Discriminative Cues Research Articles

Hybrid Open-Set Segmentation With Synthetic Negative Data.

Open-set segmentation can be conceived by complementing closed-set classification with anomaly detection. Many of the existing dense anomaly detectors operate through generative modelling of regular data or by discriminating with respect to negative data. These two approaches optimize different objectives and therefore exhibit different failure modes. Consequently, we propose a novel anomaly score that fuses generative and discriminative cues. Our score can be implemented by upgrading any closed-set segmentation model with dense estimates of dataset posterior and unnormalized data likelihood. The resulting dense hybrid open-set models require negative training images that can be sampled from an auxiliary negative dataset, from a jointly trained generative model, or from a mixture of both sources. We evaluate our contributions on benchmarks for dense anomaly detection and open-set segmentation. The experiments reveal strong open-set performance in spite of negligible computational overhead.

Patterned wireless transcranial optogenetics generates artificial perception.

Synthesizing perceivable artificial neural inputs independent of typical sensory channels remains a fundamental challenge in the development of next-generation brain-machine interfaces. Establishing a minimally invasive, wirelessly effective, and miniaturized platform with long-term stability is crucial for creating a clinically meaningful interface capable of mediating artificial perceptual feedback. In this study, we demonstrate a miniaturized fully implantable wireless transcranial optogenetic encoder designed to generate artificial perceptions through digitized optogenetic manipulation of large cortical ensembles. This platform enables the spatiotemporal orchestration of large-scale cortical activity for remote perception genesis via real-time wireless communication and control, with optimized device performance achieved by simulation-guided methods addressing light and heat propagation during operation. Cue discrimination during operant learning demonstrates the wireless genesis of artificial percepts sensed by mice, where spatial distance across large cortical networks and sequential order-based analyses of discrimination performance reveal principles that adhere to general perceptual rules. These conceptual and technical advancements expand our understanding of artificial neural syntax and its perception by the brain, guiding the evolution of next-generation brain-machine communication.

Taste enhances the ability to express a preference for a congruent odor in rats.

Foods that make up a typical diet are characterized by a rich set of sensory qualities that are perceived through multiple different modalities. It is well known that multisensory aspects of food are integrated to create our perception of flavor, which in turn affects our behavioral responses to food. However, the principles underlying multisensory integration of flavor-related sensory signals and how they inform perceptual judgments remain poorly understood, partly due to lack of control over flavor experience in human subjects. Here, we used rats as a model to overcome this limitation and tested the hypothesis that taste can enhance discriminability of retronasal odor cues. In a series of two-bottle tests, animals chose between two odorized solutions after learning to associate one of the odors with saccharin. When odors were highly similar, animals showed little preference for the saccharin-associated odor. When adding saccharin to both bottles-rendering one of the solutions' congruent-animals' preference for the saccharin-associated odor was significantly enhanced. No effect of taste was observed when using dissimilar odor pairs or novel taste stimuli. These findings suggest that congruent taste stimuli selectively enhance odor identity representations, aiding in the discriminability of perceptually similar flavors. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

Learning competence of the temperate facultative cleaner wrasse Thalassoma pavo (Labridae).

Cleaner fishes remove parasites from other fishes called "clients," thereby contributing to a healthier ecosystem. Although the behavior and learning abilities of dedicated and tropical cleaner fishes have been broadly studied, a limited number of studies investigated the behavior of facultative and temperate cleaner fishes and, to the best of our knowledge, none focused on their cognitive abilities. Here, we tested the learning abilities of a species of temperate facultative cleaner, the ornate wrasse Thalassoma pavo in laboratory conditions, based on two problems. These two problems, or tasks, are relevant in two different contexts: the first one, deemed as mutualistically relevant, the cue-based discrimination task, and the second one, the spatial-based discrimination task, which is relevant in a non-cleaning context, when fish navigate through their environment to find food and return to their territories. We found that T. pavo individuals were able to solve these two tasks but excelled at the spatial task rather than with the cue discrimination. The same individuals were also challenged to learn the reverse protocol of these tasks and were again most successful in learning the reverse spatial discrimination problem, but not the cue. Contrary to the dedicated cleaner wrasse Labroides dimidiatus, this temperate facultative cleaner wrasse is slower to learn mutualistic relevant problems but competent in solving spatially derived problems. This may be due to the specific demands of their socio-ecological environment, with facultative cleaners having a greater component of non-mutualistic skills (spatial component), which prepares them to search for alternative food sources if necessary (e.g., feeding on the substrate) or even to expand territories more easily and less prepared to deal with mutualistic exchanges compared to dedicated cleaners that specialize to become increasingly socially competent.

