EPM (European Physiology module)
The experiment examines changes in spatial orientation and perception due to spaceflight conditions.
These changes will be assessed by recording behavioural measures (speed and accuracy) as well as neurophysiological signals (EEG, EMG) during performance of a series of visuo-motor tasks.
It involves recording of the electroencephalographic activity of the brain (EEG dynamics) and event related potentials (ERP) during performance of a visual-orientation perception and visuo-motor tracking task that humans and astronauts may encounter on a daily basis. Within the experiment, 5 cognitive processes (Perception, Attention, Memorization, Decision and Action) will be studied.
The stimulus set will also contain task-irrelevant novel visual stimuli to allow assessment of electrophysiological correlates of novelty processing. Psychophysical analyses will also be measured during these tasks. EEG and ERP recordings will also allow evaluation of the arousal levels of the subjects. In addition to conventional spectral analysis, EEG will be quantified with maps of linear and nonlinear complexity. As the novel conditions of microgravity accompanied by a multitude of stressors may place an increased load on the cognitive capacity of the human brain, we hypothesize that sensory signals and motor responses must be processed and interpreted in a new reference frame.
In addition to the sensitivity to changes in spatial orientation the experiment is designed to be particularly responsive to assess changes in prefrontal brain functioning. This area is known to be especially important for the higher organisation of behaviour and particularly vulnerable to stressors such as fatigue, sleep loss or hypoxia. By assessing measures of prefrontal functioning the experiment may provide insight to the causes of occasional slips in operational performance of astronauts.
The complexitiy of methods does not allow performing such experiments in parabolic flights while bed-rest studies cannot offer the opportunity to examine spatial orientation in the absence perceptual cues provided by gravity.
EEG: electroencephalogram, for measuring overall electrical activity in the brain
EMG: electromyogram, for measuring electrical activity in the muscles
ECG: electrocardiogram, for measuring electrical activity in the heart
EOG: electro-oculogram, for measuring electrical activity in the eye
Role of the gravitational component of the efference copy in the control of upper limb movements (CNES)
2nd Joint European Partial gravity Parabolic Flight campaign 2012
Role of the gravitational component of the efference copy in the control of upper limb movements (CNES)
1st Joint European Partial gravity Parabolic Flight campaign - 2011
Effects of Changing Gravity on Ocular-motor coordination
51st ESA Parabolic Flight Campaign 2009
Dexterous Manipulation in microgravity
48th ESA Parabolic Flight Campaign 2008
NEUROCOG - Directed attention brain potentials in virtual 3D space in Weightlessness
ISS 5S, 8S, 9, 10 - 2002, 2004, 2005
The experiment is composed of 2 principal experimental tasks related to our hypotheses – Visual Orientation and Visuomotor Tracking – plus additional, standardized EEG tasks performed as a means of assessing general effects of the space station environment on EEG signals. The Visual Orientation task is designed to assess the influence of weightlessness to perception of spatial directions.
Task 0: EEG control tasks
Subjects perform one or two standard EEG control tasks in a period of 5 minutes to provide baseline data on known phenomena. The exact protocols to be performed may include an eyes-open/eyes-closed paradigm, a visual “oddball” paradigm based on oriented visual stimuli or a standard visually evoked potential (VEP) from an alternating checkerboard pattern. In all cases the subject simply observed the laptop screen while the visual stimuli are presented.
Task 1: Visual Orientation Perception
The Visual Orientation task will be performed in 3 conditions with variations of the amount of spatial cognitive difficulty and the visual reference frame.
Condition 1 (Lines Task):
In Condition 1. the subject has to decide whether the orientation of 2 consecutively presented lines are same or different. Task irrelevant stimuli (pictures) will also be presented occasionally in the place of the probe stimulus. Subjects should not press either button when presented with these novelty stimuli.
Condition 2 (Clock Task, no frame condition):
In Condition 2 the reference orientation is specified by a digitally presented clock-time, which is to be compared to a consecutively-presented direction indicated by a dot on an imaginary analog clock face. Task irrelevant stimuli (pictures of butterflies) will also be presented occasionally in the place of the probe stimulus. Subjects should not press either button when presented with these novelty stimuli.
