Publications by authors named "Elisabeth Friedrich"

Article Synopsis
  • Communicative actions influence one person's prediction of another's response, sometimes leading to false perceptions, like thinking two people are interacting when only one is present (referred to as seeing a "Bayesian ghost").
  • The study involved applying real vs. sham TMS (transcranial magnetic stimulation) on the left premotor cortex and observing participants’ ability to detect a masked agent based on gestures.
  • Results showed that participants were more likely to incorrectly identify a second agent during communicative gestures compared to individual gestures, and surprisingly, real TMS increased false alarms instead of decreasing them, highlighting the role of the premotor cortex in social perception.
View Article and Find Full Text PDF

Predicting actions from non-verbal cues and using them to optimise one's response behaviour (i.e. interpersonal predictive coding) is essential in everyday social interactions.

View Article and Find Full Text PDF

Based on our prior experiences we form social expectations and anticipate another person's response. Under certain conditions, these expectations can be so strong that they lead to illusory perception of another person who is actually not there (i.e.

View Article and Find Full Text PDF

Top-down predictions of future events shaped by prior experience are an important control mechanism to allocate limited attentional resources more efficiently and are thought to be implemented as mental templates stored in memory. Increased evoked gamma activity and theta:gamma phase-phase coupling over parieto-occipital areas have previously been observed when mental templates meet matching visual stimuli. Here, we investigated how these signatures evolve during the formation of new mental templates and how they relate to the fidelity of such.

View Article and Find Full Text PDF

Nesting of fast rhythmical brain activity (gamma) into slower brain waves (theta) has frequently been suggested as a core mechanism of multi-item working memory (WM) retention. It provides a better understanding of WM capacity limitations, and, as we discuss in this review article, it can lead to applications for modulating memory capacity. However, could cross-frequency coupling of brain oscillations also constructively contribute to a better understanding of the neuronal signatures of working memory compatible with theoretical approaches that assume flexible capacity limits? Could a theta-gamma code also be considered as a neural mechanism of flexible sharing of cognitive resources between memory representations in multi-item WM? Here, we propose potential variants of theta-gamma coupling that could explain WM retention beyond a fixed memory capacity limit of a few visual items.

View Article and Find Full Text PDF

Neurofeedback training (NFT) approaches were investigated to improve behavior, cognition and emotion regulation in children with autism spectrum disorder (ASD). Thirteen children with ASD completed pre-/post-assessments and 16 NFT-sessions. The NFT was based on a game that encouraged social interactions and provided feedback based on imitation and emotional responsiveness.

View Article and Find Full Text PDF

Brain-computer interfaces (BCIs) translate oscillatory electroencephalogram (EEG) patterns into action. Different mental activities modulate spontaneous EEG rhythms in various ways. Non-stationarity and inherent variability of EEG signals, however, make reliable recognition of modulated EEG patterns challenging.

View Article and Find Full Text PDF

Individuals with severe motor impairment can use event-related desynchronization (ERD) based BCIs as assistive technology. Auto-calibrating and adaptive ERD-based BCIs that users control with motor imagery tasks ("SMR-AdBCI") have proven effective for healthy users. We aim to find an improved configuration of such an adaptive ERD-based BCI for individuals with severe motor impairment as a result of spinal cord injury (SCI) or stroke.

View Article and Find Full Text PDF

Autism Spectrum Disorder (ASD) is an increasingly prevalent condition with core deficits in the social domain. Understanding its neuroetiology is critical to providing insights into the relationship between neuroanatomy, physiology and social behaviors, including imitation learning, language, empathy, theory of mind, and even self-awareness. Equally important is the need to find ways to arrest its increasing prevalence and to ameliorate its symptoms.

View Article and Find Full Text PDF

Individuals with autism spectrum disorder (ASD) show deficits in social and communicative skills, including imitation, empathy, and shared attention, as well as restricted interests and repetitive patterns of behaviors. Evidence for and against the idea that dysfunctions in the mirror neuron system are involved in imitation and could be one underlying cause for ASD is discussed in this review. Neurofeedback interventions have reduced symptoms in children with ASD by self-regulation of brain rhythms.

View Article and Find Full Text PDF

This study implemented a systematic user-centered training protocol for a 4-class brain-computer interface (BCI). The goal was to optimize the BCI individually in order to achieve high performance within few sessions for all users. Eight able-bodied volunteers, who were initially naïve to the use of a BCI, participated in 10 sessions over a period of about 5 weeks.

View Article and Find Full Text PDF

Objective: The study aimed to improve brain-computer interface (BCI)-usability by using distinct control strategies and evaluating performance, brain activity and psychological variables on a long-term basis over several months.

Methods: Fourteen able-bodied users participated in 10 sessions, plus a follow-up session. Users were trained to control an EEG-based 4-class BCI with the mental tasks, word association, mental subtraction, spatial navigation, and motor imagery.

View Article and Find Full Text PDF

Objective: The aim of this study was to examine the temporal stability of event-related desynchronization/synchronization (ERD/S) patterns over several sessions as a function of mental task, frequency band, brain region and time interval during the imagery period.

Methods: Nine volunteers participated in four sessions within 2 weeks of multi-channel EEG recordings. They performed seven mental tasks (i.

View Article and Find Full Text PDF

Motor imagery is the task most commonly used to induce changes in electroencephalographic (EEG) signals for mental imagery-based brain computer interfacing (BCI). In this study, we investigated EEG patterns that were induced by seven different mental tasks (i.e.

View Article and Find Full Text PDF

Objective: Mental imagery-based brain-computer interface (BCI)-protocols mostly allow users to focus on the task without external interferences. Environmental stimuli, however, may hamper users' ability to generate proper brain activity patterns. The aim of this study was to investigate whether users are able to retain satisfactory BCI control during auditory distraction, and whether distinct mental tasks are affected differently from auditory distraction.

View Article and Find Full Text PDF

The scanning protocol is a novel brain-computer interface (BCI) implementation that can be controlled with sensorimotor rhythms (SMRs) of the electroencephalogram (EEG). The user views a screen that shows four choices in a linear array with one marked as target. The four choices are successively highlighted for 2.

View Article and Find Full Text PDF

Surgical reduction of fat surplus is usually performed on healthy individuals and is reported as a safe procedure as it is not associated with a lethal outcome. Due to the anticipation of peri- and postoperative bleeding as a result of the large wound area, which may have a negative influence on the cosmetic result, patients often receive no or only inadequate anticoagulation. We report three cases in which surgical reduction of fat surplus led to sudden collapse and cardiac arrest.

View Article and Find Full Text PDF

During the summer months of the year 2001, six forensic cases (one is reported in the present paper), a pig carrion study in the city of Vienna (latitude 48 degrees 12'N, longitude 16 degrees 22'E) and several liver-baited traps north of Vienna, yielded large numbers of maggots of the blowfly Chrysomya albiceps (Wiedemann) (Diptera: Calliphoridae). Apart from some records from France, reports of C. albiceps from the palearctic region north of the Alps (i.

View Article and Find Full Text PDF