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1.
Vestn Otorinolaringol ; 85(5): 18-23, 2020.
Artigo em Russo | MEDLINE | ID: mdl-33140928

RESUMO

Studies of the recent years are devoted to using the auditory steady-state responses (ASSR) as an evaluation method of amplification outcomes. In this case stimulation is performed in the sound field via loudspeaker with a hearing aid (HA) in patient's ear. GOAL: Estimation the optimal stimulation parameters of ASSR in free field, which provide maximum correlation with behavioral thresholds. MATERIALS AND METHODS: 26 subjects were included in the study: 10 with normal hearing (4 adults and 6 children) and 16 children (1-16 years old) with sensorineural hearing loss (SNHL). Aided and unaided ASSR thresholds were compared with corresponding behavioral thresholds (BT). All recordings were conducted in free sound field. We used mono-frequency stimulation method at 500-4000 Hz career frequencies. Modulation frequency was set as 40 Hz. Types of stimuli modulation: AM/FM modulation, exponential modulation (AM2), three carrier frequencies and modulated Chirp-tone (Chirp). RESULTS: In normal hearing subjects the difference between ASSR and BT varied from 0 dB to 35 dB, and the significant correlation between them was observed (p<0.05). The maximum difference between ASSR and BT in children with SNHL was at 500 Hz (15.6±4.3 dB), minimum - at 2 and 4 kHz (8±2.9 dB and 7±3 dB respectively). In aided condition maximum difference was detected at 500 Hz (10.2±3.8 dB), minimum - at 1 and 2 kHz (7.8±2.8 and 7.3±3.1 dB respectively). We got significantly less difference between ASSR and BT in all test conditions using following types of stimuli: at 500 Hz and 1000 Hz - AM2 (p<0.01); at 2 and 4 kHz - Chirp (p<0.05 and p<0.01 respectively). Thereby, free field ASSR might be used as an objective method of evaluation the amplification outcomes in children with SNHL.


Assuntos
Auxiliares de Audição , Perda Auditiva Neurossensorial , Estimulação Acústica , Adolescente , Adulto , Limiar Auditivo , Criança , Pré-Escolar , Perda Auditiva Neurossensorial/diagnóstico , Testes Auditivos , Humanos , Lactente
3.
Annu Int Conf IEEE Eng Med Biol Soc ; 2020: 5228-5231, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-33019163

RESUMO

This paper presents a smartphone based system for presenting light and sound stimulation to a user for neuromodulation experiments. A smartphone platform was used to increase ease of use and enable out-of-the-clinic experiments. The created Android app provides both visual and auditory entrainment stimuli, along with a real-time extraction of ongoing electroencephalogram (EEG) phase using a Phase Locked Loop (PLL) for enabling closed loop simulations. Both visual and auditory stimulation is provided accurately in the 1-20 Hz range using the smartphone class hardware. Test results for both gave R squared fit values of 1 between a fitted line and the measured stimulation frequencies. Data from 13 subjects showed the PLL could track EEG phase in the slow oscillation band with an error of 14.83±38.47°, with an average of 0.04±0.20 ms processing overhead per sample.


Assuntos
Smartphone , Estimulação Acústica , Eletroencefalografia , Som
4.
Annu Int Conf IEEE Eng Med Biol Soc ; 2020: 3877-3880, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-33018847

RESUMO

Ultrasound can be clearly perceived by bone-conduction, and this "bone-conducted ultrasound (BCU)" can transmit speech information by using amplitude modulation (AM). Further, BCU can be perceived not only on the head but also on the distal parts of the body like the neck, trunk and arms. This "distantly-presented BCU" can be applied to the novel interface that can transmit sound information selectively to specific users who touches the vibrator. However, the ability to transmit sound information of distantly-presented BCU is unclear. First, to assess frequency discrimination ability, difference limens for frequency (DLFs) of the distantly-presented AM-BCU were measured with/without a low-pass masking noise that masked the self-demodulated components generated by the nonlinearity of biological tissues. DLFs comparable to that of air-conducted sounds were observed, whereas DLFs significantly increased above 1 kHz under the masking condition. These results suggest that practical frequency discrimination ability can be obtained even when BCUs were presented to distal body parts. Additionally, it is indicated that the demodulated components may contribute to transmitting frequency information above 1 kHz. Second, monosyllable articulation and word intelligibility tests were conducted in Japanese. The intelligibility and articulation at the neck were 55% and 38% respectively, whereas they decreased as the stimulus placement gets farther from the head. The results suggest the distantly-presented BCU device can be applied to transmission of speech information.


