Bimodal Combinations Research Articles

Bimodal surface lattice resonance sensing based on asymmetric metasurfaces

The surface lattice resonance (SLR) is a prominent mechanism to produce ultranarrow spectrum line shape, which can enhance the localized electric field and restrain radiation losses. However, the present research mainly focuses on the single-mode SLR and does not involve the multiplexing and higher-order SLRs. To promote the practicability of SLR, we propose bimodal reflection-type SLRs excited by the natural light based on three kinds of asymmetric optical metasurfaces systemically, which are applied to refractive index sensing with high figures of merit (FoMs) experimentally. The rectangular lattice metasurface breaks the C4 symmetry and produces concurrently (±1, 0) and (0, ±1) order SLRs, with FoMs of 33.50 and 28.85, respectively. In addition, the metasurface composed of two different patches belongs to a spatial multiplexing design and can also realize nearly identical SLR responses. Furthermore, the asymmetric dimer metasurface excites two SLRs with distinct orders meanwhile, where the high-order SLR originates from the trapping of the corresponding Rayleigh anomaly waves. The above-mentioned metasurface designs have flexibility and regularity, whose resonance wavelengths, sensitivities, and bimodal combinations can be attained at will by tuning period lengths, arranging different patches, or forming a dimer meta-atom. The research takes a significant step for bimodal SLR development and application, especially in the sensing field.

Combination of visuo-tactile and visuo-vestibular correlations in illusory body ownership and self-motion sensations.

Previous studies have shown that illusory ownership over a mannequin's body can be induced through synchronous visuo-tactile stimulation as well as through synchronous visuo-vestibular stimulation. The current study aimed to elucidate how three-way combinations of correlated visual, tactile and vestibular signals contribute to the senses of body ownership and self-motion. Visuo-tactile temporal congruence was manipulated by touching the mannequin's body and the participant's unseen real body on the trunk with a small object either synchronously or asynchronously. Visuo-vestibular temporal congruence was manipulated by synchronous or asynchronous presentation of a visual motion cue (the background rotating around the mannequin in one direction) and galvanic stimulation of the vestibular nerve generating a rotation sensation (in the same direction). The illusory experiences were quantified using a questionnaire; threat-evoked skin-conductance responses (SCRs) provided complementary indirect physiological evidence for the illusion. Ratings on the illusion questionnaire statement showed significant main effects of synchronous visuo-vestibular and synchronous visuo-tactile stimulations, suggesting that both of these pairs of bimodal correlations contribute to the ownership illusion. Interestingly, visuo-tactile synchrony dominated because synchronous visuo-tactile stimulation combined with asynchronous visuo-vestibular stimulation elicited a body ownership illusion of similar strength as when both bimodal combinations were synchronous. Moreover, both visuo-tactile and visuo-vestibular synchrony were associated with enhanced self-motion perception; self-motion sensations were even triggered when visuo-tactile synchrony was combined with visuo-vestibular asynchrony, suggesting that ownership enhanced the relevance of visual information as a self-motion cue. Finally, the SCR results suggest that synchronous stimulation of either modality pair led to a stronger illusion compared to the asynchronous conditions. Collectively, the results suggest that visuo-tactile temporal correlations have a stronger influence on body ownership than visuo-vestibular correlations and that ownership boosts self-motion perception. We present a Bayesian causal inference model that can explain how visuo-vestibular and visuo-tactile information are combined in multisensory own-body perception.

Goal-directed aiming under restricted viewing conditions with confirmatory sensory feedback

A substantial body of research has examined the speed-accuracy tradeoff captured by Fitts’ law, demonstrating increases in movement time that occur as aiming tasks are made more difficult by decreasing target width and/or increasing the distance between targets. Yet, serial aiming movements guided by internal spatial representations, rather than by visual views of targets have not been examined in this manner, and the value of confirmatory feedback via different sensory modalities within this paradigm is unknown. Here we examined goal-directed serial aiming movements (tapping back and forth between two targets), wherein targets were visually unavailable during the task. However, confirmatory feedback (auditory, haptic, visual, and bimodal combinations of each) was delivered upon each target acquisition, in a counterbalanced, within-subjects design. Each participant performed the aiming task with their pointer finger, represented within an immersive virtual environment as a 1 cm white sphere, while wearing a head-mounted display. Despite visual target occlusion, movement times increased in accordance with Fitts’ law. Though Fitts’ law captured performance for each of the sensory feedback conditions, the slopes differed. The effect of increasing difficulty on movement times was least influential in the haptic condition, suggesting more efficient processing of confirmatory haptic feedback during aiming movements guided by internal spatial representations.

