Behavioral Assessment of Zwicker Tone Percepts in Gerbils.

The Zwicker tone illusion - an auditory phantom percept after hearing a notched noise stimulus - can serve as an interesting model for acute tinnitus. Recent mechanistic models suggest that the underlying neural mechanisms of both percepts are similar. To date it is not clear if animals do perceive the Zwicker tone, as up to now no behavioral paradigms are available to objectively assess the presence of this phantom percept. Here we introduce, for the first time, a modified version of the gap pre-pulse inhibition of the acoustic startle reflex (GPIAS) paradigm to test if it is possible to induce a Zwicker tone percept in our rodent model, the Mongolian gerbil. Furthermore, we developed a new aversive conditioning learning paradigm and compare the two approaches. We found a significant increase in the GPIAS effect when presenting a notched noise compared to white noise gap pre-pulse inhibition, which is consistent with the interpretation of a Zwicker tone percept in these animals. In the aversive conditioning learning paradigm, no clear effect could be observed in the discrimination performance of the tested animals. When investigating the first 33% of the correct conditioned responses, an effect of a possible Zwicker tone percept can be seen, i.e. animals show identical behavior as if a pure tone was presented, but the paradigm needs to be further improved. Nevertheless, the results indicate that Mongolian gerbils are able to perceive a Zwicker tone and can serve as a neurophysiological model for human tinnitus generation.

Assessment of body perception disturbances in complex regional pain syndrome: A systematic review using the COSMIN guideline.

OBJECTIVE: To conduct a systematic review to identify which tools are being used to assess body perception disturbances in Complex Regional Pain Syndrome (CRPS) and to provide an evidence-based recommendation in the selection of an assessment tool, based on measurement properties. DATABASES AND DATA TREATMENT: Five electronic databases (EMBASE, Pubmed, PsycInfo, Science Direct and Web of Science) were searched for English or French written articles, with no time restrictions. All original articles using a body perception assessment tool with adult patients with CRPS were selected, regardless of their design (controlled trials, single case, qualitative study). Two investigators screened abstracts, selected full articles and extracted data independently. RESULTS: Thirty-eight full-text papers were obtained and three main methods to evaluate body perception disturbances were identified: The Bath Body Perception Disturbance Scale, the Neglect-like Symptoms questionnaire adapted from Galer and the patient's body perception description. No full psychometric assessments were found. The Limb Laterality Recognition Task was also used in conjunction with another method. CONCLUSIONS: Three main assessment methods for CRPS body perception disturbances are currently used. Full psychometric evaluation has not been completed for any of the assessment methods. As a consequence, we could not fully apply the COSMIN guideline. To date, there is no agreement concerning the use of a specific questionnaire or scale. The results indicate a need for further research such as psychometric properties of these questionnaires. SIGNIFICANCE: This systematic review identified body perception disturbances assessment methods and their the psychometric properties in order to provide help and guidance to researchers and clinicians to investigate those clinical features.

Reality and illusion: the assessment of angular separation of multi-modal signallers in a duetting bird.

The spatial distribution of cooperating individuals plays a strategic role in territorial interactions of many group-living animals, and can indicate group cohesion. Vocalizations are commonly used to judge the distribution of signallers, but the spatial resolution of sounds is poor. Many species therefore accompany calls with movement; however, little is known about the role of audio-visual perception in natural interactions. We studied the effect of angular separation on the efficacy of multimodal duets in the Australian magpie-lark, Grallina cyanoleuca. We tested specifically whether conspicuous wing movements, which typically accompany duets, affect responses to auditory angular separation. Multimodal playbacks of duets using robotic models and speakers showed that birds relied primarily on acoustic cues when visual and auditory angular separations were congruent, but used both modalities to judge separation between the signallers when modalities were spatially incongruent. The visual component modified the effect of acoustic separation: robotic models that were apart weakened the response when speakers were together, while models that were together strengthened responses when speakers were apart. Our results show that responses are stronger when signallers are together, and suggest that males were are able to bind information cross-modally on the senders' spatial location, which is consistent with a multisensory illusion.