Assuntos
Condução Óssea , Fala , Estimulação Acústica , Limiar Diferencial , Ultrassonografia
5.
Annu Int Conf IEEE Eng Med Biol Soc ; 2020: 3881-3884, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-33018848

RESUMO

Bone-conducted ultrasound (BCU) is perceived even by the profoundly sensorineural deaf and has been applied to the development of a novel hearing aid. In the BCU hearing aid, the vibrator is pressed onto the mastoid process of the temporal bone (the osseous bulge behind the ear). However, BCU can be heard on distal parts of the body; e.g., the muscle of the neck, the clavicle and the upper limbs. Some studies have been carried out to develop other BCU hearing devices using this "distant presentation". However, the possibility of the localization of distantly-presented BCU has not been verified. In this study, we investigated whether listeners could use the interaural time differences (ITDs) and intensity differences (IIDs) as cues for lateralization (left/right discrimination) of distantly-presented BCU. The results showed that lateralization based on ITDs and IIDs is possible to some extent, even for the distant presentation, whereas lateralization become difficult as the stimulus placement gets further from the head. Lateralization based on IIDs was more accurate than that based on ITDs. IIDs seem to give more effective cues than ITDs in the lateralization of BCU.


Assuntos
Condução Óssea , Auxiliares de Audição , Estimulação Acústica , Audição , Testes Auditivos
6.
Annu Int Conf IEEE Eng Med Biol Soc ; 2020: 3260-3263, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-33018700

RESUMO

Auditory stream segregation is an important function of the auditory system, and the extent to which this function works has a major impact on listener's ability to recognize auditory objects in complex listening environments. However, cochlear implant (CI) listeners are poorly equipped for this challenge, mainly owing to the impoverished sensory information available via their implants. The purpose of this study was to examine two factors, i.e., frequency separation and time interval, affecting the auditory stream segregation in vocoder simulations simulating CI speech processing based on an event-related potential (ERP) experiment. The pure-tone stimuli were processed by a vocoding process, and presented to normal-hearing listeners in an ERP experiment. Experimental results showed that a large frequency separation or a short time interval led to a larger mismatch negativity (MMN) response. The MMN results in this work suggested that the degree of auditory stream segregation was affected by frequency separation and time interval, and MMN could serve as a potential index for future ERP studies on auditory stream segregation in CI users.


Assuntos
Implante Coclear , Implantes Cocleares , Estimulação Acústica , Percepção Auditiva , Potenciais Evocados , Humanos
7.
Annu Int Conf IEEE Eng Med Biol Soc ; 2020: 5921-5924, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-33019322

RESUMO

Over the last decade Vibro-Acoustic Therapy (VAT) was used for several clinical applications. This paper investigates the use of AcusticA®, an innovative VAT solution represented by a wooden chaise longue that follows the construction principles of a "musical instrument that stimulates the whole body" in relation to the sound frequencies produced by the music tracks. Ten healthy young subjects were enrolled for this study. Wearable sensors were used to monitor the human physiological response during the VAT session but also during a traditional acoustic therapy (AT) to highlight similarity and differences of those stimulations. Signals from heart activity, brain activity and electrodermal activity were analyzed to investigate the response during the non-stimulated and the stimulated phases. Additionally, two supervised classification algorithms were used to investigate whether the extracted instances could be grouped into two different groups. The results identify a trend of the attention and meditation features extracted from brain activity, which pointed out the relax efficacy of the VAT.Clinical Relevance - There are not significant differences (p<0.05) in the physiological response between the VAT and the AT stimulation, but during the VAT the alpha coefficients were significant different during the stimulated phase. Finally, the classification algorithms were able to classify the groups with an accuracy equal to 100% in the best case.


Assuntos
Música , Estimulação Acústica , Acústica , Algoritmos , Humanos , Monitorização Fisiológica
8.
Artigo em Inglês | MEDLINE | ID: mdl-33017932

RESUMO

This study analyzed the selective attention processing related to cognitive load on simultaneous interpretation (SI). We tested simultaneous interpreter's brain function using EEG signals and calculated inter-trial coherence (ITC) extracted by the 40-Hz auditory steady-state response (ASSR). In this experiment, we set two conditions as Japanese-English translation and Japanese shadowing cognition. We also compared two subject groups: S rank with more than 15 years of SI experience (n=7) and C rank with less than one year experience (n=15). As a result, the ITCs for S rank in interpreting conditions were more significantly increased than C rank in the shadowing conditions (ITC: p<0.001). Our results demonstrate that 40-Hz ASSR might be a good indicator of selective attention and cognitive load during SI in ecologically valid environmental conditions. It can also be used to detect attention and cognitive control dysfunction in ADHD or schizophrenia.