Modulation instability induced by intermodal cross-phase modulation in step-index multimode fiber.

Based on linear stability analysis, we theoretically investigate the onset condition and gain spectrum of intermodal cross-phase modulation-induced noise-seeded modulation instability taking place in the normal dispersion regime of step-index multimode fiber, specially designed to support four modes (LP01, LP11, LP21, LP02) at 1064nm. For the case of total power being distributed equally in certain bimodal combinations, the peak sideband frequency scales as the square root of total power, and peak gain increases linearly with total power. For the case of total power being distributed unequally, there exists an optimal power ratio to obtain peak gain, which does not depend on total power significantly. When the mode group velocity mismatch is considered, the range and peak values of gain spectra are notably increased.

Determination Of Elementary Students’ Learning Styles Reviewed From Gender Aspects

Students use different styles or ways of receiving and managing information during learning. VARK learning style was developed based on the physiological aspect of students in the form of sensory modalities. This survey research was conducted at 30 elementary schools in Ambon City. The data of student learning was obtained by filling out the learning style questionnaire developed by Fleming. The results showed that 88.7% of students used a learning style (unimodal) and 11.3% of students combined more than one learning style (multimodal). For the unimodal learning styles, kinesthetic is most prevalent in male and female students with a percentage of 58.6%, whereas visuals are least found with a percentage of 6%. The study also revealed that multimodal learning styles were found at all bimodal, trimodal, and quadmodal combinations. The more blend of learning style, hence the frequency of determination of student learning style even less.. The combination of multiple unimodal learning styles with large numbers will result in multimodal learning styles with large numbers.

Tamoxifen in trimodal therapy with cytotoxic drugs and hyperthermia in vivo significantly enhance therapeutic efficacy against B16-F10 melanoma.

The aim of the study was to investigate whether use of the antiestrogen tamoxifen and heat treatment in combined therapy with the well-known anticancer drugs cisplatin, dacarbazine and cyclophosphamide enhances their therapeutic efficacy on mouse B16-F10 melanoma in vivo. The results of systemic melanoma therapy have been mostly disappointing. Therefore, there is still a great need for strategies that can improve existing chemotherapy options. The tumor model for the investigation of antitumor activity was a mouse B16-F10 melanoma transplanted into the footpad of C57BL/6 Zgr/Hr mice. Drugs were given intraperitoneally 15 min before the application of local hyperthermia, and tumor growth and mouse survival were followed. Hyperthermia alone determined a significant delay of tumor growth, but mouse survival was not affected. In bimodal combinations with hyperthermia, all the tested antitumor drugs significantly increased both tumor growth delay and mouse survival. Tamoxifen alone did not show any inhibitory effect on B16-F10 melanoma in vivo. However, in the trimodal therapy with a particular drug and hyperthermia, it potentiated the inhibitory effects of the respective bimodal treatments, especially that of cyclophosphamide and hyperthermia. Our results obtained on the mouse B16-F10 melanoma in vivo confirmed the enhanced therapeutic efficacy of the trimodal therapy tamoxifen, hyperthermia and anticancer drug combinations in melanoma treatment. Further studies should optimize the heat-drug time scheduling and drug doses that will result in the best possible therapeutic achievement for these trimodal therapy options.

Superadditive and Subadditive Neural Processing of Dynamic Auditory-Visual Objects in the Presence of Congruent Odors.

Our sensory experiences comprise a variety of different inputs at any given time. Some of these experiences are unmistakable, others are ambiguous and profit from additional sensory information. Here, we explored whether the presence of a congruent odor influences the neural processing and sensory interaction of audio-visual objects using degraded videos (V) and sounds (A) of dynamic objects in unimodal and bimodal (AV) combinations without or with a congruent odor (VO, AO, AVO). Analyses of EEG data revealed superadditive and subadditive interaction effects. The topography and timing of these effects suggest evaluative rather than sensory processes as the underlying cause. Together, the results suggest that the mere presence of an odor affects the processing of A, V, and AV objects differently while multisensory interactions of AV and AVO objects have common neuronal mechanisms pointing to a robust, modality-independent network for the processing of redundant sensory information.

