Download IN THE FOCUS A journey to MARS – Exercise as

Brain Products Press Release
April 2012, Volume 42
IN THE FOCUS
A journey to MARS – Exercise as neurocognitive enhancement
by Stefan Schneider & Vera Abeln, German Sport University Cologne, Institute of Movement and Neurosciences
Moscow (Russia): Six men. 200 m2. 520 days. Mars in sight.
A combined study of the Russian, European, German and
Chinese space agencies simulated a 520 day journey to the red
planet, the earth’s nearest neighbor in space. Starting June
3rd 2010 to November 4th 2012 three Russians, two Europeans
and one Chinese inhabited a specifically designed MARSspaceship located in the Institute for Biomedical Problems
(IBMP) in the heart of Moscow. Their journey included a 240
day trip to MARS, a 40day exploration time of
the Martian surface as
well as the 240-day trip
back to earth. Also on
board: A greenhouse
to supply the crew with
fresh
salad
and
vegetables,
a
huge
refrigerator carrying all
the food for 520 days –
and an experiment of the
Institute of Movement
and Neurosciences at
the
German
Sport
University
Cologne,
supported by a 16
channel V-Amp system
from Brain Products.
Figure 1: 16 ch actiCAP
system) as well as the design of appropriate countermeasures
predominated, with ongoing duration of missions (currently
astronauts and cosmonauts stay for an average of six months
on board of the International Space Station (ISS)), neuropsychological challenges increase and in order to maintain
and enhance mission success and mission safety it seems of
utterly importance to define stressors and develop adequate
countermeasures. This has been done exhaustively during
the last decade and a significant number of studies have well
defined corner points to ensure mission success and mission
safety during long-term inhabitation of space. However, these
studies mainly remained on a descriptive level without formulating
consequences or identifying appropriate countermeasures.
Today more and more researchers agree that the next step
would be to define and evaluate adequate countermeasures to
ensure mission safety and mission success during long-term
inhabitation of space.
Life in
zero gravity
II. Psychological stressors2
Life in space is accompanied by a number of stressors, which
can be classified in physiological stressors, provoked by
e.g. missing gravity or disruption of circadian rhythms, and
psychological stressors e.g. caused by the isolated and
confined environment. Whereas physiological stressors mainly
manifest in bodily symptoms as changes in the cardiovascular
and musculoskeletal system, psychological stressors affect
executive function, decision making and mental health and
therefore might be of relevance for mission safety and mission
success.
-
3,8
Brain activity
-
e.g. isolation
Cognitive capabilities,
mantal health and
general wellbeing
6,7
1
Iwasaki et al, J Physiol 2007
Fowler et al, Ergonomics 2000
3
Cheron et al, Brain Res 2006
4
Schneider et al, Med Sci Sport Exerc 2010
5
Kanas, Aviat Space Environ Med. 1998
6
Schneider et al, Physiol Behav 2009
7
Hillman, Neuroscience 2009
8
Schneider et al, Neuroimage 2008
+
2
+
Scientific background
2,5
I. Physiological stressors1
e.g. cardiovascular changes
4,7
Sport
+
Brain activity
negative effect
positive effect
Figure 2: Life in zero gravity
So it’s not only that life science in space integrated a holistic
approach realizing that the interaction of physiology and
psychology seems of utterly importance, but also started to
evaluate possible strategies to prevent and counteract different
kinds of stressors. Here exercise plays a dominant role, as
exercise is not only able to counteract physiological problems
occurring during space flight but also might act to counteract
the accumulation of psychological stressors (better to hit the
treadmill than your neighbors nose when stressed) (Figure 3).
Accordingly life in space is not only a challenge to diverse
biological systems (e.g. impairments in immune defense, 90
minute day-night circles), but also has an impact on the whole
human being: Day-to-day work life is tense and demands high
precision, time management and discipline. In addition the
supply with nearly everything, especially food and contact to
family and friends, is limited.
With ongoing duration of missions and mission simulations
respectively, during the last years a change in paradigms is
observable. Whereas in the last three decades problems in
peripheral physiology (cardiovascular system, musculoskeletal
www.brainproducts.com
Figure 3: Meassuring the effects of exercise on brain cortical activity
page 2 of 19
Brain Products Press Release
Our research interests are dedicated to understand the effects
of exercise on brain cortical activity and relating effects in
cognitive performance and emotional well-being. From a
number of studies we know that exercise has a positive impact
on mood and cognitive performance, but so far the underling
neurophysiological effects remain widely unknown. This
is probably due the limitation of imaging processes during
and immediately after exercise. Neither PET nor fMRI deliver
acceptable temporal resolution or are applicable during
exercise. In contrast, EEG in combination with source localization
algorithms offers the possibility to record and localize brain
cortical activity easily in extreme and remote environments.
