Content uploaded by Anton Varlamov
Author content
All content in this area was uploaded by Anton Varlamov on Oct 18, 2017
Content may be subject to copyright.
International Journal of Psychophysiology 50 (2003)205–212
0167-8760/03/$ - see front matter 䊚2003 Elsevier B.V. All rights reserved.
doi:10.1016/S0167-8760Ž03.00156-9
Trait anxiety impact on the EEG theta band power changes during
appraisal of threatening and pleasant visual stimuli
Ljubomir I. Aftanas*, Sergey V. Pavlov, Natalia V. Reva, Anton A. Varlamov
Psychophysiology Laboratory, State-Research Institute of Physiology, Siberian Branch, Russian Academy of Medical Sciences,
Timakova str. 4, 630117, Novosibirsk, Russia
Received 5 March 2003; received in revised form 1 July 2003; accepted 7 July 2003
Abstract
The main objective of the present investigation was to examine whether trait anxiety construct would influence
EEG event-related synchronization (ERS)of the theta power during viewing of visual threatening stimuli. The 62-
channel EEG was recorded while low (LA, ns18)and high (HA, ns18)trait-anxious subjects viewed sequentially
presented neutral, threatening and pleasant pictures. Between-group differences, related to stimulus emotionality, were
linked to the test period of 0–1000 ms after stimulus onset. In the low theta (4–6 Hz)at prefrontal sites HA exhibited
deficient ERS in response to both threatening and pleasant stimuli in the right hemisphere, whereas LA yielded larger
right than left hemisphere ERS in response to all the three stimulus categories. In the upper theta (6–8 Hz)group
differences were associated with posterior cortical regions: HA exhibited the largest ERS to threatening and the
lowest to pleasant stimuli, whereas LA prompted the largest ERS to pleasant and the lowest to neutral pictures. It is
suggested that low theta right prefrontal hypoactivation favoring left hemispheric (i.e. more analytical)activity along
with higher upper theta ERS of posterior cortical regions (i.e. enhanced higher order visual processing)to threatening
stimuli could form the basis for neuropsychologically observed general bias towards threatening information in HA.
䊚2003 Elsevier B.V. All rights reserved.
Keywords: EEG; Trait anxiety; Emotion; Threat; Low theta; Upper theta; Event-related synchronization; Hemispheric asymmetry
High trait anxiety is a complex phenomenon
that includes a range of distinct attentional, emo-
tional and somatic reactions as well as cognitive
efforts to conceptualize apparent cause of anxious
feelings. Studies have found among a wide array
of behavioral differences the most indicative pecu-
liarity of the high trait anxiety—a selective bias
towards threatening stimuli (e.g. McNally, 1998;
*Corresponding author. Tel.: q7-383-233-4387; fax: q7-
385-232-4254.
E-mail address: aftanas@iph.ma.nsc.ru (L.I. Aftanas).
Derryberry and Reed, 2002). Direct neurophysiol-
ogical evidences that high anxious individuals
selectively attend and deploy more processing
resources to threatening information are limited to
findings from visual ERP study of semantic prim-
ing paradigm (Weinstein, 1995)and emotional
gambling procedure (Aftanas et al., 1996).
There is increasing evidence that the analysis of
brain oscillations is a powerful tool for clarifying
cortical mechanisms of emotional processing (e.g.
Aftanas et al., 1996, 2001, 2002; Keil et al., 2001;
206 L.I. Aftanas et al. / International Journal of Psychophysiology 50 (2003) 205–212
Doppelmayr et al., 2002). Promising results were
obtained with the event-related synchronizationy
desynchronization (ERDyERS)method (Pfurt-
scheller and Lopes da Silva, 1999). Previous
studies of the ERDyERS to emotion-related stimuli
in narrow frequency bands have revealed that this
EEG quantification method can uncover the corti-
cal correlates of relatively small differences in
emotion processing (Krause et al., 2000; Aftanas
et al., 2001, 2002)and personality (Aftanas et al.,
1996, 2003). In this paper we focus mainly on
theta frequency range. Nowadays event related
theta oscillations can be considered as important
building-blocks of functional signaling in the nerv-
ous system related to cognitive and emotional
processing and cortico–hyppocampal–limbic
interaction (for review see Basar et al., 2001).A
strong theta band power increase during concen-
trated task performance (Sasaki et al., 1996),
memory operations (reviewed by Klimesch, 1999),
and affective processing (Aftanas et al., 2001,
2002; Aftanas and Golocheikine, 2001)has been
reported. In our earlier investigations we have
found good evidence that phasic increase in narrow
theta band of approximately 4–6 Hz reliably
reflects early discrimination (in the time window
of approximately 200–500 ms after stimulus
onset)of emotionally salient (both positive and
negative)and neutral stimuli (Aftanas et al., 2001,
2002, 2003). Higher theta ERS for emotional than
for neutral stimuli was also observed in a study
from another research group (Doppelmayr et al.,
2002). Effect of the early theta synchronization
may theoretically be related to motivated attention.
