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The e ec o sad mood on ea ly senso y e en - ela ed po en ials o ask-i ele an
aces
© 2023 The Au ho (s). Published by Else ie B.V.
Published e sion
Li, Xueqiao; Vuo iainen, Elisa; Xu, Qian u; As ikainen, Piia
Li, X., Vuo iainen, E., Xu, Q., & As ikainen, P. (2023). The e ec o sad mood on ea ly senso y
e en - ela ed po en ials o ask-i ele an aces. Biological Psychology, 178, A icle 108531.
h ps://doi.o g/10.1016/j.biopsycho.2023.108531
2023
Biological Psychology 178 (2023) 108531
A ailable online 3 Ma ch 2023
0301-0511/© 2023 The Au ho (s). Published by Else ie B.V. This is an open access a icle unde he CC BY license (h p://c ea i ecommons.o g/licenses/by/4.0/).
The e ec o sad mood on ea ly senso y e en - ela ed po en ials o
ask-i ele an aces
Xueqiao Li
a
,
1
,
*
, Elisa Vuo iainen
b
, Qian u Xu
c
, Piia As ikainen
a
a
Cen e o In e disciplina y B ain Resea ch, Depa men o Psychology, Uni e si y o Jy askyla, P.O. Box 35, 40014 Jy ¨
askyl¨
a, Finland
b
Human In o ma ion P ocessing Labo a o y, Facul y o Social Sciences / Psychology, Tampe e Uni e si y, 33014 Tampe e, Finland
c
Cen e o Machine Vision and Signal Analysis, Uni e si y o Oulu, 90014 Oulu, Finland
ARTICLE INFO
Keywo ds:
ERP
Facial exp ession
Mood induc ion
P1
ABSTRACT
I has been shown ha he pe cei e ’s mood a ec s he pe cep ion o emo ional aces, bu i is no known how
mood a ec s p ea en i e b ain esponses o emo ional acial exp essions. To examine he ques ion, we expe -
imen ally induced sad and neu al mood in heal hy adul s be o e p esen ing hem wi h ask-i ele an pic u es o
aces while an elec oencephalog aphy was eco ded. Sad, happy, and neu al aces we e p esen ed o he pa -
icipan s in an igno e oddball condi ion. Di e en ial esponses (emo ional – neu al) o he P1, N170, and P2
ampli udes we e ex ac ed and compa ed be ween neu al and sad mood condi ions. Emo ional acial exp essions
modula ed all he componen s, and an in e ac ion e ec o exp ession by mood was ound o P1: an emo ional
modula ion o happy aces, which was ound in neu al mood condi ion, disappea ed in sad mood condi ion. Fo
N170 and P2, we ound la ge esponse ampli udes o bo h emo ional aces, ega dless o he mood. The esul s
add o he p e ious beha io al indings showing ha mood al eady a ec s low-le el co ical ea u e encoding o
ask-i ele an aces.
1. In oduc ion
Mood is an emo ional s a e ha is igh ly linked o indi iduals’
cogni i e p ocesses (Clo e & Hun singe , 2007; Dolan, 2002). Fo
ins ance, people’s cu en mood in luences he p ocessing o acial in-
o ma ion, such as judgemen (Bouhuys e al., 1995) and he ecogni ion
o acial emo ions (Schmid & Schmid Mas , 2010). Howe e , li le is
known abou how mood in luences ask-i ele an ace p ocessing and
i s b ain basis. In he p esen s udy, we in es iga e how
labo a o y-induced sad mood compa ed wi h neu al mood a ec s
co ical e en - ela ed po en ials (ERPs) o ask-i ele an acial exp es-
sions in heal hy indi iduals.
Wi h high empo al esolu ion, ERPs enable he in es iga ion o he
b ain’s senso y-cogni i e unc ions. P e ious s udies ha e ound ha
acial exp essions modula e obliga o y ERPs, such as P1, N170, and P2,
e en when he aces a e ask i ele an (MacNama a e al., 2012; Mül-
le -Ba do e al., 2016, 2018; San os e al., 2008; Vald´
es-Con oy e al.,
2014). S udies ha ha e u ilized a as pe iodic p esen a ion o s imuli
o a e changes in acial exp essions (i.e., an oddball condi ion) ha e
ound ha e en sub le changes in he emo ional exp ession o aces a e
de ec ed as and au oma ically (Dzhelyo a e al., 2017; Leleu e al.,
2018). In addi ion, in he oddball condi ion, ERPs o a ely p esen ed
emo ional aces among epea ed neu al aces wi h a longe in e s im-
ulus in e al and longe s imulus p esen a ion du a ion ( ypically
400–600 ms s imulus-onse asynch ony and 200 ms s imulus du a ion)
ha e shown emo ional modula ion e en when he aces a e no a ended
(As ikainen e al., 2013; As ikainen & Hie anen, 2009; Chang e al.,
2010; Kimu a e al., 2012; K eegipuu e al., 2013; Liu e al., 2016; S e-
anics e al., 2012; Zhao & Li, 2006). In hese s udies, esponses o
in equen ly p esen ed ea ul and happy aces ha e mos ly been
in es iga ed.
O he obliga o y isual ERPs, P1 is a posi i e pola i y componen
ha is elici ed by a isual s imulus and peaking a app oxima ely 100 ms
a e s imulus onse a he le and igh occipi al elec ode si es ( o
aces, see, e.g., Ba y & Taylo , 2003; Holmes e al., 2008; Mülle -Ba -
do e al., 2018; Rellecke e al., 2012). P1 is sugges ed o e lec an
ea ly au oma ic p ocessing o aces, and i s ampli ude is modula ed by
low-le el isual ea u es in aces (La inus & Taylo , 2006; Rossion &
Caha el, 2011; Schindle e al., 2021; Vuilleumie & Pou ois, 2007).
Some p e ious s udies ha e epo ed emo ional modula ion o he P1
* Co esponding au ho .
E-mail add ess: [email p o ec ed] (X. Li).
1
P esen add ess: Depa men o Psychology, Uni e si y o Jy askyla, P.O. Box 35, 40014, Jy ¨
askyl¨
a, Finland.
Con en s lis s a ailable a ScienceDi ec
Biological Psychology
jou nal homepage: www.else ie .com/loca e/biopsycho
h ps://doi.o g/10.1016/j.biopsycho.2023.108531
Recei ed 30 Oc obe 2022; Recei ed in e ised o m 25 Janua y 2023; Accep ed 1 Ma ch 2023
Biological Psychology 178 (2023) 108531
2
ampli ude, which is mos ly ound as a la ge esponse ampli ude o
nega i e (e.g., ang y, ea ul) aces compa ed wi h neu al o happy
aces (e.g., Pou ois e al., 2005; Rellecke e al., 2012; Smi h e al., 2013;
S e anics e al., 2012; o a e iew, see Vuilleumie & Pou ois, 2007).
