16.423 SBE
(
N
eu
r
ove
s
tibu
l
a
r
Counter
m
ea
s
u
r
e
s
)
Neurovestibular Illusions and
Countermeasures
16.423 SBE
(
N
eu
r
ove
s
tibu
l
a
r
Counter
m
ea
s
u
r
e
s
)
Space Illusions
I
n
w
e
i
ghtless
n
e
ss, “do
w
n” cu
es from the inn
e
r ear otolith or
gans
are abse
n
t. Astronauts are tho
ught to rel
y
m
o
re heavil
y o
n
vision.
M
an
y
astro
n
a
u
ts perceive a
“subjectiv
e
vertical”. W
hen it chang
es
directio
n, it can cause disor
i
en
tation and moti
on sickness.
Inv
e
rsi
o
n
Illu
sion
s
-
Common
imme
dia
t
ely
afte
r re
achin
g or
bit
Visual
Reo
rie
nta
t
io
n
Illu
sio
n
s
(VR
I
s) -
s
urface
below
fee
t
seem
s like
floo
r
EVA acro
ph
obia
-
s
udd
en
fea
r
of fallin
g tow
ards th
e
Ea
r
t
h
16.423 SBE
(
N
eu
r
ove
s
tibu
l
a
r
Counter
m
ea
s
u
r
e
s
Neural Encoding of
Orientation
S
tudies h
a
ve
shown th
at
animals con
s
t
r
u
c
t
inte
rn
al
neu
ral rep
r
e
s
entation
s
o
f
their spa
t
ial
environm
ent.
–“
Place cel
l
s
” have a
respons
e com
pone
nt
related to the a
n
imal
’s
locatio
n
in an e
n
vironm
ent.
–“
Head D
i
rectio
n
” cells
dischar
ge as a
function of
the anima
l’s he
ad directi
on
in a horiz
ontal
plan
e,
inde
pen
dent of
the animal
’
s
place, be
havi
o
r
,
or head
pitch or roll (u
p
to 90 deg).
16.423 SBE
(
N
eu
r
ove
s
tibu
l
a
r
Counter
m
ea
s
u
r
e
s
)
HD cell responses in 0-G
1-G
1.
8-G
0-G on
ceilin
g
0-G
on
fl
oo
r,
wal
l
Floor
Wal
l
Cei
ling
Prof. Jeff
T
aub
e, Dartmouth C
o
lle
ge
Similar
VRIs
o
ccur
w
i
t
h
Place
cell respo
n
ses
(McNaughto
n
et al., 1999)
16.423 SBE
(
N
eu
r
ove
s
tibu
l
a
r
Counter
m
ea
s
u
r
e
s
)
Neurovestibular Risks
of
Spaceflight
I
mpaired cognitiv
e and/or physic
a
l performance
D
isorientation and inability to egress safely or
perform other physical tasks
I
mpaired neuromusc
u
lar coordination and/or strength
A
utonom
ic dysfunction
P
ermanent impairment of orientation or balance
function
16.423 SBE
(
N
eu
r
ove
s
tibu
l
a
r
Counter
m
ea
s
u
r
e
s
)
Countermeasures using VR
Exper
ience in mockups, parabolic flight, and neutral
buoy
ancy and VR simulators is anec
dotally
helpful.
16.423 SBE
(
N
eu
r
ove
s
tibu
l
a
r
Counter
m
ea
s
u
r
e
s
)
Preflight Adaptation Training
J
SC, early 1990’s
D
evice for
Orientation and Motion Environments (DOME) apparatus
T
ilt Translation
Device (TTD) device
16.423 SBE
(
N
eu
r
ove
s
tibu
l
a
r
Counter
m
ea
s
u
r
e
s
)
Visual Clues to Orientation
T
hree types of visual information contribute to our
sense of gravitational orientation:
–
M
otion o
f
th
e
visual su
rrou
ndings
R
oll rotati
on of a large fie
l
d te
xtured disp
la
y in
duces an i
llus
i
on
of self-rotation
(vection) an
d self-tilt.
–
T
ilt of the visual frame
T
ilt can cause displ
a
ceme
nt of the visual or p
o
stural vertica
l
.
–
V
isual polarit
y
I
ntrinsic pol
arit
y -
O
bjects hav
e a princi
ple a
x
is and perc
ept
ual
“top” and “bott
o
m”.