Crossmodal interactions in the perception of expressivity in musical performance

In musical performance, bodily gestures play an important role in communicating expressive intentions to audiences. Although previous studies have demonstrated that visual information can have an effect on the perceived expressivity of musical performances, the investigation of audiovisual interactions has been held back by the technical difficulties associated with the generation of controlled, mismatching stimuli.With the present study, we aimed to address this issue by utilizing a novel method in order to generate controlled, balanced stimuli that comprised both matching and mismatching bimodal combinations of different expressive intentions. The aim of Experiment 1 was to investigate the relative contributions of auditory and visual kinematic cues in the perceived expressivity of piano performances, and in Experiment 2 we explored possible crossmodal interactions in the perception of auditory and visual expressivity. The results revealed that although both auditory and visual kinematic cues contribute significantly to the perception of overall expressivity, the effect of visual kinematic cues appears to be somewhat stronger. These results also provide preliminary evidence of crossmodal interactions in the perception of auditory and visual expressivity. In certain performance conditions, visual cues had an effect on the ratings of auditory expressivity, and auditory cues had a small effect on the ratings of visual expressivity.

Max Brake Force as a Measure of Perceived Urgency in a Driving Context

Participants drove a simulated vehicle while completing an n-back task of high or low cognitive demand. Concurrently, they responded via brake press to signals presented in either a single modality (auditory, visual or tactile) or a bimodal combination. Participants were asked to indicate the perceived urgency of each signal by adjusting the force applied in their brake response. Signals were designed to be of “high” or “low” urgency based on previous research for both unimodal and bimodal combinations. Participants were capable of subjectively judging perceived urgency independent of response time and responded to bimodal (relative to unimodal) and high (relative to low) urgency stimuli with significantly greater brake force. However, both factors interacted with cognitive demand indicating that the magnitude of these differential responses was reduced under high demand. Implications for warning evaluation in an in-vehicle driving context are discussed.

Differential Contributions of Vision, Touch and Muscle Proprioception to the Coding of Hand Movements

To further elucidate the mechanisms underlying multisensory integration, this study examines the controversial issue of whether congruent inputs from three different sensory sources can enhance the perception of hand movement. Illusory sensations of clockwise rotations of the right hand were induced by either separately or simultaneously stimulating visual, tactile and muscle proprioceptive channels at various intensity levels. For this purpose, mechanical vibrations were applied to the pollicis longus muscle group in the subjects’ wrists, and a textured disk was rotated under the palmar skin of the subjects’ right hands while a background visual scene was projected onto the rotating disk. The elicited kinaesthetic illusions were copied by the subjects in real time and the EMG activity in the adductor and abductor wrist muscles was recorded. The results show that the velocity of the perceived movements and the amplitude of the corresponding motor responses were modulated by the nature and intensity of the stimulation. Combining two sensory modalities resulted in faster movement illusions, except for the case of visuo-tactile co-stimulation. When a third sensory input was added to the bimodal combinations, the perceptual responses increased only when a muscle proprioceptive stimulation was added to a visuo-tactile combination. Otherwise, trisensory stimulation did not override bimodal conditions that already included a muscle proprioceptive stimulation. We confirmed that vision or touch alone can encode the kinematic parameters of hand movement, as is known for muscle proprioception. When these three sensory modalities are available, they contribute unequally to kinaesthesia. In addition to muscle proprioception, the complementary kinaesthetic content of visual or tactile inputs may optimize the velocity estimation of an on-going movement, whereas the redundant kinaesthetic content of the visual and tactile inputs may rather enhance the latency of the perception.

Tamoxifen in Trimodal Therapy with Cytotoxic Drugs and Hyperthermia in Vivo Significantly Enhance Therapeutic Efficacy against B16-F10 Melanoma