If so, early theta synchronization may be advocated
for investigating cortical concomitants of trait
anxiety.
The main objective of the present investigation
was to examine whether trait anxiety would influ-
ence early (up to 1000 ms after stimulus onset)
theta synchronization during viewing of visual
threatening stimuli. The first prediction deals with
our EEG findings on association of lateralized
frontal theta synchronization with stimulus emo-
tionality (Aftanas et al., 2001, 2002)as well as
data on trait anxiety impact on frontal activation
asymmetries (Carter et al., 1986; Heller et al.,
1997; Nitschke et al., 1999). The prediction was
that emotion-related frontal theta activation asym-
metries may be influenced by the trait anxiety
construct. This suggestion was partly supported by
recently revealed disruptive impact of alexithymia
(another personality trait, marked by deficient
emotional processing)on the early frontal theta
synchronization (Aftanas et al., 2003). The second
prediction is related to the highest sensitivity of
parieto-temporo-occipital theta synchronization to
visual stimulus emotionality (Aftanas et al., 2001,
2002, 2003). It was hypothesized that high anxiety
individuals would show larger differences between
their responses to threatening and neutral stimuli
over these regions.
A total of 215 Novosibirsk State University
students between the age of 18 and 26 years were
prescreened with the Spielberger State-Trait Anxi-
ety (STAI)inventory (Spielberger et al., 1983;
Hanin, 1989). Subjects with score above and
below the median (STAI-ts43)were selected to
represent high and low anxiety groups. The final
sample included 18 low anxious (13 malesy5
females)and 18 high-anxious (11 malesy7
females)right-handed subjects. Actual means for
1
the two groups were 36.17 (S.D.s5.01)and 52.67
(S.D.s5.78), respectively. All the Ss were right-
handed. The full details of the method were
described earlier (Aftanas et al., 2002). Shortly,
each subject viewed sequentially presented pictures
from the International Affective Picture System
(IAPS, Center for the Study of Emotion and
Attention, 1999). Only neutral, high arousal pleas-
ant and threatening stimuli were used for analysis
(8 stimuli per category, 2 presentations). As in the
Houtveen et al.’s study of anxiety (2001), the
neutral stimuli showed various kinds of emotion-
ally neutral objects (e.g. household utensils),
whereas the threatening pictures showed mutilated
people and body parts as well as crying faces. One
half of the pleasant pictures showed heterosexual
couples engaged in sexual activity, another one—
playing pets. The 62-channel EEG (bandpass
2
The ‘final sample’ assumes also that 10 participants were
1
dropped out by neurophysiological reasons (see below).
The following pictures formed 3 categories of interest:
2
neutral—7002, 7004, 7006, 7009, 7010, 7020, 7150, 7175;
threatening—2800, 3080, 3150, 3170, 3261, 9040, 9405, 9410;
pleasant—1440, 1460, 1722, 1920, 4658, 4659, 4660, 4669.
207L.I. Aftanas et al. / International Journal of Psychophysiology 50 (2003) 205–212
0.3–50 Hz, -6-dB gain, G-12-dByoctave slope)
was recorded using 128-channel ESI system (ESI-
128, NeuroScan Labs.)and Scan 4.1.1 software.
