Dissociating Cognitive From Affective Theory of Mind a TMS Study

Embed Size (px)

Citation preview

  • 8/21/2019 Dissociating Cognitive From Affective Theory of Mind a TMS Study

    1/12

    Research report 

    Dissociating cognitive from affective theory of mind:

    A TMS study

    Elke Kalbea,b,*, Marius Schlegelb, Alexander T. Sackc, Dennis A. Nowaka,Manuel Dafotakisa,b, Christopher Bangardd, Matthias Brande, f ,Simone Shamay-Tsooryg, Oezguer A. Onura,b and Josef Kesslerb

    aInstitute of Neuroscience and Medicine (INM-3), Cognitive Neurology Section, Research Centre Juelich, GermanybDepartment of Neurology, University Hospital of Cologne, GermanycDepartment of Cognitive Neuroscience, Faculty of Psychology, Maastricht University, The NetherlandsdDepartment of Radiology, University Hospital of Cologne, GermanyeDepartment of General Psychology, Cognition, University of Duisburg-Essen, Germanyf Erwin L. Hahn Institute for Magnetic Resonance Imaging, Essen, Germanyg Department of Psychology and Brain and Behavior Center, University of Haifa, Israel

    a r t i c l e i n f o

    Article history:

    Received 5 September 2008

    Reviewed 9 December 2008Revised 6 April 2009

    Accepted 9 July 2009

    Action editor Elena Rusconi

    Published online 29 July 2009

    Keywords:

    Theory of Mind

    Transcranial magnetic stimulation

    Dorsolateral prefrontal cortex

    5 cm rule

    a b s t r a c t

    Introduction: ‘‘Theory of Mind’’ (ToM), i.e., the ability to infer other persons’ mental states, is

    a key function of social cognition. It is increasingly recognized to form a multidimensional

    construct. One differentiation that has been proposed is that between cognitive andaffective ToM, whose neural correlates remain to be identified. We aimed to ascertain the

    possible role of the right dorsolateral prefrontal cortex (DLPFC) for cognitive ToM as

    opposed to affective ToM processes.

    Methods:  1 Hz repetitive transcranial magnetic stimulation (rTMS) was used to interfere

    offline with cortical function of the right DLPFC in healthy male subjects who subsequently

    had to perform a computerized task assessing cognitive and affective ToM.

    Results: RTMS over the right DLPFC induced a selective effect on cognitive but not affective

    ToM. More specifically, a significant acceleration of reaction times in cognitive ToM

    compared to affective ToM and control items was observed in the experimental (right

    DLPFC) compared to the control (vertex) rTMS stimulation condition.

    Conclusions:  Our findings provide evidence for the functional independence of cognitive

    from affective ToM. Furthermore, they point to an important role of the right DLPFC within

    neural networks mediating cognitive ToM. Possible underlying mechanisms of the accel-eration of cognitive ToM processing under rTMS are discussed.

    ª 2009 Elsevier Srl. All rights reserved.

    *   Corresponding author. Institute of Neuroscience and Medicine (INM-3), Cognitive Neurology Section, Research Center Ju ¨ lich,Leo-Brandt-Str. 5, D-52425 Juelich, Germany.

    E-mail address: [email protected] (E. Kalbe).

    a v a i l a b l e a t w w w . s c i e n c e d i r e c t . c o m

    j o u r n a l h o m e p a g e :   w w w . e l s e v i er . c o m / l o c a t e / c o r t ex

    0010-9452/$ – see front matter  ª 2009 Elsevier Srl. All rights reserved.

    doi:10.1016/j.cortex.2009.07.010

    c o r t e x 4 6 ( 2 0 1 0 ) 7 6 9 – 7 8 0

    mailto:[email protected]://www.elsevier.com/locate/cortexhttp://www.elsevier.com/locate/cortexmailto:[email protected]

  • 8/21/2019 Dissociating Cognitive From Affective Theory of Mind a TMS Study

    2/12

    1. Introduction

    Theory of mind (ToM) is defined as the ability to attribute

    mental states, such as desires, intentions and beliefs, to other

    people in order to explain and predict their behavior (Frith and

    Frith, 1999). It constitutes a central aspect of social cognition

    which is regarded to be a highly specialized, human-specificskill that forms a crucial prerequisite to function in social

    groups (Adolphs, 2003a, 2003c; Herrmann et al., 2007). ToM is

    commonly regarded to be mediated by a complex neural

    network including the medial prefrontal cortex (mPFC), the

    superior temporal sulcus region, the temporal pole (Frith and

    Frith, 2003; Siegal and Varley, 2002), and the amygdalae

    (Adolphs, 2003b). Many lesion studies (e.g.,   Eslinger et al.,

    2007; Griffin et al., 2006; Happé et al., 1999; Siegal et al., 1996;

    Stuss et al., 2001; Winner et al., 1998) and functional imaging 

    studies (e.g., Brunet et al., 2000; Gallagher et al., 2000; Sommer

    et al., 2007; Vogeley et al., 2001) suggest that ToM and other

    social cognitive functions are mediated predominantly by

    a network lateralized to the right hemisphere, althoughevidence for bilateral (e.g., Vo ¨ llm et al., 2006;Hynes et al., 2006)

    and left-sided involvement also exists (e.g.,   Baron-Cohen

    et al., 1999; Calarge et al., 2003; Channon and Crawford, 2000;

    Fletcher et al., 1995; Goel et al., 1995), probably depending on

    task type and modality (Kobayashi et al., 2007).

    Recent social cognitive neuroscience has begun to define

    subcomponents of the complex concept we refer to as ToM.

    One important differentiation is that of ‘affective’ versus

    ‘cognitive’ ToM, although different terms have been used for

    these and related concepts (overview in  Baron-Cohen and

    Wheelwright, 2004; Kalbe et al., 2007). Whereas cognitive ToM,

    for example assessed with so-called false belief tasks, is

    thought to require cognitive understanding of the differencebetween the speaker’s knowledge and that of the listener

    (knowledge about beliefs), affective ToM, for example tested

    with faux pas and irony tasks, is supposed to require in

    addition an empathic appreciation of the listener’s emotional

    state (knowledge about emotions) (Shamay-Tsoory et al.,

    2006).  Brothers (1995, 1997)  had postulated a unitary social

    ‘editor’ which is specialized for processing others’

    social intentions but which could not be dissociated into ‘hot’

    social cognition (i.e., processing others’ emotional expres-

    sions) and ‘cold’ social cognition (i.e., attributing and pro-

    cessing cognitive mental states such as beliefs). However,

    Eslinger et al. (1996) reported a dissociation between affective

    and cognitive aspects of ‘empathy’ in brain damaged patients.Furthermore, Blair (2005) and Blair and Cipolotti (2000) argued

    that divergent results concerning ToM dysfunctions in socio-

    pathy may be attributed to a selective deterioration of affec-

    tive social cognition (‘emotional empathy’), while individuals

    with autism show more difficulties with cognitive than with

    emotional empathy. Recently, Shamay-Tsoory and colleagues

    found selective deficits of affective as opposed to cognitive

    ToM in various patients groups (Shamay-Tsoory and Aharon-

    Peretz, 2007; Shamay-Tsoory et al., 2006, 2005).

    Already Eslinger (1998) suggested that different regions in

    the prefrontal cortex may be relevant for these distinct func-

    tions, with a dorsolateral prefrontal cortex (DLPFC) system

    mediating cognitive empathy and the orbitofrontal cortex

    mediating affective empathy.   Shamay-Tsoory et al. (2005)

    confirmed the special role of the ventromedial prefrontal

    cortex (VMPFC) in processing affective ToM and argued that

    cognitive ToM may rather involve both the VMPFC and dorsal

    parts of the prefrontal cortex (Shamay-Tsoory and Aharon-

    Peretz, 2007). Further confirmation for partially differential

    mechanisms in processing affective and cognitive ToM was

    recently provided by functional magnetic resonance imaging (fMRI) studies (Hynes et al., 2006). These studies underline the

    particular role of medial and orbital PFC for affective

    perspective taking and show involvement of dorsolateral

    prefrontal structures for cognitive ToM. Kobayashi et al. (2007)

    and Sommer et al. (2007) found involvement especially of the

    right-hemispheric DLPFC in false belief tasks (which can be

    categorized as cognitive ToM tasks).

    In summary, research so far (a) suggests a distinction

    betweenaffectiveand cognitive ToM functions and (b) point to

    at least partly different neural correlates mediating these two

    subcomponents. However, while the role of the VMPFC for

    affective ToM is well documented, neural substrates of 

    cognitive ToM are less well defined but may include theDLPFC.

