Directed Attention Brain Potentials in Virtual 3-D Space in Weightlessness (Neurocog)
Research Area: Nervous and Vestibular Systems
Expedition(s): 5, 7-11
Principal Investigator(s): ● Guy Cheron, Université Libre de Bruxelles, Brussels, Belgium
RESEARCH OBJECTIVES
A key concept in the field of neuromotor control is that of defining the frames of reference
used by the central nervous system (CNS) to interpret sensory information and to control
movements. At the level of individual sensors and effectors, the coordinate systems employed
are well defined. It is not in the coordinate system of an individual receptor, but rather, in
examining the coordination of sensory and motor activity that the question of reference frames
becomes interesting. This experiment tests the role of gravity in defining the reference frames
used for 3-D navigation and for representing the orientation of our own bodies and the
orientation of visual stimuli. A series of psychophysical tests are used to compare how human
subjects perform these types of task both on the ground and in the weightless conditions of
orbital flight. Evoked potentials are also measured through surface electrodes applied to the
scalp in order to measure the spatial and temporal components of information processing in
the brain in the absence of gravity.
RESULTS
Three main results were shown in
the Neurocog experiment. First,
weightlessness specifically affects
visual-evoked potential related to
the presentation of a virtual 3-D
navigation tunnel: subjects observed
a simulated passive movement
through a virtual tunnel. Each tunnel
contained a bend. After subjects
emerged from the end of the tunnel,
they were asked to report the
perceived turn angle by adjusting a
visual indicator with a trackball. On
Earth, the estimation of pitch turns is
greater for forward (nose-down) turns versus backward (nose-up) turns. This asymmetry does
not exist to this extent in weightlessness. Second, weightlessness increases the alpha rhythm
gain during the transition between eyes-closed and eyes-opened states. Finally, moving in
virtual navigation induces midfrontal N200 event related potentials supported by a transient
theta ringing altered in weightlessness.
The research from this experiment is continuing with a follow-on experiment (Neurocog-2),
which is embedded within the ESA-sponsored Neurospat experiment.
Execution of Neurocog experiment using visual tunnel. ESA