Each stimulus was presented for 6 s with a random
interstimulus interval. After the picture offset, three
affective dimensions of pleasure, arousal and dom-
inance (in a 9-point scale for each dimension)
were assessed using computerized Self-Assessment
Manikin (SAM)scales. Only artefact free trials
(EOG-corrected and visually inspected)were
retained for analyses. According to the ERDyERS
method (Pfurtscheller and Lopes da Silva, 1999),
changes in band power were defined as the per-
centage of a decrease (ERD)or increase (ERS)in
band power during the test interval (6000 ms after
stimulus onset)as compared to the reference inter-
val (y3000 to y1000 ms before picture onset).
For each subject ERDyERS was calculated within
theta-1 (4–6 Hz)and theta-2 (6-8 Hz)frequency
bands and averaged according to emotional
categories.
As in our previous works (Aftanas et al., 2001,
2002), electrodes were collapsed into 12 clusters.
This procedure resulted in 6 regional means for
each hemisphere: anterior temporal—AT (AF7,
F7yAF8, F8), frontal—F (AF3, F3, F5yAF4, F4,
F6), central—C (FC3, FC5, C3, C5, CP3, CP5y
FC4, FC6, C4, C6, CP4, CP6), parietotemporal—
PT (P5, P7yP6, P8), parietal—P (P3yP4), and
occipital—O (PO3, PO5, PO7, O1yPO4, PO6,
PO8, O2). The average ERDyERS values across
the respective electrode sites were calculated for
these regional means for each time interval of 100
ms and each valence category.
The statistical analysis of self-report valence
scores revealed highly significant effect of valence
(Fs286.56, P-0.001). For pleasant pictures,
2, 68
()
overall SAM-ratings were significantly higher
(Ms7.17)as compared to neutral (Ms5.32)and
threatening (Ms2.14)pictures. In turn, valence
ratings for neutral stimuli were significantly higher
as compared to threatening pictures. The stimulus
categories varied robustly in arousal level
(Fs48.48, P-0.001)which was rated sig-
2, 68
()
nificantly higher for both pleasant (Ms4.32)and
threatening (Ms5.11)as compared to neutral
(Ms2.80)pictures (all post hocs at P-0.01).
Neither the main effect of group for valence
wFs0.08, P-0.78xand arousal wFs2.55,
1,34 1,34
() ()
P-0.12xratings nor the interaction between group
and emotional category for these dependent meas-
ures wFs1.06, P-0.33xand wFs1.46,
2,68 2,68
() ()
P-0.24x, respectively)reached significance.
First we checked for putative preexisting group
differences in the mean power (mV)of the
2
reference interval (y3000 to y1000 ms before
picture onset). There were no statistically signifi-
cant differences between the two experimental
groups in both frequency bands (for rationale see
e.g. Klimesch et al., 2001).
According to preliminary analyses of ERS meas-
ures, group differences were associated only with
the first 1000 ms out of total 6000 ms of the test
interval. For each frequency band the 5-way ANO-
VAs with the factors of Group (GR 2: low anxiety,
high anxiety), Valence (VAL 3: neutral, threaten-
ing and pleasant), Hemisphere (HEM 2: left and
right hemisphere), Location (LOC 6: AT, F, C, PT,
P, O), and Time (TIME 10: 100, 200, 300, 400,
500, 600, 700, 800, 900 and 1000 ms after stimulus
onset)were computed with repeated measurements
on the last four factors. Since very selective effects
may not be detected by complex ANOVAs, effects
related to group, stimulus emotionality and hemi-
sphere were calculated for separate symmetrical
regions (e.g. Tomarken and Davidson, 1994)using
4-way wGR(2)=VAL (3)=HEM(2)=TIME(10)x
ANOVAs. Significant interactions were examined
through simple effects to locate the source of the
interaction. Our apriori hypotheses focused on
theta-ERS measures over lateral anterior (AT)and
posterior (PT, P, O)regions (Aftanas et al., 2001,
2002)and predicted group differences involving
emotional content and hemispheres at these
regions. For all analyses degrees of freedom were
Greenhouse–Geisser corrected where appropriate.
Replicating our previous findings in the low
(4–6 Hz)theta band the valence main effect
wFs3.48, P-0.041xalong with the
2,68
()
VAL =LOC wFs5.64, P-0.001xand
10,340
()
VAL =HEM=LOC wFs2.83, P-0.035x
10,340
()
interactions indicate that over posterior cortical
regions (PT,P,O)all affective pictures induced
larger amount of theta ERS than neutral stimuli
with greater impact on the right hemisphere (Fig.
