant coping strategies in TIA patients. Posttraumatic growth seems to be a common phenomenon after TIA, which may have important implications for treatment and rehabilitation.

Neuromagnetic representation of melodic contour processing in human auditory cortex.

The pattern of ups and downs in a sequence with varying pitch can be heard as a melodic contour. Contrary to single pitch, the neural representation of melodic contour information in the auditory cortex is rarely investigated, and it is not clear whether the processing entails a hemispheric asymmetry. The present magnetoencephalography study assessed the neuromagnetic responses of N = 18 normal-hearing adults to four-note sequences with fixed vs. varying pitch that were presented either monaurally or diotically; data were analyzed using minimum-norm reconstructions. The first note of the sequences elicited prominent transient activity in posterior auditory regions (Planum temporale), especially contralateral to the ear of entry. In contrast, the response to the subsequent notes originated from more anterior areas (Planum polare) and was larger for melodic contours than for fixed pitch sequences, independent from the ear of entry and without hemispheric asymmetry. Together, the results point to a gradient in the early cortical processing of melodic contours, both in spatial and functional terms, where posterior auditory activity reflects the onset of a pitch sequence and anterior activity reflects its subsequent notes, including the difference between sequences with fixed pitch and melodic contours.

A direct comparison of voice pitch processing in acoustic and electric hearing.

In single-sided deafness patients fitted with a cochlear implant (CI) in the affected ear and preserved normal hearing in the other ear, acoustic and electric hearing can be directly compared without the need for an external control group. Although poor pitch perception is a crucial limitation when listening through CIs, it remains unclear how exactly the cortical processing of pitch information differs between acoustic and electric hearing. Hence, we separately presented both ears of 20 of these patients with vowel sequences in which the pitch contours were either repetitive or variable, while simultaneously recording functional near-infrared spectroscopy (fNIRS) and EEG data. Overall, the results showed smaller and delayed auditory cortex activity in electric hearing, particularly for the P2 event-related potential component, which appears to reflect the processing of voice pitch information. Both the fNIRS data and EEG source reconstructions furthermore showed that vowel sequences with variable pitch contours evoked additional activity in posterior right auditory cortex in electric but not acoustic hearing. This surprising discrepancy demonstrates, firstly, that the acoustic detail transmitted by CIs is sufficient to distinguish between speech sounds that only vary regarding their pitch information. Secondly, the absence of a condition difference when stimulating the normal-hearing ears suggests a saturation of cortical activity levels following unilateral deafness. Taken together, these results provide strong evidence in favour of using CIs in this patient group.

Behavioral and neurophysiological correlates of emotional face processing in borderline personality disorder: are there differences between men and women?

Emotional dysregulation is a core feature of borderline personality disorder (BPD); it is, for example, known to influence one's ability to read other people's facial expressions. We investigated behavioral and neurophysiological foundations of emotional face processing in individuals with BPD and in healthy controls, taking participants' sex into account. 62 individuals with BPD (25 men, 37 women) and 49 healthy controls (20 men, 29 women) completed an emotion classification task with faces depicting blends of angry and happy expressions while the electroencephalogram was recorded. The cortical activity (late positive potential, P3/LPP) was evaluated using source modeling. Compared to healthy controls, individuals with BPD responded slower to happy but not to angry faces; further, they showed more anger ratings in happy but not in angry faces, especially in those with high ambiguity. Men had lower anger ratings than women and responded slower to angry but not happy faces. The P3/LPP was larger in healthy controls than in individuals with BPD, and larger in women than in men; moreover, women but not men produced enlarged P3/LPP responses to angry vs. happy faces. Sex did not interact with behavioral or P3/LPP-related differences between healthy controls and individuals with BPD. Together, BPD-related alterations in behavioral and P3/LPP correlates of emotional face processing exist in both men and women, supposedly without sex-related interactions. Results point to a general 'negativity bias' in women. Source modeling is well suited to investigate effects of participant and stimulus characteristics on the P3/LPP generators.

Cortical activity evoked by voice pitch changes: A combined fNIRS and EEG study.