Assuntos
Eletroencefalografia , Potenciais Evocados Auditivos , Estimulação Acústica , Atenção , Sincronização de Fases em Eletroencefalografia
9.
Annu Int Conf IEEE Eng Med Biol Soc ; 2020: 200-203, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-33017964

RESUMO

A central question in neuroscience is how the brain processes real-world sensory input. For decades most classical studies focus on carefully controlled artificial stimuli. More recently researchers started to investigate brain activity under more realistic conditions. The main challenge in this setting is the analysis of the complex signals obtained with modern neuroimaging methods in response to natural stimuli. Inter-subject correlations (ISCs) have become a popular paradigm to study brain activation under natural stimulation. The underlying assumption of this analysis is that features of natural stimuli that are perceived and processed by all subjects exposed to the same stimulus result in similar activation patterns across subjects. Higher degrees of realism in stimulation, for instance audiovisual stimulation is more realistic than auditory stimulation, is usually associated with higher ISC values. We can confirm these findings in experiments in which we present a movie stimulus with varying degrees of realism. Extending previous findings we highlight the importance of artifact removal when evaluating ISCs and show that the impact of realism in natural stimulation on ISCs is frequency-dependent. A major challenge associated with this type of analysis is that it can be difficult to attribute the correlation strength to the physiological process of interest. In this study, we demonstrate that ISCs of neural activation as measured by electroencephalogram (EEG) recordings are influenced significantly by non-neural artifacts such as occulograms. Our findings highlight the potential of inter-subject correlations as a biomarker for immersion: If more realistic stimuli consistently lead to higher inter-subject correlations, then inter-subject correlations can serve as a quantitative marker for how engaging audiovisual stimuli are perceived.Clinical relevance- Future research will evaluate if correlation levels among subjects, who are exposed to natural stimuli are affected by neurological diseases such as Alzheimers, Parkinsons, and Schizophrenia among others.


Assuntos
Artefatos , Eletroencefalografia , Estimulação Acústica , Encéfalo , Neuroimagem
10.
Annu Int Conf IEEE Eng Med Biol Soc ; 2020: 960-963, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-33018144

RESUMO

A good understanding of the origin of stimulus-frequency otoacoustic emission (SFOAE) fine structure in human ears and its probe level-dependency has potential clinical significance. In this study, we develop a two-component additive model, with total SFOAE unmixed into short- and long-latency components (or reflections) using time windowing method, to investigate the origin of SFOAE fine structure in humans from 40 to 70 dB SPL. The two-component additive model predicts that a spectral notch seen in the amplitude fine structure is produced when short- and long-latency components have opposite phases and comparable magnitudes. And the depth of spectral notch is significantly correlated with the amplitude difference between the two separated components, as well as their degree of opposite phase. Our independent evidence for components contributing to SFOAE fine structure suggests that amplitude, phase and delay fine structure in the human SFOAEs are a construct of the complex addition of two or more internal reflections with different phase slops in the cochlea.


Assuntos
Cóclea , Emissões Otoacústicas Espontâneas , Estimulação Acústica , Humanos
11.
Annu Int Conf IEEE Eng Med Biol Soc ; 2020: 2889-2892, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-33018610

RESUMO

Understanding the fundamental roles of brainstem function resulting in proper motor control is critical to motor-rehabilitation after brain injuries. In particular, vestibular and reticular formation nuclei are thought to be associated with spasticity in chronic stroke patients. We used two kinds of stimuli in 10 healthy subjects to activate these nuclei while collecting high-resolution (1.5-mm) fMRI across the majority of brainstem. Optokinetic stimuli evoked illusory self-motion to activate the vestibular nuclei. Acoustic-startle stimuli were sets of loud tones designed to activate of the reticular formation. We summarized the response represented in a form of activation volume, mean percent signal change, and the phase delay (time lag) following the stimulus. We observed patterns of significant activations in the brainstem but did not find significant differences between the stimulus. We conclude that more sensitive measurement techniques are needed to reliably detect vestibular and reticular formation nuclei responses.