Howe e , se e al s udies ha e no ound emo ional modula ion o he P1
ampli ude (As ikainen & Hie anen, 2009; Faja e al., 2016; F ühholz
e al., 2011; I ie & Nea h-Ta a es, 2017; Jiang e al., 2009; Mülle --
Ba do e al., 2016; Ruohonen e al., 2020), and one s udy has obse ed
la ge P1 ampli udes o neu al aces compa ed wi h happy aces
(Hagemann, S aube, & Schulz, 2016).
P1 is ollowed by N170, which is a nega i e pola i y componen
peaking a app oxima ely 170 ms a e s imulus onse a he le and
igh pa ie o-occipi al si es (As ikainen e al., 2013; Ba y & Taylo ,
2003; Ben in e al., 1996; Ruohonen e al., 2020). Fo ace p ocessing,
N170 is sugges ed o e lec ea ly isual p ocessing o ace s uc u e
(Ben in e al., 1996; Eime , 2000), and i is commonly modula ed by
acial exp essions. Tha is, emo ional aces usually elici la ge N170
ampli udes han neu al aces (e.g., As ikainen e al., 2013; As ikainen &
Hie anen, 2009; Ba y & Taylo , 2003; Ben in e al., 1996; Blau e al.,
2007; K ombholz e al., 2007; Lepp¨
anen e al., 2007; o e iews, see
Hinojosa e al., 2015; Schindle e al., 2021; howe e , o lack o
emo ional modula ion o N170 see Eime & Holmes, 2002, Eime e al.,
2003, Holmes e al., 2003).
P2 is a componen ha is associa ed wi h au oma ic a en ion and
spa ial ea u e p ocessing o isual s imuli and is usually elici ed by aces
app oxima ely 200 ms a e s imulus onse a pos e io elec ode si es
(Ca e i´
e e al., 2001; La inus & Taylo , 2006; Schweinbe ge & Neu-
mann, 2016). Some s udies ha e epo ed la ge P2 ampli udes o
non-nega i e han nega i e aces (e.g., happy and neu al s. ea ul
aces, I ie & Nea h-Ta a es, 2017; neu al s. ang y aces, Raz e al.,
2014; happy s. ea ul aces, S e anics e al., 2012; howe e , o la ge
P2 o neu al han happy aces see Raz e al., 2014), while some ha e
epo ed la ge P2 esponses o nega i e aces compa ed wi h
non-nega i e aces (e.g., ang y and ea ul s. happy and neu al, Cal o
e al., 2013), o no e ec s o acial exp ession on P2 esponses (Pescha d
e al., 2013; Zhao & Li, 2006). In sum, he esul s o he emo ional
modula ion o P2 o ace s imuli ha e shown mixed esul s. The s udies
ha e included h ea ening aces ( ea ul and ang y), bu he e is a lack o
esea ch using sad aces in s imulus ma e ials.
In addi ion o modula ion due o emo ional exp essions, he obliga-
o y ERPs o aces a e modula ed by he con ex in which hey a e
p esen ed ( o a e iew, see Wiese & B osch, 2012). Fo ins ance, P1
was la ge in ampli ude when emo ional acial exp ession and body
exp ession we e cong uen han incong uen (Mee en e al., 2005). A
s udy using an a ec i e p iming pa adigm showed ha he N170
esponse o a ace was la ge in ampli ude when an a ec i ely cong uen
e sus incong uen pic u e was p esen ed be o e i (happy aces elici ed
a la ge esponse when p esen ed a e posi i e s. nega i e p imes,
while sad aces elici ed a la ge esponse when p esen ed a e nega i e
s. posi i e p imes; As ikainen & Hie anen, 2013). Inc eased N170 e-
sponses we e also ound when he aces we e p esen ed in ea ul scenes
compa ed wi h neu al scenes (Righa & de Gelde , 2006), and a la ge
N170 ampli ude o ea ul aces was obse ed when he aces and scenes
we e cong uen (Righa & de Gelde , 2008). To he bes o ou
knowledge, he e a e no s udies in es iga ing he e ec o con ex ual
in o ma ion on he P2 esponse o acial exp essions.
The obliga o y ERPs o acial exp essions a e also a ec ed by iewe -
ela ed ac o s. Fo example, a la ge P1 ampli ude was also obse ed o
disgus ed aces compa ed wi h neu al aces a e expe iencing social
exclusion (Kawamo o, Ni ono, & U a, 2014). In addi ion, al e ed b ain
esponses ha e been obse ed in se e al di e en neu ode elopmen al
and psychia ic condi ions (K eml´
aˇ
cek e al., 2016). Pe cep ual p o-
cessing o sad aces has been in es iga ed especially in mood diso de s.
Fo example, p e ious s udies ha e ound ha in dep essi e diso de
ea ly co ical ERPs a e al e ed speci ically o sad aces in ela ion o
neu al aces ( o so called nega i e in o ma ion p ocessing bias in
dep ession, see Beck, 2008; o ela ed empi ical e idence, see Chang
e al., 2010; Dai & Feng, 2012; Ruohonen e al., 2020; Wu e al., 2016;
Zhang e al., 2016; Zhao e al., 2015). Howe e , i is no known whe he
hese b ain esponses show a simila nega i e bias in heal hy pa ici-
pan s when hey a e in sad mood.
In he p esen s udy, we in es iga e he e ec o sad mood on
pe cep ual ERPs (i.e., P1, N170, and P2) o aces by expe imen ally
inducing sad and neu al mood in heal hy adul s (a wi hin-subjec s
design). We ollow a p e ious s udy’s mood induc ion p ocedu e (Rob-
inson e al., 2012), u ilizing Vel en’s mood s a emen s and music o
induce he a ge moods. A e he mood induc ion p ocedu e, we p e-
sen he pa icipan s wi h sad and happy de ian aces in e spe sed wi h
neu al s anda d aces in an igno e oddball pa adigm (as in Ruohonen
e al., 2020). We in es iga e he emo ional modula ion o ERPs by
calcula ing di e en ial ERPs o he emo ional acial exp essions
(emo ional - neu al) a he di e en p ocessing s ages o ace pe cep ion
as e lec ed by P1, N170, and P2 (As ikainen & Hie anen, 2009; Chang
e al., 2010; S e anics e al., 2012; Zhao & Li, 2006).
I a simila nega i e bias exis s in sad mood as in clinical dep ession,
i can be expec ed ha ERPs would show al e ed ampli udes o di e -
en ial esponses o sad aces in sad mood compa ed wi h neu al mood.
This hypo hesis is based on p e ious s udies showing la ge ERP e-
sponses o sad aces in dep essed pa icipan s (Dai & Feng, 2012; Ruo-
honen e al., 2020; Wu e al., 2016; Zhang e al., 2016; Zhao e al., 2015),
al hough one s udy using an igno e oddball condi ion has epo ed
smalle ERP ampli udes in dep essed han non-dep essed pa icipan s
(Chang e al., 2010). P e ious beha io al s udies applying mood in-
duc ion me hods ha e also ound mood-cong uen e ec s on conscious
ace ecogni ion asks (Bouhuys e al., 1995; Schmid & Schmid Mas ,
2010). Howe e , i is unclea whe he a simila e ec as ha ound o
conscious ecogni ion asks can be expec ed o ask-i ele an p o-
cessing o aces e lec ing au oma ic senso y unc ions o he b ain.
