Discriminative Cues Research Articles

Characterization, Experimental Validation and Pilot User Study of the Vibro-Inertial Bionic Enhancement System (VIBES).

This study presents the characterization and validation of the VIBES, a wearable vibrotactile device that provides high-frequency tactile information embedded in a prosthetic socket. A psychophysical characterization involving ten able-bodied participants is performed to compute the Just Noticeable Difference (JND) related to the discrimination of vibrotactile cues delivered on the skin in two forearm positions, with the goal of optimising vibrotactile actuator position to maximise perceptual response. Furthermore, system performance is validated and tested both with ten able-bodied participants and one prosthesis user considering three tasks. More specifically, in the Active Texture Identification, Slippage and Fragile Object Experiments, we investigate if the VIBES could enhance users' roughness discrimination and manual usability and dexterity. Finally, we test the effect of the vibrotactile system on prosthetic embodiment in a Rubber Hand Illusion (RHI) task. Results show the system's effectiveness in conveying contact and texture cues, making it a potential tool to restore sensory feedback and enhance the embodiment in prosthetic users.

Conditioned inhibition of fear and reward in male and female rats

Stimuli in our environment are not always associated with an outcome. Some of these stimuli, depending on how they are presented, may gain inhibitory value or simply be ignored. If experienced in the presence of other cues predictive of appetitive or aversive outcomes, they typically gain inhibitory value and become predictive cues indicating the absence of appetitive or aversive outcomes. In this case, these cues are referred to as conditioned inhibitors. Here, male and female Long Evans rats underwent cue discrimination training where a reward cue was paired with sucrose, a fear cue with footshock, and an inhibitor cue resulted in neither sucrose or footshock. During a subsequent summation test for conditioned inhibition of fear and reward, the inhibitor cue was presented concurrently with the reward and fear cues without any outcome, intermixed with trials of reinforced reward and fear trials. Males showed significant conditioned inhibition of freezing, while females did not, which was not dependent on estrous. Both males and females showed significant conditioned inhibition of reward. During a retardation of fear acquisition test, the inhibitor was paired with footshock and both males and females showed delayed acquisition of fear. During a retardation of reward acquisition test, the inhibitor was paired with sucrose, and females showed delayed acquisition of reward, while males did not. In summary, males and females showed significant reward-fear-inhibitor cue discrimination, conditioned inhibition of reward, and retardation of fear acquisition. The main sex difference, which was not estrous-dependent, was the lack of conditioned inhibition of freezing in females. These data imply that while the inhibitor cue gained some inhibitory value in the females, the strength of this inhibitory value may not have been great enough to effectively downregulate freezing elicited by the fear cue.

A skin-integrated device for neck posture monitoring and correction

Cervical spondylosis is a common disease that is often caused by long-term abnormal cervical curvature due to activities such as reading books and using computers or smartphones. This paper explores building an untethered and skin-integrated device in an e-skin form factor to monitor and haptically correct neck posture. The proposed design features a multilayered structure that integrates all flexible electronic circuits and components into a compact skin space while being untethered and skin conformal. An accelerometer in the e-skin attaches to the neck for posture sensing, while four vibration actuators closely touch the neck skin to provide localized vibrotactile stimuli that encode four-direction correction cues of neck flexion pm alpha and lateral bending pm beta. To ensure the reliability of posture sensing and vibrotactile rendering during neck movement, it is necessary to prevent the e-skin device from shifting position. Thus, a hollow structure-based method is implemented for stably attaching the e-skin to the neck skin. Experiments validated the e-skin device’s sensing precision, skin-conformal compliance, stickiness, stability and effectiveness during the motion of neck postures, including its discrimination of localized four-direction vibrotactile cues. A user study verified the device’s performance for sensing and correcting different abnormal neck postures during activities such as using smartphones, reading books, and processing computer files. The proposed e-skin device may create opportunities for more convenient cervical spondylosis prevention and rehabilitation.

