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1.
Basic Clin Neurosci ; 15(2): 133-146, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-39228447

RESUMO

Binaural beat (BB), as a non-invasive auditory beat stimulation type, has found its potential applications in cognitive domains. This review presents a proper summary to deepen our understanding of the soundness of the BB technique by looking into its applications, possible mechanisms of action, effectiveness, limitations, and potential side effects. BB has been claimed to improve cognitive and psychological functions such as memory, attention, stress, anxiety, motivation, and confidence. We have also looked into preclinical and clinical research studies that have been performed using BB and proposed changes in the brain following the application of BB stimulations, including EEG changes. This review also presents applications outside the cognitive domain and evaluates BB as a possible treatment method.

2.
Cureus ; 16(8): e66120, 2024 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-39229405

RESUMO

Musical hallucinations (MH) represent a rare and complex auditory phenomenon where individuals perceive music without external stimuli. This case study explores auditory Charles Bonnet syndrome (ACBS) in a 51-year-old male with a history of bilateral sensorineural hearing loss. The patient reported hearing recognizable prayer chants, initially perceived as external sounds from a nearby temple. Over time, these hallucinations persisted and interfered with his daily activities, prompting medical consultation. Despite the absence of psychiatric illness, the patient was diagnosed with ACBS and treated with risperidone, an atypical antipsychotic. The intervention led to a significant reduction in the frequency and intensity of the hallucinations, alongside improved sleep and concentration. The patient also experienced a recurrence of symptoms upon discontinuation of the medication, highlighting the importance of adherence to treatment. This case underscores the need for awareness and understanding of non-psychotic auditory hallucinations in individuals with hearing impairments. The pathophysiology of MH is not fully understood but is believed to involve abnormal activity in the auditory associative cortices due to sensory deprivation. Treatment approaches often include both pharmacological and non-pharmacological strategies, such as optimizing hearing with aids and providing psychoeducation. This study contributes to the limited literature on ACBS and emphasizes the efficacy of antipsychotics in managing MH. Further research is essential to explore the underlying mechanisms and to develop comprehensive management plans for patients experiencing these distressing auditory phenomena. The findings advocate for a multidisciplinary approach to treatment, integrating audiological and psychiatric care to improve patient outcomes.

3.
Eur J Neurosci ; 2024 Sep 05.
Artigo em Inglês | MEDLINE | ID: mdl-39237477

RESUMO

Age-related hearing impairment (ARHI) is commonly associated with decreased auditory temporal resolution caused by auditory neurodegeneration. Age-related deterioration in gap detection ability, resulting in poor temporal auditory processing, is often attributed to pathophysiological changes in both the peripheral and central auditory systems. This study aimed to investigate whether the gap detection ability declines in the early stages of ageing and to determine its usefulness in detecting peripheral and central auditory degeneration. The study used 1-month-old (1 M), 6-month-old (6 M) and 12-month-old (12 M) mice to examine changes in gap detection ability and associated auditory pathophysiology. Although hearing thresholds did not significantly differ between the groups, the amplitude of auditory brainstem response (ABR) wave I decreased significantly in an age-dependent manner, consistent with age-related cochlear synaptopathy. The relative ABR amplitude ratio of waves 2 and 5 to wave 1 was significantly increased in 12 M mice, indicating that the central auditory system had increased in relative neuroactivity. A significant increase in gap detection thresholds was observed in 12 M mice compared to 1 M mice. Although cochlear synaptopathy and central hyperactivity were positively correlated with gap detection thresholds, central hyperactivity strongly influenced gap detection ability. In the cochlear nucleus and auditory cortex, the inhibitory synaptic expression of GAD65 and the expression of parvalbumin were significantly decreased in 12 M mice, consistent with central hyperactivity. Evaluating gap detection performance may allow the identification of decreased auditory temporal resolution in the early stages of ARHI, which is strongly associated with auditory neurodegeneration.