Discriminative stimulus properties of two training doses of gabapentin in rats: Substitution by pregabalin, diazepam, and pentobarbital.

Gabapentin is used for the treatment of many conditions, including seizures, pain, and anxiety. Increasing reports of nonprescribed use suggest that gabapentin may elicit positive subjective effects. The present study was conducted to examine the subjective effects of gabapentin using rats trained to discriminate either a 30.0 mg/kg or 300.0 mg/kg dose of gabapentin versus vehicle on a two-choice drug discrimination task. Both doses of gabapentin were established as discriminative stimuli, and the 300.0 mg/kg dose was more readily established compared to the 30.0 mg/kg dose. Full substitution (> 80% gabapentin-lever responding) occurred by the training drug and by the gabapentinoid compound pregabalin. Partial substitution (> 20% gabapentin-lever responding) was shown by the opioid compounds morphine and fentanyl, and dose combinations of the opioid receptor antagonist naltrexone with the gabapentin training doses reduced the percentage of gabapentin-lever responding to below 80%. Partial substitution for both training doses of gabapentin occurred with the cannabinoid Δ⁹-tetrahydrocannabinol. The barbiturate compound pentobarbital and the benzodiazepine compound diazepam were only tested for substitution for the 300.0 mg/kg dose of gabapentin and these compounds produced full substitution. These findings demonstrate that gabapentin establishes a robust discriminative cue and exhibits stimulus effects closely similar to pregabalin, pentobarbital, and diazepam. Since pregabalin, pentobarbital, and diazepam carry a risk of problematic use and are classified as controlled substances, further evaluations of gabapentin's risks in this regard are warranted. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

MixImages: An Urban Perception AI Method Based on Polarization Multimodalities.

Intelligent urban perception is one of the hot topics. Most previous urban perception models based on semantic segmentation mainly used RGB images as unimodal inputs. However, in natural urban scenes, the interplay of light and shadow often leads to confused RGB features, which diminish the model's perception ability. Multimodal polarization data encompass information dimensions beyond RGB, which can enhance the representation of shadow regions, serving as additional data for assistance. Additionally, in recent years, transformers have achieved outstanding performance in visual tasks, and their large, effective receptive field can provide more discriminative cues for shadow regions. For these reasons, this study proposes a novel semantic segmentation model called MixImages, which can combine polarization data for pixel-level perception. We conducted comprehensive experiments on a polarization dataset of urban scenes. The results showed that the proposed MixImages can achieve an accuracy advantage of 3.43% over the control group model using only RGB images in the unimodal benchmark while gaining a performance improvement of 4.29% in the multimodal benchmark. Additionally, to provide a reference for specific downstream tasks, we also tested the impact of different combinations of polarization types on the overall segmentation accuracy. The proposed MixImages can be a new option for conducting urban scene perception tasks.

Low‐resolution activity recognition using super‐resolution and model ensemble networks

AbstractIn real‐world video super‐resolution, the complexity and diversity of degradations pose substantial challenges during both training and inference. Videos captured in real‐world settings often depict activities at varying resolutions. Typically, these activities are filmed from a distance that reduces the resolution of imagery, which thus lacks discriminative features. To address this problem, we introduce an activity recognition solution. First, a unique integration of data transformation and attention‐based average discriminator are employed for super‐resolution feature augmentation. This approach mitigates the lack of discriminative cues in low‐resolution videos. Subsequently, high‐resolution features extracted from the recovered data are directly fed into a model ensemble for activity recognition. We evaluate the resulting method on the TinyVIRAT‐v2 and HMDB51 datasets, achieving improved visual quality by leveraging the super‐resolution and model ensemble strategy. The proposed method enhances the quality of textures and boosts activity recognition in low‐resolution videos.