Functional near-infrared spectroscopy (fNIRS) and electroencephalography (EEG) data were simultaneously obtained from normal-hearing listeners presented with continuous natural vowel sequences to study the interrelation of the haemodynamic and electrophysiological cortical responses evoked by voice pitch changes. fNIRS topographies and distributed ERP source reconstructions both indicated additional activity in the right superior temporal cortex if the prosodic contours varied between successive vowels, rather than being the same throughout the sequences. The source-level ERPs furthermore revealed two temporally and spatially separable adaptation processes in superior temporal cortex: Firstly, the early P1 component was bilaterally attenuated when vowels with the same prosodic contours were presented repeatedly, reflecting sensory adaptation. Secondly, the later P2 and sustained potential components were smaller in the right hemisphere during sequences without prosodic changes, which is taken to represent an attention-based adaptation effect. The present results demonstrate the convergence of both methods and demonstrate which ERPs underlie the right-lateralised activity in superior temporal cortex evoked in response to pitch changes that has been observed in many neuroimaging studies.

Correction: Modeling and MEG evidence of early consonance processing in auditory cortex.

[This corrects the article DOI: 10.1371/journal.pcbi.1006820.].

Early cortical processing of pitch height and the role of adaptation and musicality.

Pitch is an important perceptual feature; however, it is poorly understood how its cortical correlates are shaped by absolute vs relative fundamental frequency (f0), and by neural adaptation. In this study, we assessed transient and sustained auditory evoked fields (AEFs) at the onset, progression, and offset of short pitch height sequences, taking into account the listener's musicality. We show that neuromagnetic activity reflects absolute f0 at pitch onset and offset, and relative f0 at transitions within pitch sequences; further, sequences with fixed f0 lead to larger response suppression than sequences with variable f0 contour, and to enhanced offset activity. Musical listeners exhibit stronger f0-related AEFs and larger differences between their responses to fixed vs variable sequences, both within sequences and at pitch offset. The results resemble prominent psychoacoustic phenomena in the perception of pitch contours; moreover, they suggest a strong influence of adaptive mechanisms on cortical pitch processing which, in turn, might be modulated by a listener's musical expertise.

Predictors of posttraumatic stress following transient ischemic attack: An observational cohort study.

OBJECTIVE: Transient ischemic attack (TIA) has been reported to be frequently followed by symptoms of post-TIA posttraumatic stress disorder (post-TIA PTSD). Risk factors for post-TIA PTSD remain largely unknown. We aimed to identify predictors of post-TIA PTSD development to enable post-TIA PTSD risk assessment and inform future development of treatment and prevention interventions. METHOD: TIA patients were examined twice for this observational cohort study. Symptoms of post-TIA PTSD, depression and anxiety were assessed shortly after TIA during in-hospital stay (T1) and three months after TIA (T2). The impact of known general PTSD risk factors (psychiatric history, peritraumatic dissociation, social support), psychological resilience factors (sense of coherence, mindfulness, attachment style) and TIA characteristics (affected circulatory territory, symptom type and duration) at T1 on post-TIA PTSD symptom severity at T2 was tested using hierarchical multiple linear regression. RESULTS: Sixty-one patients (83.6%) completed the study at T2. Fifteen patients (24.6%) were classified as post-TIA PTSD⊕ at T2. In multiple linear regression analysis, age, sex, psychiatric history, peritraumatic dissociation and social support together explained 39.9% of variance of post-TIA posttraumatic stress symptom severity. Sense of coherence and mindfulness explained further 17.8% of variance. Clinical TIA characteristics were not associated with post-TIA PTSD. CONCLUSIONS: Post-TIA PTSD is a common phenomenon. General PTSD risk factors can be applied for post-TIA PTSD risk assessment. Sense of coherence and mindfulness are promising target variables for post-TIA PTSD treatment and prevention interventions.

Transient and sustained processing of musical consonance in auditory cortex and the effect of musicality.