4.
Elife ; 132024 Sep 10.
Artigo em Inglês | MEDLINE | ID: mdl-39255194

RESUMO

Across the animal kingdom, neural responses in the auditory cortex are suppressed during vocalization, and humans are no exception. A common hypothesis is that suppression increases sensitivity to auditory feedback, enabling the detection of vocalization errors. This hypothesis has been previously confirmed in non-human primates, however a direct link between auditory suppression and sensitivity in human speech monitoring remains elusive. To address this issue, we obtained intracranial electroencephalography (iEEG) recordings from 35 neurosurgical participants during speech production. We first characterized the detailed topography of auditory suppression, which varied across superior temporal gyrus (STG). Next, we performed a delayed auditory feedback (DAF) task to determine whether the suppressed sites were also sensitive to auditory feedback alterations. Indeed, overlapping sites showed enhanced responses to feedback, indicating sensitivity. Importantly, there was a strong correlation between the degree of auditory suppression and feedback sensitivity, suggesting suppression might be a key mechanism that underlies speech monitoring. Further, we found that when participants produced speech with simultaneous auditory feedback, posterior STG was selectively activated if participants were engaged in a DAF paradigm, suggesting that increased attentional load can modulate auditory feedback sensitivity.


The brain lowers its response to inputs we generate ourselves, such as moving or speaking. Essentially, our brain 'knows' what will happen next when we carry out these actions, and therefore does not need to react as strongly as it would to unexpected events. This is why we cannot tickle ourselves, and why the brain does not react as much to our own voice as it does to someone else's. Quieting down the brain's response also allows us to focus on things that are new or important without getting distracted by our own movements or sounds. Studies in non-human primates showed that neurons in the auditory cortex (the region of the brain responsible for processing sound) displayed suppressed levels of activity when the animals made sounds. Interestingly, when the primates heard an altered version of their own voice, many of these same neurons became more active. But it was unclear whether this also happens in humans. To investigate, Ozker et al. used a technique called electrocorticography to record neural activity in different regions of the human brain while participants spoke. The results showed that most areas of the brain involved in auditory processing showed suppressed activity when individuals were speaking. However, when people heard an altered version of their own voice which had an unexpected delay, those same areas displayed increased activity. In addition, Ozker et al. found that the higher the level of suppression in the auditory cortex, the more sensitive these areas were to changes in a person's speech. These findings suggest that suppressing the brain's response to self-generated speech may help in detecting errors during speech production. Speech deficits are common in various neurological disorders, such as stuttering, Parkinson's disease, and aphasia. Ozker et al. hypothesize that these deficits may arise because individuals fail to suppress activity in auditory regions of the brain, causing a struggle when detecting and correcting errors in their own speech. However, further experiments are needed to test this theory.


Assuntos
Retroalimentação Sensorial , Fala , Humanos , Masculino , Feminino , Adulto , Retroalimentação Sensorial/fisiologia , Fala/fisiologia , Adulto Jovem , Córtex Auditivo/fisiologia , Lobo Temporal/fisiologia , Percepção da Fala/fisiologia , Eletroencefalografia , Eletrocorticografia , Estimulação Acústica
5.
Hear Res ; 453: 109104, 2024 Aug 14.
Artigo em Inglês | MEDLINE | ID: mdl-39255528

RESUMO

Auditory spatial attention detection (ASAD) seeks to determine which speaker in a surround sound field a listener is focusing on based on the one's brain biosignals. Although existing studies have achieved ASAD from a single-trial electroencephalogram (EEG), the huge inter-subject variability makes them generally perform poorly in cross-subject scenarios. Besides, most ASAD methods do not take full advantage of topological relationships between EEG channels, which are crucial for high-quality ASAD. Recently, some advanced studies have introduced graph-based brain topology modeling into ASAD, but how to calculate edge weights in a graph to better capture actual brain connectivity is worthy of further investigation. To address these issues, we propose a new ASAD method in this paper. First, we model a multi-channel EEG segment as a graph, where differential entropy serves as the node feature, and a static adjacency matrix is generated based on inter-channel mutual information to quantify brain functional connectivity. Then, different subjects' EEG graphs are encoded into a shared embedding space through a total variation graph neural network. Meanwhile, feature distribution alignment based on multi-kernel maximum mean discrepancy is adopted to learn subject-invariant patterns. Note that we align EEG embeddings of different subjects to reference distributions rather than align them to each other for the purpose of privacy preservation. A series of experiments on open datasets demonstrate that the proposed model outperforms state-of-the-art ASAD models in cross-subject scenarios with relatively low computational complexity, and feature distribution alignment improves the generalizability of the proposed model to a new subject.