1). As these effects have been reported and dis-
208 L.I. Aftanas et al. / International Journal of Psychophysiology 50 (2003) 205–212
Fig. 1. Topographical distribution of the theta-1 ERS in the
right (R)and left (L)hemispheres induced by neutral, threat-
ening and pleasant stimuli in the time window of 0–1000 ms
(averaged for both groups).
Fig. 2. Topographical distribution of the theta-1 ERS in the
right (R)and left (L)hemispheres in low and high anxiety
individuals for all the stimulus categories in the time window
of 0–1000 ms.
Fig. 3. Time course of theta-1 ERS changes in the right (R)
and left (L)hemispheres of the AT region induced by neutral,
threatening and pleasant stimuli in the time window of 0–1000
ms after stimulus onset in low and high anxiety individuals.
cussed earlier (Aftanas et al., 2001, 2002),no
further description will be given. A GR main
effect wFs4.37, P-0.044x, implicated in
1, 34
()
GR=HEM=LOC interaction wFs5.34, P-
5, 170
()
0.002xspecified that between group differences
are related to anterior cortical sites and hemi-
spheres (Fig. 2). The overall larger right than left
hemisphere ERS for LA was supported by signif-
icant within group main effect of HEM wFs
1, 17
()
19.66, P-0.001x. By contrast, as indexed by
HEM=LOC interaction wFs16.74, P-
5,85
()
0.001x, HA individuals manifested higher right
than left hemisphere ERS in posterior (PT, P, O)
regions wall FG16.30, all PF0.001xand no
1,17
()
asymmetries in anterior (AT, F and C)regions wall
FF3.48, all PG0.079x. Simple effects
1,17
()
revealed that group differences were significant
only for right hemisphere at AT, F, and C regions
wall FG5.65, all PF0.023xindicating right
1,34
()
hemisphere hyposynchronization in HA individu-
als. The 4-way ANOVAs
wGR(2)=VAL (3)=HEM(2)=TIME(10)xfor
symmetrical regions specified further that AT
region was the only one associated with group
differences, hemisphere and stimulus emotionality.
This is indexed by GR=VAL =HEM=TIME
interaction wFs2.39, P-0.048x, presented
18,612
()
in the Fig. 3. As can be seen from this figure, LA
individuals exhibit larger right than left hemisphere
ERS in response to all the stimulus categories
209L.I. Aftanas et al. / International Journal of Psychophysiology 50 (2003) 205–212
Fig. 4. Topographical distribution of the theta-2 ERS induced
by neutral, threatening and pleasant stimuli in low and high
anxiety individuals in the time window of 0–1000 ms.
wHEM: Fs6.65, P-0.019x, whereas HA sub-
1,17
()
jects evidence no asymmetries wHEM: Fs
1,17
()
1.74, P-0.20x. Simple ANOVAs by categories
specify that there were no associations with the
group factor for the neutral stimuli. By contrast,
according to the interaction GR=HEM=TIME
wFs2.76, P-0.021xfor threatening and
9,306
()
GR=HEM wFs5.19, P-0.029xfor pleasant
1,34
()
stimuli, HA vs. LA individuals exhibit decreased
right hemisphere synchronization with a tendency
of relatively larger left than right hemisphere
synchronization. For threatening stimuli this
decrease is time dependent and is restricted to
100–600 ms after stimulus onset wall FG5.68,
1,34
()
all PF0.023x.
In the upper (6–8 Hz)theta the performed 5-
way ANOVA yielded GR=VAL wFs5.98,
2,68
()
P-0.004xand GR=VAL =LOC wFs3.98,
10,340
()
P-0.008xinteractions, indicating that between
group differences are associated with posterior
cortical regions and depend on stimulus emotion-
ality (Fig. 4). As indexed by simple ANOVAs for
PT, P, and O regions, HA individuals yield signif-
icantly larger ERS to threatening than to pleasant
pictures wall FG7.60, all PF0.013x, whereas
1,17
()
ERS values to neutral stimuli were close to these
prompted by threatening pictures. By contrast, LA
participants yielded larger ERS to pleasant than to
neutral pictures wall FG8.06, all PF0.011x,
1,17
()
and no differences between neutral and threatening
stimuli. Another important feature is that at
between-group level in the PT region LA vs. HA
individuals show larger ERS in response to pleas-
ant stimuli wFs5.26, P-0.028x.