Semantic-Guided Information Alignment Network for Fine-Grained Image Recognition

Existing <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">fine-grained image recognition</i> works have attempted to dig into low-level details for emphasizing subtle discrepancies among sub-categories. However, a potential limitation of these methods is that they integrate the low-level details and high-level semantics directly, and neglect their content complementarity and spatial corresponding correlation. To handle this limitation, we propose an end-to-end Semantic-guided Information Alignment Network (SIA-Net) to dynamically pick out the low-level details under the guidance of accurate semantics to make selected details spatially corresponding to high-level semantics and complementary in content. Technically, SIA-Net consists of an Accurate Semantic Calibration (ASC) module for providing accurate semantics and a Discriminative Feature Alignment (DFA) module for aggregating low-level details and high-level semantics using accurate semantics generated by ASC. ASC learns the pixel-level feature shifting caused by convolutional operations, which is utilized for replacing the incorrectly highlighted semantics by shifting discriminative semantics or background features. After obtaining the accurate semantic features, DFA digs into the complementary details and simultaneously makes the selected details spatially corresponding via applying the guidance of accurate semantics to obtain the reassembly features. Finally, the reassembly features, which serve as discriminative cues, are used for more accurate discriminative region localization. Extensive experiments verify that our proposed method yields the best performance under the same settings with the most competitive approaches on CUB-birds, Stanford-Cars, and FGVC Aircraft datasets.

Neural discrimination of facial cues associated with trustworthiness in adults and 6-month-old infants as revealed by fast periodic visual stimulation.

Adults and children easily distinguish between fine-grained variations in trustworthiness intensity based on facial appearance, but the developmental origins of this fundamental social skill are still debated. Using a fast periodic visual stimulation (FPVS) oddball paradigm coupled with electroencephalographic (EEG) recording, we investigated neural discrimination of morphed faces that adults perceive as low- and high-trustworthy in a sample of 6-month-old infants (N = 29; 56% male; Mage = 196.8 days; all White) and young adults (N = 21; 40% male; Mage = 24.61 years; all White) recruited in Italy. Stimulus sequences were presented at 6 Hz with deviant faces interleaved every fifth stimulus (i.e., 1.2 Hz); oddball category (high/low trustworthiness) was varied within subjects. FPVS responses were analyzed at both frequencies of interest and their harmonics as a function of deviant type (high- vs. low-trustworthy) over occipital and occipitolateral electrode clusters. For both infants and adults, the baseline response did not differ between trustworthiness conditions. Significant responses were centered on the right parietal electrodes in infants, and on the occipital and left occipitotemporal clusters in adults. Oddball responses were significant for both infants and adults, with cross-age differences in the topographical localization of the response on the scalp. Overall, results suggest that, by the age of 6 months, infants discriminate between faces that adults rate as high and low in trustworthiness, extending prior evidence of early sensitivity to this face dimension in humans. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

Cochlear Implant Users can Effectively Combine Place and Timing Cues for Pitch Perception.

The study objective was to characterize cochlear implant (CI) pitch perception for pure, complex, and modulated tones for frequencies and fundamental frequencies in the ecologically essential range between 110 and 440 Hz. Stimulus manipulations were used to examine CI users' reliance on stimulation place and rate cues for pitch discrimination. The study was a within-subjects design with 21 CI users completing pitch discrimination measures using pure, complex, and modulated tones. Stimulus manipulations were used to test whether CI users have better pitch discrimination for low-pass compared with high-pass filtered harmonic complexes, and to test whether they have better pitch discrimination when provided a covarying place cue when listening to amplitude-modulated tones. Averaged across conditions, participants had better pitch discrimination for pure tones compared with either complex or amplitude-modulated tones. Participants had better pitch discrimination for low-pass compared with high-pass harmonic complexes and better pitch discrimination for amplitude-modulated tones when provided a covarying place cue. CI users integrate place and rate cues across the ecologically essential pitch range between 110 and 440 Hz. We interpret the observed better pitch discrimination for low-pass compared with high-pass filtered harmonics complexes, and for amplitude-modulated tones when provided a covarying place cue, as evidence for the importance of providing place-of-excitation cues for fundamental frequencies below 440 Hz. Discussion considers how such encoding could be implemented with existing devices.