6.
Curr Biol ; 34(17): 4062-4070.e7, 2024 Sep 09.
Artigo em Inglês | MEDLINE | ID: mdl-39255755

RESUMO

Some species have evolved the ability to use the sense of hearing to modify existing vocalizations, or even create new ones, which enlarges their repertoires and results in complex communication systems.1 This ability corresponds to various forms of vocal production learning that are all possessed by humans and independently displayed by distantly related vertebrates.1,2,3,4,5,6,7 Among mammals, a few species, including the Egyptian fruit bat,8,9,10 would possess such vocal production learning abilities.7 Yet the necessity of an intact auditory system for the development of the Egyptian fruit bat typical vocal repertoire has not been tested. Furthermore, a systematic causal examination of learned and innate aspects of the entire repertoire has never been performed in any vocal learner. Here we addressed these gaps by eliminating pups' sense of hearing at birth and assessing its effects on vocal production in adulthood. The deafening treatment enabled us to both causally test these bats' vocal learning ability and discern learned from innate aspects of their vocalizations. Leveraging wireless individual audio recordings from freely interacting adults, we show that a subset of the Egyptian fruit bat vocal repertoire necessitates auditory feedback. Intriguingly, these affected vocalizations belong to different acoustic groups in the vocal repertoire of males and females. These findings open the possibilities for targeted studies of the mammalian neural circuits that enable sexually dimorphic forms of vocal learning.


Assuntos
Quirópteros , Aprendizagem , Vocalização Animal , Animais , Quirópteros/fisiologia , Vocalização Animal/fisiologia , Aprendizagem/fisiologia , Feminino , Masculino , Retroalimentação Sensorial/fisiologia , Percepção Auditiva/fisiologia , Audição/fisiologia
7.
J Neural Eng ; 2024 Sep 10.
Artigo em Inglês | MEDLINE | ID: mdl-39255830

RESUMO

Potential usage of dry electrodes in emerging applications such as wearable devices, flexible tattoo circuits, and stretchable displays requires that, to become practical solutions, issues such as easy fabrication, strong durability, and low-cost materials must be addressed. The objective of this study was to propose soft and dry electrodes developed from polydimethylsiloxane (PDMS) and carbon nanotube (CNT) composites. Connected with both conventional and in-house NTAmp biosignal instruments for comparative studies, performances of the proposed dry electrodes were evaluated through electromyogram (EMG), electrocardiogram (ECG), and electroencephalogram (EEG) measurements. Results demonstrated that the capability of the PDMS/CNT electrodes to receive biosignals was on par with that of commercial electrodes (adhesive and gold-cup electrodes). Depending on the type of stimuli, a signal-to-noise ratio (SNR) of 5-10 dB range was achieved. The results of the study show that the performance of the proposed dry electrode is comparable to that of commercial electrodes, offering possibilities for diverse applications. These applications may include the physical examination of vital medical signs, the control of intelligent devices and robots, and the transmission of signals through flexible materials.

8.
Brain Lang ; 257: 105459, 2024 Sep 05.
Artigo em Inglês | MEDLINE | ID: mdl-39241469

RESUMO

Transcranial direct current stimulation (tDCS) targeting Broca's area has shown promise for augmenting language production in post-stroke aphasia (PSA). However, previous research has been limited by small sample sizes and inconsistent outcomes. This study employed a double-blind, parallel, randomized, controlled design to evaluate the efficacy of anodal Broca's tDCS, paired with 20-minute speech and language therapy (SLT) focused primarily on expressive language, across 5 daily sessions in 45 chronic PSA patients. Utilizing the Western Aphasia Battery-Revised, which assesses a spectrum of linguistic abilities, we measured changes in both expressive and receptive language skills before and after intervention. The tDCS group demonstrated significant improvements over sham in aphasia quotient, auditory verbal comprehension, and spontaneous speech. Notably, tDCS improved both expressive and receptive domains, whereas sham only benefited expression. These results underscore the broader linguistic benefits of Broca's area stimulation and support the integration of tDCS with SLT to advance aphasia rehabilitation.