    On the basis of the aforementioned considerations, we

    aimed to further examine the dissociation of cognitive and

    affective ToM processes. We tried to elucidate neural

    correlates of cognitive as opposed to affective ToM and,

    more specifically, to investigate the functional relevance of 

    the DLPFC for cognitive ToM performance. For this purpose,

    we applied 1-Hz repetitive transcranial magnetic stimula-

    tion (rTMS) to the DLPFC of 28 male right-handed healthy

    subjects prior to the performance of a computer-based ToM

    task that has previously been used to differentially assess

    cognitive versus affective ToM (Shamay-Tsoory and

    Aharon-Peretz, 2007). Although functional imaging studieshave shown somewhat contradictory results regarding lat-

    erality of ToM functions (see above) we decided to perform

    rTMS over the right DLPFC for the following reasons: (i) We

    used the ‘‘Yoni’’ paradigm introduced by   Shamay-Tsoory

    and Aharon-Peretz (2007)   in which ToM has to be inferred

    on the basis of eye gaze and facial expression. According to

    Sabbagh (2004), a right-hemispheric mechanism mediates

    the decoding of mental states based on immediate infor-

    mation, such as eye expression, while a left-hemispheric

    network is responsible for complex reasoning about mental

    states. It can be speculated that the right-hemispheric

    decoding system is utilized when performing the Yoni task

    (Shamay-Tsoory and Aharon-Peretz, 2007).   (ii) Executivefunctions have been conceptualized as a ‘‘co-opted’’ system

    for ToM processing (Siegal and Varley, 2002), and recent

    functional imaging research points to the central role of the

    right DLPFC in executive working memory operations and

    cognitive control functions (Lie et al., 2006).

    TMS is a well-established tool for inducing transient

    changes in brain activity non-invasively in conscious human

    volunteers. Over the past couple of years, this ability of 

    actively interfering with neural processing during behavioral

    performance has been increasingly used for the investigation

    of causal brain-behavior relations in higher cognitive func-

    tions (Pascual-Leone et al., 2000; Sack and Linden, 2003). RTMS

    has been applied to different areas within prefrontal cortex in

    c o r t e x 4 6 ( 2 0 1 0 ) 7 6 9 – 7 8 0770

  • 8/21/2019 Dissociating Cognitive From Affective Theory of Mind a TMS Study

    3/12

    order to successfully interfere with higher cognitive functions

    such as visual (Mottaghy et al., 2002; Oliveri et al., 2001) and

    spatial (Koch et al., 2005) working memory, verbal and

    nonverbal memory encoding (Floel et al., 2004), divided

    attention (Wagner et al., 2006), decision making (van’t Wout

    et al., 2005), or the implementation of fairness-related

    behavior (Knoch et al., 2006a, 2006b). RTMS has been used in

    few studies to examine the sensorimotor side of empathy forpain (Avenanti et al., 2005, 2009). Only one rTMS study

    specifically addressed neural correlates of ToM using rTMS,

    finding both dorsolateral and temporo-parietal involvement

    (Costa et al., 2008). However, no differentiation was made

    between cognitive and affective ToM.

    For our study, we hypothesized dissociable effects of rTMS

    over the right DLPFC on ToM. More specifically, on the basis of 

    the assumption that the DLPFC is involved in the neural

    network which mediates cognitive but not affective ToM, we

    expected a selective effect of rTMS over the right DLPFC on

    cognitive but not affective ToM processes.

    2. Methods

    2.1. Sample

    Twenty-eight male, right-handed subjects (mean age: 24.0,

    standard deviation – SD: 2.7) without neurological or psychi-

    atric history were included in the study. All subjects had

    completed German high school with the highest degree (Abi-

    tur) and currently underwent higher university education in

    various fields but not psychology. The study protocol was

    approved by the local Ethics committee. All subjects signed

    informed consent and underwent a medical safety screening 

    according to international safety guidelines for the use of TMS(Wassermann, 1998). Cognitive dysfunction was excluded

    with the cognitive screening instrument DemTect (Kalbe et al.,

    2004; Kessler et al., 2000), subtest 4 (reasoning) of the German

    intelligence test battery ‘‘Leistungspru ¨ fsystem’’ (LPS 4,  Horn,

    1983), and the Trail Making Test A and B (TMT,  Reitan, 1979;

    Tombaugh, 2004). Mean group scores were 17.4 (SD: 1.1) out of 

    18 points in theDemTect, C-scores of 7.3(SD: 1.5) for theLPS 4,

    and percentiles of 4.4 (SD: 2.8) and 4.7 (SD: 2.9) for TMT

    subtests A and B, respectively.

    2.2. ToM tasks

    A German version of the ‘‘reading the mind in the eyes’’ test(Baron-Cohen et al., 2001) was used as a general measure of 

    ToM abilities. To measure cognitive and affective ToM in the

    TMS experiment we used a German modified version of the

    ‘‘Yoni’’ task introduced by Shamay-Tsoory et al. (2006). It is

    based on a task previously described by  Baron-Cohen and

    Goodhart (1994) and involves the ability to judge mental states

    via analysis of verbal cues, eye gaze, and facial expression. In

    each of the 60 items presented on a computer screen, a face

    named Yoni is shown in the middle with four coloured

    pictures in the corners showing either faces or examples of 

    a semantic category (e.g., animals, fruits). An incomplete

    sentence about what image Yoni is referring to is also pre-

    sented, and the subject has to judge which of the four stimuli

    in the corners best fills the gap of the sentence. The items can

    be subdivided into three types of categories with 20 items

    each, that is (i) cognitive ToM (cog), (ii) affective ToM (aff), and

    (iii) control physical condition (phy), with ten first order and

    tensecond order itemsin each category (Fig. 1). While answers

    in the physical condition only require analysis of physical

    attributes of the character, choices in the cognitive and

    affective ToM items require mental inferences based on verbalcues (contained in the sentences), eye gaze and/or facial

    expression. More specifically, in the first order ToM stimuli

    Yoni’s mental state about one of the four images in the

    corners has to be inferred: Yoni is thinking of . (cog1, German:

    Yoni denkt an.), or  Yoni loves   .   (aff1, German:  Yoni mag.),

    while in the more complex second order ToM items the four

    stimuli in the corners consist of faces, and an inference

    regarding the interaction between Yoni’s and the other stim-

    uli’s mental state is necessary. In the second order cognitive

    items with the sentence Yoni is thinking of the . that . wants

    (cog2, German: Yoni denkt an die., die . will ), both the verbal

    and facial cues are neutral. In the second order affective items

    with the sentence Yoni loves the . that . loves, (German: Yonimag die., die . mag) both cues are affective. The item sets of 

    all item subcategories are comparable with regard to sentence

    complexity and visual complexity.

    The task was programmed with the software PRESENTA-

    TION. The total task duration was 10 min and 30 sec. All items

    were presented in randomized order for a maximum of 10 sec

    during which the subjects had to answer by tapping a button

    on the square number keyboard on the right side of the

    console. The position of the answer buttons (1, 7, 9, 3) corre-

    sponded to the positions of the four stimuli in the corners of 

    thescreen.As soon as subjects answered,a plain white screen

    was shown until the end of the 10 sec time interval. Between

    these fixed time intervals a black fixation cross on a whitescreen was presented for .5 sec. In order to ensure compara-

    bility of reaction times (RTs), subjects always had to use the

    same finger (right middle or index finger) to respond and

    return to the starting position on button 5 in the middle of the

    number keyboard after each item. For all items, RTs and

    accuracy were registered.

    Before rTMS stimulation and administration of the real

    test, all subjects received an introduction to the Yoni task with

    four explaining slides, and a training that resembled the test

    but with only 21 items (7 cognitive, 7 affective, and 7 physical)

    not included in the test.

    2.3. Magnetic resonance imaging (MRI) localisation of rTMS target site

    Each participant underwent a high resolution whole brain

    anatomical MRI scan performed on a whole body 1.5 T

    scanner (Achieva 1.5, Philips Medicine Systems, Best, the

    Netherlands). This allowed for defining the rTMS target site

    based on individual anatomical brain structure.To allow exact

    positioning of rTMS over the DLPFC, nifedipine capsules were

    sticky-taped over two frontal areas navigated prior to MRI

    scanning by two common landmark procedures for the

    DLPFC. The first of these two procedures determines DLPFC by

    detecting the ‘‘motor hot spot’’ for the abductor pollicis brevis

    muscle within the hand area of the primary motor cortex by

    c o r t e x 4 6 ( 2 0 1 0 ) 7 6 9 – 7 8 0   771

  • 8/21/2019 Dissociating Cognitive From Affective Theory of Mind a TMS Study

    4/12

    single pulse TMS and then moving 5 cm anterior and in

    parallel to the midsagital line (George et al., 1995). The secondapproach uses the international 10–20 system to localize

    DLPFC as corresponding to F4 (Herwig et al., 2003) (see Fig. 2).