Reframing dopamine: A controlled controller at the limbic-motor interface.

Pavlovian influences notoriously interfere with operant behaviour. Evidence suggests this interference sometimes coincides with the release of the neuromodulator dopamine in the nucleus accumbens. Suppressing such interference is one of the targets of cognitive control. Here, using the examples of active avoidance and omission behaviour, we examine the possibility that direct manipulation of the dopamine signal is an instrument of control itself. In particular, when instrumental and Pavlovian influences come into conflict, dopamine levels might be affected by the controlled deployment of a reframing mechanism that recasts the prospect of possible punishment as an opportunity to approach safety, and the prospect of future reward in terms of a possible loss of that reward. We operationalize this reframing mechanism and fit the resulting model to rodent behaviour from two paradigmatic experiments in which accumbens dopamine release was also measured. We show that in addition to matching animals' behaviour, the model predicts dopamine transients that capture some key features of observed dopamine release at the time of discriminative cues, supporting the idea that modulation of this neuromodulator is amongst the repertoire of cognitive control strategies.

Learning Foreground Information Bottleneck for few-shot semantic segmentation

Few-shot semantic segmentation aims to segment unseen classes with only a few annotated samples, which has great values for the real-world application in the wild. However, since the target class is treated as the background in the training, the network tends to extract much irrelevant nuisance factors, which results in the feature undermining problem for the target class. Consequently, it is difficult to produce an accurate segmentation map. To address this problem, in this paper, we apply the information bottleneck theory to few-shot semantic segmentation and propose the Foreground Information Bottleneck (FIB) module. Based on the support information, FIB module filters out the irrelevant information and promotes the foreground-related feature paradigms. Meanwhile, to solve the intractable mutual information and enable the end-to-end optimization of FIB module, we derive the Foreground Information Bottleneck Loss (FIBLoss) according to the inherent attribute of few-shot segmentation. Moreover, since there exists severe noise interference in the wild, we design a Target Information Refinement (TIR) block to further exploit discriminative cues of foreground. TIR block calculates the pairwise interaction and exploits the detailed information of the foreground object, which is beneficial to the feature refinement. Extensive experiments on two challenging datasets reflect the proposed FIB module significantly improves the performance of few-shot segmentation and delivers the state-of-the-art results.

A CNN Approach for Emotion Recognition via EEG

Emotion recognition via electroencephalography (EEG) has been gaining increasing attention in applications such as human–computer interaction, mental health assessment, and affective computing. However, it poses several challenges, primarily stemming from the complex and noisy nature of EEG signals. Commonly adopted strategies involve feature extraction and machine learning techniques, which often struggle to capture intricate emotional nuances and may require extensive handcrafted feature engineering. To address these limitations, we propose a novel approach utilizing convolutional neural networks (CNNs) for EEG emotion recognition. Unlike traditional methods, our CNN-based approach learns discriminative cues directly from raw EEG signals, bypassing the need for intricate feature engineering. This approach not only simplifies the preprocessing pipeline but also allows for the extraction of more informative features. We achieve state-of-the-art performance on benchmark emotion datasets, namely DEAP and SEED datasets, showcasing the superiority of our approach in capturing subtle emotional cues. In particular, accuracies of 96.32% and 92.54% were achieved on SEED and DEAP datasets, respectively. Further, our pipeline is robust against noise and artefact interference, enhancing its applicability in real-world scenarios.

VIBES: Vibro-Inertial Bionic Enhancement System in a Prosthetic Socket.

