Brain networks underlying tactile softness perception: A functional magnetic resonance imaging study.

Humans are adept at perceiving physical properties of an object through touch. Tangible object properties can be categorized into two types: macro-spatial properties, including shape and orientation; and material properties, such as roughness, softness, and temperature. Previous neuroimaging studies have shown that roughness and temperature are extracted at nodes of a network, such as that involving the parietal operculum and insula, which is different from the network engaged in processing macro-spatial properties. However, it is unclear whether other perceptual dimensions pertaining to material properties engage the same regions. Here, we conducted a functional magnetic resonance imaging study to test whether the parietal operculum and insula were involved in extracting tactually-perceived softness magnitude. Fifty-six healthy right-handed participants estimated perceived softness magnitude using their right middle finger. We presented three stimuli that had the same shape but different compliances. The force applied to the finger was manipulated at two levels. Classical mass-univariate analysis showed that activity in the parietal operculum, insula, and medial prefrontal cortex was positively associated with perceived softness magnitude, regardless of the applied force. Softness-related activity was stronger in the ventral striatum in the high-force condition than in the low-force condition. The multivariate voxel pattern analysis showed higher accuracy than chance levels and control regions in the parietal operculum/insula, postcentral gyrus, posterior parietal lobule, and middle occipital gyrus. These results indicate that a distributed set of the brain regions, including the parietal operculum and insula, is involved in representing perceived softness.

A new carbapenem drug dosage metric for carbapenem usage and correlation with carbapenem resistance of Pseudomonas aeruginosa.

The emergence and dissemination of antimicrobial resistance is a worldwide problem. Inappropriate antimicrobial use contributes to this resistance, and several metrics of drug usage have been used to monitor their consumption and rational use. We examined several existing drug metrics, and developed a new one, dose/duration-density (D/d2), for a the best correlation between carbapenem usage and carbapenem resistance of Pseudomonas aeruginosa. The annual changes of antimicrobial use density (AUD), days of therapy (DOT), daily dose (DD) and D/d2 for meropenem, imipenem and total carbapenems was analyzed for a correlation with carbapenem susceptibility of P. aeruginosa from 2006 through 2015 at a university hospital. The substitution of meropenem for imipenem usage, and an approximate 10% increase in carbapenem susceptibility of P. aeruginosa occurred over the study period. There were significant correlations of the meropenem susceptibility of P. aeruginosa and meropenem usage as measured by the meropenem DD, of imipenem susceptibility and imipenem AUD and DOT, and overall carbapenem susceptibility and imipenem DOT. The D/d2 for meropenem, imipenem and total carbapenems had significant correlations with individual and all carbapenem susceptibility of P. aeruginosa. These D/d2 is the best single carbapenem use metric for correlating carbapenem usage with P. aeruginosa resistance. Further studies are warranted to consider the value of D/d2 for other antimicrobials and bacteria.

Cross-Modal Associations between Sounds and Drink Tastes/Textures: A Study with Spontaneous Production of Sound-Symbolic Words.

Many languages have a word class whose speech sounds are linked to sensory experiences. Several recent studies have demonstrated cross-modal associations (or correspondences) between sounds and gustatory sensations by asking participants to match predefined sound-symbolic words (e.g., "maluma/takete") with the taste/texture of foods. Here, we further explore cross-modal associations using the spontaneous production of words and semantic ratings of sensations. In the experiment, after drinking liquids, participants were asked to express their taste/texture using Japanese sound-symbolic words, and at the same time, to evaluate it in terms of criteria expressed by adjectives. Because the Japanese language has a large vocabulary of sound-symbolic words, and Japanese people frequently use them to describe taste/texture, analyzing a variety of Japanese sound-symbolic words spontaneously produced to express taste/textures might enable us to explore the mechanism of taste/texture categorization. A hierarchical cluster analysis based on the relationship between linguistic sounds and taste/texture evaluations revealed the structure of sensation categories. The results indicate that an emotional evaluation like pleasant/unpleasant is the primary cluster in gustation.

Discourse Goals Affect the Process and Product of Nominal Metaphor Production.