Cost-utility analysis of transcranial direct current stimulation therapy with and without virtual illusion for neuropathic pain for adults with spinal cord injury in Canada.

OBJECTIVE: To undertake a cost-utility analysis comparing virtual illusion (VI) and transcranial direct current stimulation (tDCS) combination therapy, tDCS alone and standard pharmacological care in Ontario, Canada from a societal perspective over a three-month time horizon. DESIGN: Cost-utility analysis using Markov model methods. SETTING: Community setting in Ontario, Canada. PARTICIPANTS: Individuals with spinal cord injury and neuropathic pain (NP) resistant to pharmacological therapy. INTERVENTIONS: Virtual illusion and transcranial direct current stimulation, transcranial direct current stimulation alone and standard pharmacological therapy. OUTCOME MEASURES: Incremental costs, quality adjusted life years (QALY) and incremental cost effectiveness ratio. RESULTS: The incremental cost effectiveness ratio of VI and tDCS therapy cost is $3,396 per QALY (2020 Canadian dollars) when compared to standard care. The incremental cost per QALY of tDCS therapy alone is $33,167. VI and tDCS therapy had lower incremental costs (-$519) and higher incremental QALYs (0.026) compared to tDCS alone. From a public healthcare payer perspective, there is a 74% probability that VI and tDCS therapy and 54% probability that tDCS alone would be cost effective at a $50,000 per QALY willingness-to-pay threshold. Our findings remained relatively robust in various scenario analyses. CONCLUSION: Our findings suggest that at three-months after therapy, VI and tDCS combination therapy may be more cost effective than tDCS therapy alone. Based on conventional health technology funding thresholds, VI and tDCS combination therapy merits consideration for the treatment of NP in adults with spinal cord injuries.

The Brentano Illusion Test (BRIT): An implicit task of perceptual processing for the assessment of visual field defects in neglect patients.

In brain damaged patients with unilateral spatial neglect (USN), the differential diagnosis between the presence and absence of a unilateral visual half-field deficit (VHFD) is hampered by the similarity of their phenomenology. The absence of stimuli detection in the contralateral visual field, indeed, can be due to the co-occurrence of USN and VHFD or the sole presence of the USN. The disentangling of the two conditions is required to devise more specific rehabilitation programmes. Daini et al. [2002. Exploring the syndrome of spatial unilateral neglect through an illusion of length. Experimental Brain Research, 144(2), 224-237.] reported a difference in performance for the two conditions when the tasks required the bisection of Brentano illusory stimuli. Only when USN and VHFD co-occurred, the leftward illusory effect was disrupted. Based on previous findings, in this cross-sectional study, we developed the Brentano Illusion Test (BRIT), a clinical tool that helps the identification of VHFD in USN patients. The BRIT is a simple behavioural test of line bisection aimed at verifying the presence or absence of implicit processing in USN and thus helping the diagnosis of VHFD in USN patients; it also provides normative data for the line bisection task and the length effect.

Manipulating The Body Representation: Assessment Of A Novel Platform.

The Rubber Hand Illusion can be used to induce the illusion that a fake hand is part of one's own body. Thus, it can be used to alter the body representation. It was also reported that the Rubber Hand Illusion induces a proprioceptive drift of one's real hand toward the fake hand. The Rubber Hand Illusion can be induced when the fake hand is placed farther in the sagittal plane (distally) compared to the real hand. In this case, the induced update of the body representation is an elongation of the arm. Virtual Reality and haptic technologies can be used to manipulate the perceived scenario in a virtual version of the Rubber Hand Illusion, the Virtual Hand Illusion. We developed a novel platform consisting in a virtual reality application integrating an optical motion capture device and haptic stimulators to study the manipulation of the body representation. We developed two experimental protocols to induce embodiment of an elongated arm: one validated in previous studies, that employs congruent visuo-motor-tactile stimulation, and one reproducing the typical Virtual Hand Illusion where only congruent visuo-tactile stimulation was employed. We tested both protocols with healthy participants.

The stereoscopic advantage for vection persists despite reversed disparity.