1,34
()
No differences were found for both the valence
and arousal factors between participants classified
as low and high anxiety in their self-reported
emotional ratings to emotional pictures. This find-
ing is consistent with the literature showing that
subjects with high trait anxiety may have accurate
judgements of simple affect-laden external visual
stimuli (e.g. Houtveen et al., 2001).
In the low theta band group differences emerged
at prefrontal sites in the early test period of 0–
1000 ms. The most striking feature of this pattern
was larger right than left hemisphere synchroni-
zation to all the three stimulus categories in low
anxiety group. By contrast, high anxiety partici-
pants to both threatening and pleasant stimuli
showed asymmetry in favor of the left hemisphere
due to deficient synchronization in the right hem-
isphere. Considering that in the time period of 0–
700 ms theta power increase reflects orienting,
selective attention, stimulus decoding and memory
processes (Basar et al., 2001), emerging time-
dependent between-group differences over anterior
cortical leads may index differences in individual
strategies, associated with hemispheric specializa-
tion for information processing and attention. Ten-
dency of low anxiety individuals to orient to novel
stimuli with global perceptual right-hemisphere
strategy is less apparent in high anxiety partici-
pants, who seem to rely more on left hemisphere
processing mode which is more restricted, analytic
and focused (e.g. Tucker et al., 1978; Tyler and
Tucker, 1982). Seemingly paradoxical left hemi-
sphere (i.e. more analytical)bias to pleasant stim-
uli in our investigation may also be in line with
experimental psychology data suggesting that high
anxiety persons are motivated to attend not only
to threatening information, but also to sources of
safety helping to cope with threat (Derryberry and
Reed, 2002). We are also congruent with pilot
fMRI studies (Canli et al., 1998, 2001; Berthoz et
al., 2002)showing that limbic structures (including
cingulate and amygdala), which are associated
with the generation of frontal theta activity (for
review see Basar et al., 2001; Asada et al., 1999)
exhibit considerable variance in their responsive-
210 L.I. Aftanas et al. / International Journal of Psychophysiology 50 (2003) 205–212
ness to emotionally positive or negative stimuli
across participants. This variance is related to
personality factors of neuroticism (Canli et al.,
1998, 2001)and alexithymia (Berthoz et al., 2002;
Aftanas et al., 2003), which positively correlate
with trait anxiety. It seems also likely that anxiety-
dependent prefrontal low theta reflects activity of
the ‘anterior attentional system’ (Posner and Peter-
sen, 1990; Posner and Rothbart, 1998). This sys-
tem is located within frontal regions (anterior
cingulate cortex)that are interconnected with lim-
bic and frontal motivational systems. It is viewed
as an executive system that carries out more
voluntary attentional functions and is suggestively
involved in mediating coping strategies in anxiety
(Derryberry and Reed, 2002). The left hemisphere
bias found here for high anxiety group corresponds
to EEG studies, reporting greater frontal left than
right hemisphere activity (Carter et al., 1986;
Heller et al., 1997)in high anxiety participants
classified on the basis of worry or anxious appre-
hension. Our findings are also congruent with
recent PET study of induced anticipatory anxiety,
which represents a complex combination of future-
oriented cognitive state and negative affect, attrib-
utable to anxious apprehension, and involves
relatively increased activity in the left orbitofrontal
cortex, left insula and left anterior cingulate cortex
(Chua et al., 1999). Finally, as well as in Heller
et al.’s EEG study of anxiety (1997), our frontal
data support the suggestion that the magnitude of
the asymmetry favoring the left hemisphere rather
than the level of left-hemisphere activity in isola-
tion is inherent for anxious apprehension.