2. Ma e ials and me hods
2.1. Pa icipan s
The esea ch p o ocol was ca ied ou in acco dance wi h he
Decla a ion o Helsinki and was app o ed by he E hics Commi ee o
he Uni e si y o Jy ¨
askyl¨
a. W i en in o med consen was ob ained
om all he pa icipan s be o e he measu emen s a ed. The sample
size was es ima ed wi h a p io i powe analysis implemen ed wi h
G*Powe ( e sion 3.1; Faul, E d elde , & Lang, 2007) based on medium
e ec size (
η
2
p =0.06; Cohen, 1988). The e we e no mood induc ion
s udies in es iga ing he mood e ec on ask-i ele an ace p ocessing,
and p e ious s udies in es iga ing ERP modula ions (P1, N170, and P2)
o he acial exp essions on he manipula ion o cong uen a ec i e
con ex s ha e a ely epo ed he e ec size. The e o e, we es ima e a
medium e ec size o he p esen s udy based on p e ious oddball
s udies showing emo ional modula ion o ea ly ERPs o aces in heal hy
pa icipan s (Kimu a e al., 2012; S e anics e al., 2012) and in me h-
odological simila s udies compa ing dep ession pa ien s and heal hy
con ols (e.g., Ruohonen e al., 2020; Zhang e al., 2016). A epea ed
measu es ANOVA was se o he a p io i powe analysis, wi h Mood
(Neu al s. Sad), Exp ession (Sad-Neu s. Happy-Neu), and Hemisphe e
(Le s. Righ ) as wi hin-subjec s ac o s. The e ec size speci ica ions
a e se as in G*Powe 3.0. The esul o he calcula ion showed a
equi emen o 19 pa icipan s o achie e a s a is ical powe o (1 - β)
=0.90 and a signi icance le el o
α
=0.05.
Thi y- wo heal hy pa icipan s who we e na i e Finnish speake s
olun ee ed o he s udy. The pa icipan s we e ec ui ed ia he email
lis s o he Uni e si y o Jy ¨
askyl¨
a and h ough he ad e isemen lye s
in Jy ¨
askyl¨
a. The inclusion c i e ia o all pa icipan s we e age be ween
18 and 40 yea s, igh -handedness, no mal o co ec ed- o-no mal
ision, and no sel - epo ed his o y o psychia ic diso de s, b ain
X. Li e al.
Biological Psychology 178 (2023) 108531
3
auma o neu ological diseases. Pa icipan s who had a sco e o 10 o
highe in Beck’s Dep ession In en o y-II (BDI-II; Beck e al., 1996) we e
excluded, because he dep essi e symp oms ha e e ec s on ERPs o
emo ional aces (Ruohonen e al., 2020). Females who we e p egnan o
b eas eeding we e also excluded om he expe imen s because o he
ho monal changes. The e iciency o mood induc ion was also consid-
e ed as a c i e ion o inclusion. Pa icipan s who e alua ed hei mood
o sad di ec ion wi h 10% changes om he baseline on he sad mood
measu emen day we e included.
Ten pa icipan s we e excluded om he inal sample: one due o he
exclusion c i e ia based on BDI sco es, i e due o he insu icien
numbe o ials in hei EEG da a caused by excessi e EEG a i ac s, and
ou had ine icien mood induc ion. The e o e, in o al, he e we e
wen y- wo pa icipan s included in he inal sample. The demog aphics
o he pa icipan s included o he da a a e epo ed in Table 1.
2.2. P ocedu e
Neu al mood and sad mood we e induced o all pa icipan s on wo
sepa a e days in a coun e balanced o de be ween he pa icipan s. Tha
is, hal o he pa icipan s had neu al mood induc ion on he i s
measu emen day and sad mood induc ion on he second day, and o
ano he hal o he pa icipan s his o de was e e sed. Fo each mea-
su emen day, he p ocedu es we e he same and consis ed o h ee main
pa s: a Mood Induc ion p ocedu e, an expe imen o Masked ace
de ec ion, and an expe imen o Task-i ele an ace pe cep ion (an
igno e oddball pa adigm). Be o e and a e he Mood Induc ion p o-
cedu e, he Masked ace de ec ion expe imen , and he Task-i ele an
ace pe cep ion expe imen , pa icipan s we e asked o sel -e alua e
hei mood by d awing a e ical line in he Visual Analog Mood Scale
(VAMS; Lu ia, 1975). The scale anges om e y sad (0 cm) o e y
happy (10 cm). In he p esen s udy, esul s o he mood e alua ion
(VAMS) and he Task-i ele an ace pe cep ion expe imen a e e-
po ed. The p ocedu e and he s imulus pa adigm o he s udy is illus-
a ed in Fig. 1.
When he pa icipan s a i ed a he lab on he i s measu emen
day, hey we e asked o ill he BDI-II be o e he eco ding. Du ing he
expe imen s, pa icipan s we e sea ed on a chai in a sound and elec-
ici y p oo shielding oom and moni o ed ia a ideo came a. The
s imuli (mood s a emen s and acial images) we e p esen ed a he
cen e o a 58.4 cm (23 in.) compu e sc een (Asus VG236H, 1920 ×
1080 pixels, e esh a e 100 Hz). The sc een was 1 m in on o he
pa icipan , and he e was a speake on he ceiling abo e he pa icipan
o play he music du ing mood induc ion p ocedu e. The olume o he
music was adjus ed o each pa icipan a an app op ia e le el. The
ligh s we e u ned o du ing he whole measu emen . To help he pa -
icipan s s ay in he neu al/sad mood wi hou dis u bance om he
esea che , all he ins uc ions we e gi en be o e he measu emen
began. The ins uc ions o he asks we e also p esen ed on he sc een
be o e each sec ion, which helped he pa icipan s easily s a and
con inue he expe imen by hemsel es.
Fo each measu emen day, he eco ding s a ed wi h a wo-minu e
es ing s age ha included a one-minu e eyes open and a one-minu e
eyes closed sessions. A e he es ing s age eco ding, he pa icipan s
s a ed he mood induc ion p ocedu e by p essing a bu on. Du ing he
mood induc ion p ocedu e, e e y s a emen was p esen ed o 15 s.
Music was played a he same ime un il pa icipan s ead all he
s a emen s. The du a ion o he mood induc ion p ocedu e was
app oxima ely 15 min. A e ha , he Masked ace de ec ion expe imen
s a ed in which pa icipan s e alua ed whe he he p esen ed ace was a
sad ace o a neu al ace (da a om his expe imen a e no epo ed
he e). A e he Masked ace de ec ion expe imen , he e was a 2-minu e
b eak while he music o he a ge mood was playing again, which was
in ended o help pa icipan s ge back o he mood be o e he Task-
i ele an ace pe cep ion expe imen .