    The exact individual position of the DLPFC was determined at

    the junction of BA 8 and BA 9 caudal to the medial section of 

    the medial frontal gyrus based on the anatomical brain scan of 

    each participant. This prefrontal section was used because the

    dorsal part of the lateral prefrontal cortex is most clearlyrelated with complex executive functions (Lie et al., 2006;

    Miller and Cohen, 2001; Petrides, 2005). Furthermore, this area

    has been found to be active during false belief reasoning 

    which can be conceptualized as a cognitive ToM task (Sommer

    et al., 2007).

    Fig. 2 – a. Montreal Neurological Institute (MNI) headmesh showing the average locations of the two capsules in Talairach

    coordinates. Capsule 1 indicates the stimulation site as determined by the 5 cm rule ( x[51±6,  y[34±11,  z[53±7).

    Capsule 2 indicates F4, the stimulation site as determined by the 10–20 system ( x[46±4,  y[49±5,  z[45± 6). b.

    Anatomical regions shown on segmentations of the MNI template.

    Fig. 1 – Item examples of the Yoni ToM task modified from Shamay-Tsoory et al. (2007) used in our TMS experiment.

    c o r t e x 4 6 ( 2 0 1 0 ) 7 6 9 – 7 8 0772

  • 8/21/2019 Dissociating Cognitive From Affective Theory of Mind a TMS Study

    5/12

    In order to navigate the rTMS coil to the exact scalp posi-

    tion for stimulation of the DLPFC, the location of the DLPFC

    was calculated in relation to the anatomical locations

    proposed by each landmark procedure in three-dimensional

    MRI reconstruction. The final actual rTMS could either be

    based on one of the locations indicated by the two landmark

    procedures or on a different location on the scalp when both

    methods failed to overlie the intended cortical target site. Theadvantage of this approach is two-fold: first it provides

    a precise and individual determination of the MRI-guided

    rTMS target site and second it offers an empirical assessment

    of the accuracy and validity of the two most commonly used

    standard anatomical landmark approaches for localizing BA 9.

    2.4. TMS protocol

    A Magstim Rapid2 stimulator (Magstim company, Whitland,

    UK), set at 100% of the individual resting motor threshold, and

    a 70 mm figure of eight coil were used to deliver a 15 min

    single train of 900 1 Hz rTMS at 100% of the motor threshold.

    Stimulation parameters were chosen according to the 1 Hzprocedure described by Maeda et al. (2000) which has shown

    to result in a 10–15 min reduction of cortical excitability of the

    target area. For the detection of the resting motor threshold

    the coil was placed tangentially over the right primary motor

    cortex at the optimal site for the response of the left first

    dorsal interosseus muscle. The resting motor threshold was

    defined as the stimulator output intensity that evoked at least

    5 out of 10 motor potentials of a minimum amplitude of 100 mV

    from the contralateral first dorsal interosseus muscle (mean

    was 58.4%, SD: 4%). Each subject received rTMS at two

    different locations – one at the cortical target site of right BA9,

    and one vertex (Cz) stimulation as control condition (Best-

    mann et al., 2002; Koch et al., 2006; Pascual-Leone et al., 1996).Cz was localized according to the international 10–20 system

    ( Jasper, 1958). Concerning coil orientation, the figure eight coil

    was held tangentially to subjects’ cortex in the angle of motor

    spot localization. This corresponded roughly to an angle of 45

    to midsagital line of the subject’s cortex. Holding the coil was

    done manually with both hands during the entire stimulation.

    2.5. Procedure

    The study was conducted as a within-subject design, where

    half of the subjects were stimulated at the target area first, and

    the other half was stimulated at the control site first. The

    sequence of stimulation was randomly assigned to eachparticipant. Subsequently to the first stimulation the subject

    was tested with the Yoni ToM task. After a 30 min inter-

    stimulation break the second stimulation was conducted after

    which again the YoniToM task was administered. ToM testing 

    startedimmediately after stimulation. To ensure that subjects

    were familiar with the task so that simple learning effects

    during test administration under rTMS could be avoided, all

    subjects received an introduction and training of the Yoni task

    prior to the first stimulation. Furthermore, to ensure that

    subjects did not occupy themselves with the experiment at

    hand during the 30 min inter-stimulation break they had to

    administer a filler task during that break. For this purpose,

    a questionnaire (personality questionnaire NEO-FFI, Borkenau

    and Ostendorf, 1993) was chosen which was cognitively not

    demanding, did not interfere with the experiment, and had an

    administration time of approximately 30 min.

    2.6. Statistical analysis

    All statistical analyses were carried out using the Statistical

    Package for the Social Sciences (SPSS) version 15 for Windows(Release 15.0.0, Chicago: SPSS Inc.). After checking for statis-

    tical normal distribution of the data with the Kolmogorov–

    Smirnov-Test, a general linear model repeated measures

    analysis on the factors ToM condition (cognitive ToM   vs

    affective ToM vs  control physical items of the Yoni task) and

    rTMS stimulation condition (experimental   vs   control) was

    employed. For post-hoc testing paired samples   t-tests with

    corrected  a  were used.

    3. Results

    3.1. General ToM abilities

    In the ‘reading the mind in the eyes’ task the group reached

    a mean of 25.6 (SD¼ 2.1) points (max. score¼ 36) indicating 

    age- and gender-adequate ToM abilities according to the

    normative data provided by Baron-Cohen et al. (2001).

    3.2. TMS adverse events

    Side effects that occurred due to rTMS stimulation were mild

    headache after stimulation in two subjects, eye or nose

    twitching during stimulation in 16 subjects and jaw contrac-

    tions during stimulation in one subject. One candidate subject

    suffered a syncope during motor spot localization afterapplication of 15 single pulses at different output intensities

    with a maximum of 70%. After an Electroencephalography

    (EEG) recording with normal results the subject was excluded

    from further participation.

    3.3. Experimental ToM task ‘‘Yoni’’: RTs

    Mean RTs of the main Yoni ToM task categories for the

    experimental and control stimulation conditions are indi-

    cated in   Table 1. Control physical items were processed

    significantly faster than cognitive (t¼ 11.223, df ¼ 27, p < .001)

    and affective (t¼ 11.92, df ¼ 27,  p < .001) items in the experi-

    mental as well as in the control stimulation condition(t¼ 9.987, df ¼ 27,  p < .001 for cognitive and  t ¼ 8.739, df ¼ 27,

     p< .001 for affective items). Affective items were processed

    significantly faster than cognitive items in the experimental

    condition (t¼ 11.920, df ¼ 27,   p< .001) and in the control

    condition (t¼ 3.700, df ¼ 27, p < .001).

    In a general linear model repeated measure analysis, the

    factors stimulation site (two stages: experimental  vs  control)

    and item type (three stages: cognitive vs  affective vs  control),

    and the between-subject factor order of condition (experi-

    mental – control   vs  control – experimental) were used, the

    latter of which is important to account for possible order

    effects. In this analysis, there was a significant main effect for

    stimulation site [Pillai’s Trace¼ .262,  F(1,27)¼ 9.230,  p ¼ .005]

    c o r t e x 4 6 ( 2 0 1 0 ) 7 6 9 – 7 8 0   773

  • 8/21/2019 Dissociating Cognitive From Affective Theory of Mind a TMS Study

    6/12

    and item category [Pillai’s Trace¼ .853,   F(2,26)¼ 72.603,

     p< .001] and a significant interaction effect between the

    factors item category and stimulation site [Pillai’s

    Trace¼ .258,   F(2,26)¼ 4.337,   p¼ .024]. However, neither the

    interaction stimulation site with order of condition nor theinteraction item category with order of condition nor the three

    wayinteraction stimulation site with item category with order

    of condition were significant [Pillai’s Trace¼ .128,

    F(2,27)¼ 3.802,   p¼ .062; Pillai’s Trace¼ .036,   F(2,26)¼ .471,

     p¼ .630; and Pillai’s Trace¼ .111,   F(2,26)¼ 1.558,   p¼ .230,

    respectively]. Thus when stimulated experimentally

    compared to control stimulation, subjects differed signifi-

    cantly in their RTs between categories, and order of stimula-

    tion did not influence this rTMS effect on ToM performance.

    Post-hoc paired samples   t-test, with a corrected   a   of .016

    between experimental and control stimulation for the item

    categories elicited that only RTs in the cognitive ToM category

    differed significantly (t¼3.618, df ¼ 27, p ¼ .001) (Fig. 3).These significant differences corresponded to a fastening 

    of RTs in cognitive ToM items in the experimental stimulation

    condition. The delta between the two conditions ranged from

    23 to 287 msec across individuals. When subcategories were

    analyzed (cog1, cog2, aff1, aff2, phy1, phy2,  Table 1) with

    paired samples t-test and a corrected  a  of .008 only RTs in the

    cog2 category differed significantly (t¼3.171, df ¼ 27,

     p¼ .004) (Fig. 4). For the cog1 category, p  was .021.