In the upper theta band the two groups of
subjects display different activation patterns over
posterior cortical regions. Low anxiety individuals
yielded the largest synchronization to pleasant
pictures whereas high anxiety participants exhib-
ited significantly larger synchronization to threat-
ening than to pleasant pictures. We speculate that
enhanced by threatening pictures upper theta syn-
chronization in parieto-occipito-temporal cortex,
mediating memory and imagery processes (see,
e.g. Crawford et al., 1996; Keil et al., 2001),may
be a correlate of longer lasting, higher order visual
processing, in which sustained attention is allocat-
ed to motivationally relevant stimuli. In turn,
elevated synchronization to neutral stimuli in high
anxiety subjects may suggest that these individuals
perceived them as emotionally ambiguous and may
have prompted efforts to imbue them with emo-
tional significance. In view of the trait anxiety
construct overall, the largest upper theta synchro-
nization to pleasant stimuli in low anxiety group
may be attributed to proneness of these individuals
for greater reward sensitivity and positive affect,
whereas the largest synchronization to threatening
cues in high anxiety individuals may be due to
their proneness for enhanced punishment sensitiv-
ity and negative affect (Gray, 1991; McFatter,
1994; Zelenski and Larsen, 1999).
The obtained findings point to disregulation of
theta neural oscillating networks at early phases of
emotional processing in high trait anxiety. When
bringing together both theta bands, changes in
theta activity may be related to working memory
(Klimesch, 1999)and to suggestion that emotion-
related theta synchronization reflects more exten-
sive working memory processing (Aftanas et al.,
2002). Based on research showing that working
memory utilizes the posterior association cortex,
involved in the storage of sensory information,
and the pre-frontal cortex which updates the infor-
mation (e.g. Gevins et al., 1997; Klimesch, 1999;
Grunwald et al., 2001), revealed peculiarities of
theta synchronization in high anxiety individuals
may point to disregulation of normal processing
within the working memory system, claimed by a
current theory of anxiety effects in cognition (Hop-
ko et al., 1998).
Getting back to our predictions we may con-
clude that they are conceptually supported.
Revealed in the low theta right prefrontal hypoac-
tivation favoring left hemisphere (i.e. more ana-
lytical)activity along with higher theta power
increase of posterior cortical regions (i.e. enhanced
higher order visual processing)to threatening visu-
al stimuli could form the basis for neuropsychol-
ogically observed general bias towards threatening
information in high anxiety individuals (see, e.g.
McNally, 1998; Derryberry and Reed, 2002). The
expected group differences could be more pro-
nounced if participants experienced real (i.e. per-
sonally oriented)threat to the self instead of
looking at the emotional pictures (i.e. symbolized
211L.I. Aftanas et al. / International Journal of Psychophysiology 50 (2003) 205–212
threat). Another issue of the data is that in future
investigations of anxiety more attention should be
directed to processing peculiarities of positive
emotional material (for short review see Derryber-
ry and Reed, 2002).
The findings in the low and upper theta dem-
onstrate also that the use of broad frequency band
of approximately 4–8 Hz would mask potentially
interesting results. We suggest that there may exist
some dynamical relationship between low and
upper theta neuronal networks during emotional
appraisal. It is highly indicative that functional
heterogeneity of these frequency bands was also
reported in other studies of emotional (Aftanas et
al., 2003)and cognitive (Klimesch et al., 2001)
activity. This special question needs further
exploration.
Overall we may assume that ‘the selectively
distributed integrative theta system’ (Basar et al.,
2001)can be regarded as an important component
of evaluative brain systems, which is related to
emotional appraisal and features individual differ-
ences in affective processing at its early phases.
References
Aftanas, L.I., Koshkarov, V.I., Pokrovskaja, V.L., Lotova, N.V.,
1996. Pre- and post-stimulus processes in affective task and
event-related desynchronization (ERD): do they discrimi-
nate anxiety coping styles. Int. J. Psychophysiol. 24,
197–212.
Aftanas, L.I., Golocheikine, S.A., 2001. Human anterior and
frontal midline theta and lower alpha reflect emotionally
positive states and internalized attention: high-resolution
EEG investigation of meditation. Neurosci. Lett. 310, 57–60.
Aftanas, L.I., Varlamov, A.A., Pavlov, S.V., Makhnev, V.P.,
2001. Event-related synchronization and desynchronization
during affective processing: emergence of valence-related
time-dependent hemispheric asymmetries in theta and upper
alpha band. Int. J. Neurosci. 110, 197–219.