Condition 3 (Clock Task, frame condition):
In Condition 3 the same comparison is to be made in the presence of a visually orienting rectangular frame. The ambiguity of the visual reference shall be more influential in 0g.
In 1g conditions vertical and horizontal directions are processed more readily as compared to oblique directions.
According to existing evidence the phenomenon referred as the Oblique Effect is influenced by misalignment of proprioceptive and gravitational references. The task entails matching the directions of visually presented reference lines to those of consecutive probe lines. Enhancement of early (N1 and P1) components of the ERP evoked by reference lines of various orientations reflect preferred processing of non-oblique directions in the primary visual areas. Increased speed and accuracy of responses as well as enhancement of late (P3b) components of ERP shall indicate readiness of decision making and reacting to the preferred directions. All of these differences are expected to be diminished in 0g as compared to pre- and post-flight controls in 1g. Task irrelevant novel pictures are presented occasionally in place of probe lines. These stimuli typically evoke an ERP component (P3a) originating from and sensitive to the functionality of the prefrontal brain areas.
Diminished P3a should indicate weakened pre-frontal functioning due to various environmental stressors, fatigue and sleep loss in spaceflight conditions. Independent ground based control studies will apply various stressors to distinct study groups in order to investigate the differences in the patterns of changes caused by each of these
Task 2: Visuomotor Tracking
In the Visuomotor Tracking task astronaut subjects will observe a virtual environment displayed on a computer screen that simulates what would be observed when piloting a space ship. The desired heading will be indicated on the screen by means of a moving visual target. At the beginning of each trial, target movements will reflect random, zero-mean noise. At some moment in time, however, the target will deviate from the nominal straight-ahead position. Subjects will be required to perform as quickly as possible a manual adjustment to the system by pressing on a small isometric joystick operated with the hand.
Recordings of EEG during this task will provide an indication of which brain regions are related to the perception of movement. ERPs will be computed from EEG traces synchronised and averaged with respect to different events occurring during the task, such as the moment when the visual target starts to deviate or the moment when the subject responds. The figure below provides an example of EEG recordings from 3 different electrodes (FZ, CZ, PZ) at different places on the scalp. Signals averaged over many trials in response to a visual event occurring at time 0. The labels N1, P2, N2 and P3 indicate deviations of the EEG signal that are known to correspond to different aspects of the task that the subject must perform. These and other potentials will be studied in the NeuroSpat experiment. For instance, the preparation of movement will be analysed by means of the recording of the slow potentials (readiness potentials (RP), directed action potentials (DAP) and relaxation potentials (RXP). The amount of cortical control of action will be quantified by means of the cortico-muscular coherence method (cross-correlation between EEG and EMG rhythms).
In addition to the tasks measurement of short periods of resting EEG activity with eyes open and eyes closed as well as ERPs evoked by flashing checkerboard stimuli provide calibration and reference data. Photomodeling based on pictures taken after mounting the electrode cap provide exact measurement of electrode positions.
Ground Seated: The subject is seated upright comfortably in a chair. If using the laptop computer with tunnel and mask, a ground support stand is adjusted to position the mask/tunnel/laptop at the level of the eyes for viewing. The height of the elbow pads is adjusted to allow the subject to comfortable grasp the grips on the laptop support.
In-flight Freefloating: The subject adopts a freefloating or quasi-freefloating posture and should have no rigid contact with the station structure during the performance of the experiment in this mode.
The results are expected to provide better insight to the mechanisms of altered working capacity particularly at early stages of space adaptation. Such understanding may provide for the development of effective countermeasures. The results will contribute to the better understanding of adaptation processes that take place in spatial perception in weightlessness. The development of a novel electrophysiological paradigm may provide a tool for testing spatial cognition altered in pathological conditions. The result will provide a better understanding of neurophysiological changes occurring in normal aging.
