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Friday September 20th,
2013 from 10:00 to 16:00
Location: Building Euler (auditorium a002), UCL Louvain-la-Neuve (parking Rédimé and building 3a: D9 on map).
Program:
10:00 Renaud Ronsse, iMMC/CEREM, UCLouvain.
10:45 Coffee break
11:15 Pieter Medendorp, Donders Institute for Brain, Cognition and Behaviour, Radboud University, Nijmegen.
12:00 Frank Bremmer, AG Neurophysik, Philipps-Universität Marburg.
12:45 Lunch break
13:30 Gunnar Blohm, Centre for Neuroscience Studies, Queen's University, Kingston, Canada.
15:00 Guillaume Leclercq, ICTEAM/INMA and IoNS/COSY, UCLouvain. PhD Thesis defense (location for the defense: auditorium SUD 19)
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Detailed program: 10:00 Renaud Ronsse, iMMC/CEREM, UCLouvain “Primitive-based entrainment in upper- and lower-limb periodic movement assistance by using adaptive oscillators".
Abstract:
Motor primitives were initially identified in animals (and indirectly
in humans) as a library of basis movements being coordinated to
generate any complex motor behavior. They provide an elegant way to
account for learning, adaptation, coordination, and modularity. In
robotics, the use of motor primitives has gained a lot of attention
within the last decade. Dynamical systems provide a well-developed
method for coding robotic motor primitives, offering advantages
regarding stability to disturbances, multi-joint coordination, etc. In
this talk, we will discuss how to apply the concept of motor primitives
in rehabilitation robotics, i.e. at the intersection of motor control
and robotics. In particular, the proposed approach builds upon
attractive properties of a particular class of dynamic motion
primitive, namely adaptive oscillators. Two experiments validating our
approach will be presented: a simple upper-limb sinusoidal movement and
a walking experiment using the LOPES platform. In both cases, evidences
will be presented to illustrate that the healthy participants were
actually assisted during movement execution. Owing to the intrinsic
periodicity of daily life movements involving the lower-limbs, we
postulate that this approach holds promise for the design of innovative
rehabilitation and assistance protocols for the lower-limb, requiring
little to no user-specific calibration. Finally, some perspectives on
ongoing research projects will be given, with a particular focus on
preliminary studies with post-stroke patients and lower-limb amputees.
10:45 Coffee break
11:15 Pieter Medendorp, Donders Institute for Brain, Cognition and Behaviour, Radboud University, Nijmegen.
“Vestibular Processing in State Estimation and Motor Learning.”
Abstract:
The brain must convert and integrate noisy sensory and motor signals to
maintain and update its internal estimates of the state of the body and
objects around us and uses these state estimates in generating goal-directed
movements. During this processing, populations of neurons must exchange
information within and across reference frames. In this talk, I will address
the behavioral mechanisms for state estimation in challenging conditions,
when the effects of inertial forces and body-motion must be integrated, and
their physiological correlates in the brain.
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12:00 Frank Bremmer, AG Neurophysik, Philipps-Universität Marburg.
“Vision during eye movements”
Abstract:
Primates move their eyes more often than their heart beats. Different
from our introspection, visual perception during eye movements is not
veridical. Instead, eye movements induce multi-facetted perceptual
errors. It is generally agreed, that understanding the neural bases of
misperceptions allows for a deeper understanding of the neural
mechanisms underlying veridical perception during everyday life. Over
the last years we have studied in detail the influence of eye movements
on spatial perception and spatial encoding. We performed psychophysical
studies in humans together with neurophysiological recordings in
non-human primates. Our results unequivocally show that the functional
properties of neurons in macaque extrastriate and parietal cortex are
suited to explain previously described visual perceptual effects during
eye movements. 12:45 Lunch 13:30 Gunnar Blohm, Centre for Neuroscience Studies, Queen's University, Kingston, Canada
“Depth coding and parietal cortex involvement in reference frame transformations for reaching”
Abstract:
Converging evidence has pointed towards the posterior parietal cortex
for playing a key role in the sensory-to-motor reference frame
transformation required for reaching. However, so far causal evidence
for its involvement has been missing. Here I present a case study of a
patient with uni-lateral posterior parietal cortex damage showing
reference frame transformation deficits confined to the impaired visual
field. Specifically, this patient does not fully account for head roll
signals into the reach plan resulting in head-roll-dependent
mis-reaches. Moreover, it is unclear how a crucial aspect of
sensory-to-motor transformations, i.e. movement depth, could be coded
in the parietal-frontal network involved in reach planning. I will
present artificial neural network simulations proposing potential
neural properties that one should find when recording in areas involved
in the sensory-to-motor transformation for reach depth.
15:00 Guillaume Leclercq, UCLouvain, ICTEAM/INMA and IoNS/COSY
PhD thesis public defense auditorium SUD19:
“The velocity visuomotor transformation for manual tracking” Abstract:
Humans
often perform visually guided arm movements in a dynamic environment
(e.g. catching a ball). To do so, the brain uses the visual (retinal)
information about the target trajectory to generate the arm movement.
However, the target can be seen under different eye-head postures
and/or we are often in motion ourselves (our eyes, head or whole body),
which complicates the planning of the arm movement. Indeed, the retinal
and spatial motions of an object differ, depending on the 3D
eye-head-shoulder kinematics. This thesis investigates whether the
planning of arm movements towards moving targets takes these
extra-retinal signals into account, or whether it relies on feedback
mechanisms.
We designed behavioral experiments with human
participants performing manual tracking movements and we developed an
accurate model of the 3D eye-head kinematics, to distinguish between
theses hypotheses. We show that the brain takes the 3D eye and head
position and velocity into account for the planning of manual tracking.
Second this thesis investigates the potential neural mechanisms used by
the brain to perform this velocity visuomotor transformation. Using a
physiologically-inspired artificial neural network, we probed the
artificial unit properties using electrophysiology methods. Our results
were validated by data in the neurophysiology literature and new
predictions to be tested by the neurophysiology community are proposed.
17: Drink
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last update: September 9th, 2013
Author: Philippe LEFEVRE
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