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.

Predictive value of the General Movements Assessment and Standardized Infant NeuroDevelopmental Assessment in infants at high risk of neurodevelopmental disorders.

AIM: To compare the predictive values of the General Movements Assessment (GMA) and the Standardized Infant NeuroDevelopmental Assessment (SINDA) neurological scale for atypical neurodevelopmental outcome in 3-month-old at-risk infants. METHOD: A total of 109 infants (gestational age 30 weeks; range: 24-41; 52 males) attending a non-academic outpatient clinic were assessed with the GMA and the SINDA at 3 (2-4) months corrected age. The GMA pays attention to the complexity of general movements and presence of fidgety movements. Atypical neurodevelopmental outcome at 24 months corrected age (and older) implied cerebral palsy (CP) or a Bayley Mental Development Index or Bayley Psychomotor Development Index lower than 70. RESULTS: At 24 months corrected (and older) age, 16 children had an atypical outcome, including 14 children with CP. Regarding markedly reduced general movement complexity in combination with absent or sporadic fidgety movements, the GMA predicted an atypical outcome with specificity, positive, and negative predictive values greater than 0.900, and sensitivity of 0.687 (95% confidence interval [CI] = 0.460-0.915). SINDA predicted an atypical outcome with sensitivity, specificity, and negative predictive value greater than 0.900 and a positive predictive value of 0.652 (95% CI = 0.457-0.847). Regarding absent fidgety movements only or markedly reduced general movement complexity, the GMA predicted the outcome less well than both general movement criteria. INTERPRETATION: The SINDA and GMA both predict neurodevelopmental outcome well, but SINDA is easier to learn than the GMA; being a non-video-based assessment, it allows caregiver feedback during the consultation whereas the GMA usually does not.

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

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

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.

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.

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.

Standardized Infant NeuroDevelopmental Assessment developmental and socio-emotional scales: reliability and predictive value in an at-risk population.

AIM: To assess the reliability and predictive validity of the developmental and socio-emotional scales of the Standardized Infant NeuroDevelopmental Assessment (SINDA). METHOD: To assess reliability, two sets of three assessors forming eight assessor-pairs independently rated the developmental and socio-emotional scales of 60 infants. To evaluate predictive validity, 223 infants (gestational age 30wks [range 23-41wks]; 117 males, 106 females) attending a non-academic outpatient clinic were assessed by different assessors with SINDA's neurological, developmental, and socio-emotional scales. Atypical neurodevelopmental outcome at a corrected age of 24 months or older implied a Bayley Mental or Psychomotor Developmental Index score of less than 70 or neurological disorder (including cerebral palsy). Behavioural and emotional disorders were classified according to the International Classification of Diseases, 10th Revision. Predictive values were calculated from SINDA (2-12mo corrected age, median 7mo) and typical versus atypical outcome, and for intellectual disability only (Mental Developmental Index <70). RESULTS: Assessors highly agreed on the developmental and socio-emotional assessments (developmental scores: Spearman's rank correlation coefficient ρ=0.972; single socio-emotional behaviour items: Cohen's κ=0.783-0.896). At 24 months or older, 65 children had atypical outcome. Atypical neurological scores predicted atypical outcome (sensitivity 83%, specificity 96%); atypical developmental scores predicted intellectual disability (sensitivity 77%, specificity 92%). Atypical emotionality and atypical self-regulation were associated with behavioural and emotional disorders. INTERPRETATION: SINDA's three scales are reliable, and have a satisfactory predictive validity for atypical developmental outcome at 24 months or older in a non-academic outpatient setting. SINDA's developmental scale has promising predictive validity for intellectual disability. SINDA's socio-emotional scale is a tool for caregiver counselling. WHAT THIS PAPER ADDS: Standardized Infant NeuroDevelopmental Assessment (SINDA)'s developmental and socio-emotional scales have excellent interrater reliability. Replication of the satisfactory validity of SINDA's neurological scale for atypical outcome.

