Embodied Precision : Intranasal Oxytocin Modulates Multisensory Integration

© 2018 Massachusetts Institute of Technology.Multisensory integration processes are fundamental to our sense of self as embodied beings. Bodily illusions, such as the rubber hand illusion (RHI) and the size-weight illusion (SWI), allow us to investigate how the brain resolves conflicting multisensory evidence during perceptual inference in relation to different facets of body representation. In the RHI, synchronous tactile stimulation of a participant's hidden hand and a visible rubber hand creates illusory body ownership; in the SWI, the perceived size of the body can modulate the estimated weight of external objects. According to Bayesian models, such illusions arise as an attempt to explain the causes of multisensory perception and may reflect the attenuation of somatosensory precision, which is required to resolve perceptual hypotheses about conflicting multisensory input. Recent hypotheses propose that the precision of sensorimotor representations is determined by modulators of synaptic gain, like dopamine, acetylcholine, and oxytocin. However, these neuromodulatory hypotheses have not been tested in the context of embodied multisensory integration. The present, double-blind, placebo-controlled, crossover study ( N = 41 healthy volunteers) aimed to investigate the effect of intranasal oxytocin (IN-OT) on multisensory integration processes, tested by means of the RHI and the SWI. Results showed that IN-OT enhanced the subjective feeling of ownership in the RHI, only when synchronous tactile stimulation was involved. Furthermore, IN-OT increased an embodied version of the SWI (quantified as estimation error during a weight estimation task). These findings suggest that oxytocin might modulate processes of visuotactile multisensory integration by increasing the precision of top-down signals against bottom-up sensory input.Peer reviewedFinal Accepted Versio

Explicit Delegation Using Configurable Cookies

Password sharing is widely used as a means of delegating access, but it is open to abuse and relies heavily on trust in the person being delegated to. We present a protocol for delegating access to websites as a natural extension to the Pico protocol. Through this we explore the potential characteristics of delegation mechanisms and how they interact. We conclude that security for the delegator against misbehaviour of the delegatee can only be achieved with the cooperation of the entity offering the service being delegated. To achieve this in our protocol we propose configurable cookies that capture delegated permissions.We are grateful to the European Research Council for funding this research through grant StG 307224 (Pico)

Red Button and Yellow Button: Usable Security for Lost Security Tokens

Currently, losing a security token places the user in a dilemma: reporting the loss as soon as it is discovered involves a significant burden which is usually overkill in the common case that the token is later found behind a sofa. Not reporting the loss, on the other hand, puts the security of the protected account at risk and potentially leaves the user liable. We propose a simple architectural solution with wide applicability that allows the user to reap the security benefit of reporting the loss early, but without paying the corresponding usability penalty if the event was later discovered to be a false alarm.The authors with a Cambridge affiliation are grateful to the European Research Council for funding this research through grant StG 307224 (Pico). Goldberg thanks NSERC for grant RGPIN-341529. We also thank the workshop attendees for comments

Randomised trial of glutamine, selenium, or both, to supplement parenteral nutrition for critically ill patients

Peer reviewedPublisher PD

The Lagrange and Markov spectra from the dynamical point of view

This text grew out of my lecture notes for a 4-hours minicourse delivered on October 17 \& 19, 2016 during the research school "Applications of Ergodic Theory in Number Theory" -- an activity related to the Jean-Molet Chair project of Mariusz Lema\'nczyk and S\'ebastien Ferenczi -- realized at CIRM, Marseille, France. The subject of this text is the same of my minicourse, namely, the structure of the so-called Lagrange and Markov spectra (with an special emphasis on a recent theorem of C. G. Moreira).Comment: 27 pages, 6 figures. Survey articl

To have and have not: Variations on secret sharing to model user presence

We address the problem of locking and unlocking a device, such as a laptop, a phone or a security token, based on the absence or presence of the user. We detect user presence by sensing the proximity of a subset of their possessions, making the process automatic and effortless. As in previous work, a master key unlocks the device and a secret-sharing scheme allows us to reconstruct this master key in the presence of k-out-of-n items. We extend this basic scheme in various directions, e.g. by allowing items to issue a dynamically variable number of shares based on how confident they are that the user is present. The position we argue in this paper is that a multi-dimensional approach to authentication that fuses several contextual inputs, similar to that already adopted by major web sites, can also bring advantages at the local scale.This is the author accepted manuscript. The final published version is available at http://dl.acm.org/citation.cfm?id=2641705&CFID=518729474&CFTOKEN=85977065

Attitudes and impressions of participants in a study of the causes of childhood cancer

Researchers and ethics committees are increasingly concerned about the perceived emotional impact on individuals following participation in epidemiologic studies. This attitudinal survey was designed to investigate this issue among 751 of the parents who had already given an interview in the UK Childhood Cancer Study (UKCCS), one of the largest case-control studies ever undertaken to investigate the aetiology of cancer in children. Information was collected by postal questionnaire on their reasons for agreeing to take part in the UKCCS, on whether questions had caused distress or difficulty and what their feelings were immediately after the interview and at the time of this survey. Parents were asked if they felt they had benefited in any way by taking part and control parents were asked if they would have taken part without prior consent of their doctor. 90% of both cases and controls felt glad to have taken part immediately after the interview and few reported any anxiety at having done so; 95% of both cases and controls felt satisfied that they had made a worthwhile contribution. Although 18% of cases felt tense and 14% felt unhappy after the interview, over 90% of them felt glad that they had taken part a few weeks later. Of particular interest is that 38% of cases and 24% of controls said they had positively benefited from taking part in the UKCCS and 96% of control mothers did not mind their family doctor giving permission for them to be contacted. © 2001 Cancer Research Campaign http://www.bjcancer.co