Daily life visuomotor activities, associated with prism exposure, are a useful tool for rehabilitating USN patients. This new treatment may widen the compliance with prism exposure treatments and their feasibility within home-based programs.

Order of Authors: Cristina Cacciari, PhD; Nadia Bolognini, PhD; Irene Senna; Maria Concetta Pellicciari, PhD; Carlo Miniussi, PhD; Costanza Papagno Abstract: We used Transcranial Magnetic Stimulation (TMS) to assess whether reading literal, nonliteral (i.e., metaphorical, idiomatic) and fictive motion sentences modulates the activity of the motor system. Sentences were divided into three segments visually presented one at a time: the noun phrase, the verb and the final part of the sentence. Single pulse-TMS was delivered at the end of the sentence over the leg motor area in the left hemisphere and motor evoked potentials (MEPs) were recorded from the right gastrocnemius and tibialis anterior muscles. MEPs were larger when participants were presented with literal, fictive and metaphorical motion sentences than with idiomatic motion or mental sentences. These results suggest that the excitability of the motor system modulated by the motor component of the verb is preserved in fictive and metaphorical motion sentences.Dear Editor, Thank you very much for accepting our manuscript. We have answered all the remaining points raised by Rev #1 and we are attaching in a separate file our responses.We hope that our manuscript is now suitable for publication in Brain and Language Sincerely, Costanza Papagno, PhD, MD Milano, May 9 th 2011 Cover LetterThis study adds evidence in the debate concerning the role of the primary motor cortex in the comprehension of motion verbs, showing that the motor component of the verb is preserved in fictive and metaphorical sentences, while it is not when motion verbs are used in idiomatic contexts. Res.: we have briefly summarized the pilot experiment in which we found MEP activation effects for idiomatic sentences when TMS was delivered immediately after the verb, when the subject was animate. We have added the following paragraph:We performed a previous experiment on eight healthy participants (six females, mean age 29±3 years; mean education 17±1 years; Handedness Inventory test mean score 97.4%) using the same material and procedure, except that TMS was delivered immediately after the second segment, so that participants only read the noun phrase and the (motion or mental) verb before receiving TMS. This means that up to that point participants were unaware of the literal, metaphorical or idiomatic nature of the sentences that only emerged afterwards (with the exception of sentences with an inanimate subject). In this experiment the effect of the sentence type on motor cortical excitability was evaluated using the MEP changes expressed in terms of the ratio (∆) between motion and mental (i.e., control) sentences. A repeated measure ANOVA with Sentence type (literal, fictive, idiomatic or metaphorical motion) as within-subject factor was used. The analysis did not show any significant effect on the GCM muscle [F (3, 21) SummaryWe used Transcranial Magnetic Stimulation (TMS) to assess whether reading literal, nonliteral (i.e., metaphorical, idiomatic) and fictive motion sentences modul...

Figure 1: Left: The basic virtual mirror scenario consists of an empty room and a simplistic mirror avatar. Right: The extended scenario employed in the experiment, where the target movement is shown by a semi-transparent blue "ghost character". AbstractLatency between a user's movement and visual feedback is inevitable in every Virtual Reality application, as signal transmission and processing take time. Unfortunately, a high end-to-end latency impairs perception and motor performance. While it is possible to reduce feedback delay to tens of milliseconds, these delays will never completely vanish. Currently, there is a gap in literature regarding the impact of feedback delays on perception and motor performance as well as on their interplay in virtual environments employing full-body avatars. With the present study at hand, we address this gap by performing a systematic investigation of different levels of delay across a variety of perceptual and motor tasks during full-body action inside a Cave Automatic Virtual Environment. We presented participants with their virtual mirror image, which responded to their actions with feedback delays ranging from 45 to 350 ms. We measured the impact of these delays on motor performance, sense of agency, sense of body ownership and simultaneity perception by means of psychophysical procedures. Furthermore, we looked at interaction effects between these aspects to identify possible dependencies. The results show that motor performance and simultaneity perception are affected by latencies above 75 ms. Although sense of agency and body ownership only decline at a latency higher than 125 ms, and deteriorate for a latency greater than 300 ms, they do not break down completely even at the highest tested delay. Interestingly, participants perceptually infer the presence of delays more from their motor error in the task than from the actual level of delay. Whether or not participants notice a delay in a virtual environment might therefore depend on the motor task and their performance rather than on the actual delay.

Our body is made of flesh and bones. We know it, and in our daily lives all the senses constantly provide converging information about this simple, factual truth. But is this always the case? Here we report a surprising bodily illusion demonstrating that humans rapidly update their assumptions about the material qualities of their body, based on their recent multisensory perceptual experience. To induce a misperception of the material properties of the hand, we repeatedly gently hit participants' hand with a small hammer, while progressively replacing the natural sound of the hammer against the skin with the sound of a hammer hitting a piece of marble. After five minutes, the hand started feeling stiffer, heavier, harder, less sensitive, unnatural, and showed enhanced Galvanic skin response (GSR) to threatening stimuli. Notably, such a change in skin conductivity positively correlated with changes in perceived hand stiffness. Conversely, when hammer hits and impact sounds were temporally uncorrelated, participants did not spontaneously report any changes in the perceived properties of the hand, nor did they show any modulation in GSR. In two further experiments, we ruled out that mere audio-tactile synchrony is the causal factor triggering the illusion, further demonstrating the key role of material information conveyed by impact sounds in modulating the perceived material properties of the hand. This novel bodily illusion, the ‘Marble-Hand Illusion', demonstrates that the perceived material of our body, surely the most stable attribute of our bodily self, can be quickly updated through multisensory integration.