Restricted participation: Drivers, experiences and implications of disability stigma in Ethiopia

Background: Community-based inclusive development (CBID) acknowledges society's critical role in supporting the active participation of persons with disabilities. However, research on how this approach relates to the context-sensitive socially situated barriers of disability stigma is underexplored. Objectives: This study aimed to understand the drivers and experiences of disability stigma in Ethiopia, from the perspective of persons with disabilities engaged in CBID programmes, and to establish how disability stigma acts as a barrier to participation. Methods: An inductive methodological approach guided the research design. Mixed methods were used including a narrative review of disabilities studies literature, 16 semi-structured interviews with persons with disabilities, and a quantitative survey of 970 persons with disabilities across three communities in Ethiopia. Results: Informed by theories of epistemic justice, this study identified specific indicators of meaningful participation and examined how these relate to experiences of disability stigma. The study found that the participation of adults with disabilities in society is restricted across different areas of life. Misconceptions about the causes of disability and social perceptions regarding the capacities of persons with disabilities are found to exacerbate stigma and act as a barrier to participation. Conclusion: Targeted efforts to challenge internalised norms and harmful beliefs within CBID approaches are required to address disadvantages arising from embedded disability stigma. Contribution: This study makes conceptual, empirical and practical contributions that advance insights into the relationship between disability stigma and participation in Ethiopia and the dimensions of epistemic justice relevant to understanding the nature and drivers of disability stigma.

Evidências de validade do teste informatizado para avaliação das funções executivas / Evidence of validity of the computerized test for evaluating executive functions / Evidencia de validez de la prueba computarizada para evaluación de funciones ejecutivas

Funções executivas (FE) referem-se ao conjunto de habilidades que, de forma integrada, coordenam o comportamento e a cognição. Assim, o comprometimento no desenvolvimento das FE está ligado a vários desfechos negativos ao longo da vida. Portanto, a avaliação dessas habilidades na infância é essencial para identificar e prevenir prejuízos na vida adulta. Este estudo teve como objetivo investigar evidências de validade do Teste Informatizado para Avaliação das Funções Executivas (Tafe) pelo critério de idade e pelo padrão de correlação entre medidas do TAFE e outras medidas de FE. Para isso, foi utilizada uma amostra de 51 crianças, entre 4 e 10 anos de idade, matriculadas em uma escola privada na cidade de Goiânia (GO), da pré-escola ao 4º ano do ensino fundamental. Como instrumentos, foram utilizados, além do Tafe, as tarefas de Bloco de Corsi, Teste de Trilhas A e B, Teste de Trilhas Pré-Escolares, Teste de Stroop Pré-Escolares e Subteste Dígitos da Escala Wechsler de Inteligência. Foram conduzidas análises estatísticas Kruskal Wallis para verificar a evidência de validade por relação com idade e análises de correlação não paramétrica de Spearman para avaliar as evidências de validade convergente. O instrumento investigado mostrou-se efetivo para discriminar entre as diferentes faixas etárias, assim, sensível ao desenvolvimento das FE. Os resultados obtidos no Tafe correlacionaram-se aos obtidos em outros testes que também avaliaram FE, mostrando claros padrões de convergência. Logo, as análises dos resultados fornecem evidências de validade ao Tafe, derivadas a partir de diferentes estratégias de investigação.(AU)

Executive functions (EF) refer to the set of skills that, in an integrated way, coordinate behavior and cognition. Thus, the commitment in developing EF is linked to several negative outcomes throughout life. Therefore, the assessment of these abilities in childhood is essential to identify and prevent possible harm in adult life. This study aimed to investigate evidences of validity of the Computerized Test for Evaluation of Executive Functions (TAFE) by the age criterion and by the pattern of correlation between TAFE measures and other EF measures. To this end, a sample of 51 children, between 4 and 10 years old, enrolled in a private school in the municipality of Goiânia (GO), from preschool to the 4th year of elementary school, was used. As instruments, in addition to TAFE, the tasks of Corsi Block, Trails Test A and B, Preschool Trails Test, Preschool Stroop Test and the Digits Subtest of the Wechsler Intelligence Scale were used. Kruskal Wallis statistical analyzes were conducted to verify the evidence of validity by age criteria and Spearman's nonparametric correlation analysis to assess evidence of convergent validation. The instrument investigated was effective to discriminate between different age groups, thus being sensitive to the development of EF. The results obtained in TAFE were correlated with those obtained in other tests that also assess FE, showing patterns of convergence. Therefore, the analysis of the results provides validation evidence to TAFE, derived from different investigation methods.(AU)