In recent years, electroencephalography and magnetoencephalography (MEG) have both been used to investigate the response in human auditory cortex to musical sounds that are perceived as consonant or dissonant. These studies have typically focused on the transient components of the physiological activity at sound onset, specifically, the N1 wave of the auditory evoked potential and the auditory evoked field, respectively. Unfortunately, the morphology of the N1 wave is confounded by the prominent neural response to energy onset at stimulus onset. It is also the case that the perception of pitch is not limited to sound onset; the perception lasts as long as the note producing it. This suggests that consonance studies should also consider the sustained activity that appears after the transient components die away. The current MEG study shows how energy-balanced sounds can focus the response waves on the consonance-dissonance distinction rather than energy changes and how source modeling techniques can be used to measure the sustained field associated with extended consonant and dissonant sounds. The study shows that musical dyads evoke distinct transient and sustained neuromagnetic responses in auditory cortex. The form of the response depends on both whether the dyads are consonant or dissonant and whether the listeners are musical or nonmusical. The results also show that auditory cortex requires more time for the early transient processing of dissonant dyads than it does for consonant dyads and that the continuous representation of temporal regularity in auditory cortex might be modulated by processes beyond auditory cortex.NEW & NOTEWORTHY We report a magnetoencephalography (MEG) study on transient and sustained cortical consonance processing. Stimuli were long-duration, energy-balanced, musical dyads that were either consonant or dissonant. Spatiotemporal source analysis revealed specific transient and sustained neuromagnetic activity in response to the dyads; in particular, the morphology of the responses was shaped by the dyad's consonance and the listener's musicality. Our results also suggest that the sustained representation of stimulus regularity might be modulated by processes beyond auditory cortex.

Modeling and MEG evidence of early consonance processing in auditory cortex.

Pitch is a fundamental attribute of auditory perception. The interaction of concurrent pitches gives rise to a sensation that can be characterized by its degree of consonance or dissonance. In this work, we propose that human auditory cortex (AC) processes pitch and consonance through a common neural network mechanism operating at early cortical levels. First, we developed a new model of neural ensembles incorporating realistic neuronal and synaptic parameters to assess pitch processing mechanisms at early stages of AC. Next, we designed a magnetoencephalography (MEG) experiment to measure the neuromagnetic activity evoked by dyads with varying degrees of consonance or dissonance. MEG results show that dissonant dyads evoke a pitch onset response (POR) with a latency up to 36 ms longer than consonant dyads. Additionally, we used the model to predict the processing time of concurrent pitches; here, consonant pitch combinations were decoded faster than dissonant combinations, in line with the experimental observations. Specifically, we found a striking match between the predicted and the observed latency of the POR as elicited by the dyads. These novel results suggest that consonance processing starts early in human auditory cortex and may share the network mechanisms that are responsible for (single) pitch processing.

Neuromagnetic correlates of voice pitch, vowel type, and speaker size in auditory cortex.

Vowel recognition is largely immune to differences in speaker size despite the waveform differences associated with variation in speaker size. This has led to the suggestion that voice pitch and mean formant frequency (MFF) are extracted early in the hierarchy of hearing/speech processing and used to normalize the internal representation of vowel sounds. This paper presents a magnetoencephalographic (MEG) experiment designed to locate and compare neuromagnetic activity associated with voice pitch, MFF and vowel type in human auditory cortex. Sequences of six sustained vowels were used to contrast changes in the three components of vowel perception, and MEG responses to the changes were recorded from 25 participants. A staged procedure was employed to fit the MEG data with a source model having one bilateral pair of dipoles for each component of vowel perception. This dipole model showed that the activity associated with the three perceptual changes was functionally separable; the pitch source was located in Heschl's gyrus (bilaterally), while the vowel-type and formant-frequency sources were located (bilaterally) just behind Heschl's gyrus in planum temporale. The results confirm that vowel normalization begins in auditory cortex at an early point in the hierarchy of speech processing.

Locating Melody Processing Activity in Auditory Cortex with Magnetoencephalography.

This paper describes a technique for isolating the brain activity associated with melodic pitch processing. The magnetoencephalograhic (MEG) response to a four note, diatonic melody built of French horn notes, is contrasted with the response to a control sequence containing four identical, "tonic" notes. The transient response (TR) to the first note of each bar is dominated by energy-onset activity; the melody processing is observed by contrasting the TRs to the remaining melodic and tonic notes of the bar (2-4). They have uniform shape within a tonic or melodic sequence which makes it possible to fit a 4-dipole model and show that there are two sources in each hemisphere--a melody source in the anterior part of Heschl's gyrus (HG) and an onset source about 10 mm posterior to it, in planum temporale (PT). The N1m to the initial note has a short latency and the same magnitude for the tonic and the melodic sequences. The melody activity is distinguished by the relative sizes of the N1m and P2m components of the TRs to notes 2-4. In the anterior source a given note elicits a much larger N1m-P2m complex with a shorter latency when it is part of a melodic sequence. This study shows how to isolate the N1m, energy-onset response in PT, and produce a clean melody response in the anterior part of auditory cortex (HG).