    To analyse whether RTs were stable over the duration of 

    the task for cognitive ToM items, paired samples  t-tests of the

    first versus the second half data were performed for eachcondition. No significant differences were observed for cog1,

    cog 2, and total cognitive ToM items indicating that there were

    no learning effects.

    3.4. Experimental ToM task ‘‘Yoni’’: accuracy

    There were no incorrect answers from any subject. The mean

    number of misses (analyzed for all item categories) was 3.5

    (SD¼ 3.3) in the experimental and 2.8 (SD ¼ 2.9) in the control

    condition. Only four out of 28 subjects (14.3%) had no misses

    indicating that there was no ceiling effect in performance and

    that task difficulty was adequate. A general linear model

    repeated measures procedure for misses in the Yoni ToM taskusing the factors also included in the RT analysis (i.e., ToM

    condition and rTMS stimulation condition) showed no

    significant results, even though there was a trend for inter-

    action between the factors stimulation site and item category

    [Pillai’s Trace¼ .188,   F(2,26)¼ 3.009,   p¼ .067]. Remarkably,

    within-group comparison of misses in the cog2 items in

    Table 1 – Mean RTs in msec of answers to the categories of the Yoni ToM task in the two rTMS conditions.

    Control stimulation Experimental stimulation   p-value

    Mean RT (ms) (SD) Mean RT (ms) (SD)

    Cognitive items (total) 2908 (629) 2625 (587) .001*

    cog1 1989 (445) 1849 (431) .021

    cog2 3827 (936) 3402 (801) .004*

    Affective items (total) 2658 (580) 2565 (586) .199

    aff1 2130 (530) 2032 (544) .330

    aff2 3187 (699) 3096 687 .167

    Physical items (total) 1997 (406) 1881 (415) .042

    phy1 1707 (368) 1655 (370) .248

    phy2 2287 (486) 2107 (488) .028

    * p < .05

    Fig. 3 – Reaction time differences control minus

    experimental condition for cognitive and affective ToM

    items.

    Fig. 4 – Reaction time differences control minus

    experimental condition for subcategories of cognitive,

    affective, and physical items.

    c o r t e x 4 6 ( 2 0 1 0 ) 7 6 9 – 7 8 0774

  • 8/21/2019 Dissociating Cognitive From Affective Theory of Mind a TMS Study

    7/12

    control versus experimental condition did not show a signifi-

    cant difference (Wilcoxon test, Z¼1.447, p¼ .148), indicating 

    that there was no specific effect in this item subcategory that

    might be related to the results of the RT analysis.

    4. Conclusion

    The main finding of our study is that rTMS over the right

    DLPFC has a selective effect on cognitive but not affective ToM

    performance. This result is in concordance with the recently

    advanced view that these processes are subcomponents of the

    complex concept we refer to as ToM and are at least partially

    independent (Blair and Cipolotti, 2000; Eslinger, 1998; Eslinger

    et al., 1996). Evidence for a functional dissociability of the

    independence of cognitive and affective ToM also comes from

    patient studies, which show selective deterioration of affec-

    tive ToM in patients with ventromedial damage (Shamay-

    Tsoory and Aharon-Peretz, 2007; Shamay-Tsoory et al., 2005),

    more pronounced dysfunction in affective than in cognitive

    ToM in patients with schizophrenia (Shamay-Tsoory et al.,2006), and also from psychophysiological findings (using skin

    conductance responses) in healthy control subjects (Kalbe

    et al., 2007). Furthermore, imaging studies have found

    partially different networks mediating cognitive and affective

    ToM (Hynes et al., 2006; Vo ¨ llm et al., 2006). Although a side

    result of our study, it should be noted in this context that we

    found faster RTs for affective than for cognitive ToM items in

    both conditions – a finding that is in concordance with ‘‘Yoni’’

    results of  Shamay-Tsoory and Aharon-Peretz (2007) and also

    with behavioral results from a study that used cognitive and

    emotional ToM short stories matched in word length ( Hynes

    et al., 2006). Albeit speculative at this point, the affective items

    might be easier than the cognitive items in the Yoni task sincethey involve an additional cue formakingthe decision: a smile

    or a frown. This may enhance ToM processing. Alternatively,

    the results could also reflect different mechanisms underlying 

    cognitive and affective ToM. Referring to the two fundamen-

    tally different mechanisms that have been proposed to

    explain the process of mentalizing, ‘simulation theory’ posits

    that other people’s mental states are represented by repli-

    cating or mimicking the mental life of the other person and

    thus ‘slipping in the other person’s shoes’, while according to

    the ‘theory theory’, others’ mental states are modelled ratio-

    nally by a knowledge system that is independent from one’s

    own mental states (Gallese and Goldman, 1998). Instead of 

    favouring one of these mechanisms, it has been hypothesizedthat both of them exist and that cognitive ToM may primarily

    represent a cognitive process which relies on ‘theories’ of 

    mind corresponding to the ‘theory theory’ while simulation

    may rather be the underlying mechanism for affective ToM

    (Adolphs, 2002; Adolphs et al., 2000; Heims et al., 2004; Kalbe

    et al., 2007; Mitchell et al., 2005; Shamay-Tsoory and Aharon-

    Peretz, 2007). Shamay-Tsoory et al. (2005) suggest that simu-

    lation mechanism is essential at the beginning of the persons’

    affective ToM process and is further used for making infer-

    ences regarding the other persońs affective mental states.

    Affective ToM processing or ‘empathy’ is regarded to rely on

    brain structures that develop early in ontogeny including the

    limbic system and might thus be mediated by more automatic

    and direct neural circuits as compared to cognitive mentaliz-

    ing, that could pose more demands on cognitive resources

    (Hynes et al., 2006; Mitchell et al., 2005; Satpute and

    Lieberman, 2006; Singer, 2006) – and might thus be faster. In

    this context it seems to be relevant to consider theconnections

    between limbic and prefrontal sections. The amygdala, which

    is the key structure in evaluating emotional sensory stimuli

    (e.g.,  Phelps, 2006; Phelps and LeDoux, 2005) is both directlyand indirectly connected with the orbitofrontal/ventromedial

    part of the frontal lobe (e.g., Brand and Markowitsch, 2006). In

    addition, the amygdala is linked to fast automatic responses

    via its connections with hypothalamic nuclei and the brain

    stem. Amygdala activation can therefore result in fast auto-

    nomic arousal (e.g., measured by skin conductance responses),

    which is then perceived by somatosensory cortex. Information

    about the emotionality of stimuli can significantly influence

    evaluative processes, such as decision making, ToM, and other

    complex function (Adolphs, 2001, 2003a, 2003b, 2003c; Bechara

    et al., 2003; Brand et al., 2007; Damasio, 1994, 1996). This is

    most likely the case due to the aforementioned connections

    between amygdala and orbitofrontal cortex which has alsobeen named ‘‘expanded limbic system’’ (Nauta, 1979). It is

    hypothesized that this limbic contribution to higher cognitive

    functions, in particular within the field of social cognition and

    those tasks that depend upon intuitive processes, is linked to

    faster reactions, as the emotional system acts fast, parallel,

    associative etc. (c.f.;  Kahneman, 2003). This may – at least

    partially – explain why we found faster reactions to affective

    compared to cognitive ToM items. Taken together our results

    corroborate the notion that cognitive and affective ToM are

    functionally dissociable processes.

    RTMS over the right DLPFC in our study induced an accel-

    eration of RTs in cognitive ToM, not a decrease as might have

    been expected. Certainty about the reliability of this finding comes from the facts that (1) training effects can be excluded,

    as all subjects received a training before testadministration so

    that they were customized to the task, and more importantly,

    RTs for cognitive ToM items were stable over the duration of 

    the task (2) training or order effects on specific task trials or

    items can be excluded, as the order of the items within the

    Yoni task as well as the order of rTMS stimulation condition

    were randomized across subjects, and also given the result

    that there were no statistical effects for the factor order of 

    condition in the general linear model repeated measure

    analysis (3) there was a statistically significant interaction

    effect between the factors item category (cognitive vs affective

    vs   control items) and stimulation site (experimental   vscontrol). This latter effect stems from a significant difference

    of RTs only in cognitive items between experimental and

    control stimulation. One possible explanation for the fact that

    processing of cognitive ToM items was faster after rTMS over

    the DLPFC is that our control stimulation has led to decreased

    RTs, not vice versa. However, this is unlikely, as rTMS stim-

    ulation over the vertex has beenused as control stimulation in

    numerous studies using a wide variety of paradigms, and to

    the knowledge of the authors has not been shown to have any

    specific effect on visual exploration (e.g.,  Nyffeler et al., 2008)

    or other functions (Wiener et al., 2010; Viggiano et al., 2008).