He e we epo he esul s om he Task-i ele an ace pe cep ion
expe imen . I u ilized an igno e oddball s imulus condi ion, in which
pa icipan s we e ins uc ed o keep hei gaze a he cen e o he sc een
while concen a e on a calcula ion ask by con inuously adding 6 in he
calcula ion in hei mind and igno e he acial s imuli. The pa icipan s
we e asked o ell hei esul s o he calcula ion wice be ween he
s imulus p esen a ion.
Fo all he measu emen s, E-P ime 2.0 so wa e (Psychology So -
wa e Tools, Inc., Sha psbu g, PA, USA) was used o con ol he p e-
sen a ion o he s imuli.
2.3. Ma e ials o mood induc ion p ocedu e
In acco dance wi h a p e ious s udy (Robinson e al., 2012), Vel en’s
mood s a emen s (Vel en, 1967) and music, ob ained om neu al and
sad condi ions, we e u ilized o induce he a ge mood (ei he neu al o
sad).
The e we e 60 one-sen ence s a emen s applied o he neu al and
sad mood induc ion. Fo he neu al mood induc ion, s a emen s
desc ibed he gene al knowledge o objec i e ac s (e.g., ‘The Chinese
language has many dialec s, including Can onese, Manda in, and Wu.’).
Fo he sad mood induc ion, s a emen s we e speci ic o sel -de alua ion
and soma ic symp oms ela ed o dep ession (e.g., ‘I ha e oo many bad
hings in my li e.’). The mood s a emen s we e ansla ed om English
o Finnish. A ew s a emen s we e modi ied o i in o he p esen Finnish
exp ession s yle and cul u e. The o iginal and ansla ed s a emen s a e
p esen ed in Supplemen a y Table 1. Du ing he neu al mood induc-
ion, each sen ence was p esen ed o he sc een in black colo on a whi e
backg ound. Du ing he sad mood induc ion, he sen ence was p esen ed
in g ey colo and he backg ound was blue. Conce ning he music o
mood induc ion, Adagio in G Mino by Tomaso Albinoni was selec ed o
he sad mood, and The Plane s, Op. 32: VII Nep une, he Mys ic by
Gus a Hols was used o induce he neu al mood. The design o sen-
ence p esen a ion and he music selec ions we e made based on a
p e ious s udy (Robinson e al., 2012).
2.4. Face s imulus p esen a ion in he ERP eco ding
Sad, happy and neu al aces we e selec ed om he KDEF s imulus
se (The Ka olinska Di ec ed Emo ional Faces; Lundq is e al., 1998).
The selec ions we e made based on he e alua ions o unbiased hi a es
(a p obabili y combined wi h co ec ness o iden i ying s imulus and
co ec ness o using esponse) o each acial exp ession in a p e ious
s udy (Goele en e al., 2008). The a e age unbiased hi a es o all he
exp essions we e mo e han 0.79 (all unbiased hi a es o sad >0.58;
o happy >0.8; and o neu al >0.73). Ac o s o ace ma e ials we e 6
emales and 6 males (age be ween 20 and 30 yea s). All he selec ed
acial images we e con e ed in o g ey scale in o de o adjus hei
luminance o an equaled mean le el by using a MATLAB oolbox
(SHINE: spec um, his og am, and in ensi y no maliza ion and equal-
iza ion; Willenbockel e al., 2010). A e ha , he acial images we e
co e ed by a g ey ame in o de o only p esen he inne egion o he
aces. The aces we e p esen ed a a isual angle o 3.03◦×4.11◦, and
he esolu ion o he acial images was 209 ×283 pixels (wid h ×
heigh ). The lis o he KDEF Ids and mean luminance o all he s imuli
used in he expe imen is showed in Supplemen a y Table 2.
Table 1
Demog aphic in o ma ion o he pa icipan s. SD =s anda d de ia ion, BDI-II
=Beck’s Dep ession In en o y, Second Edi ion.
Va iable Pa icipan s (n =22)
Age Mean (SD) 26.6 yea s (4.4 yea s)
Range 20–38 yea s
Gende Male 10
Female 12
BDI-II Mean (SD) 2.05 (2.17)
Range 0–7
X. Li e al.
Biological Psychology 178 (2023) 108531
4
In he oddball condi ion, a neu al ‘s anda d’ ace (p =0.8) was
in e spe sed wi h a sad o a happy ‘de ian ’ ace (p =0.1 o each
de ian ype). The s imuli we e p esen ed in a pseudo- andom o de
wi h a es ic ion ha he e we e a leas wo s anda d aces be ween
consecu i e de ian aces, and he acial iden i y in he pic u es changed
om ial o ial. The s imulus du a ion was 200 ms, and he in e -
s imulus in e al (ISI) was andomly ei he 450 ms, 500 ms, o 550 ms.
The igno e oddball condi ion ook abou 15 min and 1200 acial s imuli
(960 neu al s anda d aces, 120 sad and 120 happy de ian aces) we e
p esen ed.
2.5. EEG eco ding and analysis
Con inuous EEG was eco ded by a Neu One sys em (Bi ium Bio-
signals L d, Kuopio, Finland) wi h a 128-channel Hyd oCel Geodesic
Senso Ne (Hyd oCel Geodesic Senso Ne , Elec ic Geodesic Inc, USA).
The da a we e eco ded a a 1000 Hz sampling a e and we e il e ed
online wi h a 250 Hz high cu -o . The e ex elec ode (Cz) was se as
he e e ence elec ode du ing he eco ding.
The EEG da a we e p e-p ocessed wi h MNE py hon (G am o , 2013;
MNE e sion: 0.21.2; Py hon: 3.8.6). Fi s , bad channels wi h an
ex ensi e amoun o noise we e in e pola ed using he sphe ical spline
me hod (Pe in e al., 1989). Nex , he elec ode signals we e band-pass
il e ed a 0.1–30 Hz (ze o-phase o e lap-add FIR il e ing). The lowe
ansi ion bandwid h was 0.1 Hz (−6 dB cu o equency: 0.05 Hz), and
he uppe ansi ion bandwid h was 7.5 Hz (−6 dB cu -o equency:
33.755 Hz). The il e leng h was 33001 samples (33.001 s). The da a
we e e- e e enced o line o an a e age o e all channels. Then, da a
we e segmen ed in o epochs om 100 ms be o e and 600 ms a e he
onse o he s imulus. Baseline co ec ion was applied o each epoch by
sub ac ing he mean ol age o he 100 ms p e-s imulus pe iod om all
da a poin s o he epoch. Bad epochs wi h eye blinks and o he a i ac s
we e semiau oma ically emo ed when he epoch exceeded an ampli-
ude o ±50
μ
V.