Las funciones ejecutivas (FE) se refieren al conjunto de habilidades que coordinan la conducta y la cognición. Así, el deterioro en el desarrollo de FE está relacionado con varios resultados negativos durante la vida. Por tanto, la valoración de estas habilidades en la infancia es fundamental para identificar y prevenir posibles daños en la vida adulta. Este estudio tuvo como objetivo investigar la evidencia de validez de la Prueba Computarizada para Evaluación de Funciones Ejecutivas (Tafe) por el criterio de edad y convergencia entre las medidas Tafe y otras medidas de FE. Para ello, se utilizó una muestra de 51 niños, de entre 4 y 10 años de edad, matriculados en un colegio privado de Goiânia (Goiás, Brasil) desde la preescolar hasta 4.º de primaria. Como instrumentos, además del Tafe, se utilizaron las tareas de Bloque de Corsi, el Test de los senderos A y B, el Test de los Senderos Preescolares, el Test de Stroop Preescolar y la Subprueba de Dígitos de la Escala Wechsler de Inteligencia. Se realizaron análisis estadísticos de Kruskal Wallis para verificar la validez por criterios de edad y análisis de correlación no-paramétrica de Spearman para evaluar la evidencia de validez convergente. Tafe demostró ser efectivo para discriminar entre diferentes grupos de edad, así es sensible al desarrollo de FE. Los resultados en Tafe se correlacionaron con los obtenidos en otras pruebas de FE, lo que muestra claros patrones de convergencia. Por tanto, el análisis aporta evidencias de validez para Tafe, derivadas de diferentes estrategias de investigación.(AU)

Comparison and combination of gamified neurofeedback training and general behavioral training.

With the rapid development of the international community, foreign language learning has become increasingly important. Listening training is a particularly important component of foreign language learning. The most difficult aspect of listening training is the development of speech discrimination ability, which is crucial to speech perception. General behavioral training requires a substantial amount of time and attention. To address this, we previously developed a neurofeedback (NF) training system that enables unconscious learning of auditory discrimination. However, to our knowledge, no studies have compared NF training and general behavioral training. In the present study, we compared the learning effects of NF training, general behavioral training, and a combination of both strategies. Specifically, we developed a gamified and adapted NF training of auditory discrimination. We found that both NF training and general behavioral training enhanced behavioral performance, whereas only NF training elicited significant changes in brain activity. Furthermore, the participants that used both training methods exhibited the largest improvement in behavioral performance. This indicates that the combined use of NF and general behavioral training methods may be optimal for enhancing auditory discrimination ability when learning foreign languages.

Temporal loudness weights: Primacy effects, loudness dominance and their interaction.

Loudness judgments of sounds varying in level across time show a non-uniform temporal weighting, with increased weights assigned to the beginning of the sound (primacy effect). In addition, higher weights are observed for temporal components that are higher in level than the remaining components (loudness dominance). In three experiments, sounds consisting of 100- or 475-ms Gaussian wideband noise segments with random level variations were presented and either none, the first, or a central temporal segment was amplified or attenuated. In Experiment 1, the sounds consisted of four 100-ms segments that were separated by 500-ms gaps. Previous experiments did not show a primacy effect in such a condition. In Experiment 2, four- or ten-100-ms-segment sounds without gaps between the segments were presented to examine the interaction between the primacy effect and level dominance. As expected, for the sounds with segments separated by gaps, no primacy effect was observed, but weights on amplified segments were increased and weights on attenuated segments were decreased. For the sounds with contiguous segments, a primacy effect as well as effects of relative level (similar to those in Experiment 1) were found. For attenuation, the data indicated no substantial interaction between the primacy effect and loudness dominance, whereas for amplification an interaction was present. In Experiment 3, sounds consisting of either four contiguous 100-ms or 475-ms segments, or four 100-ms segments separated by 500-ms gaps were presented. Effects of relative level were more pronounced for the contiguous sounds. Across all three experiments, the effects of relative level were more pronounced for attenuation. In addition, the effects of relative level showed a dependence on the position of the change in level, with opposite direction for attenuation compared to amplification. Some of the results are in accordance with explanations based on masking effects on auditory intensity resolution.

Encoding of acquired sound-sequence salience by auditory cortical offset responses.