Cortical Representation of Afferent Bodily Signals in Borderline Personality Disorder: Neural Correlates and Relationship to Emotional Dysregulation.

IMPORTANCE: The ability to perceive and regulate one's own emotions has been tightly linked to the processing of afferent bodily signals (interoception). Thus, disturbed interoception might contribute to the core feature of emotional dysregulation in borderline personality disorder (BPD), as increased levels of depersonalization, body image disturbances, and reduced sensitivity to physical pain suggest poor body awareness in BPD. OBJECTIVE: To determine neural correlates of disturbed body awareness in BPD and its associations with emotional dysregulation and to explore improvements in body awareness with BPD symptom remission. DESIGN, SETTING, AND PARTICIPANTS: Case-control study performed at Heidelberg University Hospital, Heidelberg, Germany. Heartbeat evoked potentials (HEPs), an indicator of the cortical representation of afferent signals from the cardiovascular system, were investigated in 34 medication-free patients with BPD, 31 healthy volunteers, and 17 medication-free patients with BPD in remission. The HEPs were assessed using 5-minute resting-state electroencephalograms and parallel electrocardiograms. Core BPD symptoms, history of childhood traumatization, and psychiatric disorders were assessed by means of self-reports and structured interviews. To measure neural correlates of disturbed body awareness, high-resolution T1-weighted structural magnetic resonance imaging scans were collected and analyzed using voxel-based morphometry and region-of-interest-based approaches. The study was performed between 2012 and 2014, and data analysis was performed in 2014. MAIN OUTCOMES AND MEASURES: Mean HEP amplitudes in resting-state electroencephalograms and their correlation with self-reported emotional dysregulation, as well as with gray matter volume. RESULTS: Patients with BPD had significantly reduced mean HEP amplitudes compared with healthy volunteers (F1,61 = 11.32, P = .001), whereas the mean HEP amplitudes of patients with BDP in remission lie somewhere in between these 2 groups of participants (P > .05). The HEP amplitudes were negatively correlated with emotional dysregulation (R = -0.30, P = .01) and positively associated with gray matter volume in the left anterior insula (R = 0.53, P < .05) and the bilateral dorsal anterior cingulate cortex (R = 0.47, P < .05), 2 structures that have been identified as core regions for interoception. CONCLUSIONS AND RELEVANCE: The results indicate state-dependent deficits in the cortical processing of bodily signals in patients with BPD, which appear to be associated with core features of BPD. The analysis of patients with BPD in remission suggests an improvement in cortical representation of bodily signals with symptom remission. Results recommend the integration of techniques to strengthen bodily awareness in psychotherapeutic interventions of BPD.

Duifhuis pitch: neuromagnetic representation and auditory modeling.

When a high harmonic is removed from a cosine-phase harmonic complex, we hear a sine tone pop out of the perception; the sine tone has the pitch of the high harmonic, while the tone complex has the pitch of its fundamental frequency, f0. This phenomenon is commonly referred to as Duifhuis Pitch (DP). This paper describes, for the first time, the cortical representation of DP observed with magnetoencephalography. In experiment 1, conditions that produce the perception of a DP were observed to elicit a classic onset response in auditory cortex (P1m, N1m, P2m), and an increment in the sustained field (SF) established in response to the tone complex. Experiment 2 examined the effect of the phase spectrum of the complex tone on the DP activity: Schroeder-phase negative waves elicited a transient DP complex with a similar shape to that observed with cosine-phase waves but with much longer latencies. Following the transient DP activity, the responses of the negative and positive Schroeder-phase waves converged, and the increment in the SF slowly died away. In the absence of DP, the two Schroeder-phase conditions with low peak factors both produced larger SFs than cosine-phase waves with large peak factors. A model of the auditory periphery that includes coupling between adjacent frequency channels is used to explain the early neuromagnetic activity observed in auditory cortex.

Object recognition deficit in early- and adult-onset schizophrenia regardless of age at disease onset.