Reliability and predictive validity of the Standardized Infant NeuroDevelopmental Assessment neurological scale.

AIM: To assess reliability and predictive validity of the neurological scale of the Standardized Infant NeuroDevelopmental Assessment (SINDA), a recently developed assessment for infants aged 6 weeks to 12 months. METHOD: To assess reliability, three assessors independently rated video-recorded neurological assessments of 24 infants twice. Item difficulty and discrimination were determined. To evaluate predictive validity, 181 infants (median gestational age 30wks [range 22-41wks]; 92 males, 89 females) attending a non-academic outpatient clinic were assessed with SINDA's neurological scale (28 dichotomized items). Atypical neurodevelopmental outcome at 24 months or older corrected age implied a Bayley Mental Developmental Index or Psychomotor Developmental Index lower than 70 or a diagnosis of cerebral palsy (CP). Predictive values were calculated from SINDA (2-12mo corrected age, median 3mo) and typical versus atypical outcome. RESULTS: Intraclass correlation coefficients of intrarater and interrater agreement of the neurological score varied between 0.923 and 0.965. Item difficulty and discrimination were satisfactory. At 24 months or older, 56 children (31%) had an atypical outcome (29 had CP). Atypical neurological scores (below 25th centile, ≤21) predicted atypical outcome and CP with sensitivities of 89% and 100%, and specificities of 94% and 81% respectively. INTERPRETATION: SINDA's neurological scale is reliable and in a non-academic outpatient setting has a satisfactory predictive validity for atypical developmental outcome, including CP, at 24 months or older. WHAT THIS PAPER ADDS: The Standardized Infant NeuroDevelopmental Assessment's neurological scale has a good to excellent reliability. The scale has promising predictive validity for cerebral palsy. The scale has promising predictive validity for other types of atypical developmental outcome.

CONFIABILIDAD Y VALIDEZ PREDICTIVA DE LA ESCALA NEUROLÓGICA DE LA EVALUACIÓN DEL NEURODESARROLLO INFANTIL ESTANDARIZADA: OBJETIVO: Evaluar la confiabilidad y la validez predictiva de la escala neurológica de la Evaluación del Neurodesarrollo Infantil Estandarizada (SINDA), una evaluación desarrollada recientemente para bebés de 6 semanas a 12 meses. MÉTODO: Para evaluar la confiabilidad, tres evaluadores evaluaron dos veces, de forma independiente, las evaluaciones neurológicas grabadas en videos de 24 recién nacidos. Se determinaron la dificultad del ítem y la discriminación. Para evaluar la validez predictiva, se evaluaron 181 neonatos (mediana de edad gestacional de 30 semanas [rango 22-41 semanas], 92 varones, 89 mujeres) que asisten a una clínica ambulatoria no académica con la escala neurológica de SINDA (28 ítems dicotomizados). El resultado del desarrollo neurológico atípico a los 24 meses o mayor edad corregida implicaba un índice de desarrollo mental o índice de desarrollo psicomotor Bayley inferior a 70 o un diagnóstico de parálisis cerebral (PC). Los valores predictivos se calcularon a partir de SINDA (edad corregida 2-12mo, mediana 3meses) y resultado típico versus a atípico. RESULTADOS: Los coeficientes de correlación intraclase de la concordancia intra e inter codificador del puntaje neurológico variaron entre 0.923 y 0.965. La dificultad del item y la discriminación fueron satisfactorias. A los 24 meses o más, 56 niños (31%) tuvieron un resultado atípico (29 tuvieron PC). Las puntuaciones neurológicas atípicas (por debajo del percentil 25, ≤21) predijeron un resultado atípico y PC con sensibilidades del 89% y del 100%, y especificidades del 94% y del 81%, respectivamente. INTERPRETACIÓN: La escala neurológica de SINDA es confiable y en un entorno ambulatorio no académico tiene una validez predictiva satisfactoria para la detección del desarrollo atípico, incluido la PC, a los 24 meses o más.