Behaviorally relevant sounds are often composed of distinct acoustic units organized into specific temporal sequences. The meaning of such sound sequences can therefore be fully recognized only when they have terminated. However, the neural mechanisms underlying the perception of sound sequences remain unclear. Here, we use two-photon calcium imaging in the auditory cortex of behaving mice to test the hypothesis that neural responses to termination of sound sequences ("Off-responses") encode their acoustic history and behavioral salience. We find that auditory cortical Off-responses encode preceding sound sequences and that learning to associate a sound sequence with a reward induces enhancement of Off-responses relative to responses during the sound sequence ("On-responses"). Furthermore, learning enhances network-level discriminability of sound sequences by Off-responses. Last, learning-induced plasticity of Off-responses but not On-responses lasts to the next day. These findings identify auditory cortical Off-responses as a key neural signature of acquired sound-sequence salience.

Behavioral effect of mismatch negativity neurofeedback on foreign language learning.

Listening is critical for foreign language learning. Listening difficulties can occur because of an inability to perceive or recognize sounds while listening to speech, whereas successful listening can boost understanding and improve speaking when learning a foreign language. Previous studies in our laboratory revealed that EEG-neurofeedback (NF) using mismatch negativity event-related brain potential successfully induced unconscious learning in terms of auditory discrimination of speech sounds. Here, we conducted a feasibility study with a small participant group (NF group and control group; six participants each) to examine the practical effects of mismatch negativity NF for improving the perception of speech sounds in a foreign language. Native Japanese speakers completed a task in which they learned to perceive and recognize spoken English words containing the consonants "l" or "r". Participants received neurofeedback training while not explicitly attending to auditory stimuli. The results revealed that NF training significantly improved the proportion of correct in discrimination and recognition trials, even though the training time for each word pair was reduced to 20% of the training time reported in our previous study. The learning effect was not affected by training with three pairs of words with different vowels. The current results indicate that NF resulted in long-term learning that persisted for at least 2 months.

Effect of oxytocin nasal spray on auditory automatic discrimination measured by mismatch negativity.

RATIONALE: As a treatment for cognitive dysfunction in schizophrenia, oxytocin nasal sprays potentially improve social cognition, facial expression recognition, and sense of smell. Mismatch negativity (MMN) is an event-related potential (ERP) reflecting auditory discrimination while MMN deficits reflect cognitive function decline in schizophrenia. OBJECTIVES: To determine whether oxytocin nasal spray affects auditory MMN METHODS: We measured ERPs in healthy subjects during an auditory oddball task, both before and after oxytocin nasal spray administration. Forty healthy subjects were randomly assigned to either the oxytocin or placebo group. ERPs were recorded during the oddball task for all subjects before and after a 24 international unit (IU) intranasal administration, and MMN was compared between the two groups. RESULTS: Participants who received oxytocin had significantly shorter MMN latencies than those who received a placebo. Oxytocin had no significant effect on the Change in MMN amplitude. CONCLUSIONS: The shortened MMN latencies that were observed after oxytocin nasal spray administration suggest that oxytocin may promote the comparison-decision stage.

A measure of smell enables the creation of olfactory metamers.

Wavelength is a physical measure of light, and the intricate understanding of its link to perceived colour enables the creation of perceptual entities such as metamers-non-overlapping spectral compositions that generate identical colour percepts1. By contrast, scientists have been unable to develop a physical measure linked to perceived smell, even one that merely reflects the extent of perceptual similarity between odorants2. Here, to generate such a measure, we collected perceptual similarity estimates of 49,788 pairwise odorants from 199 participants who smelled 242 different multicomponent odorants and used these data to refine a predictive model that links odorant structure to odorant perception3. The resulting measure combines 21 physicochemical features of the odorants into a single number-expressed in radians-that accurately predicts the extent of perceptual similarity between multicomponent odorant pairs. To assess the usefulness of this measure, we investigated whether we could use it to create olfactory metamers. To this end, we first identified a cut-off in the measure: pairs of multicomponent odorants that were within 0.05 radians of each other or less were very difficult to discriminate. Using this cut-off, we were able to design olfactory metamers-pairs of non-overlapping molecular compositions that generated identical odour percepts. The accurate predictions of perceptual similarity, and the ensuing creation of olfactory metamers, suggest that we have obtained a valid olfactory measure, one that may enable the digitization of smell.

Health care of sexual and gender minorities: an integrative literature review.