    Furthermore, a decrease of RTs after vertex stimulation would

    not explain the differential effect on cognitive ToM as

    c o r t e x 4 6 ( 2 0 1 0 ) 7 6 9 – 7 8 0   775

  • 8/21/2019 Dissociating Cognitive From Affective Theory of Mind a TMS Study

    8/12

    compared to the affective ToM and control items. Thus the

    interpretation that RTs in response to cognitive ToM items

    were fastened after rTMS over the right DLPFC seems valid.

    One possible explanation for this result is that our stimulation

    protocol could have had a facilitating effect when applied over

    the right DLPFC and not an inhibitory one when applied over

    the primary motor cortex (Maeda et al., 2000). For example,

    Sack and Linden (2003)   point out that one particular rTMSprotocol can have either inhibitory or facilitatory effects

    depending on the cortical area where it is applied and the

    behavioral task to be tested. In addition, stimulation charac-

    teristics, such as intensity, distribution, depth of penetration,

    and accuracy, depend on factors such as scalp-cortex distance

    or extent and conductivity of the stimulated tissue. In support

    of these considerations, Dra ¨ ger and co-workers found that

    specific language (namely picture-word verification) function

    was inhibited when a 1 Hz protocol with 600 pulses was con-

    ducted on Wernicke’s area and facilitated whenit was used on

    Broca’s area (Dra ¨ ger et al., 2004). Despite these constraints,

    Machii et al. (2006)   in their recent review come to the

    conclusion that deducing stimulation parameters which arevalid for motor areas and applying them to the study of 

    cognitive function is the standard procedure which has shown

    to produce coherent results. Thus, although general questions

    remain regarding the effect of our specific rTMS protocol, it is

    definite that our stimulation protocol interfered with normal

    processing of ToM in the DLPFC.

    Assuming that our rTMS protocol inhibited excitability of 

    the right DLPFC, the fastening of RTs during the cognitive ToM

    tasks suggest that normal functioning of the right DLPFC is

    detrimental for performance in cognitive ToM processing.

    Thus inhibition of the right DLPFC must have facilitated other

    brain regions relevant for task performance, possibly by the

    mechanism of ‘‘transcallosal inhibition’’. It is known that lowfrequency rTMS has been shown to reduce transcallosal

    inhibition within the motor system and may facilitate corti-

    cospinal excitability of the not stimulated motor cortex (Gilio

    et al., 2003; Pal et al., 2005). 1 Hz rTMS over the primary motor

    cortex facilitates function of the contralateral homologue by

    reduction of transcallosal inhibition (Kobayashi et al., 2004;

    Takeuchi et al., 2005). Comparable effects have also been

    demonstrated for higher cortical functions. For example,

    hampering function of the relevant left-hemispheric language

    areas, either by stroke or after rTMS, causes enhanced neural

    activation of the contralateral homotopic areas (Heiss et al.,

    2002; Thiel et al., 2006). Also, the processing of specific

    emotions suchas anger or anxietyknown to be lateralized canbe modulated by rTMS over the right PFC ( van Honk et al.,

    2002). Finally, low frequency rTMS stimulation of the right

    frontal cortex is as effective as high frequency rTMS stimu-

    lation of the left frontal cortex in patients with depression

    (Isenberg et al., 2005).

    In context of the task under discussion inhibition of the

    right DLPFC by 1 Hz rTMS may have released left DLPFC from

    transcallosal inhibition and resulted in enhanced function

    within this area. This would point to a left rather than a right-

    hemispheric DLPFC relevance for cognitive ToM. There is

    evidence for involvement of the left PFC in ToM processing 

    (e.g.,  Baron-Cohen et al., 1999; Calarge et al., 2003; Channon

    and Crawford, 2000; Fletcher et al., 1995; Gallagher et al., 2000;

    Goel et al., 1995). Sabbagh (2004) suggested two anatomically

    and functionally different ToM networks in the human cortex:

    a right-hemispheric one, especially in the orbitofrontal and

    medial temporal cortex, mediating ‘decoding mental states

    from outside cues’, and a left-hemispheric network, especially

    in the left medial frontal cortex, mediating ‘reasoning about

    those mental states’. Left-sided cortical involvement in ToM

    processing also includes lateral prefrontal structures (e.g.,Baron-Cohen et al., 1999; Channon and Crawford, 2000; Sha-

    may-Tsoory and Aharon-Peretz, 2007). In line with these

    results, Satpute and Lieberman (2006)  recently proposed the

    framework of a ‘reflexive’ system for automatic social

    perception (which relies on limbic/ventromedial and temporal

    structures and is needed to code the trait and evaluative

    implications of an observed behavior), as opposed to

    a ‘reflective’ system for controlled socialperception. The latter

    system is supposed to be mediated, among other structures,

    partly by the lateral prefrontal cortex, which is known to

    mediate reasoning and logic, analogy, mathematical problem-

    solving as well as working memory and other executive

    functions.   Satpute and Lieberman (2006)   propose that thisreflective system is involved when ‘symbolic computation’ is

    necessary in a ToM task. More precisely, the system could

    provide a corrective process of automatically generated

    hypothesis about interpretations of behavior (mediated by

    other structures), i.e., a ‘selection process’ (see also   Leslie

    et al., 2004, 2005), and is needed where multiple mental

    perspectives have to be considered, self knowledge inhibited,

    and beliefs considered in relation to subsequent mental states

    (Bull et al., 2007).

    In line with the aforementioned arguments one may

    speculate that rTMS induced inhibition of right DLPFC func-

    tioning may cause stronger involvement of emotional reac-

    tions to cognitive tasks compared to intact right DLPFCfunctions. The DLPFC is connected with other prefrontal areas

    (ventrolateral and orbitofrontal sections) and basal ganglia,

    via thalamic nuclei (Alexander and Crutcher, 1990; Alexander

    et al., 1990; Barbas, 2000; Brand and Markowitsch, 2008) and

    DLPFC functioning can inhibit orbitofrontal and limbic acti-

    vation involved in social cognition and emotion processing 

    (for a discussion of disinhibition and prefrontal cortex see

    Zamboni et al., 2008). Accordingly an inhibition of the right

    DLPFC may result in a disinhibition of orbitofrontal func-

    tioning that then facilitates solving cognitive ToM items in

    a more emotional and therefore faster way than usually done,

    at least as long as the items are not too complex and do not

    necessarily involve an executive component.Although ToM and executive functions can be deteriorated

    independently and thus seem dissociable (e.g.,   Fine et al.,

    2001; Lough et al., 2001; Pickup, 2008; Rowe et al., 2001; Stone

    et al., 1998), an association between the two has frequently

    been shown (e.g.,  Channon and Crawford, 2000; Kobayashi

    et al., 2007; Perner and Lang, 1999; Perner et al., 2002; Sabbagh

    et al., 2006). It appears as if executive functions serve as a ‘co-

    opted’ system (next to a ‘core’ ToM system), which is neces-

    sary to succeed at least in particular variants of ToM tasks

    (Siegal and Varley, 2002). Cognitive ToM tasks which require

    attributions about the propositional attitudes such as belief,

    knowledge, intentions, are more likely to fall intothis category

    than affective ToM tasks that are associated with the ability to

    c o r t e x 4 6 ( 2 0 1 0 ) 7 6 9 – 7 8 0776

  • 8/21/2019 Dissociating Cognitive From Affective Theory of Mind a TMS Study

    9/12

    empathize (Shamay-Tsoory et al., 2002) and may involve

    implicit affect sharing (Singer, 2006) through simulation pro-

    cessing (Mitchell et al., 2005). We thus conclude that the

    DLPFC involvement in our study reflects contributions of 

    executive functions in solving cognitive ToM items as

    assessed in the Yoni task. However, when right DLPFC func-

    tioning is reduced (via rTMS), integrity of the left DLPFC seems

    to be sufficient to deal with the executive component of thetask. In addition, it might be that – in this case – an additional

    contribution of limbic structures (i.e., the right orbitofrontal

    section), which results from less inhibition by the right DLPFC,

    may facilitate solving the cognitive ToM items.

    In summary, our study provides empirical evidence for the

    functional independence of cognitive and affective ToM.

