The Japanese Psychonomic Society
NII-Electronic Library Service
The JapanesePsychonomic Society
The
YnPanese
Jburnal
ofRs}/chonomic
Sctence
2009,
Vol,
28,
No.
1,
175-l76
Summary
ofAwarded
Presentation2P37
Cortical
distribution
of
expansion/contractionasymmetric
responses
in
human
adults
and
to
radial
infantsi)
NobuSHiRAi*'
t,
Tomoko
IMuRA*2,
Deirdre
BiRTLEs*3,
Shirley
ANKER*3,
Shigeru
IcmHARA*,
John
WATTAM-BELL*2,
Janette
ATKiNsoN*3,
and
Oliver
BRADDicK*4
7bkpuo
Metropogitan
Uitiversity*,
Primate
Research
institute,
Klyoto
Ubeiversily*2,
Uitiversity
Collage
London*3,
Uitiversily
of
drford*`
The
distribution
of
cortical activityto
radial expansion or contraction motion with adults andinfants
(3
to
4
months
and
4
to
5
months
of
age)
was
examined
by
measuring
steady-state visua] evokedpotentials
with ahigh-density
electrode array.A
motion
pattern
which waseither
radial
expansion
or
contraction
was alternatelypresented
with
apattern
of
random motion,and
the
mean amplitude ofthe
fundamental
harmonie
cornponent<Fl)
correspondingto
the
pattern
alternation
frequency
{2
Hz)
was
measured.
The
result$
iridicated
the
adults
showed
greater
activity
to
contractionthan
to
expansionin
the
rightparietal
area.Although
the
older(but
notthe
younger)
infants
also
showed
contraction
bias,
the
bias
was
spread
over
the
whDle
oecipitoparietal
area,
These
results
suggest
that
in
adults
radiaL
motion
processing
may
be
achieved
by
different
neural mechanisms
to
those
in
infants.
Key
vvords: radia] expansionlcontraction, visua] evokedpotentials,
asymmetry,cortical
tion
A
previous
studyindicated
that
significant cortical activityto
radial expansion or contraction motion, acritica] cue of
motion
in
perception
of
depth
and self-motion, emerges at approximately4
months ofage
(Shirai,
Birt]es,
Wattam-Bell,
Yamaguchi,
Ka-nazawa,Atkinson,
&
Braddick,
tn
press).
Hewever
it
is
still
unclear
whether
infants'
cortical
responsesto
radial
motion
are
comparable
to
those
of
adults.
We
investigated
this
topic
by
measuringthe
corticaldis-trib'ution
of
activitv
associated
with
radia]
motion
processing
in
human
infants
and adults.Method
Participants
Twelve
infants
aged
3
to
4
months
(mean
age==106.9days,
SD=
±8.8)
and17
infants
t)This
research was supportedby
Research
Grant
G0601007
frorn
the
Medical
Research
Council,
andgrant-in-aid
for
scienttfic researchfrom
the
Japan
Society
for
the
Promotion
oiScience
<19-1464)
t
The
corresponding author,N,S.,
is
currentlywith
Department
ofPsychology,
Niigata
versity,
2-8050
Ikarashi,
Nishi-ku,
Niigata-city,
Niigata
950-2]
81
E-mail.shirai@human.niigata-u,ac.jp
aged
4
to
5
months(mean
age=139.5days,
SD=
±
11.7)
participated.
They
werehealthy
full-term
in-fants
and
born
within14
days
from
due
date.
The
infants
did
nothave
any strabismus or signifieantrefractive
error,
Twenty
adults
(mean
age='
24.5
years,
SD
= ±6.2)
alsoparticipated
and
weretested
in
the
same
way
as
the
infants,
Stimuli
Dynamic
dot
patterns
which
alternated
between
radial expansion(or
contraction) andran-dom
motion
were
used
as
stirnuli.
The
alternatien
occurred
every250
ms(2
Hz
in
temporal
frequency),
Each
dot
pattern
consisted
of2000
white
dots
(clot
diameter=O.37deg)
distributed
on
a
black
fie]d
(width=49
deg,
height=37
deg).
The
dots
moved at constant speed<6.8degfs),
There
weretwo
experi・
mental
conditions:
the
expansion
condition
(expan-sion
vs.random
alternation)
and
the
contractioncon-dition
(contraction
vs. random alternation),Apparatusandprocedures
Thestimuliwerepre-sented on a
17-inch
CRT
monitor with a refresh rateof
60Hz,
a resoluZion of1,024
×768pixels,
and aviewing
distance
o'r40
cm.The
visual evokedpoten-tials
were
recorded
with
a
high-density
128
channel
EEG
recording
system
(Electrica]
Geodesics,
Inc.,
EGI
Copyright
2009.