OBJECTIVES: to describe health care practices aimed at lesbians, gays, bisexuals, transvestites, and transsexuals. METHODS: an integrative literature review based on systematic steps, in MEDLINE, LILACS AND SciELO databases and/or electronic libraries. It was held from September to November 2018, with articles published between 2012 and 2017, available in full in Portuguese, English, and Spanish, addressing health care to that population group. RESULTS: fourteen articles were included. Most of the articles were about the trajectory of individuals within health services and showed limitations and obstacles in the use of these services. FINAL CONSIDERATIONS: there is evidence that factors related to organization of services, attitude of professionals, stigma, and discrimination experienced undermine health care practices. Therefore, it is essential to carry out educational activities in health services and educational institutions.

Δ9-tetrahydrocannabinol: Drug discrimination abuse liability testing in female Lister Hooded rats: Trials, tribulations and triumphs.

INTRODUCTION: The assessment of the abuse potential of CNS-active drugs is a regulatory requirement. Drug discrimination is one of the nonclinical tests that contribute to this assessment by providing information on a drug's potential to induce a discriminative stimulus comparable to that of a known drug of abuse. AIM: The objective was to validate drug discrimination in the rat for the purpose of supporting regulatory submissions for novel drugs with potential cannabinoid-like activity. METHODS: Ten female Lister hooded rats were trained to discriminate no-drug from Δ9-THC (1.5 mg/kg, IP) under a FR10 schedule of reinforcement. Once trained, a Δ9-THC dose-response curve was obtained using doses of 0.25, 0.75, 1.5, and 3 mg/kg, IP. This was followed by evaluation of amphetamine (0.3 mg/kg, SC); morphine (3 mg/kg, IP); midazolam (2.5 mg/kg, PO); and the synthetic cannabinoids WIN55,212-2 (0.75 to 2 mg/kg, IP), CP-47,497 (0.5 to 2 mg/kg, IP), and JWH-018 (1 mg/kg, IP) for their discriminative stimulus similarity to Δ9-THC. RESULTS: Pharmacological specificity was demonstrated by achieving the anticipated dose-response curve for Δ9-THC, and a vehicle-like response for the non-cannabinoid drugs. Although full generalisation was obtained for JWH-018, in contrast to published literature, WIN55,212-2 and CP-47,497 failed to generalise to Δ9-THC. DISCUSSION: Based on the literature review performed in light of the results obtained, contrasting and unpredictable behavioural responses produced by cannabinoids in animals and humans raises the question of the reliability and relevance of including drug discrimination and self-administration studies within an abuse potential assessment for novel cannabinoid-like drugs.

Corticocortical and Thalamocortical Changes in Functional Connectivity and White Matter Structural Integrity after Reward-Guided Learning of Visuospatial Discriminations in Rhesus Monkeys.

The frontal cortex and temporal lobes together regulate complex learning and memory capabilities. Here, we collected resting-state functional and diffusion-weighted MRI data before and after male rhesus macaque monkeys received extensive training to learn novel visuospatial discriminations (reward-guided learning). We found functional connectivity changes in orbitofrontal, ventromedial prefrontal, inferotemporal, entorhinal, retrosplenial, and anterior cingulate cortices, the subicular complex, and the dorsal, medial thalamus. These corticocortical and thalamocortical changes in functional connectivity were accompanied by related white matter structural alterations in the uncinate fasciculus, fornix, and ventral prefrontal tract: tracts that connect (sub)cortical networks and are implicated in learning and memory processes in monkeys and humans. After the well-trained monkeys received fornix transection, they were impaired in learning new visuospatial discriminations. In addition, the functional connectivity profile that was observed after the training was altered. These changes were accompanied by white matter changes in the ventral prefrontal tract, although the integrity of the uncinate fasciculus remained unchanged. Our experiments highlight the importance of different communication relayed among corticocortical and thalamocortical circuitry for the ability to learn new visuospatial associations (learning-to-learn) and to make reward-guided decisions.SIGNIFICANCE STATEMENT Frontal neural networks and the temporal lobes contribute to reward-guided learning in mammals. Here, we provide novel insight by showing that specific corticocortical and thalamocortical functional connectivity is altered after rhesus monkeys received extensive training to learn novel visuospatial discriminations. Contiguous white matter fiber pathways linking these gray matter structures, namely, the uncinate fasciculus, fornix, and ventral prefrontal tract, showed structural changes after completing training in the visuospatial task. Additionally, different patterns of functional and structural connectivity are reported after removal of subcortical connections within the extended hippocampal system, via fornix transection. These results highlight the importance of both corticocortical and thalamocortical interactions in reward-guided learning in the normal brain and identify brain structures important for memory capabilities after injury.