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L. Balázs, I. Czigler, A. Grosz, M. Emri, P. Mikecz, S. Szakáll, L. Tron, (2005), "Environmental challenge impairs prefrontal brain functions", Journal of Gravitational Physiology, Vol 12(1), P31-P32.
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G. Cheron, A.M. Cebolla, M. Petieau, A. Bengoetxea, E. Palmero-Soler, A. Leroy, B. Dan, (2009), "Adaptive changes of rhythmic EEG oscillations in space implications for brain-machine interface applications", International Review of Neurobiology, 86, pp. 171-187.
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C. De Saedeleer, M. Vidal, M. Lipshits, A. Bengoetxea, A.M. Cebolla, A. Berthoz, G. Cheron, J. McIntyre, (2013), "Weightlessness alters up/down asymmetries in the perception of self-motion", Experimental Brain Research, 226, 1, pp. 95-106.
T. Hoellinger, M. Petieau, M. Duvinage, T. Castermans, K. Seetharaman, A.M. Cebolla, A. Bengoetxea, Y. Ivanenko, B. Dan, G. Cheron, (2013), "Biological oscillations for learning walking coordination: dynamic recurrent neural network functionally models physiological central pattern generator", Frontiers in Computational Neuroscience, 7, 70.
L. Balázs, I. Barkaszi, I. Czigler, E. Takács, (2014), "Spaceflight conditions influence event related brain electrical activity", 6th International Congress of Medicine in Space and Extreme Environments (ICMS), 16-19 September 2014, Berlin, Germany..
G. Cheron, A. Leroy, E. Palmero-Soler, C. De Saedeleer, A. Bengoetxea, A.M. Cebolla, M. Vidal, B. Dan, A. Berthoz, J. McIntyre, (2014), "Gravity influences top-down signals in visual processing", PLoS One, 9, 1, DOI: 10.1371/journal.pone.0082371, pp. e82371.
A.M. Cebolla, E. Palmero-Soler, B. Dan, G. Cheron, (2014), "Modulation of the N30 generators of the somatosensory evoked potentials by the mirror neuron system", Neuroimage, 95, doi: 10.1016/j.neuroimage.2014.03.039, pp. 48-60.
A.M. Cebolla, M. Petieau, B. Dan, L. Balázs, J. McIntyre, G. Cheron, (2016), "Cerebellar contribution to visuo-attentional alpha rhythm: insights from weightlessness", Nature Scientific Reports, 6:37824, DOI: 10.1038/srep37824.
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Frank De Winne performing Neurospat
ISS030-E-116907 (13 February 2012) Wearing an Electroencephalogram (EEG) electrode cap, European Space Agency astronaut Andre Kuipers, Expedition 30 flight engineer, performs a NeuroSpat science session in the Columbus laboratory of the International Space Station. NeuroSpat investigates the ways in which crew members' three-dimensional visual & space perception is affected by long-duration stays in weightlessness. Credit: NASA/ESA
ISS030-E-116908 (13 February 2012) Wearing an Electroencephalogram (EEG) electrode cap, European Space Agency astronaut Andre Kuipers, Expedition 30 flight engineer, performs a NeuroSpat science session in the Columbus laboratory of the International Space Station. NeuroSpat investigates the ways in which crew members' three-dimensional visual & space perception is affected by long-duration stays in weightlessness. Credit: NASA/ESA
Paolo Nespoli in December 2010 in the European Columbus laboratory, setting up the Neurospat experiment. Neurospat measures the effect of Gravitational Context on EEG Dynamics. It is a study of spatial cognition, novelty processing and sensorimotor integration, composed of two principal experimental tasks: visual orientation and visuomotor tracking, plus additional, standardized electroencephalogram (EEG) tasks performed as a means of assessing general effects of the space station environment on EEG signals.
ISS026-E-012919 (20 December 2010) European Space Agency astronaut Paolo Nespoli, Expedition 26 flight engineer, moves the Neurospat hardware (including light shield and frame) used for the Bodies in the Space Environment (BISE) experiment, in the Columbus Module aboard the International Space Station.