Two-stage deep learning classification for diabetic retinopathy using gradient weighted class activation mapping

The fundus images of patients with Diabetic Retinopathy (DR) often display numerous lesions scattered across the retina. Current methods typically utilize the entire image for network learning, which has limitations since DR abnormalities are usually localized. Training Convolutional Neural Networks (CNNs) on global images can be challenging due to excessive noise. Therefore, it's crucial to enhance the visibility of important regions and focus the recognition system on them to improve accuracy. This study investigates the task of classifying the severity of diabetic retinopathy in eye fundus images by employing appropriate preprocessing techniques to enhance image quality. We propose a novel two-branch attention-guided convolutional neural network (AG-CNN) with initial image preprocessing to address these issues. The AG-CNN initially establishes overall attention to the entire image with the global branch and then incorporates a local branch to compensate for any lost discriminative cues. We conduct extensive experiments using the APTOS 2019 DR dataset. Our baseline model, DenseNet-121, achieves average accuracy/AUC values of 0.9746/0.995, respectively. Upon integrating the local branch, the AG-CNN improves the average accuracy/AUC to 0.9848/0.998, representing a significant advancement in state-of-the-art performance within the field.

Perception of Facial Cues to Trustworthiness in Infancy: Insights from the Spatial Frequency Filtering Approach

AbstractA crucial aspect of human social competence is the ability to spontaneously and rapidly infer from facial cues whether others are likely to approach us with friendliness or hostility—that is, trustworthiness. The rapid and automatic nature of these inferences has prompted the claim that they may originate from evolutionary pressures to detect potential threats, thus enhancing our chances of survival. However, the developmental origins of this social skill remain a topic of ongoing debate. Recent evidence shows that infants' brains and looking time behaviors differentiate between faces varying along the trustworthiness continuum, but the question about the nature of the facial cues they rely on remains open. In this review, we propose the spatial frequency (SF) filtering approach (i.e., the selective removal of spatial frequency bands from the image) as a useful tool for investigating this question, and specifically whether infants' discrimination of facial expressions of emotion share common visual and neural mechanisms with discrimination of facial cues associated with trustworthiness inferences. The SF filtering approach could shed light on the neural and perceptual mechanisms underlying trustworthiness perception in infancy, providing insights into whether and how these mechanisms change across development. The evidence gathered through this method would prove critical to the understanding of the developmental origins of trustworthiness perception.

Effects of the Synthetic Cathinone α-Pyrrolidinobutiothiophenone (α-PBT) on Discriminative Stimulus Effects and Intracranial Self-Stimulation Thresholds in Male Rats.

Recently, the abuse of synthetic cathinones is increasing among young people. α-Pyrrolidinobutiothiophenone (α-PBT), a synthetic cathinone, is a designer drug that is freely traded online with no legal restrictions. Moreover, there is currently no scientific basis for legal regulation. Here, we examined the addictive properties of α-PBT using a drug discrimination (DD) task. We also investigated the role of α-PBT in brain stimulation reward (BSR) using an intracranial self-stimulation (ICSS) paradigm in rats. Initially, the rats were trained to discriminate between cocaine and saline. After the discrimination training criteria were met, we determined the dose-effect curves of cocaine and conducted generalization tests with α-PBT and α-pyrrolidinopentiothiophenone (α-PVT) using a cumulative dosing protocol. In a separate set of studies, we examined the dopaminergic mechanisms underlying the function of α-PBT as an interoceptive stimulus (17.8 mg/kg) by intraperitoneally injecting either the dopamine (DA) D1 antagonist SCH23390 (0.06 and 0.12 mg/kg) or the D2 antagonist eticlopride (0.05 and 0.1 mg/kg) 15 min before DD testing. Brain reward function was measured using an ICSS procedure to examine the effects of α-PBT on ICSS threshold under the frequency-rate procedure. Our results showed that α-PBT functioned as a discriminative cue similar to cocaine in rats. More importantly, SCH23390 abolished the effects of α-PBT as an interoceptive stimulus in a dose-dependent manner in rats trained to press a lever to receive cocaine. Similarly, eticlopride dose-dependently attenuated the effect of α-PBT used as a discriminative cue. Additionally, cumulative α-PBT administration dose-dependently lowered ICSS thresholds compared with those in saline-treated rats. Furthermore, α-PBT-induced potentiation of BSR was abolished by pretreatment with both SCH23390 and eticlopride. Taken together, our results suggest that α-PBT can function as a cocaine-like discriminative cue via the activation of D1 and D2 receptors. α-PBT also appears to influence BSR by reducing the brain reward threshold via changes in D1 and D2 receptors. The present study suggests that α-PBT could have addictive properties through DA D1 and D2 receptors and thus poses a threat to humans.

Relapse after intermittent access to cocaine: Discriminative cues more effectively trigger drug seeking than do conditioned cues.