Causal Inference in Audiovisual Perception.

In our natural environment the senses are continuously flooded with a myriad of signals. To form a coherent representation of the world, the brain needs to integrate sensory signals arising from a common cause and segregate signals coming from separate causes. An unresolved question is how the brain solves this binding or causal inference problem and determines the causal structure of the sensory signals. In this functional magnetic resonance imaging (fMRI) study human observers (female and male) were presented with synchronous auditory and visual signals at the same location (i.e., common cause) or different locations (i.e., separate causes). On each trial, observers decided whether signals come from common or separate sources(i.e., "causal decisions"). To dissociate participants' causal inference from the spatial correspondence cues we adjusted the audiovisual disparity of the signals individually for each participant to threshold accuracy. Multivariate fMRI pattern analysis revealed the lateral prefrontal cortex as the only region that encodes predominantly the outcome of observers' causal inference (i.e., common vs separate causes). By contrast, the frontal eye field (FEF) and the intraparietal sulcus (IPS0-4) form a circuitry that concurrently encodes spatial (auditory and visual stimulus locations), decisional (causal inference), and motor response dimensions. These results suggest that the lateral prefrontal cortex plays a key role in inferring and making explicit decisions about the causal structure that generates sensory signals in our environment. By contrast, informed by observers' inferred causal structure, the FEF-IPS circuitry integrates auditory and visual spatial signals into representations that guide motor responses.SIGNIFICANCE STATEMENT In our natural environment, our senses are continuously flooded with a myriad of signals. Transforming this barrage of sensory signals into a coherent percept of the world relies inherently on solving the causal inference problem, deciding whether sensory signals arise from a common cause and should hence be integrated or else be segregated. This functional magnetic resonance imaging study shows that the lateral prefrontal cortex plays a key role in inferring the causal structure of the environment. Crucially, informed by the spatial correspondence cues and the inferred causal structure the frontal eye field and the intraparietal sulcus form a circuitry that integrates auditory and visual spatial signals into representations that guide motor responses.

Altered resting activity patterns and connectivity in individuals with complex regional pain syndrome.

Complex regional pain syndrome (CRPS) is a chronic neuropathic pain disorder that typically occurs in the limbs, usually the upper limb. CRPS usually develops from a peripheral event but its maintenance relies on changes within the central nervous system. While functional abnormalities in the thalamus and primary somatosensory cortex (S1) of the brain are some of the most consistently reported brain findings in CRPS, the mechanisms are yet to be explored in full, not least of all how these two regions interact and how they might relate to clinical deficits, such as the commonly reported poor tactile acuity in this condition. This study recruited 15 upper-limb CRPS subjects and 30 healthy controls and used functional magnetic resonance imaging (fMRI) to investigate infra-slow oscillations (ISOs) in critical pain regions of the brain in CRPS. As hypothesised, we found CRPS was associated with increases in resting signal intensity ISOs (0.03-0.06 Hz) in the thalamus contralateral to the painful limb in CRPS subjects. Interestingly, there was no such difference between groups in S1, however CRPS subjects displayed stronger thalamo-S1 functional connectivity than controls, and this was related to pain. As predicted, CRPS subjects displayed poor tactile acuity on the painful limb which, interestingly, was also related to thalamo-S1 functional connectivity strength. Our findings provide novel evidence of altered patterns of resting activity and connectivity in CRPS which may underlie altered thalamocortical loop dynamics and the constant perception of pain.

The Role of Sexual Orientation in the Associations Between Religiousness and Hypertension.

This study assessed the cross-sectional associations between organizational religious activity (ORA), intrinsic religiosity (IR), and hypertension in a US nationally representative sample. Data were from Wave IV of the National Longitudinal Study of Adolescent to Adult Health, collected in 2008. The sample (N = 5115, Mage = 28.96 years, 54% female) was divided into three sexual orientation categories: heterosexual, mostly heterosexual, and sexual minority. Dependent variables were systolic and diastolic blood pressure and binary cut-scores of clinical hypertension. ORA and IR were independent variables, with sexual orientation as the moderator. Multivariable analyses revealed greater ORA was associated with increased blood pressure (BP)/hypertension for the sexual minority group. There was a trend in the heterosexual group where ORA was associated with decreased BP. Generally, ORA was not associated with BP/hypertension in the mostly heterosexual group. There were no significant effects for IR. Future research should continue to examine the complex ways ORA and IR are associated with health based on sexual orientation and use longitudinal methodology to examine how ORA may impact BP/hypertension across the lifespan.

