38 research outputs found
The 'not-so-strange' body in the mirror: : A principal components analysis of direct and mirror self-observation
This document is the Accepted Manuscript version of the following article: Paul M. Jenkinson, and Catherine Preston, ‘The “not-so-strange” body in the mirror: A principal components analysis of direct and mirror self-observation’, Consciousness and Cognition, Vol. 48, pp. 262-272, first published online 4 January 2017, doi: http://dx.doi.org/10.1016/j.concog.2016.12.007 This manuscript version is made available under the CC-BY-NC-ND 4.0 license http://creativecommons.org/licenses/by-nc-nd/4.0/.In this study we adopted a psychometric approach to examine how the body is subjectively experienced in a mirror. One hundred and twenty-four healthy participants viewed their body for five minutes directly or via a mirror, and then completed a 20-item questionnaire designed to capture subjective experiences of the body. PCA revealed a two-component structure for both direct and mirror conditions, comprising body evaluations (and alienation) and unusual feelings and perceptions. The relationship between these components and pre-existing tendencies for appearance anxiety, body dysmorphic-type beliefs, dissociative symptomatology, self-objectification and delusion ideation further supported the similarity between direct and mirror conditions; however, the occurrence of strange experiences like those reported to occur during prolonged face viewing was not confirmed. These results suggest that, despite obvious differences in visual feedback, observing the body via a mirror (as an outside observer) is subjectively equivalent to observing the body directly (from our own viewpoint).Peer reviewedFinal Accepted Versio
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The onset time of the ownership sensation in the moving rubber hand illusion
The rubber hand illusion (RHI) is a perceptual illusion whereby a model hand is perceived
as part of one’s own body. This illusion has been extensively studied, but little is known
about the temporal evolution of this perceptual phenomenon, i.e., how long it takes until
participants start to experience ownership over the model hand. In the present study,
we investigated a version of the rubber hand experiment based on finger movements
and measured the average onset time in active and passive movement conditions.
This comparison enabled us to further explore the possible role of intentions and
motor control processes that are only present in the active movement condition. The
results from a large group of healthy participants (n D 117) showed that the illusion of
ownership took approximately 23 s to emerge (active: 22.8; passive: 23.2). The 90th
percentile occurs in both conditions within approximately 50 s (active: 50; passive:
50.6); therefore, most participants experience the illusion within the first minute. We
found indirect evidence of a facilitatory effect of active movements compared to passive
movements, and we discuss these results in the context of our current understanding
of the processes underlying the moving RHI
Mapping the availability of bushmeat for consumption in Central African cities
The trade of bushmeat from rural areas to supply burgeoning cities is a major conservation and livelihood concern. Using a whole-city sampling strategy we mapped the distribution and numbers of meat outlets in the Kinshasa-Brazzaville metropolitan area, two neighboring capital cities in Central Africa. We show that both cities differ in the number and density of meat outlets, with more in Brazzaville per area sampled and inhabitants. The number of meat outlets is related to human population densities and primarily concentrated along the banks of the Congo River, in the more affluent areas of the cities. Across the two cities, roughly 22% of all sampled markets (50% in Brazzaville and 19% in Kinshasa) and 24% of all visited restaurants (24% in each city) were selling bushmeat during our survey. Despite the relatively low number of establishments offering bushmeat for sale, extrapolated to the entire area and population of both cities, we expect the overall amounts of wild animal meats consumed per annum to be significantly high. We suggest that the supply of such amounts of wild animal meat will strongly impact the animal populations sourcing these cities. Our data also indicate that the number of domestic meat outlets may be adequate to supply urban dwellers with sufficient animal protein
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When passive feels active - delusion-proneness alters self-recognition in the moving rubber hand illusion
Psychotic patients have problems with bodily self-recognition such as the experience of self-produced actions (sense of agency) and the perception of the body as their own (sense of ownership). While it has been shown that such impairments in psychotic patients can be explained by hypersalient processing of external sensory input it has also been suggested that they lack normal efference copy in voluntary action. However, it is not known how problems with motor predictions like efference copy contribute to impaired sense of agency and ownership in psychosis or psychosis-related states. We used a rubber hand illusion based on finger movements and measured sense of agency and ownership to compute a bodily self-recognition score in delusion-proneness (indexed by Peters’ Delusion Inventory - PDI). A group of healthy subjects (n=71) experienced active movements (involving motor predictions) or passive movements (lacking motor predictions). We observed a highly significant correlation between delusion-proneness and self-recognition in the passive conditions, while no such effect was observed in the active conditions. This was seen for both ownership and agency scores. The result suggests that delusion-proneness is associated with hypersalient external input in passive conditions, resulting in an abnormal experience of the illusion. We hypothesize that this effect is not present in the active condition because deficient motor predictions counteract hypersalience in psychosis proneness
Caractéristiques radioélectriques d’éléments rayonnants élémentaires auto-complémentaires
Encadré par Georges Kossiavas et Jean-Yves Dauvigna
Çift aktif köprü DC-DC konvertörünün PI ve model öngörülü kontrolü karşilaştirmali çalişmasi
The use of renewable sources requires suitable power electronics for integrating energy into the network. For this purpose, bidirectional converters become essential elements. Over the past years, a particular topology of bidirectional converter has attracted the attention of researchers due to its benefits: “The Dual Active Bridge converter”. The operation and control of this topology must be thoroughly studied to increase its performance. In this thesis, a comparative evaluation of PI Control and Model Predictive Control of the DAB converter for use in a unidirectional power transfer application was conducted to choose the best control approach for the system operation.