When people with drug addiction encounter cues associated with drug use, this can trigger cravings and relapse. These cues can include conditioned stimuli (CSs) signaling drug delivery and discriminative stimuli (DSs) signaling drug availability. Compared to CS effects, DS effects are less explored in preclinical studies on cue-induced relapse. We compared CS and DS effects on reward seeking following abstinence from intermittent-access cocaine (or sucrose) self-administration. During 15-20 intermittent-access sessions, rats self-administered i.v. cocaine or sucrose pellets paired with a light-tone CS. Cocaine/sucrose was available for 5-min (signalled by a light; DS+) and unavailable for 25min (signalled by different lighting conditions; DS-), and this cycled for 4h/session. Following abstinence, we measured cocaine/sucrose seeking under extinction triggered by CS and DS presentation, and instrumental responding reinforced by these cues. Across intermittent-access sessions, rats increased lever pressing for cocaine or sucrose during DS+ periods and decreased responding during DS- periods. On days 2 and 21 of abstinence, only presentation of the DS+ or DS+ and CS combined elicited increased cocaine/sucrose-seeking behaviour (i.e., increased active lever presses). Presenting the DS- alongside the DS+ suppressed the increased cocaine-seeking behaviour otherwise produced by the DS+ . Finally, on day 21 of abstinence, rats showed equivalent levels of lever pressing reinforced by the DS+ , CS and by the DS+ and CS combined, suggesting comparable conditioned reinforcing value. After intermittent self-administration, cocaine-associated DSs and CSs acquire similar conditioned reinforcing properties, but DSs more effectively trigger increases in drug seeking.

Functional diversity of dopamine axons in prefrontal cortex during classical conditioning

Midbrain dopamine neurons impact neural processing in the prefrontal cortex (PFC) through mesocortical projections. However, the signals conveyed by dopamine projections to the PFC remain unclear, particularly at the single-axon level. Here, we investigated dopaminergic axonal activity in the medial PFC (mPFC) during reward and aversive processing. By optimizing microprism-mediated two-photon calcium imaging of dopamine axon terminals, we found diverse activity in dopamine axons responsive to both reward and aversive stimuli. Some axons exhibited a preference for reward, while others favored aversive stimuli, and there was a strong bias for the latter at the population level. Long-term longitudinal imaging revealed that the preference was maintained in reward- and aversive-preferring axons throughout classical conditioning in which rewarding and aversive stimuli were paired with preceding auditory cues. However, as mice learned to discriminate reward or aversive cues, a cue activity preference gradually developed only in aversive-preferring axons. We inferred the trial-by-trial cue discrimination based on machine learning using anticipatory licking or facial expressions, and found that successful discrimination was accompanied by sharper selectivity for the aversive cue in aversive-preferring axons. Our findings indicate that a group of mesocortical dopamine axons encodes aversive-related signals, which are modulated by both classical conditioning across days and trial-by-trial discrimination within a day.

Functional diversity of dopamine axons in prefrontal cortex during classical conditioning.

Midbrain dopamine neurons impact neural processing in the prefrontal cortex (PFC) through mesocortical projections. However, the signals conveyed by dopamine projections to the PFC remain unclear, particularly at the single-axon level. Here, we investigated dopaminergic axonal activity in the medial PFC (mPFC) during reward and aversive processing. By optimizing microprism-mediated two-photon calcium imaging of dopamine axon terminals, we found diverse activity in dopamine axons responsive to both reward and aversive stimuli. Some axons exhibited a preference for reward, while others favored aversive stimuli, and there was a strong bias for the latter at the population level. Long-term longitudinal imaging revealed that the preference was maintained in reward- and aversive-preferring axons throughout classical conditioning in which rewarding and aversive stimuli were paired with preceding auditory cues. However, as mice learned to discriminate reward or aversive cues, a cue activity preference gradually developed only in aversive-preferring axons. We inferred the trial-by-trial cue discrimination based on machine learning using anticipatory licking or facial expressions, and found that successful discrimination was accompanied by sharper selectivity for the aversive cue in aversive-preferring axons. Our findings indicate that a group of mesocortical dopamine axons encodes aversive-related signals, which are modulated by both classical conditioning across days and trial-by-trial discrimination within a day.