CONFIABILIDADE E VALIDADE PREDITIVA DA ESCALA NEUROLÓGICA DE AVALIAÇÃO PADRONIZADA NEURODESENVOLVIMENTAL INFANTIL: OBJETIVO: Avaliar a confiabilidade e validade preditiva da escala neurológica Avaliação Padronizada Neurodesenvolvimental Infantil (SINDA), uma avaliação desenvolvida recentemente para lactentes de 6 semanas a 12 meses de idade. MÉTODO: Para avaliar a confiabilidade, por duas vezes três avaliadores pontuaram independentemente avaliações neurológicas de 24 lactentes registradas em vídeo. Para avaliar a validade preditiva, 181 lactentes (idade gestacional mediana de 30 semanas[variação de 22 a 41 semanas]); 92 do sexo masculino; 89 do sexo feminino) que frequentavam uma clínica não acadêmica foram avaliados com a escala neurológica da SINDA (28 itens dicotomizados). O neurodesenvolvimento atípico na idade de 24 meses de idade corrigida ou mais tarde foi determinado por índice desenvolvimental mental da Bayley ou Item desenvolvimental psicomotor menor do que 70 ou diagnóstico de paralisia cerebral (PC). Os valores preditivos foram calculados para o SINDA (2-12 meses de idade corrigida, mediana de 3 m) e resultado típico versus atípico. RESULTADOS: Os coeficientes de correlação intraclasse de concordância intra ou inter-examinadores do escore neurológico variaram de 0,923 a 0,965. A dificuldade e discriminação do item foram satisfatórias. Aos 24 meses de idade ou mais, 56 crianças (31%) tiveram resultado atípico (29 tinham PC). Os escores neurológicos atípicos (abaixo do percentil 25, ≤21) foram preditivos de resultado atípico e PC com sensibilidades de 89% e 100%, e especificidades de 94% e 81%, respectivamente. INTERPRETAÇÃO: A escala neurológica SINDA é confiável e em um ambiente não acadêmico tem validade preditiva satisfatória para resultado atípico do desenvolvimento, incluindo PC, aos 24 meses de idade ou mais.

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).

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.

Rapid Induction of COOLing in Stroke Patients (iCOOL1): a randomised pilot study comparing cold infusions with nasopharyngeal cooling.

INTRODUCTION: Induction methods for therapeutic cooling are under investigated. We compared the effectiveness and safety of cold infusions (CI) and nasopharyngeal cooling (NPC) for cooling induction in stroke patients. METHODS: A prospective, open-label, randomised (1:1), single-centre pilot trial with partially blinded safety endpoint assessment was conducted at the neurointensive care unit of Heidelberg University. Intubated stroke patients with an indication for therapeutic cooling and an intracranial pressure (ICP)/temperature brain probe were randomly assigned to CI (4°C, 2L at 4L/h) or NPC (60L/min for 1 h). Previous data suggested a maximum decrease of tympanic temperature for CI (2.1L within 35 min) after 52 min. Therefore the study period was 1 hour (15 min subperiods I-IV). The brain temperature course was the primary endpoint. Secondary measures included continuous monitoring of neurovital parameters and extracerebral temperatures. Statistical analysis based on repeated-measures analysis of variance. RESULTS: Of 221 patients screened, 20 were randomized within 5 months. Infusion time of 2L CI was 33 ± 4 min in 10 patients and 10 patients received NPC for 60 min. During active treatment (first 30 min), brain temperature decreased faster with CI than during NPC (I: -0.31 ± 0.2 versus -0.12 ± 0.1°C, P = 0.008; II: -1.0 ± 0.3 versus -0.49 ± 0.3°C, P = 0.001). In the CI-group, after the infusion was finished, the intervention no longer decreased brain temperature, which increased after 3.5 ± 3.3 min. Oesophageal temperature correlated best with brain temperature during CI and NPC. Tympanic temperature reacted similarly to relative changes of brain temperature during CI, but absolute values slightly differed. CI provoked three severe adverse events during subperiods II-IV (two systolic arterial pressure (SAP), one shivering) compared with four in the NPC-group, all during subperiod I (three SAP, one ICP). Classified as possibly intervention-related, two cases of ventilator failure occurred during NPC. CONCLUSIONS: In intubated stroke patients, brain cooling is faster during CI than during NPC. Importantly, contrary to previous expectations, brain cooling stopped soon after CI cessation. Oesophageal but neither bladder nor rectal temperature is suited as surrogate for brain temperature during CI and NPC. Several severe adverse events in CI and in NPC demand further studying of safety. TRIAL REGISTRATION: ClinicalTrials.gov NCT01573117. Registered 31 March 2012.