Although a large number of studies have addressed metaphor comprehension, only a few attempts have so far been made at exploring the process of metaphor production. Therefore, in this paper, we address the problem of how people generate nominal metaphors or identify an apt vehicle for a given topic of nominal metaphors. Specifically, we examine how the process and product of metaphor production differ between two discourse goals of metaphor, namely an explanatory purpose (e.g., to clarify) and a literary purpose (e.g., to aesthetically pleasing). Experiment 1 analyzed the metaphors (or vehicles) generated in the metaphor production task, and demonstrated that people identified more prototypical exemplars of the property to be attributed to the topic as a vehicle for explanatory metaphors than for literary metaphors. In addition, it was found that metaphors generated for the explanatory purpose were more apt and conventional, and had high topic-vehicle similarity than those generated for the literary purpose, while metaphors generated for the literary purpose were more familiar and imageable than those for the explanatory purpose. Experiment 2 used a priming paradigm to assess the online availability of prototypical and less prototypical members of the topic property during metaphor production. The result was that both prototypical and less prototypical members were activated in producing literary metaphors, while neither members were activated in the production of explanatory metaphors. These findings indicate that the process of metaphor production is affected by discourse goals of metaphor; less prototypical members of the category are searched for a vehicle during the production of literary metaphors, and thus literary metaphors are generated with less prototypical vehicles than explanatory metaphors.

Clinical Efficacy of Therapeutic Agents for Clostridioides difficile Infection Based on Four Severity Classifications.

The Japanese guidelines for the management of Clostridioides difficile infection (CDI) recommend metronidazole (MNZ) for non-severe cases and vancomycin (VCM) for severe cases. Here, we investigated the use of CDI antimicrobials and evaluated their clinical efficacy in four severity classifications and the validity of these classifications. A retrospective chart review was conducted on 137 inpatients with an initial positive C. difficile toxin test and initiation of CDI antimicrobials between April 2015 and March 2019. For the clinical efficacy analysis of the CDI antimicrobials and validation of the severity classifications, patients treated with VCM or oral MNZ were included. The endpoints were CDI recurrence rate, 30-day mortality rate, and diarrhea cure rate. No significant differences were found between the VCM and oral MNZ groups regarding the CDI recurrence rate (10.4% vs. 12.7%, p = 0.707), 30-day mortality rate (12.5% vs. 5.6%, p = 0.162), and diarrhea cure rate (61.9% vs. 72.7%, p = 0.238), regardless of the severity. Treatment with oral MNZ for non-severe cases was promising, confirming the usefulness of treatment according to Japanese guidelines. Further investigation of the clinical efficacy of oral MNZ in patients with first-episode CDI and evaluation of the preferable severity classification are warranted.

A Community-Based Intervention to Enhance Subjective Well-Being in Older Adults: Study Design and Baseline Participant Profiles.

Promoting subjective well-being is a crucial challenge in aging societies. In 2022, we launched a community-based intervention trial (the Chofu-Digital-Choju Movement). This initiative centered on fostering in-person and online social connections to enhance the subjective well-being of older adults. This paper describes the study design and baseline survey. This quasi-experimental study involved community-dwelling older adults aged 65-84 years in Chofu City, Tokyo, Japan. A self-administered questionnaire was distributed to 3742 residents (1681 men and 2061 women), and a baseline survey was conducted in January 2022. We assessed subjective well-being (primary outcome); psychosocial, physical, and dietary factors; and the use of information and communication technology variables (secondary outcomes) among the participants. After the intervention involving online classes, community hubs, and community events, a 2-year follow-up survey will be conducted to evaluate the effects of the intervention, comparing the intervention group (participants) with the control group (non-participants). We received 2503 questionnaires (66.9% response rate); of these, the analysis included 2343 questionnaires (62.6% valid response rate; mean age, 74.4 (standard deviation, 5.4) years; 43.7% male). The mean subjective well-being score was 7.2 (standard deviation, 1.9). This study will contribute to the development of a prototype subjective well-being strategy for older adults.

Development of free-living stages of Strongyloides ratti under different temperature conditions.