Aftanas, L.I., Varlamov, A.A., Pavlov, S.V., Makhnev, V.P.,
Reva, N.V., 2002. Time-dependent cortical asymmetries
induced by emotional arousal: EEG analysis of event-related
synchronization and desynchronization in individually
defined frequency bands. Int. J. Psychophysiol. 44 (1),
67–82.
Aftanas, L.I., Varlamov, A.A., Reva, N.V., Pavlov, S.V., 2003.
Disruption of early event-related theta synchronization of
human EEG in alexithymics viewing affective pictures.
Neurosci. Lett. 340, 57–60.
Asada, H., Fukuda, Y., Tsunoda, S., Yamaguchi, M., Tonoike,
M., 1999. Frontal midline theta rhythms reflect alternative
activation of prefrontal cortex and anterior cingulate cortex
in humans. Neurosci Lett. 274, 29–32.
Basar, E., Schurmann, M., Sakowitz, O., 2001. The selectively
distributed theta system: functions. Int. J. Psychophysiol.
39, 197–212.
Berthoz, S., Artiges, E., Van De Moortele, P.F., Poline, J.B.,
Rouquette, S., Consoli, S.M., et al., 2002. Effect of impaired
recognition and expression of emotions on frontocingulate
cortices: an fMRI study of men with alexithymia. Am. J.
Psychiatry 159, 961–967.
Canli, T., Desmond, J.E., Zhao, Z., Glover, G., Gabrieli, J.D.,
1998. Hemispheric asymmetry for emotional stimuli detect-
ed with fMRI. Neuroreport 9 (14), 3233–3239.
Canli, T., Zhao, Z., Desmond, J.E., Kang, E., Gross, J.,
Gabrieli, J.D., 2001. An fMRI study of personality influenc-
es on brain reactivity to emotional stimuli. Behav. Neurosci.
115 (1), 33–42.
Carter, W.R., Johnson, M.C., Borkovec, T.D., 1986. Worry: an
electrocortical analysis. Adv. Behav. Res. Therapy 8,
193–204.
Center, for the Study of Emotion and Attention wCSEA-
NIMHx.(1999), The international affective picture system:
digitized photographs.Gainesville, FL: The Center for
Research in Psychophysiology, University of Florida.
Chua, P., Krams, M., Toni, I., Passingham, R., Dolan, R.,
1999. A functional anatomy of anticipatory anxiety. Neu-
roimage 9 (6 Pt 1), 563–571.
Crawford, H.J., Clarke, S.W., Kitner-Triolo, M., 1996. Self-
generated happy and sad emotions in low an highly hyp-
notizable persons during waking and hypnosis: laterality
and regional EEG activity differences. Int. J. Psychophysiol.
24, 239–266.
Derryberry, D., Reed, M.A., 2002. Anxiety-related attentional
biases and their regulation by attentional control. J. Abnorm.
Psychol. 111 (2), 225–236.
Doppelmayr, M., Stadler, W., Sauseng, P, Rachbauer, D.
Klimesch, W. (2002), Gender-related differences in theta
bandpower changes of the EEG during the presentation of
erotic and child related stimuli. In the: 12th Annual Confer-
ence Emotions and the Brain; Toronto, Canada 25.3.–26.3.
(Abstract).
Hanin, Y.u L., 1989. Cross-cultural perspectives in the assess-
ment of individual differences: methodological and concep-
tual issues. Voprosy Psichologii (Rus.)4, 118–125.
Heller, W., Nitschke, J.B., Etienne, M.A., Miller, G.A., 1997.
Patterns of regional brain activity differentiate types of
anxiety. J. Abn. Psychol. 106, 376–385.
Hopko, D.R., Ashcraft, M.H., Gute, J., Ruggiero, K.J., Lewis,
C., 1998. Mathematics anxiety and working memory: sup-
port for the existence of a deficient inhibition mechanism.
J. Anxiety Disord. 12 (4), 343–355.
Houtveen, J.H., Rietveld, S., Schoutrop, M., Spiering, M.,
Brosschot, J.F., 2001. A repressive coping style and affec-
tive, facial and physiological responses to looking at emo-
tional pictures. Int. J. Psychophysiol. 42, 265–277.