9.
Hear Res ; 452: 109107, 2024 Aug 28.
Artigo em Inglês | MEDLINE | ID: mdl-39241554

RESUMO

The detection of novel, low probability events in the environment is critical for survival. To perform this vital task, our brain is continuously building and updating a model of the outside world; an extensively studied phenomenon commonly referred to as predictive coding. Predictive coding posits that the brain is continuously extracting regularities from the environment to generate predictions. These predictions are then used to supress neuronal responses to redundant information, filtering those inputs, which then automatically enhances the remaining, unexpected inputs. We have recently described the ability of auditory neurons to generate predictions about expected sensory inputs by detecting their absence in an oddball paradigm using omitted tones as deviants. Here, we studied the responses of individual neurons to omitted tones by presenting individual sequences of repetitive pure tones, using both random and periodic omissions, presented at both fast and slow rates in the inferior colliculus and auditory cortex neurons of anesthetized rats. Our goal was to determine whether feature-specific dependence of these predictions exists. Results showed that omitted tones could be detected at both high (8 Hz) and slow repetition rates (2 Hz), with detection being more robust at the non-lemniscal auditory pathway.

10.
Artigo em Inglês | MEDLINE | ID: mdl-39242407

RESUMO

INTRODUCTION: Reviewing the literature, Osia 2 system implantation is predominantly performed under general anesthesia (GA). Although in the pediatric population GA is inevitable, in adult cases, especially with high anesthesiological risks, local anesthesia (LA) is an obvious solution. METHOD: The aim of this article is to provide a detailed demonstration of Osia 2 implantation under LA. In our case series of five adult implant recipients, the surgical procedure was carried out without encountering any difficulties during or after the operation. CONCLUSION: Based on our experiences, implantation of the Osia® 2 System under local anesthesia is an easy and safe method for patients.

11.
Behav Res Methods ; 2024 Sep 09.
Artigo em Inglês | MEDLINE | ID: mdl-39251527

RESUMO

Theories of visual working memory have seen significant progress through the use of continuous reproduction tasks. However, these tasks have mainly focused on studying visual features, with limited examples existing in the auditory domain. Therefore, it is unknown to what extent newly developed memory models reflect domain-general limitations or are specific to the visual domain. To address this gap, we developed a novel methodology: the Auditory Reproduction Task (ART). This task utilizes Shepard tones, which create an infinite rising or falling tone illusion by dissecting pitch chroma and height, to create a 1-360° auditory circular space. In Experiment 1, we validated the perceptual circularity and uniformity of this auditory stimulus space. In Experiment 2, we demonstrated that auditory working memory shows similar set size effects to visual working memory-report error increased at a set size of 2 relative to 1, caused by swap errors. In Experiment 3, we tested the validity of ART by correlating reproduction errors with commonly used auditory and visual working memory tasks. Analyses revealed that ART errors were significantly correlated with performance in both auditory and visual working memory tasks, albeit with a stronger correlation observed with auditory working memory. While these experiments have only scratched the surface of the theoretical and computational constraints on auditory working memory, they provide a valuable proof of concept for ART. Further research with ART has the potential to deepen our understanding of auditory working memory, as well as to explore the extent to which existing models are tapping into domain-general constraints.