Assuntos
Formação Reticular , Núcleos Vestibulares , Estimulação Acústica , Acústica , Humanos , Imagem por Ressonância Magnética
12.
Annu Int Conf IEEE Eng Med Biol Soc ; 2020: 3505-3508, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-33018759

RESUMO

The process of decoding the auditory brain for an acoustic stimulus involves finding the relationship between the audio input and the brain activity measured in terms of Electroencephalography (EEG) recordings. Prior methods focus on linear analysis methods like Canonical Correlation Analysis (CCA) to establish a relationship. In this paper, we present a deep learning framework that is learned to maximize correlation. For dealing with high levels of noise in EEG data, we employ regularization techniques and experiment with various model architectures. With a paired dataset of audio envelope and EEG, we perform several experiments with deep correlation analysis using forward and backward correlation models. In these experiments, we show that regularized deep CCA is consistently able to outperform the linear models in terms of providing improved correlation (up to 9% absolute improvement in Pearson correlation which is statistically significant). We present an analysis that highlights the benefits of using dropouts for neural network regularization in the deep CCA model.Clinical relevance - The proposed method helps to decode human auditory attention. In the case of overlapping speech from two speakers, decoding the auditory attention provides information about how well the sources are separated in the brain and which of the sources is attended. This can impact cochlear implants that use EEG for decoding attention as well as in development of BCI applications. The correlation method proposed in this work can also be extended to other modalities like visual stimuli.


Assuntos
Encéfalo , Eletroencefalografia , Estimulação Acústica , Atenção , Humanos , Ruído
13.
Nat Commun ; 11(1): 5440, 2020 10 28.
Artigo em Inglês | MEDLINE | ID: mdl-33116148

RESUMO

Despite recent progress in understanding multisensory decision-making, a conclusive mechanistic account of how the brain translates the relevant evidence into a decision is lacking. Specifically, it remains unclear whether perceptual improvements during rapid multisensory decisions are best explained by sensory (i.e., 'Early') processing benefits or post-sensory (i.e., 'Late') changes in decision dynamics. Here, we employ a well-established visual object categorisation task in which early sensory and post-sensory decision evidence can be dissociated using multivariate pattern analysis of the electroencephalogram (EEG). We capitalize on these distinct neural components to identify when and how complementary auditory information influences the encoding of decision-relevant visual evidence in a multisensory context. We show that it is primarily the post-sensory, rather than the early sensory, EEG component amplitudes that are being amplified during rapid audiovisual decision-making. Using a neurally informed drift diffusion model we demonstrate that a multisensory behavioral improvement in accuracy arises from an enhanced quality of the relevant decision evidence, as captured by the post-sensory EEG component, consistent with the emergence of multisensory evidence in higher-order brain areas.


Assuntos
Percepção Auditiva/fisiologia , Tomada de Decisões/fisiologia , Percepção Visual/fisiologia , Estimulação Acústica , Adolescente , Adulto , Comportamento de Escolha/fisiologia , Eletroencefalografia/estatística & dados numéricos , Feminino , Humanos , Masculino , Modelos Neurológicos , Modelos Psicológicos , Análise Multivariada , Estimulação Luminosa , Adulto Jovem
14.
Nat Commun ; 11(1): 5240, 2020 10 16.
Artigo em Inglês | MEDLINE | ID: mdl-33067457

RESUMO

Spoken language, both perception and production, is thought to be facilitated by an ensemble of predictive mechanisms. We obtain intracranial recordings in 37 patients using depth probes implanted along the anteroposterior extent of the supratemporal plane during rhythm listening, speech perception, and speech production. These reveal two predictive mechanisms in early auditory cortex with distinct anatomical and functional characteristics. The first, localized to bilateral Heschl's gyri and indexed by low-frequency phase, predicts the timing of acoustic events. The second, localized to planum temporale only in language-dominant cortex and indexed by high-gamma power, shows a transient response to acoustic stimuli that is uniquely suppressed during speech production. Chronometric stimulation of Heschl's gyrus selectively disrupts speech perception, while stimulation of planum temporale selectively disrupts speech production. This work illuminates the fundamental acoustic infrastructure-both architecture and function-for spoken language, grounding cognitive models of speech perception and production in human neurobiology.