In order to ensure a ‘psycho-hygienic’ or ‘neuro-enhancing’ effect
of exercise, three general principles seem to be of importance:
1. Positive aspects of exercise are discussed to be related to
specific changes in frontal lobe activity. In order to maintain
exercise capacities at a high level and taking into account limited
resources within the central nervous system (CNS), the theory
of a transient hypofrontality (Dietrich 2003) assumes a shift of
cortical activity away from frontal and temporal brain regions
(i.e. a decrease of activity in exercise irrelevant regions) towards
regions of the brain that are involved in the planning, execution
and programming of motor output like the primary motor cortex,
supplementary and associated motor areas. This down-regulation
of frontal cortex activity, which can be regarded as the main entity
for cognitive and emotional processing in the human brain, seems
to free resources, that – after exercise – could be made responsible
for an increase in cognitive performance. It is as if someone resets
the overloaded working memory of a computer.
% ot total cortex activity
70
before EXERCISE
60
after EXERCISE
50
40
***
*
30
20
10
0
Frontal
Parietal
Temporal
Occipital
neurophysiological effects (decrease in fronto-temporal brain
regions) as well as neuropsychological effects (increase in
mood and cognitive performance) of exercise are dependent
on a personal bias towards exercise (Schneider et al.
2009a; Schneider et al. 2009b). We were able to show that
passionate runners show positive effects of exercise only
if they were allowed to run at their preferred pace but not
if they were forced to run a foreseen speed, nor if they were
asked to bike instead of running (Schneider et al. 2009a;
Brümmer et al. 2011). This shows that it is not only important
to exercise, as widely recommended, but also to identify the
right kind, the right duration and the right intensity of
exercise. If these factors are not considered, neither will
subjects experience the positive effects of exercise on mental
performance, nor will they show any kind of compliance, which
is essential to have an outlasting physiological benefit.
These three principles have been the experimental preconditions for the MARS500 study. It was hypothesized that an
individualized exercise program will provoke specific changes
in brain cortical activity, namely a decrease in prefrontal
cortex activity, that will go along with an increase in cognitive
performance and mood after exercise and therefore contribute
to mission success and mission safety. Of course, data analysis
is still in progress but we are able to display already some
preliminary and selected results here:
Methods: Participants were allocated to six different exercise
protocols that were performed in random order across the
isolation: Running, biking, strength training and vibration
training. Before and after each exercise session a 16-channel EEG
was recorded in relaxed state for three minutes. Every second
week a number of commercially available cognitive tests on an
iPod® have been performed before exercise, in every other
second week after exercise. Cortical current density was
calculated in each lobe using the BrainVision Analyzers’
LORETA tool and described as percent of total cortex activity.
Subsequently post-exercise activity within each lobe was
subtracted from pre-exercise activity within each lobe.
Results show a reduced activity after exercise in the frontal and
temporal lobe (Figure 4). At the same time selected results of
the cognitive tasks (here: Chalkboard Challenge by lumosity.
com) were found to be enhanced (Figure 5). Further analysis now
Figure 4: cortex activity before and after exercise
3. Beside these two principles, we were able to define
an
exercise
prefer
encehypothesis,
assuming
that
12000
maximum of points
2. The described changes in frontal and temporal lobe activity
seem to be highly dependent on exercise intensity, which is
expressed in a dose-response relationship. Actually the same
is known from exercise psychology: Neither when intensity
(including duration) is too high nor too low, but only when
exercise intensity is on an individual optimum, positive effects of
exercise on mood and cognitive performance are reported
(Ekkekakis 2009).
April 2012, Volume 42
*
9000
6000
3000
0
before EXERCISE
after EXERCISE
Figure 5: Cognitive performance before and after exercise
page 3 of 19
Brain Products Press Release
needs (1) to determine changes across the whole isolation period
and (2) to determine if specific changes occur after specific
exercise protocols.
With respect to current models on exercise neuroscience,
these data support the idea of a transient hypofrontality
theory. Whether a dose-response relationship and an exercise
preference hypothesis exist, needs to be evaluated with a
closer look on the data. It might be that the exercise
program
during
the
confinement
will
not
confirm
these ideas, as during the daily routine, exercise is a favored
activity, distracting from the daily monotony.
Not only concerning space but also with respect to daily life
on earth these results demonstrate the relevance and
April 2012, Volume 42
effectiveness of exercise programs for physical and mental
health. The human being is made for exercise. From the early
years of mankind until the late 1970 s man has been physically
active to ensure food and survival. Only since these times
lifestyle diseases like diabetes, obesity and spinal disorders but
also mental disorders as depression increased. A regular daily
activity seems essential for a holistic health approach following
the definition of the Word Health Organization, defining health as
a „state of complete physical, mental, and social well-being.
Besides a generous support from Brain Products, this study was
supported by German Space Agency (DLR, 50WB0819). More
information about ESAs MARS500 program is available at www.
esa.int/mars500.
page 4 of 19