    Furthermore, it points to an important role of the DLPFC

    within neural networks mediating cognitive ToM. However,

    the exact role of this region within networks mediating ToM

    needs to be specified. Future studies are warranted to assess

    functional and effective brain connectivity between left and

    right DLPFC during the execution of cognitive versus affective

    ToM tasks. More concretely, fMRI connectivity studies (Fristonet al., 2003; Goebel et al., 2003) might reveal the exact neuro-

    computational mechanisms within bilateral DLPFC during 

    cognitive versus affective ToM, on the bases of which opti-

    mized rTMS protocols could be applied over left versus right

    DLPFC in order to further elicit the relevance of this region for

    cognitive ToM processes.

    Acknowledgements

    We thank Michelle Moerel, Faculty of Psychology, Maastricht

    University, for support in graphical image processing, and

    Ingo Meister and Mitra Ameli, Department of Neurology,

    University of Cologne, for assistance in MRI and rTMS.

    Furthermore, the work of the first author was funded in part

    by the EC-FP6-project DiMI, LSHBCT-2005-512146.

    r e f e r e n c e s

    Adolphs R, Damasio H, Tranel D, Cooper G, and Damasio AR. Arole for somatosensory cortices in the visual recognition of emotion as revealed by three-dimensional lesion mapping.

     Journal of Neuroscience, 20: 2683–2690, 2000.Adolphs R. Social cognition and the human brain. In Cacioppo JT,

    Berntson GG, Adolphs R, Carter CS, Davidson RJ,McClintock MK, McEwen BS, Meaney MJ, Schacter DL,Sternberg EM, Suomi SS, and Taylor SE (Eds), Foundations inSocial Neuroscience. Cambridge: MIT Press, 2002: 313–331.

    Adolphs R. Cognitive neuroscience of human social behaviour.Nature Reviews. Neuroscience, 4: 165–178, 2003a.

    Adolphs R. Investigating the cognitive neuroscience of socialbehavior. Neuropsychologia, 41: 119–126, 2003b.

    Adolphs R. Is the human amygdala specialized for processing social information? Annals of the New York Academy of Sciences,985: 326–340, 2003c.

    Adolphs R. The neurobiology of social cognition. Current Opinion inNeurobiology, 11: 231–239, 2001.

    Alexander GE and Crutcher MD. Functional architecture of basalganglia circuits: Neural substrates of parallel processing.Trends in Neurosciences, 14: 55–59, 1990.

    Alexander GE, Crutcher MD, and DeLong MR. Basal ganglia-thalamocortical circuits: Parallel substrates for motor,oculomotor, ‘‘prefrontal’’ and ‘‘limbic’’ functions. Progressin Brain Research, 85: 119–146, 1990.

    Avenanti A, Bueti D, Galati G, and Aglioti SM. Transcranial

    magnetic stimulation highlights the sensorimotor side of empathy for pain. Nature Neuroscience, 8: 955–960, 2005.

    Avenanti A, Minio-Paluello I, Bufalari I, and Aglioti SM. The painof a model in the personality of an onlooker: Influence of state-reactivity and personality traits on embodied empathyfor pain. NeuroImage, 44: 275–283, 2009.

    Barbas H. Connections underlying the synthesis of cognition,memory, and emotion in primate prefrontal cortices.  BrainResearch Bulletin, 52: 319–330, 2000.

    Baron-Cohen S and Goodhart F. The ‘‘seeing leads to knowing’’deficit in autism: The Pratt and Bryant probe. British Journalof Developmental Psychology, 12: 397–402, 1994.

    Baron-Cohen S, Ring HA, Wheelwright S, Bullmore ET,Brammer MJ, and Simmons A. Social intelligence in thenormal and autistic brain: An fMRI study.  European Journal

    of Neuroscience, 11: 1891–1898, 1999.Baron-Cohen S, Wheelwright S, Hill J, Raste Y, and Plumb I. The

    ‘‘Reading the Mind in the Eyes’’ Test revised version: A studywith normal adults, and adults with Asperger syndrome orhigh-functioning autism.  Journal of Child Psychology andPsychiatry, 42: 241–251, 2001.

    Baron-Cohen S and Wheelwright S. The empathy quotient: Aninvestigation of adults with Asperger syndrome or highfunctioning autism, and normal sex differences.   Journal of Autism and Developmental Disorders, 34: 163–175, 2004.

    Bechara A, Damasio H, and Damasio AR. Role of the amygdala indecision-making. Annals of the New York Academy of Sciences ,985: 356–369, 2003.

    Brand M, Grabenhorst F, Starcke K, Vandekerckhove MMP, andMarkowitsch HJ. Role of the amygdala in decisions under

    ambiguity and decisions under risk: Evidence from patientswith Urbach-Wiethe disease.  Neuropsychologia, 45: 1305–1317,2007.

    Brand M and Markowitsch HJ. Memory processes and theorbitofrontal cortex. In Zald D and Rauch S (Eds), TheOrbitofrontal Cortex. Oxford: Oxford University Press, 2006:285–306.

    Bestmann S, Thilo KV, Sauner D, Siebner HR, and Rothwell JC.Parietal magnetic stimulation delays visuomotor mentalrotation at increased processing demands, 2002.

    Blair RJ and Cipolotti L. Impaired social response reversal. A caseof ‘acquired sociopathy’. Brain, 123: 1122–1141, 2000.

    Blair RJ. Responding to the emotions of others: Dissociating formsof empathy through the study of typical and psychiatricpopulations.  Consciousness and Cognition, 14: 698–718, 2005.

    Borkenau P and Ostendorf F. NEO-Fü nf-Faktoren-Inventar (NEO-FFI)nach Costa und McCrae – Deutsche Fassung (nach Costa PT, and

    McCrae RR, 1985). Go ¨ ttingen: Hogrefe, 1993.Brand M and Markowitsch HJ. The role of the prefrontal cortex in

    episodic memory. In Dere E, Huston JP, and Easton A (Eds),Handbook of Episodic Memory. Amsterdam: Elsevier, 2008:317–341.

    Brothers L. Neurophysiology of the perception of intentions byprimates. In Gazziniga MS (Ed),   The Cognitive Neurosciences.Cambridge: MIT Press, 1995: 1107–1115.

    Brothers L. Friday’s Footprint: How Society Shapes the Human Mind.New York: Oxford University Press, 1997.

    Brunet E, Sarfati Y, Hardy-Bayle MC, and Decety JA. PETinvestigation of the attribution of intentions with a nonverbaltask. NeuroImage, 11: 157–166, 2000.

    c o r t e x 4 6 ( 2 0 1 0 ) 7 6 9 – 7 8 0   777

  • 8/21/2019 Dissociating Cognitive From Affective Theory of Mind a TMS Study

    10/12

    Bull R, Phillips LH, and Conway CA. The role of control functionsin mentalizing: Dual-task studies of theory of mind andexecutive function.  Cognition, 1: 7–15, 2007.

    Calarge C, Andreasen NC, and O’Leary DS. Visualizing how onebrain understands another: A PET study of theory of mind.The American Journal of Psychiatry, 160: 1954–1964, 2003.

    Channon S and Crawford S. The effects of anterior lesions onperformance on a story comprehension test: Left anterior

    impairment on a theory of mind-type task. Neuropsychologia,38: 1006–1017, 2000.

    Costa A, Torriero S, Oliveri M, and Caltagirone C. Prefrontal andtemporo-parietal involvement in taking others perspective:TMS evidence. Behavioural Neurology, 19: 71–74, 2008.

    Damasio AR. Descartes’ Error: Emotion, Reason and the Human Brain.New York: Grosset/Putnam, 1994.

    Damasio AR. The somatic marker hypothesis and the possiblefunctions of prefrontal cortex.  Philosophical Transactions of theRoyal Society of London – Series B, 351: 1413–1420, 1996.

    Dra ¨ ger B, Breitenstein C, Helmke U, Kamping S, and Knecht S.Specific and nonspecific effects of transcranial magneticstimulation on picture-word verification.  The European Journalof Neuroscience, 20: 1681–1687, 2004.

    Eslinger PJ, Satish U, and Grattan LM. Alterations in cognitive and

    affectively based empathy after cerebral damage. Journal of theInternational Neuropsychological Society, 2: 15, 1996.

    Eslinger PJ. Neurological and neuropsychological bases of empathy.  European Neurology, 39: 193–199, 1998.

    Eslinger PJ,Moore P, Troiani V,Antani S,CrossK, andKwokS. Oops!Resolving social dilemmas in frontotemporal dementia. Journalof Neurology, Neurosurgery and Psychiatry, 78: 457–460, 2007.

    Fine C, Lumsden J, and Blair RJ. Dissociation between ‘theoryof mind’ and executive functions in a patient with early leftamygdala damage. Brain, 124: 287–298, 2001.

    Fletcher PC, Happé F, Frith U, Baker SC, Dolan RJ, andFrackowiak RS. Other minds in the brain: A functional imaging study of ‘‘theory of mind’’ in story comprehension.  Cognition,57: 109–128, 1995.