The use of vibrotactile feedback is of growing interest in the field of prosthetics, but few devices fully integrate this technology in the prosthesis to transmit high-frequency contact information (such as surface roughness and first contact) arising from the interaction of the prosthetic device with external items. This study describes a wearable vibrotactile system for high-frequency tactile information embedded in the prosthetic socket. The device consists of two compact planar vibrotactile actuators in direct contact with the user's skin to transmit tactile cues. These stimuli are directly related to the acceleration profiles recorded with two IMUS placed on the distal phalanx of a soft under-actuated robotic prosthesis (Soft-Hand Pro). We characterized the system from a psychophysical point of view with fifteen able-bodied participants by computing participants' Just Noticeable Difference (JND) related to the discrimination of vibrotactile cues delivered on the index finger, which are associated with the exploration of different sandpapers. Moreover, we performed a pilot experiment with one SoftHand Pro prosthesis user by designing a task, i.e. Active Texture Identification, to investigate if our feedback could enhance users' roughness discrimination. Results indicate that the device can effectively convey contact and texture cues, which users can readily detect and distinguish.

Dual Transformer With Multi-Grained Assembly for Fine-Grained Visual Classification

Fine-grained visual classification requires distinguishing sub-categories within the same super-category, which suffers from small inter-class and large intra-class variances. This paper aims to improve the FGVC task towards better performance, for which we deliver a novel dual Transformer framework (coined Dual-TR) with multi-grained assembly. The Dual-TR is well-designed to encode fine-grained objects by two parallel hierarchies, which is amenable to capturing the subtle yet discriminative cues via the self-attention mechanism in ViT. Specifically, we perform orthogonal multi-grained assembly within the Transformer structure for a more robust representation, <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">i.e</i> ., intra-layer and inter-layer assembly. The former aims to explore the informative feature in various self-attention heads within the Transformer layer. The latter pays attention to the token assembly across Transformer layers. Meanwhile, we introduce the constraint of center loss to pull intra-class samples’ compactness and push that of inter-class samples. Extensive experiments show that Dual-TR performs on par with the state-of-the-art methods on four public benchmarks, including CUB-200-2011, NABirds, iNaturalist2017, and Stanford Dogs. The comprehensive ablation studies further demonstrate the effectiveness of architectural design choices.

Detect occluded items in X-ray baggage inspection

X-ray baggage inspection automatically determines whether there are prohibited items in passenger luggage and has recently achieved good progress due to the development of deep convolutional neural networks (DCNNs). However, the performance of X-ray baggage inspection degrades with heavily occluded and cluttered baggage owing to the interaction of the imaged objects. Inspired by the idea that discriminant cues may still exist in multiscale perceptions, discrepancies among different classes, and associations among different tasks, we propose a novel approach that exploits pseudo semantic masks to enhance the discriminant ability of feature representations. Moreover, the features at neighboring scales interact to further explore context information. We verify our method on the publicly available SIXray, OPIXray, and HIXray datasets. The results show that our method outperforms other state-of-the-art X-ray baggage inspection methods by 1.02% and 0.85% in terms of mean average precision (mAP).

Plasticity of neuronal dynamics in the lateral habenula for cue-punishment associative learning

The brain’s ability to associate threats with external stimuli is vital to execute essential behaviours including avoidance. Disruption of this process contributes instead to the emergence of pathological traits which are common in addiction and depression. However, the mechanisms and neural dynamics at the single-cell resolution underlying the encoding of associative learning remain elusive. Here, employing a Pavlovian discrimination task in mice we investigate how neuronal populations in the lateral habenula (LHb), a subcortical nucleus whose excitation underlies negative affect, encode the association between conditioned stimuli and a punishment (unconditioned stimulus). Large population single-unit recordings in the LHb reveal both excitatory and inhibitory responses to aversive stimuli. Additionally, local optical inhibition prevents the formation of cue discrimination during associative learning, demonstrating a critical role of LHb activity in this process. Accordingly, longitudinal in vivo two-photon imaging tracking LHb calcium neuronal dynamics during conditioning reveals an upward or downward shift of individual neurons’ CS-evoked responses. While recordings in acute slices indicate strengthening of synaptic excitation after conditioning, support vector machine algorithms suggest that postsynaptic dynamics to punishment-predictive cues represent behavioral cue discrimination. To examine the presynaptic signaling in LHb participating in learning we monitored neurotransmitter dynamics with genetically-encoded indicators in behaving mice. While glutamate, GABA, and serotonin release in LHb remain stable across associative learning, we observe enhanced acetylcholine signaling developing throughout conditioning. In summary, converging presynaptic and postsynaptic mechanisms in the LHb underlie the transformation of neutral cues in valued signals supporting cue discrimination during learning.