Assuntos
Córtex Auditivo/fisiopatologia , Epilepsia/fisiopatologia , Estimulação Acústica , Adulto , Córtex Auditivo/diagnóstico por imagem , Mapeamento Encefálico , Epilepsia/diagnóstico por imagem , Epilepsia/psicologia , Feminino , Humanos , Idioma , Imagem por Ressonância Magnética , Masculino , Fala , Percepção da Fala , Adulto Jovem
15.
Nat Commun ; 11(1): 4361, 2020 08 31.
Artigo em Inglês | MEDLINE | ID: mdl-32868773

RESUMO

The sensory responses of cortical neuronal populations following training have been extensively studied. However, the spike firing properties of individual cortical neurons following training remain unknown. Here, we have combined two-photon Ca2+ imaging and single-cell electrophysiology in awake behaving mice following auditory associative training. We find a sparse set (~5%) of layer 2/3 neurons in the primary auditory cortex, each of which reliably exhibits high-rate prolonged burst firing responses to the trained sound. Such bursts are largely absent in the auditory cortex of untrained mice. Strikingly, in mice trained with different multitone chords, we discover distinct subsets of neurons that exhibit bursting responses specifically to a chord but neither to any constituent tone nor to the other chord. Thus, our results demonstrate an integrated representation of learned complex sounds in a small subset of cortical neurons.


Assuntos
Córtex Auditivo/fisiologia , Percepção Auditiva/fisiologia , Neurônios/fisiologia , Estimulação Acústica/métodos , Córtex Auditivo/citologia , Sinalização do Cálcio , Eletrofisiologia/métodos , Aprendizagem/fisiologia , Microscopia de Fluorescência por Excitação Multifotônica/métodos , Neurônios/metabolismo , Análise de Célula Única/métodos
16.
Sci Data ; 7(1): 288, 2020 09 08.
Artigo em Inglês | MEDLINE | ID: mdl-32901008

RESUMO

We present high-density EEG datasets of auditory steady-state responses (ASSRs) recorded from the cortex of freely moving mice with or without optogenetic stimulation of basal forebrain parvalbumin (BF-PV) neurons, known as a subcortical hub circuit for the global workspace. The dataset of ASSRs without BF-PV stimulation (dataset 1) contains raw 36-channel EEG epochs of ASSRs elicited by 10, 20, 30, 40, and 50 Hz click trains and time stamps of stimulations. The dataset of ASSRs with BF-PV stimulation (dataset 2) contains raw 36-channel EEG epochs of 40-Hz ASSRs during BF-PV stimulation with latencies of 0, 6.25, 12.5, and 18.75 ms and time stamps of stimulations. We provide the datasets and step-by-step tutorial analysis scripts written in Python, allowing for descriptions of the event-related potentials, spectrograms, and the topography of power. We complement this experimental dataset with simulation results using a time-dependent perturbation on coupled oscillators. This publicly available dataset will be beneficial to the experimental and computational neuroscientists.


Assuntos
Estimulação Acústica , Prosencéfalo Basal/citologia , Eletroencefalografia , Neurônios/fisiologia , Animais , Potenciais Evocados , Camundongos
17.
PLoS One ; 15(9): e0239582, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32956428

RESUMO

INTRODUCTION: To survive, organisms need to organize perceptual input into coherent, usable structures. Research has illuminated the potential role of frequency of occurrence and duration as cues to extract statistical regularities from our environment. Musical stimuli provide a unique opportunity to study how these cues are used to organize auditory input into higher level perceptual entities, i.e., pitch structure, and to assess the influence of cognitive schema. METHODS: To examine the relative importance of these two cues in pitch structure perception, we constructed novel tone sequences in which frequency of occurrence and duration cues were pitted against each other. We assessed perceived pitch structure in musically trained and untrained listeners using a probe tone paradigm. RESULTS: In all experiments, a 3-tiered hierarchy of pitch structure emerged, with highest ratings for tones of longer duration, next highest for shorter, more frequent tones and lowest for probe tones that did not occur in the sequence. The hierarchy did not reflect assimilation to Western tonal schema. DISCUSSION: Our results argue against theories positing the same mechanism for the processing of duration and frequency of occurrence, and that duration is weighted preferentially. We further suggest that the organization of perceptual information will proceed according to whatever information is relevant, available, and most easily acquired.