Perceptual closure is the ability of the brain to recognize a complete object based on fragmentary information and has been known to be impaired in schizophrenia. Here, the neural integrity of perceptual closure in schizophrenia with different disease onsets was evaluated by examining the generation of event-related potential (ERP) components (P100, N180, and N(cl)). ERPs were recorded from 40 patients (19 early-onset schizophrenia, "EOS" and 21 adult-onset schizophrenia, "AOS") and 40 age-matched healthy volunteers. Brain electric source analysis (BESA) was applied to localize the cerebral generators underlying perceptual closure. Patients showed an impaired generation of N(cl) and P100 components. P100 and N(cl) amplitudes were significantly reduced in both AOS and EOS (P<0.01). Moreover, N180 and N(cl) amplitudes were significantly increased with age in controls and patients (P<0.01). In the case of the N(cl), there was also a significant interaction (P<0.001) between age and group, indicating a greater age-dependent N(cl) increase in controls compared to patients. Visual information processing during perceptual closure is impaired in schizophrenia, regardless of age at disease onset. The combined influence of age and group on the amplitude of the N(cl) might support the idea of neurodevelopmental deficits in schizophrenia.

Is the effect of tinnitus on auditory steady-state response amplitude mediated by attention?

OBJECTIVES: Auditory steady-state response (ASSR) amplitude enhancement effects have been reported in tinnitus patients. As ASSR amplitude is also enhanced by attention, the effect of tinnitus on ASSR amplitude could be interpreted as an effect of attention mediated by tinnitus. As N1 attention effects are significantly larger than those on the ASSR, if the effect of tinnitus on ASSR amplitude were due to attention, there should be similar amplitude enhancement effects in tinnitus for the N1 component of the auditory-evoked response. METHODS: MEG recordings which were previously examined for the ASSR (Diesch et al., 2010a) were analyzed with respect to the N1m component. Like the ASSR previously, the N1m was analyzed in the source domain (source space projection). Stimuli were amplitude-modulated (AM) tones with one of three carrier frequencies matching the tinnitus frequency or a surrogate frequency 1½ octave above the audiometric edge frequency in controls, the audiometric edge frequency, and a frequency below the audiometric edge. Single AM-tones were presented in a single condition and superpositions of three AM-tones differing in carrier and modulation frequency in a composite condition. RESULTS: In the earlier ASSR study (Diesch et al., 2010a), the ASSR amplitude in tinnitus patients, but not in controls, was significantly larger in the (surrogate) tinnitus condition than in the edge condition. Patients showed less evidence than controls of reciprocal inhibition of component ASSR responses in the composite condition. In the present study, N1m amplitudes elicited by stimuli located at the audiometric edge and at the (surrogate) tinnitus frequency were smaller than N1m amplitudes elicited by sub-edge tones both in patients and controls. The relationship of the N1m response in the composite condition to the N1m response in the single condition indicated that reciprocal inhibition among component N1m responses was reduced in patients compared against controls. CONCLUSIONS: In the present study, no evidence was found for an N1-amplitude enhancement effect in tinnitus. Compared to controls, reciprocal inhibition is reduced in tinnitus patients. Thus, as there is no effect on N1m that could potentially be attributed to attention, it seems unlikely that the enhancement effect of tinnitus on ASSR amplitude could be accounted for in terms of attention induced by tinnitus.

Neuromagnetic representation of musical register information in human auditory cortex.

Pulse-resonance sounds like vowels or instrumental tones contain acoustic information about the physical size of the sound source (pulse rate) and body resonators (resonance scale). Previous research has revealed correlates of these variables in humans using functional neuroimaging. Here, we report two experiments that use magnetoencephalography to study the neuromagnetic representations of pulse rate and resonance scale in human auditory cortex. In Experiment 1, auditory evoked fields were recorded from nineteen subjects presented with French horn tones, the pulse rate and resonance scale of which had been manipulated independently using a mucoder. In Experiment 2, fifteen subjects listened to French horn tones which differed in resonance scale but which lacked pulse rate cues. The resulting cortical activity was evaluated by spatio-temporal source analysis. Changes in pulse rate elicited a well-defined N1m component with cortical generators located at the border between Heschl's gyrus and planum temporale. Changes in resonance scale elicited a second, independent, N1m component located in planum temporale. Our results demonstrate that resonance scale can be distinguished in its neuromagnetic representation from cortical activity related to the sound's pulse rate. Moreover, the existence of two separate components in the N1m sensitive to register information highlights the importance of this time window for the processing of frequency information in human auditory cortex.