Reduced tactile acuity in chronic low back pain is linked with structural neuroplasticity in primary somatosensory cortex and is modulated by acupuncture therapy.

Prior studies have shown that patients suffering from chronic Low Back Pain (cLBP) have impaired somatosensory processing including reduced tactile acuity, i.e. reduced ability to resolve fine spatial details with the perception of touch. The central mechanism(s) underlying reduced tactile acuity are unknown but may include changes in specific brain circuitries (e.g. neuroplasticity in the primary somatosensory cortex, S1). Furthermore, little is known about the linkage between changes in tactile acuity and the amelioration of cLBP by somatically-directed therapeutic interventions, such as acupuncture. In this longitudinal neuroimaging study, we evaluated healthy control adults (HC, N â€‹= â€‹50) and a large sample of cLBP patients (N â€‹= â€‹102) with structural brain imaging (T1-weighted MRI for Voxel-Based Morphometry, VBM; Diffusion Tensor Imaging, DTI) and tactile acuity testing using two-point discrimination threshold (2PDT) over the lower back (site of pain) and finger (control) locations. Patients were evaluated at baseline and following a 4-week course of acupuncture, with patients randomized to either verum acupuncture, two different forms of sham acupuncture (designed with or without somatosensory afference), or no-intervention usual care control. At baseline, cLBP patients demonstrated reduced acuity (greater 2PDT, P â€‹= â€‹0.01) over the low back, but not finger (P â€‹= â€‹0.29) locations compared to HC, suggesting that chronic pain affects tactile acuity specifically at body regions encoding the experience of clinical pain. At baseline, Gray Matter Volume (GMV) was elevated and Fractional Anisotropy (FA) was reduced, respectively, in the S1-back region of cLBP patients compared to controls (P â€‹< â€‹0.05). GMV in cLBP correlated with greater 2PDT-back scores (ρ â€‹= â€‹0.27, P â€‹= â€‹0.02). Following verum acupuncture, tactile acuity over the back was improved (reduced 2PDT) and greater improvements were associated with reduced S1-back GMV (ρ â€‹= â€‹0.52, P â€‹= â€‹0.03) and increased S1-back adjacent white matter FA (ρ â€‹= â€‹-0.56, P â€‹= â€‹0.01). These associations were not seen for non-verum control interventions. Thus, S1 neuroplasticity in cLBP is linked with deficits in tactile acuity and, following acupuncture therapy, may represent early mechanistic changes in somatosensory processing that track with improved tactile acuity.

Poor neural and perceptual phoneme discrimination during acoustic variation in dyslexia.

Whereas natural acoustic variation in speech does not compromise phoneme discrimination in healthy adults, it was hypothesized to be a challenge for developmental dyslexics. We investigated dyslexics' neural and perceptual discrimination of native language phonemes during acoustic variation. Dyslexics and non-dyslexics heard /æ/ and /i/ phonemes in a context with fo variation and then in a context without it. Mismatch negativity (MMN) and P3a responses to phoneme changes were recorded with electroencephalogram to compare groups during ignore and attentive listening. Perceptual phoneme discrimination in the variable context was evaluated with hit-ratios and reaction times. MMN/N2bs were diminished in dyslexics in the variable context. Hit-ratios were smaller in dyslexics than controls. MMNs did not differ between groups in the context without variation. These results suggest that even distinctive vowels are challenging to discriminate for dyslexics when the context resembles natural variability of speech. This most likely reflects poor categorical perception of phonemes in dyslexics. Difficulties to detect linguistically relevant invariant information during acoustic variation in speech may contribute to dyslexics' deficits in forming native language phoneme representations during infancy. Future studies should acknowledge that simple experimental paradigms with repetitive stimuli can be insensitive to dyslexics' speech processing deficits.

Noise-Sensitive But More Precise Subcortical Representations Coexist with Robust Cortical Encoding of Natural Vocalizations.