Safety evaluation of nasopharyngeal cooling (RhinoChill®) in stroke patients: an observational study.

INTRODUCTION: New technologies for therapeutic cooling have become available. The objective of our study was to investigate the safety of nasopharyngeal cooling with the RhinoChill(®) device in stroke patients, focusing on systemic and neurovital parameters. METHODS: In this prospective observational study, consecutive patients with severe ischemic or hemorrhagic stroke who underwent intracranial pressure (ICP) and brain temperature monitoring have been enrolled. Ten patients who were treated with the RhinoChill(®) device were analyzed. Brain and bladder temperature and systemic and neurovital parameters were monitored continuously. Additional evaluations of safety included bleeding complications and otolaryngological examinations. RESULTS: Baseline brain temperature of 36.7 °C (SD 0.9) decreased by an average of 1.21 °C (SD 0.46) within 1 h, the effect of brain temperature decrease ranged from a maximum of 2 °C (patients 3 and 7) to a minimum of 0.6 °C (patient 4). Within the first several minutes after initiating RhinoChill(®) treatment, 3 of 10 patients experienced an increase in systolic arterial pressure by 30, 30, and 53 mmHg, respectively. Heart rate rose as well (mean 3 bpm, SD 2.9). ICP and oxygen saturation were unaffected by the treatment. We observed 1 bleeding complication in the control CT scan of patient 10. Rhinoscopical findings 3 days after nasopharyngeal cooling and at the follow-up (>6 months) and a 16-item smell test were normal. CONCLUSION: The RhinoChill(®) system cools the brain efficiently. However, steep increases in blood pressure raise serious concerns regarding the safety of its use in stroke patients.

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.

Induction of cooling with a passive head and neck cooling device: effects on brain temperature after stroke.

BACKGROUND AND PURPOSE: Therapeutic hypothermia improves clinical outcome after cardiac arrest and appears beneficial in other cerebrovascular diseases. We conducted this study to investigate the relationship between surface head/neck cooling and brain temperature. METHODS: Prospective observational study enrolling consecutive patients with severe ischemic or hemorrhagic stroke undergoing intracranial pressure (ICP) and brain temperature monitoring. Arterial pressure, ICP, cerebral perfusion pressure, heart rate, brain, tympanic, and bladder temperature were continuously registered. Fifty-one applications of the Sovika cooling device were analyzed in 11 individual patients. RESULTS: Sovika application led to a significant decrease of brain temperature compared with baseline with a maximum of -0.36°C (SD, 0.22) after 49 minutes (SD, 17). During cooling, dynamics of brain temperature differed significantly from bladder (-0.25°C [SD, 0.15] after 48 minutes [SD, 19]) and tympanic temperature (-1.79°C [SD, 1.19] after 37 minutes [SD, 16]). Treatment led to an increase in systolic arterial pressure by >20 mm Hg in 14 applications (n=7 patients) resulting in severe hypertension (>180 mm Hg) in 4 applications (n=3). ICP increased by >10 mm Hg in 7 applications (n=3), led to ICP crisis >20 mm Hg in 6 applications (n=3), and a drop of cerebral perfusion pressure <50 mm Hg in 1 application. CONCLUSIONS: Although the decrease of brain temperature after Sovika cooling device application was statistically significant, we doubt clinical relevance of this rather limited effect (-0.36°C). Moreover, the transient increases of blood pressure and ICP warrant caution.

