"Self pop-out”: agency enhances self-recognition in visual search

In real-life situations, we are often required to recognize our own movements among movements originating from other people. In social situations, these movements are often correlated (for example, when dancing or walking with others) adding considerable difficulty to self-recognition. Studies from visual search have shown that visual attention can selectively highlight specific features to make them more salient. Here, we used a novel visual search task employing virtual reality and motion tracking to test whether visual attention can use efferent information to enhance self-recognition of one's movements among four or six moving avatars. Active movements compared to passive movements allowed faster recognition of the avatar moving like the subject. Critically, search slopes were flat for the active condition but increased for passive movements, suggesting efficient search for active movements. In a second experiment, we tested the effects of using the participants' own movements temporally delayed as distractors in a self-recognition discrimination task. We replicated the results of the first experiment with more rapid self-recognition during active trials. Importantly, temporally delayed distractors increased reaction times despite being more perceptually different than the spatial distractors. The findings demonstrate the importance of agency in self-recognition and self-other discrimination from movement in social setting

Inferior frontal oscillations reveal visuo-motor matching for actions and speech: evidence from human intracranial recordings.

The neural correspondence between the systems responsible for the execution and recognition of actions has been suggested both in humans and non-human primates. Apart from being a key region of this visuo-motor observation-execution matching (OEM) system, the human inferior frontal gyrus (IFG) is also important for speech production. The functional overlap of visuo-motor OEM and speech, together with the phylogenetic history of the IFG as a motor area, has led to the idea that speech function has evolved from pre-existing motor systems and to the hypothesis that an OEM system may exist also for speech. However, visuo-motor OEM and speech OEM have never been compared directly. We used electrocorticography to analyze oscillations recorded from intracranial electrodes in human fronto-parieto-temporal cortex during visuo-motor (executing or visually observing an action) and speech OEM tasks (verbally describing an action using the first or third person pronoun). The results show that neural activity related to visuo-motor OEM is widespread in the frontal, parietal, and temporal regions. Speech OEM also elicited widespread responses partly overlapping with visuo-motor OEM sites (bilaterally), including frontal, parietal, and temporal regions. Interestingly a more focal region, the inferior frontal gyrus (bilaterally), showed both visuo-motor OEM and speech OEM properties independent of orolingual speech-unrelated movements. Building on the methodological advantages in human invasive electrocorticography, the present findings provide highly precise spatial and temporal information to support the existence of a modality-independent action representation system in the human brain that is shared between systems for performing, interpreting and describing actions

Validation of multi-body modelling methodology for reconfigurable underwater robots

This paper investigates the problem of employing reconfigurable robots in an underwater setting. The main results presented is the experimental validation of a modelling methodology for a system consisting of N dynamically connected robots with heterogeneous dynamics. Two distinct types of experiments are performed, a series of hydrostatic free-decay tests and a series of open-loop trajectory tests. The results are compared to a simulation based on the modelling methodology. The modelling methodology shows promising results for usage with systems composed of reconfigurable underwater modules. The purpose of the model is to enable design of control strategies for cooperative reconfigurable underwater systems

Phenomenology of a three-family model with gauge symmetry SU(3)_c X SU(4)_L X U(1)_X

We study an extension of the gauge group SU(3)_c X SU(2)_L X U(1)_Y of the standard model to the symmetry group SU(3)_c X SU(4)_L X U(1)_X (3-4-1 for short). This extension provides an interesting attempt to answer the question of family replication in the sense that models for the electroweak interaction can be constructed so that anomaly cancellation is achieved by an interplay between generations, all of them under the condition that the number of families must be divisible by the number of colours of SU(3)_c. This method of anomaly cancellation requires a family of quarks transforming differently from the other two, thus leading to tree-level flavour changing neutral currents (FCNC) transmitted by the two extra neutral gauge bosons $Z'$ and $Z''$ predicted by the model. In a version of the 3-4-1 extension, which does not contain particles with exotic electric charges, we study the fermion mass spectrum and some aspects of the phenomenology of the neutral gauge boson sector. In particular, we impose limits on the $Z-Z'$ mixing angle and on the mass scale of the corresponding physical new neutral gauge boson $Z_2$, and establish a lower bound on the mass of the additional new neutral gauge boson $Z'' \equiv Z_3$. For the analysis we use updated precision electroweak data at the Z-pole from the CERN LEP and SLAC Linear Collider, and atomic parity violation data. The mass scale of the additional new neutral gauge boson $Z_3$ is constrained by using updated experimental inputs from neutral meson mixing in the analysis of the sources of FCNC in the model. The data constrain the $Z-Z'$ mixing angle to a very small value of O(0.001), and the lower bounds on $M_{Z_2}$ and on $M_{Z_3}$ are found to be of O(1 TeV) and of O(7 TeV), repectively.Comment: 22 pages, 6 tables, 1 figure. To appear in J. Phys. G: Nuclear and Particle Physic

Characterising New Physics Models by Effective Dimensionality of Parameter Space

We show that the dimension of the geometric shape formed by the phenomenologically valid points inside a multi-dimensional parameter space can be used to characterise different new physics models and to define a quantitative measure for the distribution of the points. We explain a simple algorithm to determine the box-counting dimension from a given set of parameter points, and illustrate our method with examples from different models that have recently been studied with respect to precision flavour observables.Comment: 14 pages, 8 figure

Perceptual aberrations impair mental own-body transformations

Dysfunctional self and bodily processing have been reported from the schizophrenia spectrum. Here, the authors tested 72 students (40 women) to determine whether performance in a mental own-body transformation task relates to self-rated frequency of spontaneously experienced schizotypal body schema alterations (perceptual aberration). Participants provided speeded left-right decisions concerning the body of a visually depicted human figure (front view vs. back view). For men, reaction times to disembodied perspectives increased with increasing scores on a validated perceptual aberration scale. This finding constitutes behavioral evidence for the clinically postulated association between aberrant bodily experiences during everyday life and aberrant processing in a mental own-body transformation task arguably reflecting mild dysfunction at the temporo-parietal junction

Modeling of Imitation Deficits in Apraxic Patients

Poster presented at the ESF Research Conference on Brain Development and Cognition in Human Infants, Maratea (Italy

Temporal lobe epilepsy and postural orthostatic tachycardia syndrome (POTS)

We describe a 20-year-old woman suffering from right temporal epilepsy, behavioral disorder, and a complaint of paroxysmal palpitations accompanied by anxiety. Detailed cardiac evaluation revealed that the palpitations were due to episodes of marked sinus tachycardia secondary to a concomitant postural orthostatic tachycardia syndrome (POTS) and not of psychogenic origin as initially thought. Treatment with a beta-blocker resulted in the disappearance of palpitations and the associated anxiety. This is the first report of the coexistence of partial epilepsy and POTS. The recognition of such a syndrome in epileptic patients is important in order to offer appropriate therapy

Functional and neural mechanisms of embodiment: importance of the vestibular system and the temporal parietal junction

Embodiment, the sense of being localized within one's physical body, is a fundamental aspect of the self. Recent research shows that self and body processing as well as embodiment require distinct brain mechanisms. Here, we review recent clinical and neuroimaging research on multisensory perception and integration as well as mental imagery, pointing out their importance for the coding of embodiment at the temporo-parietal junction (TPJ). Special reference is given to vestibular mechanisms that are relevant for self and embodiment and to methods that interfere experimentally with normal embodiment. We conclude that multisensory and vestibular coding at the TPJ mediates humans' experience as being embodied and spatially situated, and argue that pathologies concerning the disembodied self, such as out-of-body experience or other autoscopic phenomena, are due to deficient multisensory integration at the TPJ