Fo each mood condi ion (sad mood s. neu al mood), epochs we e
a e aged sepa a ely o esponses o each de ian s imuli (sad de ian
and happy de ian ) and o esponses o he s anda d s imuli immedi-
a ely p eceding he de ian s (p e-sad neu al s anda d and p e-happy
neu al s anda d), allowing he same maximum numbe o ials o
each s imulus ca ego y. Da a we e included o u he analysis i he e
we e a leas 40 epochs a ailable o each de ian and s anda d s imulus
in each mood condi ion.
Fo P1, N170, and P2, mean ampli ude alues we e in es iga ed.
Based on p e ious li e a u e (As ikainen e al., 2013; Ba y & Taylo ,
2003; Ruohonen e al., 2020) and isual inspec ion o he g and a e -
aged da a, ime windows and elec ode clus e s a he le and igh
occipi al/pa ie o-occipi al si es we e selec ed o P1, N170, and P2
sepa a ely (Supplemen a y Fig. 1). Fo each pa icipan , he maximum
o minimum esponse ampli ude, depending on he pola i y, o each
componen we e i s de ec ed wi hin each elec ode clus e . Fo P1 and
P2, he maximum ampli ude alues we e de ec ed wi hin 80–150 ms
and wi hin 180–260 ms a e s imulus onse , espec i ely. Fo N170, he
minimum ampli ude alue was de ec ed wi hin a ime window o
130–210 ms a e he s imulus onse . A e loca ing he max-
imum/minimum esponse ampli ude, o each componen a mean
ampli ude alue om a 20-ms ime window ( ±10 ms a ound he
maximum esponse ampli ude) was calcula ed as an a e age o he
elec ode clus e . Nex , di e en ial esponses o mean ampli udes
(sad/happy de ian minus neu al s anda d) we e calcula ed o P1,
N170, and P2 o ex ac esponses o emo ional aces. The di e en ial
esponses we e used because hey can index he emo ional modula ion
o he componen .
2.6. S a is ics
Fo he a ings o mood e alua ion, VAMS1 (mood e alua ion sco es
a e es ing s age), VAMS 2 (mood e alua ion sco es a e he Mood
Induc ion p ocedu e), and VAMS4 (mood e alua ion sco es be o e he
Task-i ele an ace pe cep ion expe imen ) we e analyzed sepa a ely
and compa ed be ween he neu al and sad mood induc ion measu e-
men days (Fig. 1). Two- ailed pai ed samples - es s wi h he boo -
s apping me hod using 1000 pe mu a ions (Good, 2005) we e applied
o explo e he mood changes.
Fo he ERP ampli ude, di e en ial esponses (de ian minus s an-
da d) o P1, N170, and P2 we e ex ac ed sepa a ely o sad and happy
aces and submi ed o epea ed measu es o analysis o a iance
(ANOVA) o in es iga e e ec s o mood on di e en pe cep ual phases.
Wi hin-subjec s ac o s we e Mood (Neu al s. Sad), Exp ession (Sad-
Neu s. Happy-Neu), and Hemisphe e (Le s. Righ ). Two- ailed pai ed
samples - es s wi h he boo -s apping me hod using 1000 pe mu a ions
(Good, 2005) we e ca ied ou o u he in es iga e he signi ican in-
e ac ions ela ed o he e ec o mood ound in ANOVAs. The di e -
en ial esponses o sad and happy aces we e compa ed sepa a ely
be ween sad and neu al mood.
Whene e a signi ican mood ela ed main o in e ac ion e ec was
ound o he di e en ial esponses, he di e en ial esponses we e
Fig. 1. Illus a ion o he p ocedu e and he
s imulus pa adigm applied o bo h measu e-
men days. Fo he neu al mood condi ion,
neu al s a emen s and music we e p esen ed in
he Mood Induc ion p ocedu e; o he sad
mood condi ion, sad s a emen s and music we e
p esen ed in he Mood Induc ion p ocedu e.
The o he pa s o he measu emen we e kep
he same o bo h measu emen days. In he
p esen epo , esul s o he mood e alua ion
(VAMS) and he Task-i ele an ace pe cep ion
expe imen a e epo ed. The aces in he igu e
a e examples om he ac ual expe imen (The
Ka olinska Di ec ed Emo ional Faces; Lundq is
e al., 1998; s imulus se : AF01NES, AF07HAS,
AM05SAS). VAMS =Visual Analog Mood Scale.
X. Li e al.

Biological Psychology 178 (2023) 108531
5
compa ed agains ze o by using one sample - es s o explo e whe he
he emo ional modula ion was obse ed in each mood condi ion. When
no e ec o mood o i s in e ac ion was ound, he emo ional modula ion
was in es iga ed by calcula ing di e en ial esponses o e Mood and
Hemisphe e sepa a ely o happy and sad aces and compa ing hem
agains ze o (one sample - es s).
The p- alues (p
FDR-co ec ed
) we e co ec ed wi h he False disco e y
a e (FDR; Benjamini & Yeku ieli, 2001) p ocedu e whene e he e we e
mo e han wo pai ed samples - es s o wo one sample - es s. Pa ial
e a squa ed (
η
2
p) and Cohen’s d wi h pooled s anda d de ia ion (Cohen,
1988) a e epo ed as e ec size es ima es o ANOVAs and - es s,
espec i ely. All s a is ics wi h p- alues smalle han 0.050 we e
conside ed signi ican . The s a is ical analysis was conduc ed by using
IBM SPSS S a is ics Ve sion 26 (A monk, NY: IBM Co po a ed).
In addi ion, Bayes ac o analyses (Bayesian - es s) we e conduc ed
by u ilizing JASP so wa e (Ve sion 0.16.4; JASP Team, 2022) o
compa e he ela i e e idence o wo compe ing hypo heses: an al e -
na i e hypo hesis and a null hypo hesis. A Bayes ac o (BF
10
) g ea e
han 1 indica es ha he accep ance o he al e na i e hypo hesis is mo e
suppo i e, while a BF
10
less han 1 can be labelled as no e idence in
a ou o he al e na i e hypo hesis. Acco ding o Je eys (1998), a
BF
10
g ea e han 3 can be conside ed as mode a e e idence and a BF
10
g ea e han 10 indica es s ong e idence in a ou o he al e na i e
hypo hesis. The e o e, when a esul is no s a is ically signi ican ac-
co ding o he p- alue while a BF
10
is g ea e han 1 bu less han 3, we
de ine i as insu icien e idence o d aw a conclusion o o agains
ei he hypo hesis.