Humans and animals maintain accurate sound discrimination in the presence of loud sources of background noise. It is commonly assumed that this ability relies on the robustness of auditory cortex responses. However, only a few attempts have been made to characterize neural discrimination of communication sounds masked by noise at each stage of the auditory system and to quantify the noise effects on the neuronal discrimination in terms of alterations in amplitude modulations. Here, we measured neural discrimination between communication sounds masked by a vocalization-shaped stationary noise from multiunit responses recorded in the cochlear nucleus, inferior colliculus, auditory thalamus, and primary and secondary auditory cortex at several signal-to-noise ratios (SNRs) in anesthetized male or female guinea pigs. Masking noise decreased sound discrimination of neuronal populations in each auditory structure, but collicular and thalamic populations showed better performance than cortical populations at each SNR. In contrast, in each auditory structure, discrimination by neuronal populations was slightly decreased when tone-vocoded vocalizations were tested. These results shed new light on the specific contributions of subcortical structures to robust sound encoding, and suggest that the distortion of slow amplitude modulation cues conveyed by communication sounds is one of the factors constraining the neuronal discrimination in subcortical and cortical levels.SIGNIFICANCE STATEMENT Dissecting how auditory neurons discriminate communication sounds in noise is a major goal in auditory neuroscience. Robust sound coding in noise is often viewed as a specific property of cortical networks, although this remains to be demonstrated. Here, we tested the discrimination performance of neuronal populations at five levels of the auditory system in response to conspecific vocalizations masked by noise. In each acoustic condition, subcortical neurons better discriminated target vocalizations than cortical ones and in each structure, the reduction in discrimination performance was related to the reduction in slow amplitude modulation cues.

One-week phonemic training rebuilds the memory traces of merged phonemes in merged speakers.

The phonemic merger is a unique phenomenon which is referred to as acoustically very different phonemes are recognized as the same phoneme. In our previous study, we demonstrated that the merged speakers had lost the ability to discriminate the merged phonemes pre-attentively, as revealed by their failure in mismatch negativity (MMN) elicitation in the oddball stream of the merged phonemes /n/-/l/. In this study, we investigated the recovery of the discrimination ability via phonemic training and found that the merged speakers regained the ability of discriminating merged phonemes pre-attentively, after a 7-day /n/-/l/ phonemic training, as revealed by the reactivation of MMN brain response to the /n/-/l/ phoneme categories. Our finding indicates that separate memory traces of merged phonemes could be rebuilt during the training process.

Response outcomes gate the impact of expectations on perceptual decisions.

Perceptual decisions are based on sensory information but can also be influenced by expectations built from recent experiences. Can the impact of expectations be flexibly modulated based on the outcome of previous decisions? Here, rats perform an auditory task where the probability to repeat the previous stimulus category is varied in trial-blocks. All rats capitalize on these sequence correlations by exploiting a transition bias: a tendency to repeat or alternate their previous response using an internal estimate of the sequence repeating probability. Surprisingly, this bias is null after error trials. The internal estimate however is not reset and it becomes effective again after the next correct response. This behavior is captured by a generative model, whereby a reward-driven modulatory signal gates the impact of the latent model of the environment on the current decision. These results demonstrate that, based on previous outcomes, rats flexibly modulate how expectations influence their decisions.

Counting or discriminating the number of voices to assess binaural fusion with single-sided vocoders.

For single-sided deafness cochlear-implant (SSD-CI) listeners, different peripheral representations for electric versus acoustic stimulation, combined with interaural frequency mismatch, might limit the ability to perceive bilaterally presented speech as a single voice. The assessment of binaural fusion often relies on subjective report, which requires listeners to have some understanding of the perceptual phenomenon of object formation. Two experiments explored whether binaural fusion could instead be assessed using judgments of the number of voices in a mixture. In an SSD-CI simulation, normal-hearing listeners were presented with one or two "diotic" voices (i.e., unprocessed in one ear and noise-vocoded in the other) in a mixture with additional monaural voices. In experiment 1, listeners reported how many voices they heard. Listeners generally counted the diotic speech as two separate voices, regardless of interaural frequency mismatch. In experiment 2, listeners identified which of two mixtures contained diotic speech. Listeners performed significantly better with interaurally frequency-matched than with frequency-mismatched stimuli. These contrasting results suggest that listeners experienced partial fusion: not enough to count the diotic speech as one voice, but enough to detect its presence. The diotic-speech detection task (experiment 2) might provide a tool to evaluate fusion and optimize frequency mapping for SSD-CI patients.