Penguins perceive variations of source- and filter-related vocal parameters of species-specific vocalisations.

Animal vocalisations encode a wide range of biological information about the age, sex, body size, and social status of the emitter. Moreover, vocalisations play a significant role in signalling the identity of the emitter to conspecifics. Recent studies have shown that, in the African penguin (Spheniscus demersus), acoustic cues to individual identity are encoded in the fundamental frequency (F0) and resonance frequencies (formants) of the vocal tract. However, although penguins are known to produce vocalisations where F0 and formants vary among individuals, it remains to be tested whether the receivers can perceive and use such information in the individual recognition process. In this study, using the Habituation-Dishabituation (HD) paradigm, we tested the hypothesis that penguins perceive and respond to a shift of ± 20% (corresponding to the natural inter-individual variation observed in ex-situ colonies) of F0 and formant dispersion (ΔF) of species-specific calls. We found that penguins were more likely to look rapidly and for longer at the source of the sound when F0 and formants of the calls were manipulated, indicating that they could perceive variations of these parameters in the vocal signals. Our findings provide the first experimental evidence that, in the African penguin, listeners can perceive changes in F0 and formants, which can be used by the receiver as potential cues for the individual discrimination of the emitter.

Does the type of task affect prey discrimination learning in avian predators?

AbstractWhen learning to discriminate between palatable and unpalatable prey, predators may encounter the prey either simultaneously or in a sequence. The two types of discrimination tasks, which are frequently used in experiments focused on aposematism and mimicry, may considerably differ in difficulty, as they differ in the information available to predators during individual encounters with prey. Surprisingly, there are very few studies directly comparing the performance of predators between sequential and simultaneous discrimination tasks using otherwise identical experimental design, the same predators and prey. We tested the effect of the type of discrimination task on the effectiveness of discrimination learning in adult and juvenile great tits (Parus major). Birds were trained to discriminate between palatable and unpalatable artificial prey items baited with mealworms soaked either in water or quinine. Prey shape, colours and patterns were derived from real shield bug species. We compared the performance of birds tested with two discriminative cues, colour and pattern, using three discrimination tasks: (1) sequential—alternating presentation of one palatable and one unpalatable prey item, (2) two‐choice—simultaneous presentation of one palatable and one unpalatable prey item and (3) multiple‐choice—simultaneous presentation of multiple palatable and unpalatable prey items. Colour was a more effective discriminative cue than pattern for both adult and juvenile birds. Adults performed better than juveniles regardless of task. The birds performed equally well in the sequential and two‐choice tasks, but their performance in the multiple‐choice task was worse than in the other two tasks. However, these differences were only present when the birds used the pattern as a discriminative cue. The birds tested with colour, a more salient cue, performed equally well in all three tasks. Type of discrimination task may therefore affect the learning performance of predators, but the effect also depends on the saliency of a particular discriminative cue.

Dopamine in the dorsal bed nucleus of stria terminalis signals Pavlovian sign-tracking and reward violations.