3. Resul s
3.1. Mood induc ion
A pai ed-sample - es showed ha he e was a signi ican di e ence
in he sco es o VAMS be ween he sco es measu ed a e he mood in-
duc ion p ocedu e (VAMS 2) in neu al mood condi ion (M =5.20 cm,
SD =0.62) and he sco es o VAMS in sad mood condi ion (M =2.99 cm,
SD =1.24), (21) =8.26, p<0.001, p
FDR-co ec ed
=0.003, 95% CI
[1.65, 2.76], Cohen’s d =1.76. This e lec s a success ul mood induc-
ion. When compa ing he VAMS sco es be o e he Task-i ele an ace
pe cep ion expe imen (VAMS 4), pai ed-sample - es e eal a signi i-
can di e ence be ween he neu al mood condi ion (M =5.02 cm, SD =
0.65) and he sad mood condi ion (M =2.69 cm, SD =1.14), (21) =
9.69, p<0.001, p
FDR-co ec ed
=0.003, 95% CI [1.83, 2.83], Cohen’s
d =2.07, e lec ing ha he sad mood main ained a leas un il he Task-
i ele an ace pe cep ion expe imen began. The sco es o VAMS a e
es ing s age (VAMS 1, baseline be o e he mood induc ion p ocedu e)
did no di e be ween he wo measu emen days, p=0.075, p
FDR-co -
ec ed
=0.138. The esul s o mood e alua ion a e illus a ed in Fig. 2.
3.2. P1
Fo desc ip i e pu poses, he wa e o ms, and opog aphic maps o
he g and-a e aged P1 esponses o sad, happy, and neu al aces in each
mood a e illus a ed in Fig. 3. Mean ampli ude alues o he P1 e-
sponses o sad, happy, and neu al aces in each mood and o e mood
condi ions is shown in Table 2.
Di e en ial esponses o P1 (emo ional-neu al) submi ed o he
h ee-way epea ed measu es ANOVA wi h wi hin-subjec a iables
Mood (Neu al s. Sad), Exp ession (Sad-Neu s. Happy-Neu), and
Hemisphe e (Le s. Righ ) showed a main e ec o Exp ession, F(1,21)
=9.177, p=0.006,
η
2
p =0.304. The main e ec was modi ied by an
in e ac ion e ec o Mood and Exp ession, F(1,21) =8.022, p=0.010,
η
2
p =0.276. When compa ing he esponse be ween neu al and sad
mood sepa a ely o sad and happy di e en ial esponses, P1 di e en ial
esponses o happy aces we e mo e nega i e in ampli ude in neu al
mood condi ion (M = − 0.53
μ
V, SD =0.78) han in sad mood condi ion
(M = − 0.02
μ
V, SD =0.88): (21) = − 2.132, p=0.045, 95% CI [−1.01,
−0.01], Cohen’s d =0.61, BF
10
=1.459. No di e ences we e ound
be ween he mood condi ions in sad ace esponses: p=0.410, BF
10
=0.306. The esul s a e illus a ed in Fig. 4.
One-sample - es s compa ing he di e en ial esponse agains ze o
we e conduc ed o he P1 di e en ial esponses o happy and sad aces
o in es iga e whe he he emo ional modula ion was signi ican . In
neu al mood, he P1 di e en ial esponses o happy ace, (21) = −
3.196, p=0.004, p
FDR-co ec ed
=0.033, 95% CI [−1.14, −0.21],
Cohen’s d =0.681, BF
10
=10.075, we e signi ican agains ze o a e
he FDR p ocedu e. Fo he sad ace, he FDR co ec ed p- alue did no
indica e di e ences agains ze o, bu Bayes ac o was g ea e han 1 and
less han 3, indica ing an absence o e idence: (21) =2.107, p=0.047,
p
FDR-co ec ed
=0.196, 95% CI [0.01, 0.883], Cohen’s d =0.49, BF
10
=1.401. In sad mood, he P1 di e en ial esponses we e non-signi ican
agains ze o o bo h happy, p=0.907, p
FDR-co ec ed
>0.999, BF
10
=0.224, and sad ace, p=0.601, p
FDR-co ec ed
>0.999, BF
10
=0.253,
and o bo h aces he Bayes ac o s <1.
The e we e no o he main o in e ac ion e ec s obse ed based on
he h ee-way epea ed measu es ANOVA, all p- alues >0.113.
3.3. N170
Fo desc ip i e pu poses, he wa e o ms, and opog aphic maps o
he g and-a e aged N170 esponses o sad, happy, and neu al aces in
each mood a e illus a ed in Fig. 5. G and-a e aged ampli ude alues o
he N170 esponses o sad, happy, and neu al aces in each mood and
o e mood condi ions a e shown in Table 2.
Fo he di e en ial esponses o N170, a h ee-way epea ed mea-
su es ANOVA wi h wi hin-subjec a iables Mood (Neu al s. Sad),
Exp ession (Sad-Neu s. Happy-Neu), and Hemisphe e (Le s. Righ )
showed a main e ec o Hemisphe e, F(1,21) =5.240, p=0.033,
η
2
p
=0.2. The N170 di e en ial esponses (emo ional-neu al) we e la ge
a he igh hemisphe e (M = − 0.81
μ
V, SD =0.66) han a he le
hemisphe e (M = − 0.43
μ
V, SD =0.35). The e we e no o he main o
in e ac ion e ec s, all p- alues >0.086. The esul s a e illus a ed in
Fig. 5.
Emo ional modula ion o N170 was in es iga ed by using one-
sample - es s compa ing he di e en ial esponse agains ze o. The
N170 di e en ial esponse o e Mood and Hemisphe e o happy and
sad aces we e applied. The N170 di e en ial esponse o bo h happy,
(21) = − 5.784, p <0.001, 95% CI [−0.77, −0.36], Cohen’s d =1.23,
BF
10
=9829, and sad aces (21) = − 6.502, p <0.001, 95% CI [−0.91,
Fig. 2. Mood e alua ion scales a he baseline s age (VAMS 1), a e he Mood
Induc ion p ocedu e (VAMS 2), a e he Masked ace de ec ion expe imen
(Expe imen 1; VAMS 3), be o e he Task-i ele an ace pe cep ion expe imen
(Expe imen 2; VAMS 4), and a e he Task-i ele an ace pe cep ion expe i-
men (VAMS 5). Do s show he mean alues o VAMS a ings and e o ba s
ep esen 95% con idence in e als. VAMS =Visual Analog Mood Scale. Un-
co ec ed p- alues a e p esen ed in he igu e.
X. Li e al.
Biological Psychology 178 (2023) 108531
6
−0.47], Cohen’s d =1.39, BF
10
=2255, we e signi ican agains ze o,
e lec ing obus emo ional modula ion o he N170 ampli ude.
3.4. P2
G and-a e aged wa e o ms o P2 o each acial exp ession a e
illus a ed in Fig. 3 o desc ip i e pu poses. Mean ampli ude alues o
he P2 esponses o sad, happy, and neu al aces in each mood and o e
mood condi ions a e shown in Table 2.
Fo he di e en ial esponses o P2, a h ee-way epea ed measu es
ANOVA wi h wi hin-subjec a iables Mood (Neu al s. Sad), Exp es-
sion (Sad-Neu s. Happy-Neu), and Hemisphe e (Le s. Righ ), showed
no main o in e ac ion e ec s, all p- alues >0.123.