The aim of the study was to investigate whether use of the antiestrogen tamoxifen and heat treatment in combined therapy with the well-known anticancer drugs cisplatin, dacarbazine and cyclophosphamide enhances their therapeutic efficacy on mouse B16-F10 melanoma in vivo. The results of systemic melanoma therapy have been mostly disappointing. Therefore, there is still a great need for strategies that can improve existing chemotherapy options. The tumor model for the investigation of antitumor activity was a mouse B16-F10 melanoma transplanted into the footpad of C57BL/6 Zgr/Hr mice. Drugs were given intraperitoneally 15 min before the application of local hyperthermia, and tumor growth and mouse survival were followed. Hyperthermia alone determined a significant delay of tumor growth, but mouse survival was not affected. In bimodal combinations with hyperthermia, all the tested antitumor drugs significantly increased both tumor growth delay and mouse survival. Tamoxifen alone did not show any inhibitory effect on B16-F10 melanoma in vivo. However, in the trimodal therapy with a particular drug and hyperthermia, it potentiated the inhibitory effects of the respective bimodal treatments, especially that of cyclophosphamide and hyperthermia. Our results obtained on the mouse B16-F10 melanoma in vivo confirmed the enhanced therapeutic efficacy of the trimodal therapy tamoxifen, hyperthermia and anticancer drug combinations in melanoma treatment. Further studies should optimize the heat-drug time scheduling and drug doses that will result in the best possible therapeutic achievement for these trimodal therapy options.

Testing the bimodal/schizophrenic neutrino hypothesis in neutrinoless double beta decay and neutrino telescopes

The standard assumption is that all three neutrino mass states are either Dirac or Majorana. However, it was recently suggested by Allaverdi, Dutta and one of the authors (R.N.M.) that mixed, or bimodal, flavor neutrino scenarios are conceivable and are consistent with all known observations (these were called "schizophrenic" in the ADM paper). In that case each individual mass eigenstate can be either Dirac or Majorana, so that the flavor eigenstates are "large" admixtures of both. An example of this "bimodal" situation is to consider one mass state as a Dirac particle (with a sterile partner), while the other two are of Majorana type. Since only Majorana particles contribute to neutrinoless double beta decay, the usual dependence of this observable on the neutrino mass is modified within this scenario. We study this in detail and, in particular, generalize the idea for all possible bimodal combinations. Inevitably, radiative corrections will induce a pseudo-Dirac nature to the Dirac states at the one-loop level, and the effects of the pseudo-Dirac mass splitting will show up in the flavor ratios of neutrinos from distant cosmological sources. Comparison of the effective mass in neutrinoless double beta decay as well as flavor ratios at neutrino telescopes, for different pseudo-Dirac cases and with their usual phenomenology, can distinguish the different bimodal possibilities.

Counting visual and tactile events: The effect of attention on multisensory integration

Irrelevant events in one sensory modality can influence the number of events that are perceived in another modality. Previously, the underlying process of sensory integration was studied in conditions in which participants knew a priori which sensory modality was relevant and which was not. Consequently, (bottom-up) sensory interference and (top-down) selective attention were confounded. We disentangled these effects by measuring the influence of visual flashes on the number of tactile taps that were perceived, and vice versa, in two conditions. In the cue condition, participants were instructed on which modality to report before the bimodal stimulus was presented. In the no-cue condition, they were instructed after stimulus presentation. Participants reported the number of events that they perceived for bimodal combinations of one, two, or three flashes and one, two, or three taps. Our main findings were that (1) in no-cue conditions, the influence of vision on touch was stronger than was the influence of touch on vision; (2) in cue conditions, the integration effects were smaller than those in no-cue conditions; and (3) irrelevant taps were less easily ignored than were irrelevant flashes. This study disentangled previously confounded bottom-up and top-down effects: The bottom-up influence of vision on touch was stronger, but vision was also more easily suppressed by top-down selective attention. We have compared our results qualitatively and quantitatively with recently proposed sensory-integration models.

Multimodal Threat Cueing in Simulated Combat Vehicle

We investigated three types of display combinations for threat cueing in a simulated combat vehicle. The display combinations consisted of two bimodal combinations, a visual head-up display (HUD) combined with 3D audio; a tactile torso belt combined with 3D audio; and a multimodal combination, the HUD, tactile belt, and 3D audio combined. The participant's main task was to as fast as possible align the heading of the combat vehicle with the displayed direction to a threat. To increase general task difficulty and provide a secondary measure of mental workload, the participant also was required to identify radio calls. Threat localization accuracy was highest and reaction time shortest with the use of both the HUD combined with 3D audio and with the multimodal display. Subjective ratings of perception of initial threat direction were most positive for both the tactile belt combined with 3D audio and for the multimodal display. The ratings of perceived threat direction at the final phase of threat alignment, however, were most positive for the HUD combined with 3D audio and for the multimodal display. Thus, the multimodal display with HUD, tactile belt, and 3D audio combined proved to be beneficial for all measures.