12.
Sci Rep ; 14(1): 20994, 2024 09 09.
Artigo em Inglês | MEDLINE | ID: mdl-39251659

RESUMO

Sound recognition is effortless for humans but poses a significant challenge for artificial hearing systems. Deep neural networks (DNNs), especially convolutional neural networks (CNNs), have recently surpassed traditional machine learning in sound classification. However, current DNNs map sounds to labels using binary categorical variables, neglecting the semantic relations between labels. Cognitive neuroscience research suggests that human listeners exploit such semantic information besides acoustic cues. Hence, our hypothesis is that incorporating semantic information improves DNN's sound recognition performance, emulating human behaviour. In our approach, sound recognition is framed as a regression problem, with CNNs trained to map spectrograms to continuous semantic representations from NLP models (Word2Vec, BERT, and CLAP text encoder). Two DNN types were trained: semDNN with continuous embeddings and catDNN with categorical labels, both with a dataset extracted from a collection of 388,211 sounds enriched with semantic descriptions. Evaluations across four external datasets, confirmed the superiority of semantic labeling from semDNN compared to catDNN, preserving higher-level relations. Importantly, an analysis of human similarity ratings for natural sounds, showed that semDNN approximated human listener behaviour better than catDNN, other DNNs, and NLP models. Our work contributes to understanding the role of semantics in sound recognition, bridging the gap between artificial systems and human auditory perception.


Assuntos
Percepção Auditiva , Processamento de Linguagem Natural , Redes Neurais de Computação , Semântica , Humanos , Percepção Auditiva/fisiologia , Aprendizado Profundo , Som
13.
World J Otorhinolaryngol Head Neck Surg ; 10(3): 237-240, 2024 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-39233865

RESUMO

Introduction: Medication-related osteonecrosis of the temporal bone is rare and has been reported to be associated with the use of anti-resorptive and biologic agents. Here, we present the first case of tyrosine-kinase inhibitor-related external auditory canal (EAC) osteonecrosis as well as two cases related to anti-resorptive therapies. Methods: A retrospective case series. Results: Case one: an 84-year-old female presented with chronic otitis externa and osteonecrosis of EACs bilaterally. She had a history of osteoporosis treated with denosumab and risedronic acid. She successfully underwent left EAC reconstruction using an inferiorly-based pedicle periosteal flap while the right ear canal was managed conservatively. Case two: a 69-year-old male presented with osteonecrosis of the right EAC. He had a history of osteoporosis treated with alendronic acid and zoledronic acid. His osteonecrosis is conservatively managed with local debridement and antibiotic application. Case three: a 60-year-old male presented with osteonecrosis of the right inferior EAC. He had a history of chronic myelogenous leukemia treated with a tyrosine-kinase inhibitor, imatinib. After failing conservative therapy, he underwent right ear canal reconstruction using a periosteal vascular pedicle flap without complication and experienced complete resolution to his symptoms. Conclusion: Anti-resorptive agents and/or tyrosine kinase inhibitors may lead to dysregulation of bone remodeling and result in rare cases of temporal bone osteonecrosis. When a local debridement and antibiotic therapy fail, definitive surgical excision of necrotic bone with subsequent reconstruction of the EAC may offer patients a possible resolution in symptoms.

14.
Cureus ; 16(8): e66188, 2024 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-39233961

RESUMO

Squamous cell carcinoma (SCC) is the most common malignant tumor involving the temporal bone but generally very rare. The temporomandibular joint (TMJ), middle cranial fossa, and facial nerve canal are uncommon areas for the tumor to spread. We present the case of primary SCC of the temporal bone in a 63-year-old male presenting for otorrhea, otalgia, facial weakness, and facial pain after failing outpatient antibiotic therapy for an ear infection. Initial inpatient workup was significant for a hypertensive emergency, leukocytosis, and acute kidney injury. Opacification of cavities (i.e., left middle ear, external auditory canal (EAC)), destructive bony changes (i.e., mastoiditis, erosion of facial nerve canal, and TMJ), and invasion of the middle cranial fossa due to a soft tissue mass were noted on CT and MRI. Operative biopsy showed moderately differentiated SCC. The patient received treatment at the hospital consisting of antibiotics and supportive treatment. Plans for an outpatient PET scan and chemoradiotherapy per consultants' recommendations were arranged. The patient was discharged with appropriate medications and outpatient referrals and underwent infuse-a-port placement. Overall, this case describes some key points given the limited studies thus far. It demonstrates certain imaging characteristics of SCC of the temporal bone in the setting of a chronic ear infection. The malignancy spreads to the posterior TMJ wall and the temporal lobe, which very few cases have shown. The tumor also invades specifically the mastoid and tympanic segments of the facial nerve canal. This may be one of the first cases to showcase these features given the rarity of their simultaneous occurrence.