Emo ional modula ion o P2 was in es iga ed by using one-sample -
es s compa ing he di e en ial esponse agains ze o. The P2 di e en-
ial esponse o e Mood and Hemisphe e o happy and sad aces we e
applied. The P2 di e en ial esponse o bo h happy, (21) = − 2.554,
p=0.018, 95% CI [−0.99, −0.09], Cohen’s d =0.55, BF
10
=2.991,
and sad aces (21) = − 3.024, p=0.006, 95% CI [−1.10, −0.18],
Cohen’s d =0.65, BF
10
=7.194, we e signi ican agains ze o, indi-
ca ing obus emo ional modula ion o he P2 ampli ude.
4. Discussion
The main pu pose o he p esen s udy was o in es iga e he e ec s
o sad mood on ERPs o ask-i ele an p ocessing o acial exp essions.
By applying a mood induc ion p ocedu e, we success ully elici ed sad
and neu al mood on sepa a e days in heal hy pa icipan s. We ound a
obus emo ional modula ion o he P1 ampli ude o happy aces in
Fig. 3. G and-a e aged wa e o ms o P1 and P2 o sad, happy, and neu al aces and opog aphic maps o P1. The shadows in all he wa e o ms ep esen 95%
con idence in e als.
Table 2
Mean ampli ude alues o he P1, N170 and P2 esponses o sad, happy, and
neu al acial exp essions in neu al mood, sad mood, and o e mood condi ions.
SD =s anda d de ia ion.
ERP Exp ession Ampli ude (
μ
V)
Neu al
mood
Sad mood A e age o mood
condi ions
P1
Mean
(SD)
Sad ace 5.35 (1.55) 5.28
(1.70)
5.32 (1.55)
Happy ace 4.82 (1.51) 4.89
(1.73)
4.86 (1.55)
Neu al
ace
5.20 (1.64) 5.05
(1.82)
5.13 (1.67)
N170
Mean
(SD)
Sad ace -1.22 (1.47) -1.13
(1.50)
-1.18 (1.40)
Happy ace -1.14 (1.19) -0.82
(1.50)
-0.98 (1.31)
Neu al
ace
- 0.43
(1.26)
-0.48
(1.28)
-0.45 (1.23)
P2
Mean
(SD)
Sad ace 5.74 (2.09) 6.00
(2.66)
5.87 (2.26)
Happy ace 5.83 (2.13) 6.14
(2.31)
5.98 (2.13)
Neu al
ace
6.31 (2.17) 6.32
(2.45)
6.32 (2.21)
X. Li e al.
Biological Psychology 178 (2023) 108531
7
Fig. 4. Wa e o ms and opog aphic maps o he P1 di e en ial esponses in neu al and sad mood. The shadows in he wa e o ms ep esen 95% con idence in-
e als. The g ey ec angle shadows in he wa e o ms o di e en ial esponses show he ime window applied in he analysis o de ec he maximum esponse
ampli ude. In he analysis, a mean ampli ude alue o ±10 ms a ound he maximum esponse ampli ude was applied. The e o ba s in he ba cha s ep esen
s anda d e o o mean. Unco ec ed p- alues a e p esen ed in he igu e. #signi ican agains ze o (one sample - es ).
Fig. 5. G and-a e aged wa e o ms and opog aphic maps o N170 esponses o sad, happy, and neu al aces and he N170 di e en ial esponses. Fo he di e en ial
wa e o ms, he esponses a e a e aged o e he sad and happy exp essions and he sad and neu al moods. The shadows in all he wa e o ms ep esen 95%
con idence in e als. The g ey ec angle a ea in he wa e o ms o di e en ial esponse shows he ime window applied in he analysis o de ec peaks o indi idual
pa icipan s. In he analysis, a mean ampli ude alue o ±10 ms a ound he peak was applied. The e o ba s in he ba cha s ep esen s anda d e o o mean.
X. Li e al.
Biological Psychology 178 (2023) 108531
8
neu al mood, which disappea ed du ing sad mood. N170 and P2 did no
show modula ion by mood, bu hey we e ound o be modula ed by
emo ion. Nex , we discuss hese indings in de ail.
P1 showed an in e ac ion e ec o mood by emo ion: In neu al
mood, he di e en ial P1 esponse o happy aces was signi ican agains
ze o, e lec ing he emo ional modula ion o P1. In sad mood, he di -
e en ial esponse o happy aces was nonsigni ican , sugges ing no
emo ional modula ion in sad mood, and Bayes ac o s smalle han 1
also suppo ed his in e p e a ion. The esul s om he pos hoc es s
b eaking he in e ac ion e ec in ANOVA by di ec ly compa ing he
esponses be ween sad and neu al mood we e in line wi h he analysis
compa ing di e en ial esponses o ze o. The same compa ison o sad
aces suppo ed he null hypo hesis (no di e ence be ween he mood
condi ions). Because P1 e lec s isual ea u e encoding, ou esul s om
neu al mood can be in e p e ed as au oma ic encoding o happy aces
and possibly a less obus encoding o sad aces. The mo e obus di -
e en ial esponse o happy han sad aces can possibly be associa ed
wi h mo e ecognizable low-le el ea u es o happy han sad aces
(Cal o & Lundq is , 2008; Lepp¨
anen & Hie anen, 2007; To enham
e al., 2009). Since we used di e en ial esponses in he analyses, ou
esul s may also e lec neu al disc imina ion o happy aces om
neu al aces. In e es ingly, P1 modula ion by happy aces disappea ed
when he pa icipan s we e in sad mood, po en ially e lec ing dis up ed
encoding o happy aces in sad mood. In gene al, his esul is in line
wi h p e ious s udies showing con ex e ec s ( o P1, see Mee en e al.,
2005; Kawamo o, Ni ono, & U a, 2014; o N170, see Chen e al., 2020;
Hie anen & As ikainen, 2013; Righa & de Gelde , 2008; o LPP, see Xu
e al., 2017) on ERPs o acial exp essions. Howe e , he cu en s udy is
he i s o show he e ec o mood on ask-i ele an p ocessing o acial
exp essions. Thus, i seems o be ha sad mood a ec s no only he
conscious de ec ion o acial exp essions (Bouhuys e al., 1995; Chepe-
nik e al., 2007), bu also ask-i ele an encoding o acial ea u es.
Ou esul ega ding he mood e ec on P1 ampli ude is also in line
wi h a p e ious s udy in es iga ing he e ec o a ec i e isual con ex
on au oma ic audi o y change de ec ion in heal hy indi iduals (Pinhei o
e al., 2017). In he s udy, he pa icipan s we e p esen ed wi h a
con ex ual a ec i e pic u e (neu al, nega i e, o posi i e) while ERPs o
changes in sound we e measu ed. The au ho s in e p e ed ha he
nega i e con ex ual pic u es dis up ed pa icipan s’ p edic i e p ocess-
ing o una ended sounds, which was e lec ed by dec eased misma ch
nega i i y (MMN) ampli udes o he de ian sounds p esen ed in he
con ex o nega i e pic u es. Analogously, in he p esen s udy, we ound
ha sad mood dis up ed he encoding o happy aces, as e lec ed by
dec eased P1 ampli ude, o aces p esen ed in he oddball condi ion.