Gevins, A., Smith, M.E., McEvoy, L., Yu, D., 1997. High-
resolution EEG mapping of cortical activation related to
212 L.I. Aftanas et al. / International Journal of Psychophysiology 50 (2003) 205–212
working memory:effects of task difficulty, type of process-
ing, and practice. Cereb. Cortex. 7, 374–385.
Gray, J.A., 1991. Neural systems, emotion, and personality.
In: Madden, J. (Ed.), Neurobiology of Learning, Emotion,
and Affect. Raven Press, New York, pp. 273–306.
Grunwald, M., Weiss, T., Krause, W., Beyer, L., Rost, R.,
Gutberlet, I., et al., 2001. Theta power in the EEG of
humans during ongoing processing in a haptic object rec-
ognition task. Brain Res.Cogn. Brain Res. 11, 33–37.
Keil, A., Muller, M.M., Gruber, T., Wienbruch, C., Stolarova,
M., Elbert, T., 2001. Effects of emotional arousal in the
cerebral hemispheres: a study of oscillatory brain activity
and event-related potentials. Clin. Neurophysiol. 112 (11),
2057–2068.
Klimesch, W., 1999. EEG alpha and theta oscillations reflect
cognitive and memory performance: a review and analysis.
Brain Res. Brain Res. Rev. 29, 169–195.
Klimesch, W., Doppelmayr, M., Wimmer, H., Schwaiger, J.,
Rohm, D., Gruber, W., et al., 2001. Theta band power
changes in normal and dyslexic children. Clin. Neurophy-
siol. 112, 1174–1185.
Krause, C.M., Viemero, V., Rosenqvist, A., Sillanmaki, L.,
Astrom, T., 2000. Relative electroencephalographic desyn-
chronization and synchronization in humans to emotional
film content: an analysis of the 4–6, 6–8, 8–10 and 10–12
Hz frequency bands. Neurosci. Lett. 286, 9–12.
McFatter, R.M., 1994. Interactions in predicting mood from
extraversion and neuroticism. J. Pers. Soc. Psychol. 66 (3),
570–578.
McNally, R.J., 1998. Information-processing abnormalities in
anxiety disorders: implications for cognitive neuroscience.
Cognit. Emot. 12, 479–495.
Nitschke, J.B., Heller, W., Palmieri, P.A., Miller, G.A., 1999.
Contrasting patterns of brain activity in anxious apprehen-
sion and anxious arousal. Psychophysiology 36, 628–637.
Pfurtscheller, G., Lopes da Silva, F.H., 1999. Event-related
EEGyEMG synchronization and desynchronization. Basic
principles. Clin. Neurophysiol. 110, 1842–1857.
Posner, M.I., Petersen, S.E., 1990. The attention system of the
human brain. Ann. Rev. Neurosci. 13, 25–42.
Posner, M.I., Rothbart, M.K., 1998. Attention, self-regulation
and consciousness. Philos. Trans. Royal Soc. Lond. B. 353,
1915–1927.
Sasaki, K., Nambu, A., Tsujimoto, T., Matsuzaki, R., Kyuhou,
S., Gemba, H., 1996. Studies on integrative functions of the
human frontal association cortex with MEG. Brain Res.
Cogn. Brain Res. 5, 165–174.
Spielberger, C.D., Gorsuch., R.L., Lushene, R., Vagg, P.R.,
Jacobs, G.A., 1983. Manual for the state-trait anxiety inven-
tory. Consulting Psychologists Press, Palo Alto, CA.
Tomarken, A.J., Davidson, R.J., 1994. Frontal brain activation
in repressors and non-repressors. J. Abn. Psychol. 103,
339–349.
Tucker, D.M., Antes, J.R., Stenslie, C.E., Branhardt, T.M.,
1978. Anxiety and lateral cerebral function. J. Abnorm.
Psychol. 87, 380–383.
Tyler, K., Tucker, D.M., 1982. Anxiety and perceptual struc-
ture: individual differences in neuropsychological function.
J. Abnorm. Psychol. 91, 210–220.
Weinstein, A.M., 1995. Visual ERPs evidence for enhanced
processing of threatening information in anxious university
students. Biol. Psychiat. 37 (12), 847–858.
Zelenski, J.M., Larsen, R.J., 1999. Susceptibility to affect: a
comparison of three personality taxonomies. J. Pers. 67 (5),
761–791.