Research has shown that consistent stereoscopic information improves the vection (i.e. illusions of self-motion) induced in stationary observers. This study investigates the effects of placing stereoscopic information into direct conflict with monocular motion signals by swapping the observer's left and right eye views to reverse disparity. Experiments compared the vection induced by stereo-consistent, stereo-reversed and flat-stereo patterns of: (1) same-size optic flow, which contained monocular motion perspective information about self-motion, and (2) changing-size optic flow, which provided additional monocular information about motion-in-depth based on local changes in object image sizes. As expected, consistent stereoscopic information improved the vection-in-depth induced by both changing-size and same-size patterns of optic flow. Unexpectedly, stereo-reversed patterns of same-size optic flow also induced stronger vection-in-depth than flat-stereo patterns of same-size optic flow. The effects of stereo-consistent and stereo-reversed information on vection strength were found to correlate reliably with their effects on perceived motion-in-depth and motion after-effect durations, but not with their effects on perceived scene depth. This suggests that stereo-consistent and stereo-reversed advantages for vection were both due to effects on perceived motion-in-depth. The current findings clearly demonstrate that stereoscopic information does not need to be consistent with monocular motion signals in order to improve vection. When taken together with past findings, they suggest that stereoscopic information only needs to be dynamic (as opposed to static) in order to improve vection-in-depth.

Why Policies Fail: The Illusion of Services in the Opioid Epidemic.

CONTEXT: Although New York State is a generous provider of substance-use treatment, people who ask for help have difficulty accessing services. If the laws are on the books, the agency is there to act, and the options are available, why is treatment so hard to get? METHODS: The authors conducted 87 open-ended interviews and observed local task force meetings in Sullivan County, New York. They open coded data, identifying key topics and themes. FINDINGS: Even though New York is a best-case scenario for treatment, people who seek help cannot always access it. The state sees the problem as a lack of beds or information about beds, but people on the ground face real barriers that make it difficult to get treatment, including the medical model of detoxification, admissions criteria, staff shortages, and other life complications. CONCLUSIONS: Contrary to the policy literature, this article shows that policies may fail not because they are poorly designed or implemented but because the policy itself does not address the actual underlying problem. Furthermore, in the case of opioids, it shows how misplaced solutions can hide evidence of the underlying problem, exacerbating the very issue that policy makers want to fix.

The Ethics of Virtual Reality Technology: Social Hazards and Public Policy Recommendations.

This article explores four major areas of moral concern regarding virtual reality (VR) technologies. First, VR poses potential mental health risks, including Depersonalization/Derealization Disorder. Second, VR technology raises serious concerns related to personal neglect of users' own actual bodies and real physical environments. Third, VR technologies may be used to record personal data which could be deployed in ways that threaten personal privacy and present a danger related to manipulation of users' beliefs, emotions, and behaviors. Finally, there are other moral and social risks associated with the way VR blurs the distinction between the real and illusory. These concerns regarding VR naturally raise questions about public policy. The article makes several recommendations for legal regulations of VR that together address each of the above concerns. It is argued that these regulations would not seriously threaten personal liberty but rather would protect and enhance the autonomy of VR consumers.

Direct physiologic assessment of anomalous aortic origin of a coronary artery: Enhanced diagnostics or illusion of insight?

Fractional flow reserve and intravascular ultrasound evaluation are technically feasible in patients with congenitally abnormal coronary arteries arising from the wrong aortic sinus, including those with a slitlike orifice and presumed intramural course. Incorporation of fractional flow reserve and intravascular ultrasound into the evaluation of adults with anomalous coronary artery origins will provide additional data and may be useful in risk assessment, although these data should be interpreted with caution, as the validity of fractional flow reserve findings in this population has not been established. The applicability of fractional flow reserve thresholds for acute coronary syndromes to patients with anomalous coronary artery origins is unknown. Further study will be needed to determine how best to incorporate fractional flow reserve data in the evaluation and management of these patients.

Effects of distinctive encoding on correct and false memory: a meta-analytic review of costs and benefits and their origins in the DRM paradigm.