Assuntos
Nível de Percepção Sonora , Estimulação Acústica , Adolescente , Adulto , Sinais (Psicologia) , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Música , Psicoacústica , Fatores de Tempo , Adulto Jovem
18.
J Vis Exp ; (162)2020 08 22.
Artigo em Inglês | MEDLINE | ID: mdl-32894260

RESUMO

Emotional memory has been primarily studied with fear-conditioning paradigms. Fear conditioning is a form of learning through which individuals learn the relationships between aversive events and otherwise neutral stimuli. The most-widely utilized procedures for studying emotional memories entail fear conditioning in rats. In these tasks, the unconditioned stimulus (US) is a footshock presented once or several times across single or several sessions, and the conditioned response (CR) is freezing. In a version of these procedures, called cued fear conditioning, a tone (conditioned stimulus, CS) is paired with footshocks (US) during the training phase. During the first test, animals are exposed to the same context in which training took place, and freezing responses are tested in the absence of footshocks and tones (i.e., a context test). During the second test, freezing is measured when the context is changed (e.g., by manipulating the smell and walls of the experimental chamber) and the tone is presented in the absence of footshocks (i.e., a cue test). Most cued fear conditioning procedures entail few tone-shock pairings (e.g., 1-3 trials in a single session). There is a growing interest in less common versions involving an extensive number of pairings (i.e., overtraining) related to the long-lasting effect called fear incubation (i.e., fear responses increase over time without further exposure to aversive events or conditioned stimuli). Extended fear-conditioning tasks have been key to the understanding of fear incubation's behavioral and neurobiological aspects, including its relationship with other psychological phenomena (e.g., post-traumatic stress disorder). Here, we describe an extended fear-conditioning protocol that produces overtraining and fear incubation in rats. This protocol entails a single training session with 25 tone-shock pairings (i.e., overtraining) and a comparison of conditioned freezing responses during context and cue tests 48 h (short-term) and 6 weeks (long-term) after training.


Assuntos
Condicionamento Psicológico , Medo/fisiologia , Estimulação Acústica , Animais , Sinais (Psicologia) , Masculino , Memória/fisiologia , Ratos , Fatores de Tempo
19.
Artigo em Chinês | MEDLINE | ID: mdl-32791650

RESUMO

The symptoms of hidden hearing loss(HHL) are concealed, mainly manifested as defects in the threshold upper auditory function, which are related to noise exposure, aging and drug damage. There is no definite evidence to prove that whether the three factors participate in mechanism of synaptic damage in the cochlea. The clinical audiological characteristics of HHL are mostly as follows: the normal threshold of PTA and the wave response of ABR; the amplitude of the CAP of ABR wave Ⅰ or ECochG is lower at medium and high stimulation intensity; the lower speech recognition rate under noise, etc. Ultra-high frequency pure tone audiometry, a series of objective audiological examinations, such as ABR, ECochG and frequency-following response, speech audiometry under noise, noise exposure questionnaire evaluation were applied to detect HHL at early stage.


Assuntos
Potenciais Evocados Auditivos do Tronco Encefálico , Perda Auditiva Provocada por Ruído , Estimulação Acústica , Audiometria de Tons Puros , Limiar Auditivo , Humanos , Ruído
20.
PLoS Comput Biol ; 16(8): e1008152, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-32853256

RESUMO

A repeating triplet-sequence ABA- of non-overlapping brief tones, A and B, is a valued paradigm for studying auditory stream formation and the cocktail party problem. The stimulus is "heard" either as a galloping pattern (integration) or as two interleaved streams (segregation); the initial percept is typically integration then followed by spontaneous alternations between segregation and integration, each being dominant for a few seconds. The probability of segregation grows over seconds, from near-zero to a steady value, defining the buildup function, BUF. Its stationary level increases with the difference in tone frequencies, DF, and the BUF rises faster. Percept durations have DF-dependent means and are gamma-like distributed. Behavioral and computational studies usually characterize triplet streaming either during alternations or during buildup. Here, our experimental design and modeling encompass both. We propose a pseudo-neuromechanistic model that incorporates spiking activity in primary auditory cortex, A1, as input and resolves perception along two network-layers downstream of A1. Our model is straightforward and intuitive. It describes the noisy accumulation of evidence against the current percept which generates switches when reaching a threshold. Accumulation can saturate either above or below threshold; if below, the switching dynamics resemble noise-induced transitions from an attractor state. Our model accounts quantitatively for three key features of data: the BUFs, mean durations, and normalized dominance duration distributions, at various DF values. It describes perceptual alternations without competition per se, and underscores that treating triplets in the sequence independently and averaging across trials, as implemented in earlier widely cited studies, is inadequate.


Assuntos
Córtex Auditivo/fisiologia , Estimulação Acústica , Percepção Auditiva , Feminino , Humanos , Masculino
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