Midbrain and striatal dopamine signals have been extremely well characterized over the past several decades, yet novel dopamine signals and functions in reward learning and motivation continue to emerge. A similar characterization of real-time sub-second dopamine signals in areas outside of the striatum has been limited. Recent advances in fluorescent sensor technology and fiber photometry permit the measurement of dopamine binding correlates, which can divulge basic functions of dopamine signaling in non-striatal dopamine terminal regions, like the dorsal bed nucleus of the stria terminalis (dBNST). Here, we record GRABDA signals in the dBNST during a Pavlovian lever autoshaping task. We observe greater Pavlovian cue-evoked dBNST GRABDA signals in sign-tracking (ST) compared to goal-tracking/intermediate (GT/INT) rats and the magnitude of cue-evoked dBNST GRABDA signals decreases immediately following reinforcer-specific satiety. When we deliver unexpected rewards or omit expected rewards, we find that dBNST dopamine signals encode bidirectional reward prediction errors in GT/INT rats, but only positive prediction errors in ST rats. Since sign- and goal-tracking approach strategies are associated with distinct drug relapse vulnerabilities, we examined the effects of experimenter-administered fentanyl on dBNST dopamine associative encoding. Systemic fentanyl injections do not disrupt cue discrimination but generally potentiate dBNST dopamine signals. These results reveal multiple dBNST dopamine correlates of learning and motivation that depend on the Pavlovian approach strategy employed.

Psychological and physiological correlates of stimulus discrimination in adults.

The discrimination of cues in the environment that signal danger ("fear cue") is important for survival but depends critically on the discernment of such cues from ones that pose no threat ("safety cues"). In rodents, we previously demonstrated the underlying neurobiological mechanisms that support fear versus safety discrimination and documented that these mechanisms extend to the discrimination of reward as well. While learning about reward is equally important for survival, it remains an under-studied area of research, particularly in human studies of conditional discrimination. In the present study, we translated our rodent task of fear reward and neutral discrimination (fear, reward, and neutral discrimination [FRND]) for use in humans. Undergraduate students (N = 53) completed the FRND while electrodermal activity was recorded. Skin conductance response (SCR) amplitude, a marker of arousal response, was derived for fear, reward, and neutral cues that signaled no outcome; critical trials assessed conditional discrimination using combined fear + neutral and reward + neutral cues. Participants provided likeability ratings for each cue type. Results demonstrated that participants rated reward cues the best, fear cues the worst, and neutral cues in between, while SCR amplitude was largest for fear and reward cues and lowest for neutral cues. SCR amplitudes were reduced for fear + neutral (compared to fear) and reward + neutral cues (compared to reward). Results demonstrate that the FRND is a useful paradigm for the assessment of psychological and physiological discrimination of fear and reward. Implications and directions for future work are discussed.

Genome-Wide Analysis of the Odorant Receptor Gene Family in Solenopsis invicta, Ooceraea biroi, and Monomorium pharaonis (Hymenoptera: Formicidae)

Olfactory systems in eusocial insects play a vital role in the discrimination of various chemical cues. Odorant receptors (ORs) are critical for odorant detection, and this family has undergone extensive expansion in ants. In this study, we re-annotated the OR genes from the most destructive invasive ant species Solenopsis invicta and 2 other Formicidae species, Ooceraea biroi and Monomorium pharaonis, with the aim of systematically comparing and analyzing the evolution and the functions of the ORs in ant species, identifying 356, 298, and 306 potential functional ORs, respectively. The evolutionary analysis of these ORs showed that ants had undergone chromosomal rearrangements and that tandem duplication may be the main contributor to the expansion of the OR gene family in S. invicta. Our further analysis revealed that 9-exon ORs had biased chromosome localization patterns in all three ant species and that a 9-exon OR cluster (SinvOR4-8) in S. invicta was under strong positive selection (Ka/Ks = 1.32). Moreover, we identified 5 S. invicta OR genes, namely SinvOR89, SinvOR102, SinvOR352, SinvOR327, and SinvOR135, with high sequence similarity (>70%) to the orthologs in O. biroi and M. pharaonis. An RT-PCR analysis was used to verify the antennal expression levels of these ORs, which showed caste-specific expression. The subsequent analysis of the antennal expression profiles of the ORs of the S. invicta workers from the polygyne and monogyne social forms indicated that SinvOR35 and SinvOR252 were expressed at much higher levels in the monogyne workers than in the polygyne workers and that SinvOR21 was expressed at higher levels in polygyne workers. Our study has contributed to the identification and analysis of the OR gene family in ants and expanded the understanding of the evolution and functions of the ORs in Formicidae species.