E
xtrins
ic pol
arit
y -
S
patia
l relat
ionsh
ips bet
w
e
en obj
ects defi
ne
princi
ple a
x
is a
nd “top” or “bot
tom”.
16.423 SBE
(
N
eu
r
ove
s
tibu
l
a
r
Counter
m
ea
s
u
r
e
s
)
Visual Orientation in 0-G
ISS Experiments
(C.
O
man
, A Bertho
z,
e
t
al.)
Subjects in
dic
a
te the subjectiv
e
floor of the room.
16.423 SBE
(
N
eu
r
ove
s
tibu
l
a
r
Counter
m
ea
s
u
r
e
s
)
Visual Orientation in 0-G
ISS Experiments
(C.
O
man
, A Bertho
z,
e
t
al.)
Perceived orientation
will affect
the perception of
the
shaded
figure
and
am
biguou
s figu
re.
16.423 SBE
(
N
eu
r
ove
s
tibu
l
a
r
Counter
m
ea
s
u
r
e
s
)
Visual Orientation in Static
Real Environments
T
u
mbling Roo
m
Human Perfor
mance La
b
York Univers
i
t
y
,
T
o
ronto
Prof. I
an Howard, York
Univers
i
ty
16.423 SBE (
N
eur
oves
tibul
ar
Counterm
eas
ur
e
s
)
11/14
/00
Room surface seen by subject
Inverted to supine
Ceiling
Floor
0/6
3
, 30
, 1
No illusion
0
, 1
No illusion
Recumbent to supine
7.5
, 3
7
, 2
Recumbent to prone
3
, 2
Prone to supine
3
, 3
Supine to prone
4
, 2
Upright to prone
6
, 2
Upright to supine
8
, 1
Inverted to prone
4.2
5
5.94.63.2
3.9
4.4
Upright
Inverted
Congruent wall
Reversed wall
Wall tilted 90T
Supine
Prone
1
, 1
No illusion
0
, 0
No illusion
0
, 1
No illusion
7
, 1
Recumbent to inverted
8.5
, 0
Recumbent to erect
4
, 3
Prone to recumbent Erect to recumbent
6
, 1
5
, 1
Erect to inverted
5
, 3
Inverted to recumbent
8
, 4
Inverted to erect
9
, 2
Supine to erect
6
, 3
Supine to inverted
5
, 0
Supine to recumbent
3
, 0
Prone to erect
6
, 1
Prone to inverted
5.8
5.2
4
Recumbent Subject orientation
Means
Means
BED
CHAIR PITCH
CHAIR ROLL
BED
CHAIR PITCH
CHAIR PITCH
16.423 SBE
(
N
eu
r
ove
s
tibu
l
a
r
Counter
m
ea
s
u
r
e
s
)
Visual Orientation and
3D Spatial Memory
W
hat makes orientation and nav
igation in 6 dof
difficult?
–
B
ody movem
ents a
r
e u
n
co
nst
r
aine
d by
gravity.
–
I
nco
n
si
st
en
cies in v
i
su
al v
e
rt
ic
als o
f
t
h
e
v
a
riou
s m
o
d
u
les.
–
3
D configu
r
at
ion of m
odule
s
an
d no
de
s is difficult t
o
m
entally
image a
nd
rot
ate.
16.423 SBE
(
N
eu
r
ove
s
tibu
l
a
r
Counter
m
ea
s
u
r
e
s
)
Visual Orientation and
3D Spatial Memory
16.423 SBE
(
N
eu
r
ove
s
tibu
l
a
r
Counter
m
ea
s
u
r
e
s
)
Keep track of your starting location
16.423 SBE
(
N
eu
r
ove
s
tibu
l
a
r
Counter
m
ea
s
u
r
e
s
)
Simulated Node
16.423 SBE
(
N
eu
r
ove
s
tibu
l
a
r
Counter
m
ea
s
u
r
e
s
)
3D Spatial Memory Strategies
M
emorization of opposite pairs.
M
nemonic dev
ices to recall object locations is a
canonical view.
M
emorization of the relations
hip of object triads.
M
ental image of the node in a canonic
al or
ientation.
16.423 SBE
(
N
eu
r
ove
s
tibu
l
a
r
Counter
m
ea
s
u
r
e
s
)
VR Navigation Training Tools
