Auditory Stroop and Absolute Pitch: An fmri Study

Transcription

1 Human Bain Mapping 000:00 00 (2012) Auditoy Stoop and Absolute Pitch: An fmri Study Katin Schulze, 1,2 * Kasten Muelle, 1 and Stefan Koelsch 1,3 1 Max Planck Institute fo Human Cognitive and Bain Sciences, Leipzig, Gemany 2 Developmental Cognitive Neuoscience Unit, UCL Institute of Child Health, London, United Kingdom 3 Cluste of Excellence Languages of Emotion, Feie Univesität Belin, Belin, Gemany Abstact: To date, the undelying cognitive and neual mechanisms of absolute pitch (AP) have emained elusive. In the pesent fmri study, we investigated vebal and tonal peception and woking memoy in musicians with and without absolute pitch. Stimuli wee sine wave tones and syllables (names of the scale tones) pesented simultaneously. Paticipants listened to sequences of five stimuli, and then eheased intenally eithe the syllables o the tones. Finally paticipants indicated whethe a test stimulus had been pesented duing the sequence. Fo an auditoy stoop task, half of the tonal sequences wee conguent (fequencies of tones coesponded to syllables which wee the names of the scale tones) and half wee inconguent (fequencies of tones did not coespond to syllables). Results indicate that fist, vebal and tonal peception ovelap stongly in the left supeio tempoal gyus/sulcus (STG/STS) in AP musicians only. Second, AP is associated with the categoical peception of tones. Thid, the left STG/STS is activated in AP musicians only fo the detection of vebaltonal inconguencies in the auditoy stoop task. Finally, vebal labelling of tones in AP musicians seems to be automatic. Oveall, a unique featue of AP appeas to be the similaity between vebal and tonal peception. Hum Bain Mapp 00: , VC 2012 Wiley Peiodicals, Inc. Key wods: absolute pitch; auditoy peception; auditoy woking memoy; auditoy stoop; supeio tempoal gyus/sulcus INTRODUCTION Absolute pitch (AP) is defined as the ability to identify any pitch of the Westen musical scale without an extenal efeence tone [Miyazaki, 1988; Takeuchi and Hulse, 1993]. To date, the undelying cognitive and neual mechanisms Additional Suppoting Infomation may be found in the online vesion of this aticle. *Coespondence to: Katin Schulze, Developmental Cognitive Neuoscience Unit, UCL Institute of Child Health, 30 Guilfod Steet, London WC1N 1EH, United Kingdom. kschulze@ich.ucl.ac.uk Received fo publication 9 May 2011; Revised 26 Septembe 2011; Accepted 15 Novembe 2011 DOI: /hbm Published online in Wiley Online Libay (wileyonlinelibay. com). of AP have emained elusive. Although AP is a ae ability, undestanding the undelying pocesses is fundamental because AP can seve as a model to undestand how vey special abilities ae epesented in the bain [Zatoe, 2003] and to investigate geneal human peceptual and mnemonic pocesses in the auditoy domain [Bemudez and Zatoe, 2009]. Diffeent hypotheses have been put fowad to explain AP, fo example, categoical peception/pocessing of pitch infomation [Rakowski, 1993; Siegel, 1974], the association of tones with vebal labels [Siegel, 1974], the use of multiple coding stategies [Zatoe and Beckett, 1989], and the assumption of intenal templates of tones which decease the woking memoy (WM) load fo tonal mateial [Hantz et al., 1992; Klein et al., 1984; Zatoe et al., 1998]. These diffeent hypotheses ae not necessaily mutually exclusive. Zatoe [2003] acknowledged the potential complexity of the undelying mechanisms of AP by ascibing AP to two sepaable VC 2012 Wiley Peiodicals, Inc.