Sound localization acuity of the common marmoset (Callithrix jacchus)

The common marmoset (Callithrix jacchus) is a small arboreal New World primate which has emerged as a promising model in auditory neuroscience. One potentially useful application of this model system is in the study of the neural mechanism underlying spatial hearing in primate species, as the marmosets need to localize sounds to orient their head to events of interest and identify their vocalizing conspecifics that are not visible. However, interpretation of neurophysiological data on sound localization requires an understanding of perceptual abilities, and the sound localization behavior of marmosets has not been well studied. The present experiment measured sound localization acuity using an operant conditioning procedure in which marmosets were trained to discriminate changes in sound location in the horizontal (azimuth) or vertical (elevation) dimension. Our results showed that the minimum audible angle (MAA) for horizontal and vertical discrimination was 13.17° and 12.53°, respectively, for 2 to 32 kHz Gaussian noise. Removing the monaural spectral cues tended to increase the horizontal localization acuity (11.31°). Marmosets have larger horizontal MAA (15.54°) in the rear than the front. Removing the high-frequency (> 26 kHz) region of the head-related transfer function (HRTF) affected vertical acuity mildly (15.76°), but removing the first notch (12–26 kHz) region of HRTF substantially reduced the vertical acuity (89.01°). In summary, our findings indicate that marmosets’ spatial acuity is on par with other species of similar head size and field of best vision, and they do not appear to use monaural spectral cues for horizontal discrimination but rely heavily on first notch region of HRTF for vertical discrimination.

Short Implicit Voice Training Affects Listening Effort During a Voice Cue Sensitivity Task With Vocoder-Degraded Speech.

Understanding speech in real life can be challenging and effortful, such as in multiple-talker listening conditions. Fundamental frequency ( fo ) and vocal-tract length ( vtl ) voice cues can help listeners segregate between talkers, enhancing speech perception in adverse listening conditions. Previous research showed lower sensitivity to fo and vtl voice cues when speech signal was degraded, such as in cochlear implant hearing and vocoder-listening compared to normal hearing, likely contributing to difficulties in understanding speech in adverse listening. Nevertheless, when multiple talkers are present, familiarity with a talker's voice, via training or exposure, could provide a speech intelligibility benefit. In this study, the objective was to assess how an implicit short-term voice training could affect perceptual discrimination of voice cues ( fo+vtl ), measured in sensitivity and listening effort, with or without vocoder degradations. Voice training was provided via listening to a recording of a book segment for approximately 30 min, and answering text-related questions, to ensure engagement. Just-noticeable differences (JNDs) for fo+vtl were measured with an odd-one-out task implemented as a 3-alternative forced-choice adaptive paradigm, while simultaneously collecting pupil data. The reference voice either belonged to the trained voice or an untrained voice. Effects of voice training (trained and untrained voice), vocoding (non-vocoded and vocoded), and item variability (fixed or variable consonant-vowel triplets presented across three items) on voice cue sensitivity ( fo+vtl JNDs) and listening effort (pupillometry measurements) were analyzed. Results showed that voice training did not have a significant effect on voice cue discrimination. As expected, fo+vtl JNDs were significantly larger for vocoded conditions than for non-vocoded conditions and with variable item presentations than fixed item presentations. Generalized additive mixed models analysis of pupil dilation over the time course of stimulus presentation showed that pupil dilation was significantly larger during fo+vtl discrimination while listening to untrained voices compared to trained voices, but only for vocoder-degraded speech. Peak pupil dilation was significantly larger for vocoded conditions compared to non-vocoded conditions and variable items increased the pupil baseline relative to fixed items, which could suggest a higher anticipated task difficulty. In this study, even though short voice training did not lead to improved sensitivity to small fo+vtl voice cue differences at the discrimination threshold level, voice training still resulted in reduced listening effort for discrimination among vocoded voice cues.