It is well known that the Strongyloides species have two different developmental courses-direct and indirect development-and selection of these courses is affected by various environmental factors. This study examined the effect of temperature on the development of first-stage larvae (L1s) of Strongyloides ratti, to clarify how larvae adapt and survive at unsuitable temperatures. It was revealed that L1s cultured at 4 or 10 °C for 120 h could not develop because of growth arrest or delay. However, L1s could develop after transfer to culture at 25 °C for 48 h. Although larvae cultured at 25 °C take indirect development, larvae subjected to low-temperature stimulation (at 4 or 10 °C) take direct development into infective third-stage larvae (L3s), and only 1 min of low-temperature stimulation was sufficient to induce direct development. Morphological study of low-temperature-stimulated L3s revealed that those stimulated at 4 °C (L3-4) showed less development, but those stimulated at 10 °C (L3-10) developed as well as the control (no low-temperature stimulation). Furthermore, we revealed that L3-10 showed similar infectivity to the control when they were injected subcutaneously into rats as the final host, which indicated that L3-10 grew normally. We conclude that S. ratti has a survival strategy of growth arrest or delay if excreted in cold conditions. Moreover, even if they start development after transfer to suitable conditions, they memorize low-temperature stimulation, which leads them to direct development thereafter so that they can immediately infect the final host.

Surfactants alter mosquito's flight and physical condition.

Mosquitoes carry lethal pathogens for humans and hundreds of thousands of people are killed by mosquito-borne diseases every year. Therefore, controlling mosquitoes is essential to protect the lives of people around the world. Insecticides are highly effective in controlling mosquitoes and have been used extensively worldwide. However, they have potentially harmful effects on biodiversity and environment, and some mosquitoes are resistant to insecticide ingredients and survive upon their application. Therefore, there is a demand for a method to control mosquitoes without using conventional insecticide ingredients. Here, we used Aedes albopictus to test whether solutions with low surface tension, particularly surfactant solutions can alter mosquito behavior by spreading over the hydrophobic cuticle of mosquitoes. We found that solutions with low surface tension indeed attached to mosquitoes flying or resting on the wall, and made them fall. In addition, solutions with yet lower surface tension covered the mosquito surface more quickly and widely, knocking down or killing mosquitoes. These results suggest that surfactants such as sodium dioctyl sulfosuccinate can be used to alter mosquito behavior without relying on conventional insecticides.

Japanese Sound-Symbolic Words for Representing the Hardness of an Object Are Judged Similarly by Japanese and English Speakers.

Contrary to the assumption of arbitrariness in modern linguistics, sound symbolism, which is the non-arbitrary relationship between sounds and meanings, exists. Sound symbolism, including the "Bouba-Kiki" effect, implies the universality of such relationships; individuals from different cultural and linguistic backgrounds can similarly relate sound-symbolic words to referents, although the extent of these similarities remains to be fully understood. Here, we examined if subjects from different countries could similarly infer the surface texture properties from words that sound-symbolically represent hardness in Japanese. We prepared Japanese sound-symbolic words of which novelty was manipulated by a genetic algorithm (GA). Japanese speakers in Japan and English speakers in both Singapore and the United States rated these words based on surface texture properties (hardness, warmness, and roughness), as well as familiarity. The results show that hardness-related words were rated as harder and rougher than softness-related words, regardless of novelty and countries. Multivariate analyses of the ratings classified the hardness-related words along the hardness-softness dimension at over 80% accuracy, regardless of country. Multiple regression analyses revealed that the number of speech sounds /g/ and /k/ predicted the ratings of the surface texture properties in non-Japanese countries, suggesting a systematic relationship between phonetic features of a word and perceptual quality represented by the word across culturally and linguistically diverse samples.

The Effects of Vibratory Frequency and Temporal Interval on Tactile Apparent Motion.

Vibrotactile stimuli can be used to generate the haptic sensation of a static object or the motion of a dynamic object. Here, in this article, we investigated the effects of vibratory frequency and temporal interval on tactile apparent motion. In the experiment, we examined the effect of vibratory frequency with different temporal intervals on tactile apparent motion that results from two successive tactile stimuli on the index fingerpad. Results indicated that tactile apparent motion was perceived not only when both stimuli were either "flutter" or "vibration" stimuli, but also when one of each type was used. Specifically, when the first stimulus was introduced at 40Hz, "continuous motion" was viewed at all combinations of stimulus frequency, and "continuous motion" was clearly noted at the high-frequency combination instead of the low-frequency combination. Also, tactile apparent motion was predominantly viewed in the SOA range of 105 ms to 125 ms. We anticipate that our findings and further research will be essential resources for the design of tactile devices to represent the motion of dynamic objects.