Neurometric amplitude modulation detection in the inferior colliculus of Young and Aged rats

Amplitude modulation is an important acoustic cue for sound discrimination, and humans and animals are able to detect small modulation depths behaviorally. In the inferior colliculus (IC), both firing rate and phase-locking may be used to detect amplitude modulation. How neural representations that detect modulation change with age are poorly understood, including the extent to which age-related changes may be attributed to the inherited properties of ascending inputs to IC neurons. Here, simultaneous measures of local field potentials (LFPs) and single-unit responses were made from the inferior colliculus of Young and Aged rats using both noise and tone carriers in response to sinusoidally amplitude-modulated sounds of varying depths. We found that Young units had higher firing rates than Aged for noise carriers, whereas Aged units had higher phase-locking (vector strength), especially for tone carriers. Sustained LFPs were larger in Young animals for modulation frequencies 8–16 Hz and comparable at higher modulation frequencies. Onset LFP amplitudes were much larger in Young animals and were correlated with the evoked firing rates, while LFP onset latencies were shorter in Aged animals. Unit neurometric thresholds by synchrony or firing rate measures did not differ significantly across age and were comparable to behavioral thresholds in previous studies whereas LFP thresholds were lower than behavior.

Prelingually Deaf Children With Cochlear Implants Show Better Perception of Voice Cues and Speech in Competing Speech Than Postlingually Deaf Adults With Cochlear Implants.

Postlingually deaf adults with cochlear implants (CIs) have difficulties with perceiving differences in speakers' voice characteristics and benefit little from voice differences for the perception of speech in competing speech. However, not much is known yet about the perception and use of voice characteristics in prelingually deaf implanted children with CIs. Unlike CI adults, most CI children became deaf during the acquisition of language. Extensive neuroplastic changes during childhood could make CI children better at using the available acoustic cues than CI adults, or the lack of exposure to a normal acoustic speech signal could make it more difficult for them to learn which acoustic cues they should attend to. This study aimed to examine to what degree CI children can perceive voice cues and benefit from voice differences for perceiving speech in competing speech, comparing their abilities to those of normal-hearing (NH) children and CI adults. CI children's voice cue discrimination (experiment 1), voice gender categorization (experiment 2), and benefit from target-masker voice differences for perceiving speech in competing speech (experiment 3) were examined in three experiments. The main focus was on the perception of mean fundamental frequency (F0) and vocal-tract length (VTL), the primary acoustic cues related to speakers' anatomy and perceived voice characteristics, such as voice gender. CI children's F0 and VTL discrimination thresholds indicated lower sensitivity to differences compared with their NH-age-equivalent peers, but their mean discrimination thresholds of 5.92 semitones (st) for F0 and 4.10 st for VTL indicated higher sensitivity than postlingually deaf CI adults with mean thresholds of 9.19 st for F0 and 7.19 st for VTL. Furthermore, CI children's perceptual weighting of F0 and VTL cues for voice gender categorization closely resembled that of their NH-age-equivalent peers, in contrast with CI adults. Finally, CI children had more difficulties in perceiving speech in competing speech than their NH-age-equivalent peers, but they performed better than CI adults. Unlike CI adults, CI children showed a benefit from target-masker voice differences in F0 and VTL, similar to NH children. Although CI children's F0 and VTL voice discrimination scores were overall lower than those of NH children, their weighting of F0 and VTL cues for voice gender categorization and their benefit from target-masker differences in F0 and VTL resembled that of NH children. Together, these results suggest that prelingually deaf implanted CI children can effectively utilize spectrotemporally degraded F0 and VTL cues for voice and speech perception, generally outperforming postlingually deaf CI adults in comparable tasks. These findings underscore the presence of F0 and VTL cues in the CI signal to a certain degree and suggest other factors contributing to the perception challenges faced by CI adults.

Dual-Dependency Attention Transformer for Fine-Grained Visual Classification.

Visual transformers (ViTs) are widely used in various visual tasks, such as fine-grained visual classification (FGVC). However, the self-attention mechanism, which is the core module of visual transformers, leads to quadratic computational and memory complexity. The sparse-attention and local-attention approaches currently used by most researchers are not suitable for FGVC tasks. These tasks require dense feature extraction and global dependency modeling. To address this challenge, we propose a dual-dependency attention transformer model. It decouples global token interactions into two paths. The first is a position-dependency attention pathway based on the intersection of two types of grouped attention. The second is a semantic dependency attention pathway based on dynamic central aggregation. This approach enhances the high-quality semantic modeling of discriminative cues while reducing the computational cost to linear computational complexity. In addition, we develop discriminative enhancement strategies. These strategies increase the sensitivity of high-confidence discriminative cue tracking with a knowledge-based representation approach. Experiments on three datasets, NABIRDS, CUB, and DOGS, show that the method is suitable for fine-grained image classification. It finds a balance between computational cost and performance.