2 Schulze et al. cognitive components. He suggested fist, that AP possessos peceive and encode tones within vey naow and fixed pitch categoies (fist component: peception/encoding), and second, that these categoized pitches ae subsequently associated with (vebal) labels (associative memoy). Fist Component Peception/Encoding Seveal studies [Rakowski, 1993; Siegel, 1974] suggested that AP musicians peceive tones categoically, in contast to individuals without AP. In line with this hypothesis, neuophysiological diffeences wee obseved between AP and non-ap musicians duing the peception of tones [Hiata et al., 1999; Itoh et al., 2005; Wu et al., 2008], suggesting that peception and ealy auditoy encoding of tones might ely on diffeent pocesses in AP compaed to non-ap musicians. Using fmri, Schulze et al. [2009] obseved a stonge activation of the left supeio tempoal sulcus (STS) in AP musicians compaed to non-ap musicians duing tone peception. Independent of the ability of AP, an inceased activation of the STS is typically found when the peception of speech is compaed with the peception of non-speech in humans [Binde et al., 2000; Dehaene-Lambetz et al., 2005; Jancke et al., 2002; Liebenthal et al., 2005; Specht et al., 2005]. This diffeence is pesumably due to a categoical (e.g., speech) vesus a noncategoical (e.g., non-speech) peception, which involves the STS and/o the supeio tempoal gyus [STG; Leech et al., 2009; Liebenthal et al., 2005; Luo et al., 2005; Mottonen et al., 2006]. Theefoe, the stonge activation of the left STS in AP compaed to non-ap musicians duing pitch peception indicates a moe categoical peception in AP musicians [Bemudez and Zatoe, 2009; Schulze et al., 2009]. That is, the neual coelates subseving vebal and tonal peception might show a lage ovelap in musicians with than without AP. At a stuctual bain level, it has been suggested that AP is associated with an inceased leftwad planum tempoale asymmety [Keenan et al., 2001; Ludes et al., 2004; Schlaug et al., 1995; Zatoe et al., 1998]; howeve, these esults emain inconsistent [see Bemudez et al., 2009]. Othe studies also indicated that AP musicians show a changed connectivity in the tempoal lobe [Loui et al., 2010; Oechslin, Imfeld et al., 2009]. Theefoe, accumulating data indicate that AP is associated with both stuctual [Keenan et al., 2001; Loui et al., 2010; Ludes et al., 2004; Oechslin, Imfeld et al., 2009; Schlaug et al., 1995; Zatoe et al., 1998] and functional [Ohnishi et al., 2001; Schulze et al., 2009] modifications in the tempoal lobe. Second Component Associative Memoy The association of tones with vebal labels [Siegel, 1974; Takeuchi and Hulse, 1993] o multiple codes [Zatoe and Beckett, 1989] has been suggested to play a ole in AP and is thought to be eflected functionally and anatomically in the posteio dosal fontal egion [Bemudez et al., 2009; Bemudez and Zatoe, 2005; Zatoe et al., 1998]. In the seach fo the undelying cognitive neual substate of AP, shot-tem memoy and woking memoy had also been investigated. Event-elated potential (ERP) studies indicate that AP musicians may not, o to a lesse degee, equie a WM update duing a pitch memoy task compaed with non-ap musicians [Hantz et al., 1992; Itoh et al., 2005; Klein et al., 1984; Wayman et al., 1992; but see also Hiose et al., 2002], because intenal templates facilitate memoy fo tones [Zatoe, 2003]. These findings wee cooboated by fmri esults showing moe activation in the ight paietal lobe (supeio paietal lobule/intapaietal sulcus; SPL/IPS) in non-ap compaed to AP musicians duing a pitch WM task [Schulze et al., 2009], an aea known to be involved in WM [Baddeley, 2003; Schulze et al., 2011a]. To acknowledge potential diffeences between encoding/peception and WM [Bemudez and Zatoe, 2009; Schulze et al., 2009; Zatoe, 2003] we investigated these pocesses sepaately in the pesent fmri study. Tonal and vebal peception and WM eheasal wee compaed between AP musicians and non-ap musicians, to ou knowledge fo the fist time. If, as suggested, vebal and tonal peception ae moe simila in musicians with than without AP [Schulze et al., 2009], then a diffeence should be obseved in the left STS in non-ap musicians when compaing vebal vesus tonal peception, but not in the AP musicians. Duing tonal WM stonge activation