Automatic Estimation of Multidimensional Personality From a Single Sound-Symbolic Word.

Researchers typically use the "big five" traits (Extroversion, Agreeableness, Conscientiousness, Neuroticism, and Openness) as a standard way to describe personality. Evaluation of personality is generally conducted using self-report questionnaires that require participants to respond to a large number of test items. To minimize the burden on participants, this paper proposes an alternative method of estimating multidimensional personality traits from only a single word. We constructed a system that can convert a sound-symbolic word (SSW) that intuitively expresses personality traits into information expressed by 50 personality-related adjective pairs. This system can obtain information equivalent to the adjective scales using only a single word instead of asking many direct questions. To achieve this, we focused on SSWs in Japanese that have the association between linguistic sounds and meanings and express diverse and complex aspects of personality traits. We evaluated the prediction accuracy of the system and found that the multiple correlation coefficients for 48 personality-related adjective pairs exceeded 0.75, indicating that the model could explain more than half of the variations in the data. In addition, we conducted an evaluation experiment in which participants rated the appropriateness of the system output using a seven-point scale (with -3 as absolutely inappropriate and +3 as completely appropriate). The average score for 50 personality-related adjective pairs was 1.25. Thus, we believe that this system can contribute to the field of personality computing, particularly in terms of personality evaluation and communication.

Computer Vision System for Expressing Texture Using Sound-Symbolic Words.

The major goals of texture research in computer vision are to understand, model, and process texture and ultimately simulate human visual information processing using computer technologies. The field of computer vision has witnessed remarkable advancements in material recognition using deep convolutional neural networks (DCNNs), which have enabled various computer vision applications, such as self-driving cars, facial and gesture recognition, and automatic number plate recognition. However, for computer vision to "express" texture like human beings is still difficult because texture description has no correct or incorrect answer and is ambiguous. In this paper, we develop a computer vision method using DCNN that expresses texture of materials. To achieve this goal, we focus on Japanese "sound-symbolic" words, which can describe differences in texture sensation at a fine resolution and are known to have strong and systematic sensory-sound associations. Because the phonemes of Japanese sound-symbolic words characterize categories of texture sensations, we develop a computer vision method to generate the phonemes and structure comprising sound-symbolic words that probabilistically correspond to the input images. It was confirmed that the sound-symbolic words output by our system had about 80% accuracy rate in our evaluation.

Recognition Mechanism of the "Sara-sara Feel" of Cosmetic Powders.

The Sara-sara feel, which means "a state in which things are not damp or sticky and feel dry," is a preferred tactile sensation when people touch human skin, hair, clothing, and cosmetics. In this study, the Sara-sara feel was evaluated for silicone powder, cellulose powder, hydrophobized sericite powder, and various mixes of these powders. It was found that the highest Sara-sara feel score was achieved by the silicone powder. A multiple regression analysis showed that the Sara-sara feel was strongly correlated with a slippery feel. The relationship between certain physical properties, e.g., particle size distribution, and the slippery feel was analyzed to demonstrate how the subjects felt the slippery feel. It was observed that as the friction coefficient µ k was reduced, most subjects strongly felt the slippery feel. This coefficient slightly decreased when the composition of spherical silicone powder increased, because the contact area between spherical particles is smaller than that between plate and amorphous particles.

Brain networks underlying the processing of sound symbolism related to softness perception.

Unlike the assumption of modern linguistics, there is non-arbitrary association between sound and meaning in sound symbolic words. Neuroimaging studies have suggested the unique contribution of the superior temporal sulcus to the processing of sound symbolism. However, because these findings are limited to the mapping between sound symbolism and visually presented objects, the processing of sound symbolic information may also involve the sensory-modality dependent mechanisms. Here, we conducted a functional magnetic resonance imaging experiment to test whether the brain regions engaged in the tactile processing of object properties are also involved in mapping sound symbolic information with tactually perceived object properties. Thirty-two healthy subjects conducted a matching task in which they judged the congruency between softness perceived by touch and softness associated with sound symbolic words. Congruency effect was observed in the orbitofrontal cortex, inferior frontal gyrus, insula, medial superior frontal gyrus, cingulate gyrus, and cerebellum. This effect in the insula and medial superior frontal gyri was overlapped with softness-related activity that was separately measured in the same subjects in the tactile experiment. These results indicate that the insula and medial superior frontal gyrus play a role in processing sound symbolic information and relating it to the tactile softness information.