15.
Front Hum Neurosci ; 18: 1424920, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-39234407

RESUMO

Past studies have explored formant centering, a corrective behavior of convergence over the duration of an utterance toward the formants of a putative target vowel. In this study, we establish the existence of a similar centering phenomenon for pitch in healthy elderly controls and examine how such corrective behavior is altered in Alzheimer's Disease (AD). We found the pitch centering response in healthy elderly was similar when correcting pitch errors below and above the target (median) pitch. In contrast, patients with AD showed an asymmetry with a larger correction for the pitch errors below the target phonation than above the target phonation. These findings indicate that pitch centering is a robust compensation behavior in human speech. Our findings also explore the potential impacts on pitch centering from neurodegenerative processes impacting speech in AD.

16.
Glob Chang Biol ; 30(9): e17490, 2024 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-39254237

RESUMO

Understanding how the environment mediates an organism's ability to meet basic survival requirements is a fundamental goal of ecology. Vessel noise is a global threat to marine ecosystems and is increasing in intensity and spatiotemporal extent due to growth in shipping coupled with physical changes to ocean soundscapes from ocean warming and acidification. Odontocetes rely on biosonar to forage, yet determining the consequences of vessel noise on foraging has been limited by the challenges of observing underwater foraging outcomes and measuring noise levels received by individuals. To address these challenges, we leveraged a unique acoustic and movement dataset from 25 animal-borne biologging tags temporarily attached to individuals from two populations of fish-eating killer whales (Orcinus orca) in highly transited coastal waters to (1) test for the effects of vessel noise on foraging behaviors-searching (slow-click echolocation), pursuit (buzzes), and capture and (2) investigate the mechanism of interference. For every 1 dB increase in maximum noise level, there was a 4% increase in the odds of searching for prey by both sexes, a 58% decrease in the odds of pursuit by females and a 12.5% decrease in the odds of prey capture by both sexes. Moreover, all but one deep (≥75 m) foraging attempt with noise ≥110 dB re 1 µPa (15-45 kHz band; n = 6 dives by n = 4 whales) resulted in failed prey capture. These responses are consistent with an auditory masking mechanism. Our findings demonstrate the effects of vessel noise across multiple phases of odontocete foraging, underscoring the importance of managing anthropogenic inputs into soundscapes to achieve conservation objectives for acoustically sensitive species. While the timescales for recovering depleted prey species may span decades, these findings suggest that complementary actions to reduce ocean noise in the short term offer a critical pathway for recovering odontocete foraging opportunities.


Assuntos
Orca , Animais , Feminino , Orca/fisiologia , Masculino , Navios , Ruído/efeitos adversos , Comportamento Alimentar , Ecolocação/fisiologia , Ruído dos Transportes/efeitos adversos , Comportamento Predatório
17.
J Neurophysiol ; 2024 Sep 11.
Artigo em Inglês | MEDLINE | ID: mdl-39258776

RESUMO

The physiological diversity of inhibitory neurons provides ample opportunity to influence a wide range of computational roles through their varied activity patterns, especially via feedback loops. In the avian auditory brainstem, inhibition originates primarily from the superior olivary nucleus (SON) and so it is critical to understand the intrinsic physiological properties and processing capabilities of these neurons. Neurons in the SON receive ascending input via the cochlear nuclei: directly from the intensity-coding cochlear nucleus angularis (NA) and indirectly via the interaural timing nucleus laminaris (NL), which itself receives input from cochlear nucleus magnocellularis. Two distinct populations of SON neurons provide either inhibitory feedback to ipsilateral NA, NL, and the timing cochlear nucleus NM, or to the contralateral SON. To determine whether these populations correspond to distinct response types, we investigated their electrophysiology in brain stem slices using patch clamp electrophysiology. We identified three phenotypes: single spiking, chattering tonic, and regular tonic neurons. The two tonic phenotypes displayed distinct firing patterns and different membrane properties. Fluctuating "noisy" currents used to probe the capability of SON neurons to encode temporal features showed that each phenotype differed in sensitivity to temporally modulated input. By using cell fills and anatomical reconstructions, we could correlate the firing phenotypes with their axonal projection patterns. We found that SON axons exited via three fiber tracts with each tract composed of specific phenotypes. These results provide a basis for understanding the role of specific inhibitory cell types in auditory function and elucidate the organization of the SON outputs.