The methodology chosen for this analysis was the investigation of the system operation in three (3) different working scenarios: the steady-state, the dynamic response, and the input voltage change (disturbance). The predictive voltage control approach was developed as an S-Function for simulation in MATLAB.Yenilenebilir kaynakların kullanımı, enerjiyi ağa entegre etmek için uygun güç elektroniği gerektirir. Bu amaçla çift yönlü dönüştürücüler temel unsurlar haline gelir. Geçtiğimiz yıllarda, çift yönlü dönüştürücünün belirli bir topolojisi, faydaları nedeniyle araştırmacıların dikkatini çekmiştir: “İkili Aktif Köprü dönüştürücü”. Performansını artırmak için bu topolojinin çalışması ve kontrolü kapsamlı bir şekilde incelenmelidir. Bu tezde, sistem çalışması için en iyi kontrol yaklaşımını seçmek için tek yönlü bir güç transferi uygulamasında kullanım için DAB dönüştürücünün PI Kontrolü ve Model Tahminli Kontrolünün karşılaştırmalı bir değerlendirmesi yapılmıştır. Bu analiz için seçilen metodoloji, sistem çalışmasının üç (3) farklı çalışma senaryosunda araştırılmasıydı: kararlı durum, dinamik yanıt ve giriş voltajı değişikliği (bozulma). Tahmini voltaj kontrol yaklaşımı, MATLAB'da simülasyon için bir S-Fonksiyonu olarak geliştirilmiştir.No sponso
Correlations between the Self-recognition and the PDI score in active (red) and passive (blue) conditions.
<p>Spearman’s rank correlation: Active conditions: r = -0.002, p = 0.988. Passive conditions: r = 0.313**, p = 0.008.</p
Illustration of the moving rubber hand setup used in the study.
<p>Illustration of the moving rubber hand setup used in the study.</p
The results of the illusion questionnaire replicate previous results: participants experienced the illusion in both active synchronous and passive synchronous conditions, but not in the asynchronous conditions (Ownership Active Synchronous vs. Ownership Active Asynchronous: Z = -7.036, p < .000; Ownership Passive Synchronous vs. Ownership Passive Asynchronous: Z = -6.804, p < .000).
<p>Median and 95% CI is shown. See also <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0128549#pone.0128549.s001" target="_blank">S1 File</a>.</p
Delusion-proneness displays comorbidity with traits of autistic-spectrum disorders and ADHD.
There is an increasing body of evidence suggesting a significant comorbidity between psychotic disorders such as schizophrenia and attention-deficit/hyperactivity disorder (ADHD) or autism-spectrum disorders (ASD). Recently, research on psychosis-proneness in otherwise healthy individuals has been a promising way to better understand the mechanisms underlying psychosis. As both ADHD and ASD symptoms show a normal distribution in the general population, such trait comorbidity may confound studies on psychosis-proneness. Thus, understanding the extent to which psychosis-proneness relates to ADHD and ASD symptoms in healthy subjects is crucial for studies focusing on at-risk or psychosis-prone populations. In the present paper we tested the robustness of overlap between psychosis-proneness and ADHD/ASD symptoms, by studying correlations between the scores of three commonly-used questionnaires assessing delusion-proneness (Peters' Delusion Inventory), ADHD tendencies (Adult ADHD Self-Report Scale) and ASD tendencies (Autism Quotient), on a large sample of healthy individuals (n = 925) using raw scores, prototypical questions and a factor analysis. The results showed consistently positive correlations between psychosis-proneness and ADHD-, as well as ASD-symptoms. While the effect was weak for ASD, it was moderate for ADHD. The findings support the idea that when investigating psychosis-proneness it is crucial to also take ADHD- and ASD-tendencies into account, in order to conclude that the reported results in a given study are specific to psychosis-proneness. The observed trait correlations also suggest a common pathway in the underlying information processing of these states