Enhancement of response times to bi- and tri-modal sensory stimuli during active movements

Simultaneous activation of two sensory modalities can improve perception and enhance performance. This multi-sensory enhancement had been previously observed only in conditions wherein participants were not performing any movement. Since tactile perception is attenuated during active movements, we investigated whether a bi- and a tri-modal enhancement can occur also when participants are presented with tactile stimuli, while engaged in active movements. Participants held a pen-like stylus and performed bidirectional writing-like movements inside a restricted workspace. During these movements participants were given a uni-modal sensory signal (visual--a thin gray line; auditory--a brief sound; haptic--a mechanical resisting force delivered through the stylus) or a bi- or tri-modal combination of these uni-modal signals, and their task was to respond, by pressing a button on the stylus, as soon as any one of these three stimuli was detected. Results showed that a combination of tri-modal signals was detected faster than any of the bi-modal combinations, which in turn were detected faster than any of the uni-modal signals. These facilitations exceeded the "Race model" predictions. A breakdown of the time gained in the bi-modal combinations by hemispace, hands and gender, provide further support for the "inverse effectiveness" principle, as the maximal bi-modal enhancements occurred for the least effective uni-modal responses.

Visual dominance and attention: The Colavita effect revisited

Under many conditions, humans display a robust tendency to rely more on visual information than on other forms of sensory information. Colavita (1974) illustrated this visual dominance effect by showing that naive observers typically fail to respond to clearly suprathreshold tones if these are presented simultaneously with a visual target flash. In the present study, we demonstrate that visual dominance influences performance under more complex stimulation conditions and address the role played by attention in mediating this effect. In Experiment 1, we show the Colavita effect in the simple speeded detection of line drawings and naturalistic sounds, whereas in Experiment 2 we demonstrate visual dominance when the task targets (auditory, visual, or bimodal combinations) are embedded among continuous streams of irrelevant distractors. In Experiments 3-5, we address the consequences of varying the probability of occurrence of targets in each sensory modality. In Experiment 6, we further investigate the role played by attention on visual dominance by manipulating perceptual load in either the visual or the auditory modality. Our results demonstrate that selective attention to a particular sensory modality can modulate--although not completely reverse--visual dominance as illustrated by the Colavita effect.

Bimodal and trimodal multisensory enhancement: Effects of stimulus onset and intensity on reaction time

Manual reaction times to visual, auditory, and tactile stimuli presented simultaneously, or with a delay, were measured to test for multisensory interaction effects in a simple detection task with redundant signals. Responses to trimodal stimulus combinations were faster than those to bimodal combinations, which in turn were faster than reactions to unimodal stimuli. Response enhancement increased with decreasing auditory and tactile stimulus intensity and was a U-shaped function of stimulus onset asynchrony. Distribution inequality tests indicated that the multisensory interaction effects were larger than predicted by separate activation models, including the difference between bimodal and trimodal response facilitation. The results are discussed with respect to previous findings in a focused attention task and are compared with multisensory integration rules observed in bimodal and trimodal superior colliculus neurons in the cat and monkey.

Population screening for isoniazid acetylator phenotype.

To establish a useful method for acetylator phenotypification and therapeutic drug monitoring of patients receiving isoniazid. Sixty patients with uncomplicated pulmonary tuberculosis were given a 5-mg/kg oral dose of isoniazid each. Plasma concentrations of isoniazid and its metabolite, acetyl-isoniazid, were determined by HPLC analyses at various post-dose times. From the isoniazid concentration and the concentration ratio of acetyl-isoniazid and isoniazid (metabolic ratio), phenotypification methods were assessed. The metabolic ratios at 3 h post-dose revealed a trimodal distribution; a fast, intermediate and slow acetylator phenotype group. The 2-h and 6-h data showed different bimodal combinations of these phenotype groups. The metabolic ratio phenotypification method could be simplified by using the HPLC data directly without converting it to absolute concentrations. A single-sample test based upon the plasma isoniazid concentration, combined with the metabolic ratio of acetyl-isoniazid and isoniazid, appears to be a reliable parameter for phenotype discrimination and for bioavailability testing.