of classical WM aeas (Boca s aea, left pemoto cotex, left paietal lobe, and ceebellum) in non-ap musicians, compaed to AP musicians [Schulze et al., 2009] was expected. Auditoy Stoop Task Miyazaki [2004] conducted an auditoy stoop expeiment by pesenting AP musicians with conguent (sung tone name and fequency of sung tone name wee the same) and inconguent auditoy stimuli (sung tone name and fequency of sung tone name wee diffeent). Paticipants wee asked to epeat the syllables, ignoing the pitch. The esults showed longe eaction times fo inconguent than conguent stimuli, suppoting the notion that vebal labeling of tones is automatic fo AP musicians and difficult to suppess, even if disadvantageous. These esults wee eplicated by Itoh et al. [2005], who in addition demonstated that a left posteio tempoal negativity in AP possessos ( AP negativity ) with a latency of 150 ms was modulated by the inconguency duing a listening and pitch-naming task. In the pesent expeiment we investigated the neual coelates of peception and WM of conguent and inconguent sequences in musicians with and without AP. In contast to non-ap musicians, AP musicians wee expected to show a supeio WM pefomance fo the conguent compaed to the inconguent stimuli [Itoh et al., 2005; Miyazaki, 2004; Siegel, 1974]. 2

3 Auditoy Stoop and Absolute Pitch six AP musicians wee ight-handed accoding to the Edinbugh Handedness Inventoy [Oldfield, 1971]; mean latealization quotient was 95% fo non-ap musicians, and 56% fo AP musicians, with no significant diffeence between the two goups (Mann-Whitney test: P ¼ 0.33). An independent-samples t-test showed no diffeence between AP and non-ap musicians fo the age of musical commencement (t 14 ¼ 0.98, P ¼ 0.34). The study was appoved by the local ethics committee of the Univesity of Leipzig, and conducted in accodance with the Declaation of Helsinki. Figue 1. Pefomance in two AP test fo AP and non-ap musicians. Chance level was 25% (answes within one semitone of the pesented pitch wee egaded as a coect answe; see Mateials and Methods). Futhemoe, aeas in the left tempoal lobe [Itoh et al., 2005] wee hypothesized to show a diffeence in AP, but not in non-ap, musicians between the peception of conguent and inconguent sequences. MATERIALS AND METHODS Stimuli, pocedue, and scanning paadigm have been employed by ou goup in pevious expeiments [Schulze et al., 2011a,b]. Paticipants AP and non-ap musicians wee ecuited fom the Univesity of Music and Theate Mendelsohn Batholdy in Leipzig. Eight musicians (thee males) wee assigned to the AP goup afte pefoming two AP tests (see below). Within the AP goup mean age was 25.4 yeas (SD ¼ 4.57; ange: 21 33). AP musicians had stated thei musical taining at an aveage age of 5.94 yeas (SD ¼ 0.86 yeas) and thei AP ability was discoveed on aveage when they wee 9 yeas old (SD ¼ 5.32). Seven of the AP musicians wee not native Geman speakes, but they studied in Gemany and spoke Geman fluently (and, as can be seen in the esults, no diffeence in the vebal WM task was obseved between AP and non-ap musicians). Eight ighthanded (thee males) pofessional musicians without AP wee chosen fom a pool of 16 musicians that had taken pat in pevious expeiments [Schulze et al., 2011a,b] to match the AP goup fo age and gende. Within the non- AP goup mean age was 24.8 yeas (SD ¼ 2.00; ange: 22 27). Non-AP musicians had stated thei musical taining at an aveage age of 6.38 yeas (SD ¼ 0.92 yeas). Two paticipants, who wee not native speakes of Geman (one male, both spoke Geman fluently), wee included in the goup of non-ap musicians. Eight non-ap musicians and AP Testing AP was confimed using two established AP tests [Keenan et al., 2001; Schulze et al., 2009] in which paticipants had to name sine wave tones (duation of each tone ¼ 500 ms). The fist AP test consisted of 13 tones, anging fom F#4 (370 Hz) to F#5 (740 Hz). Each tone was pesented fou times, esulting in 52 sine wave tones. The second AP test consisted of 12 sine wave tones which wee pesented fou times, esulting in 48 tones to name. The tones in this AP test anged fom C2 (65 Hz) to G5 (1568 Hz). In accodance with pevious studies [Keenan et al., 2001; Loui et al., 2010; Miyazaki, 1988; Takeuchi and Hulse, 1993; Wad and Buns, 1982; Wynn, 1992, 1993] answes within one semitone