Visualizing Individual Perceptual Differences Using Intuitive Word-Based Input.

Numerous studies have investigated the fundamental dimensions of human tactile perceptual space using a wide range of materials. Participants generally touch materials and quantitatively evaluate variations in tactile sensations for pairs of adjectives pertaining to the material properties, such as smooth-rough and soft-hard. Thus, observers evaluate their perceptual experiences one by one in terms of adjective pairs. We previously proposed an alternative method of qualitative evaluation of tactile sensations. Our system can automatically estimate ratings of fundamental tactile properties from single sound-symbolic words. We were able to construct a word-based perceptual space by collecting words that express tactile sensations and applying them to the system. However, to explore individual differences in perceptual spaces, different databases for converting words into ratings of adjective pairs are required for each individual. To address this, in the present study we created an application that can automatically generate an individualized perceptual space by moving only a few words in the initial word-based perceptual space. In addition, we evaluated the efficacy of the application by comparing the tactile perceptual space before and after use.

Physical origin of a complicated tactile sensation: 'shittori feel'.

Shittori feel is defined as a texture that is moderately moisturized; however, many people experience 'shittori feel' when they touch a dry solid material containing little liquid. Here, shittori feel was evaluated for 12 materials. We found that the highest score of shittori feel was achieved by powders. Multiple regression analysis showed that shittori feel is a complex sense of moist and smooth feels. We analysed the relationship between the physical properties and the moist/smooth feels to show how subjects felt certain feels simultaneously. The moist and smooth feels are related to the surface roughness and friction characteristics of the materials. The moist and smooth feels can be perceived when the finger starts to move on the material surface and when the finger moves and rubs the material surface, respectively.

Controlled emotional tactile stimulation during functional magnetic resonance imaging and electroencephalography.

BACKGROUND: Tactile stimulation used to induce emotional responses is often not well-controlled. Replicating the same tactile stimulations across studies is difficult, compared to replicating visual and auditory modalities, which have standardized stimulus sets. Standardizing a stimulation method by replicating stimuli across studies is necessary to further elucidate emotional responses in neuroscience research using tactile stimulation. THE NEW METHOD: We developed a tactile stimulation device. The device's ultrasonic motor and optical force sensor have the following criteria: (1) controls the physical property of stimuli, pressure, and stroking speed; (2) measures actual touch timing; (3) is safe to use in a magnetic resonance imaging (MRI) scanner; and (4) produces low noise in electroencephalography (EEG) and MRI. RESULTS: The noise level of the device's drive was sufficiently low. For the EEG experiment, we successfully used signal processing to diminish the commercial power supply noise. For functional MRI (fMRI) scans, we found <5% signal loss occurred during device rotation. COMPARISON WITH EXISTING METHOD(S): We found no previous report about the noise level of a tactile stimulation device used to induce emotional responses during EEG and fMRI recordings. The signal loss rate was comparable with that of other robotic devices used in MRI scanners. Emotional feelings induced by this stimulation method were comparable with those elicited in other sensory modalities. CONCLUSIONS: The developed device could be used for cognitive-affective neuroscience research when conducting EEG and fMRI scans. The device should aid in standardizing affective tactile stimulation for research in psychology and cognitive neuroscience.

Bouba/Kiki in Touch: Associations Between Tactile Perceptual Qualities and Japanese Phonemes.