    Floel A, Poeppel D, Buffalo EA, Braun A, Wu CW, and Seo HJ.

    Prefrontal cortex asymmetry for memory encoding of wordsand abstract shapes. Cerebral Cortex, 14: 404–409, 2004.

    Friston KJ, Harrison L, and Penny W. Dynamic causal modelling.NeuroImage, 19: 1273–1302, 2003.

    Frith CD and Frith U. Interacting minds - a biological basis. Science,26: 1692–1695, 1999.

    Frith U and Frith CD. Development and neurophysiology of mentalizing. Philosophical Transactions of the Royal Societyof London. Series B, Biological Sciences, 358: 459–473, 2003.

    Gallese V and Goldman A. Mirror neurons and the simulationtheory of mind-reading.  Trends in Cognitive Sciences, 12:493–501, 1998.

    Gallagher HL, Happé F, Brunswick N, Fletcher PC, Frith U, andFrith CD. Reading the mind in cartoons and stories: An fMRIstudy of ‘theory of mind’ in verbal and nonverbal tasks.Neuropsychologia, 38: 11–21, 2000.

    George MS, Wassermann EM, Williams WA, Callahan A,Ketter TA, and Basser P. Daily repetitive transcranial magneticstimulation (rTMS) improves mood in depression. NeuroReport,6: 1853–1856, 1995.

    Gilio F, Rizzo V, Siebner HR, and Rothwell JC. Effects on the rightmotor hand-area excitability produced by low-frequencyrTMS over human contralateral homologous cortex.  The

     Journal of Physiology, 551: 563–573, 2003.Goebel R, Roebroeck A, Kim DS, and Formisano E. Investigating 

    directed cortical interactions in time-resolved fMRI data using vector autoregressive modeling and Granger causalitymapping.  Magnetic Resonance Imaging, 21: 1251–1261, 2003.

    Goel V, Grafman J, Sadato N, and Hallett M. Modeling otherminds. Neuroreport, 6: 1741–1746, 1995.

    Griffin R, Friedman O, Ween J, Winner E, Happe F, and Brownell H.Theory of mind and the right cerebral hemisphere: Refining the scope of impairment.  Laterality, 11: 195–225, 2006.

    Happé F, Brownell H, and Winner E. Acquired ‘theory of mind’impairments following stroke. Cognition, 70: 211–240, 1999.

    Heims HC, Critchley HD, Dolan R, Mathias CJ, and Cipolotti L.Social and motivational functioning is not critically dependenton feedback of autonomic responses: Neuropsychological

    evidence from patients with pure autonomic failure.Neuropsychologia, 42: 1979–1988, 2004.

    Heiss WD, Thiel A, Kessler J, and Herholz K. Language activationin ischemic stroke and brain tumor: A PET study. Zentralblatt

     fü r Neurochirurgie, 63: 133–140, 2002.Herrmann E, Call J, Hernàndez-Lloreda MV, Hare B, and

    Tomasello M. Humans have evolved specialized skills of socialcognition: The cultural intelligence hypothesis. Science, 317:1360–1366, 2007.

    Herwig U, Satrapi P, and Schonfeldt-Lecuona C. Using theinternational 10–20 EEG system for positioning of transcranialmagnetic stimulation.  Brain Topography, 16: 95–99, 2003.

    Horn W.  Leistungsprü  fsystem. Go ¨ ttingen: Hogrefe, 1983.Hynes CA, Baird AA, and Grafton ST. Differential role of the

    orbital frontal lobe in emotional versus cognitive perspective-

    taking. Neuropsychologia, 44: 374–383, 2006.Isenberg K, Downs D, Pierce K, Svarakic D, Garcia K, and Jarvis M.

    Low frequency rTMS stimulation of the right frontal cortex isas effective as high frequency rTMS stimulation of the leftfrontal cortex for antidepressant-free, treatment-resistantdepressed patients.  Annals of Clinical Psychiatry, 17: 153–159,2005.

     Jasper HH. The ten-twenty electrode system of the InternationalFederation.  Electroencephalography and Clinical Neurophysiology,10: 371–375, 1958.

    Kahneman D. A perspective on judgment and choice. AmericanPsychologist, 58: 697–720, 2003.

    Kalbe E, Kessler J, Calabrese P, Smith R, Passmore AP, Brand M,et al. DemTect: A new, sensitive cognitive screening test tosupport the diagnosis of mild cognitive impairment and early

    dementia.  International Journal of Geriatric Psychiatry, 19:136–143, 2004.

    Kalbe E, Grabenhorst F, Brand M, Kessler J, Hilker R, andMarkowitsch HJ. Elevated emotional reactivity in affectivebut not cognitive components of theory of mind:A psychophysiological study.  Journal of Neuropsychology, 1:27–38, 2007.

    Kessler J, Calabrese P, Kalbe E, and Berger F. DemTect: Ein neuesScreening-Verfahren zur Unterstu ¨ tzung derDemenzdiagnostik. Psycho, 26: 243–347, 2000.

    Knoch D, Gianotti LR, Pascual-Leone A, Treyer V, Regard M, andHohmann M. Disruption of right prefrontal cortex bylow-frequency repetitive transcranial magnetic stimulationinduces risk-taking behavior.  Journal of Neuroscience, 26:6469–6472, 2006a.

    Knoch D, Pascual-Leone A, Meyer K, Treyer V, and Fehr E.Diminishing reciprocal fairness by disrupting the rightprefrontal cortex. Science, 314: 829–832, 2006b.

    Kobayashi M, Hutchinson S, Theoret H, Schlaug G, and Pascual-Leone A. Repetitive TMS of the motor cortex improvesipsilateral sequential simple finger movements.   Neurology,62:  91–98, 2004.

    Kobayashi C, Glover GH, and Temple E. Children’s and adults’neural bases of verbal and nonverbal ‘theory of mind’.Neuropsychologia, 45: 1522–1532, 2007.

    Koch G, Oliveri M, Torriero S, Carlesimo GA, Turriziani P, andCaltagirone C. rTMS evidence of different delay anddecision processes in a fronto-parietal neuronal networkactivated during spatial working memory.   NeuroImage,24: 34–39, 2005.

    c o r t e x 4 6 ( 2 0 1 0 ) 7 6 9 – 7 8 0778

  • 8/21/2019 Dissociating Cognitive From Affective Theory of Mind a TMS Study

    11/12

    Koch G, Franca M, Albrecht UV, Caltagirone C, and Rothwell JC.Effects of paired pulse TMS of primary somatosensory cortexon perception of a peripheral electrical stimulus. ExperimentalBrain Research, 172: 416–424, 2006.

    Leslie AM, Friedman O, and German TP. Core mechanisms in‘‘theory of mind’’. Trends in Cognitive Sciences, 8: 528–533, 2004.

    Leslie AM, German TP, and Polizzi P. Belief-desire reasoning asa process of selection. Cognitive Psychology, 50: 45–85, 2005.

    Lie CH, Specht K, Marshall JC, and Fink GR. Using fMRI todecompose the neural processes underlying the WisconsinCard Sorting Test. NeuroImage, 30: 1038–1049, 2006.

    Lough S, Gregory C, and Hodges JR. Dissociation of socialcognition and executive function in frontal variantfrontotemporal dementia. Neurocase, 7: 123–130, 2001.

    MachiiK,CohenD,Ramos-EstebanezC,andPascual-LeoneA.Safetyof rTMS to non-motor cortical areas in healthy participants andpatients. Clinical Neurophysiology, 117: 455–471, 2006.

    Maeda F, Keenan JP, Tormos JM, Topka H, and Pascual-Leone A.Modulation of corticospinalexcitabilityby repetitivetranscranialmagneticstimulation.ClinicalNeurophysiology,111:800–805,2000.

    Miller EK and Cohen JD. An integrative theory of prefrontal cortexfunction.  Annual Review of Neuroscience, 24: 167–202, 2001.

    Mitchell JP, Banaji MR, and Macrae CN. The link between social

    cognition and self-referential thought in the medial prefrontalcortex.  Journal of Cognitive Neuroscience, 17: 1306–1315, 2005.

    Mottaghy FM, Gangitano M, Sparing R, Krause BJ, and Pascual-Leone A. Segregation of areas related to visual working memory in the prefrontal cortex revealed by rTMS. CerebralCortex, 12: 369–375, 2002.

    Nauta WJH. Expanding borders of the limbic system concept.In Rasmussen T and Marino R (Eds), Functional Neurosurgery.New York: Raven Press, 1979: 7–23.