of the pesented pitch wee egaded as coect answes, that is, the chance level of coect esponses was 25%. Paticipants wee instucted to espond as fast and as accuately as possible. Both AP and non-ap musicians pefomed the AP test. As shown in Figue 1, AP musicians pefomed significantly bette than chance (P > 0.001) in both AP tests. They gave 92% (SEM ¼ 2.2%) in the fist and 82% (SEM ¼ 5.6%) coect esponses in the second AP test. Non-AP musicians pefomed at chance level in both test (P > 0.45 fo both). AP musicians esponded on aveage within 1416 ms (SEM ¼ 453 ms) in the fist, and 2024 ms (SEM ¼ 902 ms) in the second test (eaction times wee measued with egad to the offset of the tone that had to be named). To investigate the ability of paticipants to name the tones in moe detail, they wee given an AP questionnaie. Paticipants indicated in this AP questionnaie whethe they could name some tones played by thei instument. Although non-ap musicians pefomed at chance in the AP test, six out of the eight non-ap musicians tested indicated that they can name some tones played by thei instument. Stimuli To ensue that activation diffeences wee not due to diffeent physical popeties of the stimuli, we pesented tones and syllables simultaneously. Each auditoy stimulus compised a spoken syllable and a simultaneously pesented sine wave tone (see Fig. 2), matched fo loudness. The fequencies of the sine wave tones coesponded to 3

4 Schulze et al. Auditoy Stoop Task Figue 2. Expeimental conditions. Vebal and tonal condition: Each auditoy stimulus compised of a spoken syllable and a simultaneously pesented sine wave tone. The fequencies of the sine wave tones coesponded to the fequencies of the tones of the Westen chomatic scale. The syllables wee the spoken Geman names of the scale tones (e.g., gis [g-shap], c, etc.). Conguent and inconguent condition: In 50% of the sequences the fequency of the sine wave tones coesponded to the simultaneously pesented syllables (conguent sequences) and in the emaining 50% of sequences, the fequency of the sine wave tones did not coespond to the syllables (inconguent sequences). Conguent and inconguent conditions wee only compaed duing the tonal condition. the fequencies of the tones of the Westen chomatic scale (based on A4 ¼ 440 Hz), and anged fom 261 Hz to 523 Hz (C4 C5; one octave), esulting in 13 diffeent tones of 12 pitch classes. The syllables wee spoken by a pofessional male speake and wee the Geman names of the scale tones (e.g., gis [g-shap], c, etc.), esulting in 12 diffeent syllables (tones with a fequency of 261 Hz and 523 Hz ae both efeed to as c). In each expeimental tial, five such stimuli wee pesented in a sequence. Each stimulus had duation of 400 ms, with peiods of 150 ms of silence between them, esulting in a sequence length of 2600 ms. Pocedue Thee wee two tasks, a vebal and a tonal task (see Fig. 2 fo illustation). In both tasks, paticipants listened to sequences of five auditoy stimuli (the sample stimuli sequence). They wee instucted to intenally ehease the syllables duing the vebal task o the tones duing the tonal task fo 4200 up to 6200 ms. At the end of each tial a test stimulus was pesented, consisting of the simultaneous pesentation of one syllable and one sine wave tone, and paticipants had to indicate by a button pess, whethe the syllable (in the vebal task), o the sine wave tone (in the tonal task), had aleady been pesented duing the sample stimuli sequence. The syllables wee the names of the scale tones. In 50% of the sequences the fequency of the sine wave tones coesponded to the simultaneously pesented syllables (conguent sequences) and in the emaining 50% of sequences, the fequency of the sine wave tones did not coespond to the syllables (inconguent sequences). Conguent and inconguent conditions wee only compaed duing the tones condition (see Fig. 2 fo a visualization of examples fo conguent and inconguent sequences). To ensue that, as in the conguent condition, thee would be no diffeence between the vebal and tonal contou in the inconguent sequences, the vebal and tonal contous wee matched (e.g., vebal sequence (F G A D B) and tonal sequence (A B C# F# D)). Duing a pink noise contol condition, paticipants did not pefom a vebal o tonal WM task: Pink noise was pesented instead of the