Several studies have shown cross-modal associations between sounds and vision or gustation by asking participants to match pre-defined sound-symbolic words (SSWs), such as "bouba" or "kiki," with visual or gustatory materials. Here, we conducted an explorative study on cross-modal associations of tactile sensations using spontaneous production of Japanese SSWs and semantic ratings. The Japanese language was selected, because it has a large number of SSWs that can represent a wide range of tactile perceptual spaces with fine resolution, and it shows strong associations between sound and touch. In the experiment, we used 120 everyday materials to cover basic material categories that could be associated with fundamental dimensions of tactile perception. Upon contact with these materials, participants expressed their tactile sensations by using Japanese SSWs, and at the same time, evaluated the tactile sensations by semantic differential scales using adjective pairs. Thanks to the variety of testing materials, we were able to demonstrate the existence of systematic associations between sounds and tactile fundamental perceptual dimensions in a more detailed and comprehensive way than ever done so before. In particular, we found that for vowels, positive tactile ratings were associated with the back vowel (/u/), while negative ratings were associated with the front vowels (/i/ and /e/). The central vowels (/o/ and /a/) were mainly associated with rough, hard, and dry feelings. Consonants were categorized based on vocal features and articulation. The category of the voiced consonants (e.g., /dz/ and /g/) corresponded to feelings of roughness, while that of voiceless consonants (e.g., /ʦ/, and /s/) corresponded to feelings of smoothness. The categories of the bilabial plosive (/p/ and /b/) and voiced alveolar nasal (/n/) consonants were mainly related to soft, sticky and wet feelings, while that of voiceless alveolar affricate (/ʦ/) and voiceless velar plosive (/k/) consonants were related to hard, slippery and dry feelings.

Optimal linguistic expression in negotiations depends on visual appearance.

We investigate the influence of the visual appearance of a negotiator on persuasiveness within the context of negotiations. Psychological experiments were conducted to quantitatively analyze the relationship between visual appearance and the use of language. Male and female participants were shown three female and male photographs, respectively. They were asked to report how they felt about each photograph using a seven-point semantic differential (SD) scale for six affective factors (positive impression, extraversion, intelligence, conscientiousness, emotional stability, and agreeableness). Participants then answered how they felt about each negotiation scenario (they were presented with pictures and a situation combined with negotiation sentences) using a seven-point SD scale for seven affective factors (positive impression, extraversion, intelligence, conscientiousness, emotional stability, agreeableness, and degree of persuasion). Two experiments were conducted using different participant groups depending on the negotiation situations. Photographs with good or bad appearances were found to show high or low degrees of persuasion, respectively. A multiple regression equation was obtained, indicating the importance of the three language factors (euphemistic, honorific, and sympathy expressions) to impressions made during negotiation. The result shows that there are optimal negotiation sentences based on various negotiation factors, such as visual appearance and use of language. For example, persons with good appearance might worsen their impression during negotiations by using certain language, although their initial impression was positive, and persons with bad appearance could effectively improve their impressions in negotiations through their use of language, although the final impressions of their negotiation counterpart might still be more negative than those for persons with good appearance. In contrast, the impressions made by persons of normal appearance were not easily affected by their use of language. The results of the present study have significant implications for future studies of effective negotiation strategies considering visual appearance as well as gender.

Exploring Tactile Perceptual Dimensions Using Materials Associated with Sensory Vocabulary.

Considering tactile sensation when designing products is important because the decision to purchase often depends on how products feel. Numerous psychophysical studies have attempted to identify important factors that describe tactile perceptions. However, the numbers and types of major tactile dimensions reported in previous studies have varied because of differences in materials used across experiments. To obtain a more complete picture of perceptual space with regard to touch, our study focuses on using vocabulary that expresses tactile sensations as a guiding principle for collecting material samples because these types of words are expected to cover all the basic categories within tactile perceptual space. We collected 120 materials based on a variety of Japanese sound-symbolic words for tactile sensations, and used the materials to examine tactile perceptual dimensions and their associations with affective evaluations. Analysis revealed six major dimensions: "Affective evaluation and Friction," "Compliance," "Surface," "Volume," "Temperature," and "Naturalness." These dimensions include four factors that previous studies have regarded as fundamental, as well as two new factors: "Volume" and "Naturalness." Additionally, we showed that "Affective evaluation" is more closely related to the "Friction" component (slipperiness and dryness) than to other tactile perceptual features. Our study demonstrates that using vocabulary could be an effective method for selecting material samples to explore tactile perceptual space.