Université de Fribourg

3D feedback and observation for motor learning: Application to the roundoff movement in gymnastics

Le Naour, Thibaut ; Ré, Chiara ; Bresciani, Jean-Pierre

In: Human Movement Science, 2019, vol. 66, p. 564-577

In this paper, we assessed the efficacy of different types of visual information for improving the execution of the roundoff movement in gymnastics. Specifically, two types of 3D feedback were compared to a 3D visualization only displaying the movement of the expert (observation) as well as to a more ‘traditional’ video observation. The improvement in movement execution was measured using...

Université de Fribourg

Asymmetric saccade reaction times to smooth pursuit

Bieg, Hans-Joachim ; Chuang, Lewis L. ; Bülthoff, Heinrich H. ; Bresciani, Jean-Pierre

In: Experimental Brain Research, 2015, vol. 233, no. 9, p. 2527–2538

Before initiating a saccade to a moving target, the brain must take into account the target’s eccentricity as well as its movement direction and speed. We tested how the kinematic characteristics of the target influence the time course of this oculomotor response. Participants performed a step-ramp task in which the target object stepped from a central to an eccentric position and moved at...

Université de Fribourg

Automating the timed up and go test using a depth camera

Dubois, Amandine ; Bihl, Titus ; Bresciani, Jean-Pierre

In: Sensors, 2017, vol. 18, no. 1, p. 14

Fall prevention is a human, economic and social issue. The Timed Up and Go (TUG) test is widely used to identify individuals with a high fall risk. However, this test has been criticized because its “diagnostic” is too dependent on the conditions in which it is performed and on the healthcare professionals running it. We used the Microsoft Kinect ambient sensor to automate this test in...

Université de Fribourg

Bioceramic fabrics improve quiet standing posture and handstand stability in expert gymnasts

Ciana, C. ; Gianocca, V. ; Barraud, P.A. ; Guerraz, M. ; Bresciani, Jean-Pierre

In: Gait & Posture, 2015, vol. 42, no. 4, p. 419–423

Bioceramic fabrics have been claimed to improve blood circulation, thermoregulation and muscle relaxation, thereby also improving muscular activity. Here we tested whether bioceramic fabrics have an effect on postural control and contribute to improve postural stability. In Experiment 1, we tested whether bioceramic fabrics contribute to reduce body-sway when maintaining standard standing...

Université de Fribourg

A biologically-inspired model to predict perceived visual speed as a function of the stimulated portion of the visual field

Solari, Fabio ; Caramenti, Martina ; Chessa, Manuela ; Pretto, Paolo ; Bülthoff, Heinrich H. ; Bresciani, Jean-Pierre

In: Frontiers in Neural Circuits, 2019, vol. 13, p. -

Spatial orientation relies on a representation of the position and orientation of the body relative to the surrounding environment. When navigating in the environment, this representation must be constantly updated taking into account the direction, speed, and amplitude of body motion. Visual information plays an important role in this updating process, notably via optical flow. Here, we...

Université de Fribourg

The choice of statistical methods for comparisons of dosimetric data in radiotherapy

Chaikh, Abdulhamid ; Giraud, Jean-Yves ; Perrin, Emmanuel ; Bresciani, Jean-Pierre ; Balosso, Jacques

In: Radiation Oncology, 2014, vol. 9, no. 1, p. 205

Purpose: Novel irradiation techniques are continuously introduced in radiotherapy to optimize the accuracy, the security and the clinical outcome of treatments. These changes could raise the question of discontinuity in dosimetric presentation and the subsequent need for practice adjustments in case of significant modifications. This study proposes a comprehensive approach to compare different...

Université de Fribourg

Fast and automatic assessment of fall risk by coupling machine learning algorithms with a depth camera to monitor simple balance tasks

Dubois, Amandine ; Mouthon, Audrey ; Sivagnanaselvam, Ranjith Steve ; Bresciani, Jean-Pierre

In: Journal of NeuroEngineering and Rehabilitation, 2019, vol. 16, no. 1, p. 71

Falls in the elderly constitute a major health issue associated to population ageing. Current clinical tests evaluating fall risk mostly consist in assessing balance abilities. The devices used for these tests can be expensive or inconvenient to set up. We investigated whether, how and to which extent fall risk could be assessed using a low cost ambient sensor to monitor balance tasks.Method:...

Université de Fribourg

Foggy perception slows us down

Pretto, Paolo ; Bresciani, Jean-Pierre ; Rainer, Gregor ; Bülthoff, Heinrich H

In: eLife, 2012, vol. 1, p. e00031

Visual speed is believed to be underestimated at low contrast, which has been proposed as an explanation of excessive driving speed in fog. Combining psychophysics measurements and driving simulation, we confirm that speed is underestimated when contrast is reduced uniformly for all objects of the visual scene independently of their distance from the viewer. However, we show that when contrast is...

Université de Fribourg

A key region in the human parietal cortex for processing proprioceptive hand feedback during reaching movements

Reichenbach, Alexandra ; Thielscher, Axel ; Peer, Angelika ; Bülthoff, Heinrich H. ; Bresciani, Jean-Pierre

In: NeuroImage, 2014, vol. 84, p. 615–625

Seemingly effortless, we adjust our movements to continuously changing environments. After initiation of a goal-directed movement, the motor command is under constant control of sensory feedback loops. The main sensory signals contributing to movement control are vision and proprioception. Recent neuroimaging studies have focused mainly on identifying the parts of the posterior parietal cortex...

Université de Fribourg

Looking for discriminating is different from looking for looking’s sake

Bieg, Hans-Joachim ; Bresciani, Jean-Pierre ; Bülthoff, Heinrich H. ; Chuang, Lewis L.

In: PLoS ONE, 2012, vol. 7, no. 9, p. e45445

Recent studies provide evidence for task-specific influences on saccadic eye movements. For instance, saccades exhibit higher peak velocity when the task requires coordinating eye and hand movements. The current study shows that the need to process task-relevant visual information at the saccade endpoint can be, in itself, sufficient to cause such effects. In this study, participants performed a...