sample stimuli sequence and the test stimulus to contol fo the auditoy peceptual input. Additionally, paticipants pessed a pedefined button afte the end of the sequence to account fo the moto esponse. The sequences wee pesented pseudoandomly in a blocked design, and paticipants stated eithe with a vebal o tonal block (countebalanced acoss paticipants and goups) fo a total of 10 blocks. Each block consisted of 16 expeimental sequences (1 sequence), esulting in 160 expeimental sequences, 80 pesented duing the vebal task, and 80 pesented duing the tonal task. At the beginning of each block a visual cue indicated whethe the WM task fo the next block was the vebal o tonal task. In each block, thee pink noise contol sequences (1 sequence) wee pesented additionally, esulting in a total of 30 pink noise contol sequences. The blocks and sequences used wee identical fo the tone and vebal WM task. Paticipants wee epeatedly instucted not to sing o hum aloud duing the scanning session. Behavioal Data Analysis Pefomance data (as pecentage of coect esponses) wee analyzed with the SPSS v.16 statistical softwae package (SPSS, Chicago, IL). If the data wee nomally distibuted (Shapio-Wilk test) ANOVAs and t-tests wee used to analyze within-paticipant and between-paticipant diffeences, espectively. If the data wee not nomally distibuted non-paametic test equivalents wee used (Wilcoxon tests and Mann Whitney U tests). Scanning Paadigm The scanning paadigm was a modified vesion of the spase tempoal sampling technique [Hall et al., 1999], that is, auditoy stimulation was pesented in the absence of the scanne noise. Two scans pe tial wee acquied. This allowed us to scan the hemodynamic esponse associated 4

5 Auditoy Stoop and Absolute Pitch with (a) the peception/encoding (fist scan) and (b) the eheasal (second scan) of the sequences. Five diffeent onsets of the auditoy sequence elative to the fist scan wee used to allow optimal sampling of the hemodynamic esponse associated with the encoding (scans occued 0, 500, 1000, 1500, o 2000 ms afte the auditoy pesentation). The eheasal time diffeed in length accodingly (eheasal times: 4200, 4700, 5200, 5700, o 6200 ms). The fist scan was associated with peceptual/encoding pocesses, and the second scan captued the BOLD esponse associated with the WM eheasal pocess. This scanning paadigm, which had been used by ou goup in pevious expeiments [Schulze et al., 2011a,b], enabled us to analyze data of the fist scan (encoding/peception) and second scan (WM eheasal) sepaately. Data Acquisition The expeiment was caied out on a 3T scanne (Siemens TRIO, Elangen). Befoe each functional session, an anatomical efeence data set was acquied fo each paticipant, which was standadized to the Talaiach steeotactic space [Talaiach and Tounoux, 1988]. A bunched gadient-echo EPI sequence was used with a TE of 30 ms, a flip angle of 90 and a TR of 6600 ms and an acquisition bandwidth of 100 khz. 24 axial slices wee acquied apidly within appoximately 1600 ms, so that no scanning occued duing the est of the TR. The matix dimensions wee with a field of view (FOV) of 192 mm, esulting in a voxel size of 3 3, slice thickness of 4 mm, and an inteslice gap of 1 mm. Data Analysis Pe-pocessing, statistical analysis and visualization of the fmri data wee pefomed with the softwae package LIPSIA [Lohmann et al., 2001]. An offline motion coection was pefomed on the functional images, using the Siemens motion coection potocol. Theeafte, functional slices wee aligned to a 3D steeotactic coodinate efeence system. The egistation paametes wee acquied to achieve an optimal match between the functional slices and the individual 3D efeence dataset, which was standadized to the Talaiach steeotactic space [Talaiach and Tounoux, 1988]. In addition to this linea tansfomation, a non-linea egistation was pefomed between the anatomical 3D datasets of the goup [Thiion, 1998], and the esulting defomation fields wee applied to the associated functional datasets. In the last step of pe-pocessing, the data wee smoothed with a Gaussian filte of 8-mm full width at half maximum. The statistical evaluation was based on the geneal linea model [Fiston et al., 1998]. Contast images wee geneated by computing diffeences between the paamete estimates (e.g., between the tonal and