Écran d'ordinateur | EPFL Graph Search

thumb|Un écran cathodique format 4/3. thumb|Un écran à cristaux liquides format 16/10. thumb|Un écran incurvé format 21/9. Un écran d'ordinateur est un périphérique de sortie vidéo d'ordinateur. Il affiche les images générées par la carte graphique de l'ordinateur. Grâce au taux de rafraîchissement d'écran élevé, il permet de donner l’impression de mouvement. Il permet donc de travailler agréablement, de visionner de la vidéo, des films, de jouer à des jeux vidéo, de saisir des textes, etc. Un écran à cristaux liquides (LCD) se compose d'une dalle (qui est le support des images), des circuits vidéo dont un multiplexeur électronique et une alimentation stabilisée. Types d'écrans Écrans cathodiques Type d'écran le plus ancien : les écrans à tube cathodique (ou écran CRT, qui est une abréviation de l'anglais Cathode Ray Tube) sont analogiques. Ils ont un angle de vision large et un rendu des couleurs fidèle mais ils sont lourds, volumineux et grands consommate

Interoception and Empathy Impact Perspective Taking

Jane Aspell, Olaf Blanke, Bruno Herbelin, Lukas Heydrich

Adopting the perspective of another person is an important aspect of social cognition and has been shown to depend on multisensory signals from one's own body. Recent work suggests that interoceptive signals not only contribute to own-body perception and self-consciousness, but also to empathy. Here we investigated if social cognition - in particular adopting the perspective of another person - can be altered by a systematic manipulation of interoceptive cues and further, if this effect depends on empathic ability. The own-body transformation task (OBT) - wherein participants are instructed to imagine taking the perspective and position of a virtual body presented on a computer screen - offers an effective way to measure reaction time differences linked to the mental effort of taking an other's perspective. Here, we adapted the OBT with the flashing of a silhouette surrounding the virtual body, either synchronously or asynchronously with the timing of participants' heartbeats. We evaluated the impact of this cardio-visual synchrony on reaction times and accuracy rates in the OBT. Empathy was assessed with the empathy quotient (EQ) questionnaire. Based on previous work using the cardio-visual paradigm, we predicted that synchronous (vs. asynchronous) cardio-visual stimulation would increase self-identification with the virtual body and facilitate participants' ability to adopt the virtual body's perspective, thereby enhancing performance on the task, particularly in participants with higher empathy scores. We report that participants with high empathy showed significantly better performance during the OBT task during synchronous versus asynchronous cardio-visual stimulation. Moreover, we found a significant positive correlation between empathic ability and the synchrony effect (the difference in reaction times between the asynchronous and synchronous conditions). We conclude that synchronous cardio-visual stimulation between the participant's body and a virtual body during an OBT task makes it easier to adopt the virtual body's perspective, presumably based on multisensory integration processes. However, this effect depended on empathic ability, suggesting that empathy, interoception and social perspective taking are inherently linked.

2021

Neural Correlates of Sequential Decision Making

Michael Herzog, He Xu

In chess, a series of moves is made until a delayed sparse feedback (win, loss) is issued, which makes it impossible to evaluate the value of a single move. There are powerful reinforcement learning (RL) algorithms, which can cope with these sequential decision making situations. A crucial component in these algorithms is the reward prediction error (RPE), which measures the difference between the actual reward and the predicted reward. Here, we show that the RPE is well reflected in a frontal negativity of the EEG. Participants saw an image on the computer screen and were asked to click one out of, for example, four buttons, which, depending on the choice, led to the presentation of a new image until a goal state was reached. 128-channel EEG was recorded. To estimate the RPE, we fit participants’ performance to state of the art RL algorithms. We chose the best fitting algorithm. Two time windows (170-286ms and 400-580ms) in the event-related potential (ERP) reflected well the magnitudes of the RPEs of this algorithm. The late time window ERP magnitude was highly correlated with the RPEs (r2=0.14, p

2017

Neural Correlates of Sequential Decision Making

Michael Herzog, He Xu

In chess, a series of moves is made until a delayed sparse feedback (win, loss) is issued, which makes it impossible to evaluate the value of a single move. There are powerful reinforcement learning (RL) algorithms, which can cope with these sequential decision making situations. A crucial component in these algorithms is the reward prediction error (RPE), which measures the difference between the actual reward and the predicted reward. Here, we show that the RPE is well reflected in a frontal negativity of the EEG. Participants saw an image on the computer screen and were asked to click one out of, for example, four buttons, which, depending on the choice, led to the presentation of a new image until a goal state was reached. 128-channel EEG was recorded. To estimate the RPE, we fit participants' performance to state of the art RL algorithms. We chose the best fitting algorithm to estimate the RPE. Two time windows (170-286ms and 400-580ms) in the event-related potential (ERP) reflected well the magnitudes of the RPEs of this algorithm. The late time window ERP magnitude was highly correlated with the RPEs (r2=0.14, p

2017

Interoception and Empathy Impact Perspective Taking

Jane Aspell, Olaf Blanke, Bruno Herbelin, Lukas Heydrich

2021