18.
J Neurophysiol ; 2024 Sep 11.
Artigo em Inglês | MEDLINE | ID: mdl-39258777

RESUMO

The central auditory system encompasses two primary functions: identification and localization. Spatial release from masking (SRM) highlights speech recognition in competing noise and improves the listening experience when a spatial cue is introduced between noise and target speech. This assessment focuses on the integrity of auditory function and holds clinical significance. However, infants or pre-lingual subjects sometimes provide less reliable results. This study investigates the value of cortical auditory evoked potentials (CAEPs) onset and acoustic change complex (ACC) as an objective measurement of SRM. Thirty normal-hearing young adults (11 males) were recruited. We found the spatial separation of signals and noise (±90 degrees symmetrically) resulted in a signal-to-noise ratio (SNR) improvement of 9.00 ± 1.71 dB behaviorally. It significantly enhanced cortical processing at all SNR levels, shortened CAEPs latencies, and increased amplitudes, resulting in a greater number of measurable peaks for ACC. SRM showed mild to moderate correlations with the differences between the two conditions in CAEP measures. The regression model combining N1'-P2' amplitude at 5 dB SNR (R2 = 0.26), P1 amplitude at 0 dB SNR (R2 = 0.14), and P1 latency at -5 dB SNR (R2 = 0.15), explained 45.3% of the variance in SRM. Our study demonstrates that introducing spatial cues can improve speech perception and enhance central auditory processing in normal-hearing young adults. CAEPs may contribute to predictions about SRM and hold potential for practical application.

19.
J Comput Neurosci ; 2024 Sep 11.
Artigo em Inglês | MEDLINE | ID: mdl-39259462

RESUMO

We demonstrate a model of chirp-velocity sensitivity in the inferior colliculus (IC) that retains the tuning to amplitude modulation (AM) that was established in earlier models. The mechanism of velocity sensitivity is sequence detection by octopus cells of the posteroventral cochlear nucleus, which have been proposed in physiological studies to respond preferentially to the order of arrival of cross-frequency inputs of different amplitudes. Model architecture is based on coincidence detection of a combination of excitatory and inhibitory inputs. Chirp-sensitivity of the IC output is largely controlled by the strength and timing of the chirp-sensitive octopus-cell inhibitory input. AM tuning is controlled by inhibition and excitation that are tuned to the same frequency. We present several example neurons that demonstrate the feasibility of the model in simulating realistic chirp-sensitivity and AM tuning for a wide range of characteristic frequencies. Additionally, we explore the systematic impact of varying parameters on model responses. The proposed model can be used to assess the contribution of IC chirp-velocity sensitivity to responses to complex sounds, such as speech.

20.
J Neuropsychol ; 2024 Sep 02.
Artigo em Inglês | MEDLINE | ID: mdl-39221573

RESUMO

The Tactual Span assesses tactile working memory (WM) using both hands while applying forward and backward conditions. The study objectives were to validate a one-hand version of the Tactual Span and to evaluate WM laterality in the tactile modality. Of the 145 participants, 80 performed the Tactual Span with their right hand, and 65 performed it with their left hand. Moreover, all participants performed two span tasks in the visuo-spatial and auditory modalities, each encompassing forward and backward conditions. Results revealed adequate Cronbach's alpha values for each hand in both conditions of the Tactual Span, along with a positive correlation between forward and backward conditions in each hand. However, overall performance on the Tactual Span was poorer compared to performance on the Auditory and Visuo-spatial Spans. Furthermore, in the forward condition, there was a correlation between the Auditory Span and the Tactual Span, but only for the right hand. In the backward condition, the Auditory Span correlated with the Tactual Span in both hands. The findings indicate that there is no effect of hand laterality in tactile WM, showing the two hands are related to each other in their WM function. Additionally, the one-hand version of the Tactual Span is deemed useful for evaluating tactile WM and can therefore be used in empirical and clinical settings for neuropsychological assessment purposes.

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