The
Japanese
Psychonomic
Society.
All
rights reserved.The Japanese Psychonomic Society
NII-Electronic Library Service
The JapanesePsychonomic Society
176
The
Japanese
Journal
ofPsychonomic
Science
Vo],
28,
No.
1
(a)"lS
O.8'・"vev=
O,6nt'g,.,:EOO.2
÷1
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l,
"tfpi..
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.1..,tt./t
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itT
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・
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ge
2
Eiectrecie
Electrede
Figure
1.
{a)
Results
of
the
3L4
(open
symbols)and
4-5
(filled
symbols) month-o]ds.Cb)
Results
ofthe
adults,In
both
figures,
triangles
and
circles
represent
the
results ofthe
expansion
and
contraction
conditions,respectively.
Error
bars
show ±1
SE.
;
'ti
[til$:glaontvepsu
/-R
300
system
with
HydroCel
Geodesic
Sensor
Net
128),
A
small noisytoy
was
presented
in
front
of
the
infant
to
attract
their
attention
to
the
monitor,
Each
experi-mentaL session consisted of20
sweeps of radial-random motionaLternations.
Ten
sessions
ran
for
each
experimental
condition,
so
that
waveforms were averaged across atotal
of200
sweeps
in
each
experimental
condition.
The
amplitude
of
the
signal
component atthe
pattern
alternationfrequency
(Fl)
was measuredfrem
9
occipitotemperal
e]ectrodes
at
the
positions
P5,
P7,
P07,
Ol,
Oz,
02,
P08,
P8,
andP6,
with a reference electrode at
Cz.
Results
and
Discussion
Figure
la
dlspLays
the
resultsobtained
from
the
infants.
A
three-way
ANOVA
(ageXmotion
direction
Xeleetrode),
with correcteddegrees
offreedom
by
Huynh-Feldt's
method, revealedthat
the
main effectof
age
and
of
electrode
were
significant
(F(1,
27)=:
8.72,
p<O.O06;
F(5.47,
147.7>='8,43,
p<O,OOI).
The
signthcant rnain effect of age $uggests
that
the
corti-cal activityto
radial motionpatterns
increases
be-tween
3
to
4
and4
to
5
months of age,The
interac-tion
between
age
and
motion
direction
was
also
sig-nificant(F(1,
27)=
6.28,
p<O.02>.
A
Tukey
post
hoc
comparison revealedthat
the
mean
amplitude
was
significantly
larger
in
the
contraction
condition
than
in
the
expansion conditionin
the
oldergroup
(p<
O.05).
This
correspondste
aprevious
finding
that
a
contraction-biasedcortical
activity
emerges
around
4
months of age(Shirai
et al,,in
press).
Figure
lb
illustrates
the
results obtainedfrom
the
adults.
A
two-way
ANOVA
(motion
directionXe]ec-trode},
with correcteddegrees
of
freedom
by
Huynh-Feldt's
method, revea],edthat
the
main effect ofelec-trode
andthe
interactions
between
the
two
factors
were significant
(F(3.08,
58.55)=13,31,
p<O.OO].;
F
(4.01,
76.27)=
4.20,
P<
O.O04).
A
Tukey
post
hoc
com-parison
revealedthat
the
difference
between
the
ex-pansion
and
contraction
conditions
was
(marginally)
stgnificant
only
in
the
right
parietal
electrodesP8
(p
<O,02}
andP6
{P<O,06),
The
results
from
the
infants
indicate
that
cortical activity specificto
radial motiondevelops
between
3
and
5
months,
and
the
contraction
bias
also
develops
during
approximately
the
same age range.Although
the
adults showed a sirnilarcontraction
bias,
the
cortical
distribution
of
the
bias
oi
the
adults
(the
right-parieta]
area)
was
different
to
that
of
the
in-fants
{the
whole ofthe
occipitoparietal
area),
This
implies
that
the
cortical
radial
motion
processing
of
infants
is
different
from
adults.Such
re-organizationbetween
infancy
and
adu]thood
of
the
cortical
sys-tems
responding
to
global
motion
(in
this
caserota-tion)
has
alsobeen
reportedelsewhere
(Braddick
Wattam-Bell,
Birtles,
Atkinson,
von
Hofsten,
&
Nys-tr6m,
2007).