MMN- esponses in he audi o y modali y e lec change de ec ion,
and hey ha e also been in e p e ed as an e o signal a ising om a
con lic be ween a senso y p edic ion and senso y inpu s (Ga ido e al.,
2009; Wacongne e al., 2012; o p edic i e coding heo y see, F is on,
2005). A isual coun e pa o he audi o y MMN, called he isual MMN
( MMN), has been widely epo ed o di e en changing isual ea u es,
including acial exp essions (As ikainen e al., 2013; As ikainen & Hie-
anen, 2009; Chang, e al., 2010; Kimu a e al., 2012; S e anics e al.,
2012; Xu e al., 2018; Zhao & Li, 2006). I is no able ha in many s udies
epo ing he MMN o emo ional aces, he esponses may e lec no
only he p edic i e p ocessing o he de ian aces, bu also an emo ional
modula ion o he esponses. This is because, in many s udies, he
s anda d ace in he oddball condi ion has been neu al ega ding
emo ion, while he de ian ace has been emo ional (e.g., As ikainen &
Hie anen, 2009; Chang e al., 2010; Liu e al., 2016; Zhao & Li, 2006).
Because we applied an oddball condi ion, i is possible ha ou esul s
also e lec p edic i e coding o emo ional aces. Howe e , we ha e
some easons o belie e ha he esponses in ou s udy a e modula ed by
emo ional exp essions. Fi s ly, some p e ious s udies ha e di ec ly
in es iga ed his issue. In one s udy (As ikainen e al., 2013), di e en ial
esponses o ea ul and happy aces we e compa ed when p esen ed
ei he wi h a low p obabili y among neu al aces (an oddball condi ion)
o wi h equal p obabili y wi h neu al aces (an equip obable condi-
ion). No di e ence was ound be ween independen componen s’ am-
pli udes be ween hese s imulus condi ions wi hin 100–200 ms la ency,
sugges ing ha he ampli ude modula ions wi hin his ime in e al
e lec an e ec o acial emo ion a he han s imulus p obabili y on
ERPs. Two s udies applied bo h neu al and emo ional de ian aces in
he oddball condi ion, inding an ampli ude modula ion only o
emo ional bu no o neu al aces p esen ed wi h low p obabili y
( ea ul aces: Rosbu g e al., 2019a, 2019b; ang y aces: Ko a ski e al.,
2017). Kimu a and he colleagues (2011) applied a design whe e
physically iden ical aces we e compa ed as s anda d and de ian
s imulus, and hey ound p obabili y- ela ed e ec s only wi h a la e
la ency (app oxima ely 280 ms a e he onse o he ea ul aces and
350 ms a e he onse o he happy aces). Simila ly, S e anics e al.
(2012) obse ed p obabili y- ela ed e ec s mainly wi hin he
150–220 ms and 250–360 ms la encies, bu he emo ional modula ion o
ERPs as ea ly as 80–120 ms a e he onse o aces ( ea ul de ian s s.
happy de ian s). Speci ically ela ed o P1, Ko a ski and colleagues
(2017) ound an inc eased ampli ude o bo h ang y de ian ace (in
compa ison o neu al s anda d in he oddball condi ion) and ang y ace
p esen ed in equal p obabili y wi h o he acial exp essions. In sum,
hese p e ious indings do no associa e P1 o MMN, which is de ined as
inc eased esponse o low-p obabili y de ian in con as o s anda d
s imulus, bu ins ead, hey sugges ha emo ional modula ion explains
di e en ial esponses wi hin P1 la ency. The e o e, we a e p one o
in e p e ou P1 inding in neu al mood mo e as an emo ional modu-
la ion han a p edic ion e o signal e lec ing de ec ion o a egula i y
iola ion in acial emo ion. Mo eo e , because P1 o sad aces did no
show simila obus di e en ial esponses agains neu al aces as he
happy aces in neu al mood, e en i he p obabili y o he sad and
happy aces was he same, i can be expec ed ha acial emo ion a he
i s p obabili y caused his ampli ude modula ion.
Ou indings ega ding P1 modula ion due o mood manipula ion
we e di e en om hose showing ERP al e a ions in dep ession pa-
ien s. In a p e ious s udy in dep ession pa ien s, he di e en ial P1
esponse o sad aces was g ea e compa ed wi h con ols, e lec ing
nega i e bias in in o ma ion p ocessing in dep ession (Ruohonen e al.,
2020). In his p e ious s udy, he P1 esponse also indica ed a dep essi e
s a e because he P1 ampli ude no malized when he pa icipan
eco e ed om dep ession. In he p esen s udy, signi ican modula ion
o P1 o sad aces was obse ed nei he in he neu al no sad mood.
Thus, i seems ha ea ly pe cep ual encoding o acial emo ions, as e-
lec ed by he P1 ampli ude, is no a ec ed simila ly by mood and
dep essi e s a e. This implies ha , i he inding o inc eased P1
ampli ude o sad aces in dep ession (Ruohonen e al., 2020) will be
epea ed in u u e s udies, P1 may ha e po en ial o be u ilized as a
bioma ke o a dep essi e s a e.
Ou s udy did no ind e idence o a mood-cong uen e ec on ERPs
(i.e., la ge ERP esponses o sad aces when he pa icipan s we e in sad
mood compa ed wi h he esponses in neu al mood), which has been a
common inding in p e ious beha io al s udies. P e ious beha io al
s udies applying mood induc ion me hods ha e epo ed a mood-
cong uen e ec in a ended ecogni ion asks o aces and wo ds
(Bouhuys e al., 1995; Chepenik e al., 2007). In he p esen s udy, he
pa icipan s we e asked o ocus on ma hema ical calcula ions while
hey passi ely iewed he aces. Fu u e s udies on ask-i ele an acial
exp ession p ocessing should in es iga e whe he a en i e p ocessing o
aces is mo e p one o mood-cong uen e ec s han non-a en i e
p ocessing.
In he p esen s udy, he mood e ec was ound nei he o N170 no
P2. Howe e , emo ional modula ion was e iden o bo h N170 and P2.
P e ious s udies ha e shown ha acial exp essions can modula e he
ampli ude o hese esponses ( o a e iew o N170, see Hinojosa e al.,
2015; o P2, see Cal o e al., 2013; I ie & Nea h-Ta a es, 2017; S e-
anics e al., 2012), and cong uen a ec i e con ex s, such as emo ional
p iming pic u es (Hie anen & As ikainen, 2013) and emo ional scenes
X. Li e al.