We review and meta-analyze how distinctive encoding alters encoding and retrieval processes and, thus, affects correct and false recognition in the Deese-Roediger-McDermott (DRM) paradigm. Reductions in false recognition following distinctive encoding (e.g., generation), relative to a nondistinctive read-only control condition, reflected both impoverished relational encoding and use of a retrieval-based distinctiveness heuristic. Additional analyses evaluated the costs and benefits of distinctive encoding in within-subjects designs relative to between-group designs. Correct recognition was design independent, but in a within design, distinctive encoding was less effective at reducing false recognition for distinctively encoded lists but more effective for nondistinctively encoded lists. Thus, distinctive encoding is not entirely "cost free" in a within design. In addition to delineating the conditions that modulate the effects of distinctive encoding on recognition accuracy, we discuss the utility of using signal detection indices of memory information and memory monitoring at test to separate encoding and retrieval processes.

Do primates see the solitaire illusion differently? A comparative assessment of humans (Homo sapiens), chimpanzees (Pan troglodytes), rhesus monkeys (Macaca mulatta), and capuchin monkeys (Cebus apella).

An important question in comparative psychology is whether human and nonhuman animals share similar principles of perceptual organization. Despite much empirical research, no firm conclusion has been drawn. The Solitaire illusion is a numerosity illusion in humans that occurs when one misperceives the relative number of 2 types of items presented in intermingled sets. To date, no study has investigated whether nonhuman animals perceive the Solitaire illusion as humans do. Here, we compared the perception of the Solitaire illusion in human and nonhuman primates in 3 experiments. We first observed (Experiment 1) the spontaneous behavior of chimpanzees when presented with 2 arrays composed of a different number of preferred and nonpreferred food items. In probe trials, preferred items were presented in the Solitaire pattern in 2 different spatial arrangements (either clustered centrally or distributed on the perimeter). Chimpanzees did not show any misperception of quantity in the Solitaire pattern. Next, humans, chimpanzees, rhesus monkeys, and capuchin monkeys underwent the same testing of relative quantity judgments in a computerized task that also presented the Solitaire illusion (Experiments 2 and 3). Unlike humans, chimpanzees did not appear to perceive the illusion, in agreement with Experiment 1. The performance of rhesus monkeys and capuchin monkeys was also different from that of humans, but was slightly more indicative of a potential Solitaire illusion. On the whole, our results suggest a potential discontinuity in the visual mechanisms underlying the Solitaire illusion between human and nonhuman primates.

A low-cost EEG system-based hybrid brain-computer interface for humanoid robot navigation and recognition.

This paper describes a hybrid brain-computer interface (BCI) technique that combines the P300 potential, the steady state visually evoked potential (SSVEP), and event related de-synchronization (ERD) to solve a complicated multi-task problem consisting of humanoid robot navigation and control along with object recognition using a low-cost BCI system. Our approach enables subjects to control the navigation and exploration of a humanoid robot and recognize a desired object among candidates. This study aims to demonstrate the possibility of a hybrid BCI based on a low-cost system for a realistic and complex task. It also shows that the use of a simple image processing technique, combined with BCI, can further aid in making these complex tasks simpler. An experimental scenario is proposed in which a subject remotely controls a humanoid robot in a properly sized maze. The subject sees what the surrogate robot sees through visual feedback and can navigate the surrogate robot. While navigating, the robot encounters objects located in the maze. It then recognizes if the encountered object is of interest to the subject. The subject communicates with the robot through SSVEP and ERD-based BCIs to navigate and explore with the robot, and P300-based BCI to allow the surrogate robot recognize their favorites. Using several evaluation metrics, the performances of five subjects navigating the robot were quite comparable to manual keyboard control. During object recognition mode, favorite objects were successfully selected from two to four choices. Subjects conducted humanoid navigation and recognition tasks as if they embodied the robot. Analysis of the data supports the potential usefulness of the proposed hybrid BCI system for extended applications. This work presents an important implication for the future work that a hybridization of simple BCI protocols provide extended controllability to carry out complicated tasks even with a low-cost system.