Pollen, anther, stamen, and androecium mimicry.

Floral colours represent a highly diverse communication signal mainly involved in flower visitors' attraction and guidance, but also flower discrimination, filtering non-pollinators and discouraging floral antagonists. The divergent visual systems and colour preferences of flower visitors, as well as the necessity of cues for flower detection and discrimination, foster the diversity of floral colours and colour patterns. Despite the bewildering diversity of floral colour patterns, a recurrent component is a yellow UV-absorbing floral centre, and it is still not clear why this pattern is so frequent inangiosperms. The pollen, anther, stamen, and androecium mimicry (PASAM) hypothesis suggests that the system composed of the flowers possessing such yellow UV-absorbing floral reproductive structures, the flowers displaying central yellow UV-absorbing structures as floral guides, and the pollen-collecting, as well as pollen-eating, flower visitors responding to such signals constitute the world's most speciose mimicry system. In this review, we call the attention of researchers to some hypothetical PASAM systems around the globe, presenting some fascinating examples that illustrate their huge diversity. We will also present new and published data on pollen-eating and pollen-collecting pollinators' responses to PASAM structures supporting the PASAM hypothesis and will discuss how widespread these systems are around the globe. Ultimately, our goal is to promote the idea that PASAM is a plausible first approach to understanding floral colour patterns in angiosperms.

Development of language-specific stress discrimination in European Portuguese: an electrophysiological study.

European Portuguese (EP) is a language with unpredictable stress. Previous behavioral studies have shown that without vowel reduction EP adult speakers displayed a stress deafness effect akin to that observed in speakers of fixed-stress languages, suggesting that vowel quality may be the primary cue for stress discrimination in EP. However, an event-related potentials (ERPs) study reported that EP adults were able to discriminate stress contrasts pre-attentively in the absence of vowel quality cues. These results seemed to indicate that EP adult speakers may attend to different cues in the attentive and pre-attentive stress perception. Moreover, both the behavioral and ERPs studies have revealed a processing advantage for iambic stress, which could not be predicted by the rhythmic properties of EP, the language-specific weighting of stress correlates, or the frequency distributions of trochaic and iambic stresses in EP. A recent eye-tracking study has found that EP-learning infants at 5-6 months already exhibited an iambic preference in the absence of vowel reduction, manifested by longer looking time at the iambic stress. The present study used a passive oddball paradigm to examine pre-attentive stress perception without vowel quality cues by 5-to-7-month-old EP-learning infants. Results from twenty-two participants showed that both the trochaic and iambic conditions yielded a positive discrimination response (p-MMR). In addition, the iambic condition elicited a prominent late discriminative negativity (LDN) as well as a P3a component. Our findings present the first evidence for reciprocal discrimination of stress patterns in EP-learning infants, showing that, as in adult speakers, stress processing might also differ at the pre-attentive and attentive stages in infants. Importantly, the stress perception ability in EP-learning infants seems to develop asymmetrically, with an advantage for the iambic stress pattern. The present study highlighted the role of language-specific factors that may affect developing stress perception.

What are olfaction and gustation, and do all animals have them?

Different animals have distinctive anatomical and physiological properties to their chemical senses that enhance detection and discrimination of relevant chemical cues. Humans and other vertebrates are recognized as having 2 main chemical senses, olfaction and gustation, distinguished from each other by their evolutionarily conserved neuroanatomical organization. This distinction between olfaction and gustation in vertebrates is not based on the medium in which they live because the most ancestral and numerous vertebrates, the fishes, live in an aquatic habitat and thus both olfaction and gustation occur in water and both can be of high sensitivity. The terms olfaction and gustation have also often been applied to the invertebrates, though not based on homology. Consequently, any similarities between olfaction and gustation in the vertebrates and invertebrates have resulted from convergent adaptations or shared constraints during evolution. The untidiness of assigning olfaction and gustation to invertebrates has led some to recommend abandoning the use of these terms and instead unifying them and others into a single category-chemical sense. In our essay, we compare the nature of the chemical senses of diverse animal types and consider their designation as olfaction, oral gustation, extra-oral gustation, or simply chemoreception. Properties that we have found useful in categorizing chemical senses of vertebrates and invertebrates include the nature of peripheral sensory cells, organization of the neuropil in the processing centers, molecular receptor specificity, and function.

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.