Cortical activity associated with the perception of temporal asymmetry in ramped and damped noises.

Human listeners are very sensitive to the asymmetry of time-reversed pairs of ramped and damped sounds. When the carrier is noise, the hiss -component of the perception is stronger in ramped sounds and the drumming component is stronger in damped sounds (Akeroyd and Patterson 1995). In the current study, a paired comparison technique was used to establish the relative "hissiness" of these noises, and the ratings were correlated with (a) components of the auditory evoked field (AEF) produced by these noises and (b) the magnitude of a hissiness feature derived from a model of the internal auditory images produced by these noises (Irino and Patterson 1998). An earlier AEF report indicated that the peak magnitude of the transient N100m response mirrors the perceived salience of the tonal perception (Rupp et al. 2005). The AEFs of 14 subjects were recorded in response to damped/ramped noises with half-lives between 1 and 64 ms and repetition rates between 12.5 and 100 ms. Spatio-temporal source analysis was used to fit the P50m, the P200m, and the sustained field (SF). These noise stimuli did not produce a reliable N100m. The hissiness feature from the auditory model was extracted from a time-averaged sequence of summary auditory images as in Patterson and Irino (1998). The results show that the perceptual measure of hissiness is highly correlated with the hissiness feature from the summary auditory image, and both are highly correlated with the magnitude of the transient P200m. There is a significant but weaker correlation with the SF and a nonsignificant correlation with the P50m. The results suggest that regularity in the carrier effects branching at an early stage of auditory processing with tonal and noisy sounds following separate spatio-temporal routes through the system.

Reduced phase locking to slow amplitude modulation in adults with dyslexia: an MEG study.

Perception of speech at multiple temporal scales is important for the efficient extraction of meaningful phonological elements. Individuals with developmental dyslexia have difficulty in the accurate neural representation of phonological aspects of speech, across languages. Recently, it was proposed that these difficulties might arise in part because of impaired phase locking to the slower modulations in the speech signal (<10 Hz), which would affect syllabic parsing and segmentation of the speech stream (the "temporal sampling" hypothesis, Goswami, 2011). Here we measured MEG responses to different rates of amplitude modulated white noise in adults with and without dyslexia. In line with the temporal sampling hypothesis, different patterns of phase locking to amplitude modulation at the delta rate of 2 Hz were found when comparing participants with dyslexia to typically-reading participants. Typical readers exhibited better phase locking to slow modulations in right auditory cortex, whereas adults with dyslexia showed more bilateral phase locking. The results suggest that oscillatory phase locking mechanisms for slower temporal modulations are atypical in developmental dyslexia.

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.

Simultaneous EEG/MEG yields complementary information of nociceptive evoked responses.

OBJECTIVE: Nociceptive stimuli have been studied either by dipolar modelling using electroencephalography (EEG) or magnetoencephalography (MEG), but rarely using both techniques simultaneously. This study aims to investigate the spatiotemporal representation of cortical activity in response to non-nociceptive (tactile) and nociceptive (laser) stimuli using parallel EEG-MEG recordings. METHODS: We performed simultaneous EEG and MEG recordings in 12 healthy subjects by applying pneumatic tactile and nociceptive laser stimuli on the right- and left-hand dorsum. We analyzed brain responses for both modalities and methods by means of global field power (GFP), and dipole source locations, strengths and orientations calculated in the depth to identify similarities and differences. RESULTS: Prominent GFP peaks were similar in EEG and MEG for tactile responses but different for nociceptive responses. CONCLUSIONS: Methodically, MEG was superior to EEG in detecting the earliest nociceptive laser-evoked components with earlier latency in primary- and secondary somatosensory cortices, whereas EEG was superior to MEG in detecting late nociceptive components due to radially oriented deeper cortical activity. SIGNIFICANCE: EEG and MEG revealed in part differential nociceptive waveform patterns, peak latencies, and source orientations, making combined recordings favorable to examine pain-related activity as a whole in high temporal-spatial resolution.