    Nyffeler T, Cazzoli D, Wurtz P, Lu ¨ thi M, von Wartburg R, Chaves S,et al. Neglect-likevisual explorationbehaviour after thetabursttranscranialmagneticstimulation of the rightposteriorparietalcortex. European Journal of Neuroscience, 27: 1809–1813, 2008.

    Oliveri M, Turriziani P, Carlesimo GA, Koch G, Tomaiuolo F, andPanella M. Parieto-frontal interactions in visual-object and

    visual-spatial working memory: Evidence from transcranialmagnetic stimulation.  Cerebral Cortex, 11: 606–618, 2001.

    Pal PK, Hanajima R, Gunraj CA, Li JY, Wagle-Shukla A, andMorgante F. Effect of low-frequency repetitive transcranialmagnetic stimulation on interhemispheric inhibition.  Journalof Neurophysiology, 94: 1668–1675, 2005.

    Pascual-Leone A, Rubio B, Pallardo F, and Catala MD. Rapid-ratetranscranial magnetic stimulation of left dorsolateralprefrontal cortex in drug-resistant depression. Lancet, 348:233–237, 1996.

    Pascual-Leone A, Walsh V, and Rothwell J. Transcranial magneticstimulation in cognitive neuroscience–virtual lesion,chronometry, and functional connectivity.  Current Opinionin Neurobiology, 10: 232–237, 2000.

    Perner J and Lang B. Development of theory of mind and

    executive control. Trends in Cognitive Sciences, 3: 337–344, 1999.Perner J, Lang B, and Kloo D. Theory of mind and self-control:

    More than a common problem of inhibition.  Child Development,73: 752–767, 2002.

    Petrides M. Lateral prefrontal cortex: Architectonic and functionalorganization. Philosophical Transactions of the Royal Society of London – Series B, 360: 781–795, 2005.

    Phelps ME. Emotion and cognition: Insights from studies of thehuman amygdala. Annual Review of Psychology, 57: 27–53, 2006.

    Phelps ME and LeDoux JE. Contributions of the amygdala toemotion processing: From animal models to human behavior.Neuron, 48: 175–187, 2005.

    Pickup GJ. Relationship between theory of mind and executivefunction in schizophrenia: A systematic review.Psychopathology, 41: 206–213, 2008.

    Reitan RM.   Manual for Administration of Neuropsychological TestBatteries for Adults and Children. Tucson: ReitanNeuropsychological Laboratory, 1979.

    Rowe AD, Bullock PR, Polkey CE, and Morris RG. ‘‘Theory of mind’’impairments and their relationship to executive functioning following frontal lobe excisions.  Brain, 124: 600–616, 2001.

    Sabbagh MA. Understanding orbitofrontal contributions totheory-of-mind reasoning: Implications for autism. Brain

    and Cognition, 55: 209–219, 2004.Sabbagh MA, Xu F, Carlson SM, Moses LJ, and Lee K. The

    development of executive functioning and theory of mind.Psychological Science, 17: 74–81, 2006.

    Sack AT and Linden DEJ. Combining transcranial magneticstimulation and functional imaging in cognitive brainresearch: Possibilities and limitations.   Brain Research Reviews,21: 41–56, 2003.

    Satpute AB and Lieberman MD. Integrating automatic andcontrolled processes into neurocognitive models of socialcognition. Brain Research, 1079: 86–97, 2006.

    Shamay-Tsoory SG, Tomer R, Yaniv S, and Aharon-Peretz J.Empathy deficits in Asperger syndrome: A cognitive profile.Neurocase, 8: 245–252, 2002.

    Shamay-Tsoory SG, Tomer R, Berger BD, Goldsher D, and Aharon-

    Peretz J. Impaired ‘‘affective theory of mind’’ is associatedwith right ventromedial prefrontal damage. Cognitive andBehavioral Neurology, 18: 55–67, 2005.

    Shamay-Tsoory SG, Shur S, Barcai-Goodman L, Medlovich S,Harari H, and Levkovitz Y. Dissociation of cognitive fromaffective components of theory of mind in schizophrenia.Psychiatry Research, 10: 10–18, 2006.

    Shamay-Tsoory SG and Aharon-Peretz J. Dissociable prefrontalnetworks for cognitive and affective theory of mind: A lesionstudy. Neuropsychologia, 45: 3054–3067, 2007.

    Siegal M, Carrington J, and Radel M. Theory of mind andpragmatic understanding following right hemisphere damage.Brain and Language, 53: 40–50, 1996.

    Siegal M and Varley R. Neuronal systems involved in ‘theory of mind’. Nature Reviews, 3: 463–471, 2002.

    Singer T. The neuronal basis and ontogeny of empathy and mindreading: Review of literature and implications for futureresearch.Neuroscience and Biobehavioral Reviews,30:855–863,2006.

    Sommer M, Dohnel K, Sodian B, Meinhardt J, Thoermer C, andHajak G. Neural correlates of true and false belief reasoning.NeuroImage, 35: 1378–1384, 2007.

    Stone VE, Baron-Cohen S, and Knight RT. Frontal lobecontributions to theory of mind.   Journal of CognitiveNeuroscience, 10: 640–656, 1998.

    Stuss DT, Gallup GG, and Alexander MP. The frontal lobes arenecessary for ‘theory of mind’. Brain, 124: 279–286, 2001.

    Takeuchi N, Chuma T, Matsuo Y, Watanabe I, and Ikoma K.Repetitive transcranial magnetic stimulation of contralesionalprimary motor cortex improves hand function after stroke.Stroke, 36: 2681–2686, 2005.

    Thiel A, Schumacher B, Wienhard K, Gairing S, Kracht LW, andWagner R. Direct demonstration of transcallosal disinhibitionin language networks.  Journal of Cerebral Blood Flow andMetabolism, 26: 1122–1127, 2006.

    Tombaugh TN. Trail making test A and B: Normative datastratified by age and education.  Archives of ClinicalNeuropsychology, 19: 203–214, 2004.

    van’t Wout M, Kahn RS, Sanfey AG, and Aleman A. Repetitivetranscranial magnetic stimulation over the right dorsolateralprefrontal cortex affects strategic decision-making.Neuroreport, 16: 1849–1852, 2005.

    van Honk J, Schutter DJ, d’Alfonso AA, Kessels RP, andde Haan EH. 1 Hz rTMS over the right prefrontal cortexreduces vigilant attention to unmasked but not to maskedfearful faces.   Biological Psychiatry, 52: 312–317, 2002.

    c o r t e x 4 6 ( 2 0 1 0 ) 7 6 9 – 7 8 0   779

  • 8/21/2019 Dissociating Cognitive From Affective Theory of Mind a TMS Study

    12/12

    Viggiano MP, Giovannelli F, Borgheresi A, Feurra M, Berardi N,Pizzorusso T, et al. Disruption of the prefrontal cortex functionby rTMS produces a category-specific enhancement of thereaction times during visual object identification.Neuropsychologia, 46: 2725–2731, 2008.

    Vogeley K, Bussfeld P, Newen A, Herrmann S, Happé F, Falkai P,et al. Mind reading: Neural mechanisms of theory of mind andself-perspective.  NeuroImage, 14: 170–181, 2001.

    Vo ¨ llm BA, Taylor AN, Richardson P, Corcoran R, Stirling J, andMcKie S. Neuronal correlates of theory of mind and empathy:A functional magnetic resonance imaging study ina nonverbal task.  NeuroImage, 29: 90–98, 2006.

    Wagner M, Rihs TA, Mosimann UP, Fisch HU, and Schlaepfer TE.Repetitive transcranial magnetic stimulation of thedorsolateral prefrontal cortex affects divided attentionimmediately after cessation of stimulation.   Journal of Psychiatric Research, 40: 315–321, 2006.

    Wassermann EM. Risk and safety of repetitive transcranialmagneticstimulation:Reportand suggestedguidelines fromtheInternationalWorkshopontheSafetyofRepetitiveTranscranialMagnetic Stimulation, June 5–7, 1996. Electroencephalography andClinical Neurophysiology, 108: 1–16, 1998.

    Wiener M, Hamilton R, Turkeltaub P, Matell MS, and Coslett HB.Fast forward: Supramarginal gyrus stimulation alterstime measurement.  Journal of Cognitive Neuroscience, 22: 23–31,

    2010.Winner E, Brownell H, Happe F, Blum A, and Pincus D.

    Distinguishing lies from jokes: Theory of mind deficits anddiscourse interpretation in right hemisphere brain-damagedpatients. Brain and Language, 62: 89–106, 1998.

    Zamboni G, Huey ED, Krueger F, Nichelli PF, and Grafman J.Apathy and disinhibition in frontotemporal dementia:Insights into their neural correlates.  Neurology, 71: 736–742,2008.

    c o r t e x 4 6 ( 2 0 1 0 ) 7 6 9 – 7 8 0780