the vebal condition). To estict the statistical analysis to elevant voxels inside the bain, a mask was applied to eliminate data fom outside the bain and in the venticula system. In addition, contast images showing diffeences between AP and non-ap musicians fo the vebal tonal peception wee esticted to the left hemisphee accoding to ou hypothesis [see Intoduction, and Hiata et al., 1999; Itoh et al., 2005; Loui et al., 2010; Oechslin, Imfeld et al., 2009; Schulze et al., 2009; Wilson et al., 2009]. Contast images wee enteed into a second-level andom effects analysis. One-sample t-tests wee pefomed to evaluate whethe obseved diffeences wee significantly diffeent fom zeo. To potect against false-positive activation, the esults wee coected fo multiple compaisons by the use of cluste-size and cluste-value thesholds obtained by Monte Calo simulations with a significance level of P < 0.05 [Lohmann et al., 2008]. Clustes wee obtained with a voxel-wise theshold of P < and an extent theshold of 10 voxels [Foman et al., 1995]. The activation diffeences between vebal and tonal peception; vebal and tonal eheasal; inconguent and conguent peception; and inconguent and conguent eheasal wee compaed between AP and non-ap goups using inteaction contasts (goup x condition). Significant activation diffeences obseved in these inteaction contasts wee then futhe investigated with within-goup compaisons (vebal vs. tonal peception, vebal vs. tonal eheasal, inconguent vs. conguent peception, and inconguent vs. conguent eheasal wee compaed in AP and non-ap musicians sepaately) and with between-goup compaisons (conguent peception, conguent eheasal, inconguent peception, inconguent eheasal, vebal peception, vebal eheasal, tonal peception, and tonal eheasal wee compaed between AP and non-ap musicians). Theefoe, within- and between-goup analyses wee epoted in egions showing a significant (goup condition) inteaction. RESULTS Pefomance data fo both goups is visualized in Figue 3. Pefomance of AP musicians in the tonal task was significantly bette compaed to the non-ap musicians (t 14 ¼ 2.64, P ¼ 0.02). In the vebal task, pefomance did not diffe between goups (Z ¼ 0.21; P ¼ 0.83). Significant diffeences between goups wee obseved fo the conguent condition (Z ¼ 2.7; P ¼ 0.007), but not fo the inconguent condition (Z ¼ 1.1; P ¼ 0.268; Bonfeoni coected alpha fo multiple compaisons: P < 0.025). Within-paticipant diffeences between the conguent and the inconguent condition wee neithe obseved fo the AP musicians (Z ¼ 1.28; P ¼ 0.202) no fo the non-ap musicians (Z ¼ 0.49; P ¼ 0.622). An ANOVA with within-paticipant facto Mateial (conguent/inconguent) and between-paticipant facto AP (AP and non-ap) was used to analyse eaction times. This analysis showed no main effect of Mateial (F 1,14 ¼ 0.055, P ¼ 0.82) o AP (F 1,14 ¼ 0.11, P ¼ 0.75), and no Mateial*AP Inteaction (F 1,14 ¼ 2.40, P ¼ 0.14). 5

6 Schulze et al. Figue 3. WM pefomance (in % coect esponses) fo AP and non-ap musicians pesented as a function of sequence type (conguent/inconguent) eo bas indicate the standad eo of mean (SEM). fmri Data Significant activation diffeences obseved in the inteaction contasts wee futhe investigated with within-goup and with between-goup compaisons (see Mateials and Methods). Activations ae listed in Table I and ae shown in Figue 4 (a complete list of activation diffeences between and within goups fo all conditions is povided in the Suppoting Infomation Table I). Vebal Vesus Tonal Peception and Reheasal The statistical analysis fo the contast showing diffeences between AP and non-ap musicians fo the vebal tonal peception was esticted to the left hemisphee (see Methods). AP musicians showed stonge activation of the left middle occipital gyus (BA 19) duing vebal compaed to tonal peception. In non-ap musicians an inceased BOLD esponse was obseved in the left anteio STG/STS (BA 22/38) and in the left lingual gyus (BA 18) duing vebal compaed to tonal peception (see Fig. 4). Neithe fo AP musicians no fo non-ap musicians, we obseved stonge activation fo tonal peception when compaed to vebal peception. Futhemoe, fo both goups, no functional diffeences between the vebal and the tonal condition wee obseved duing eheasal. Inconguent Vesus Conguent Peception and Reheasal The supeio fontal gyus (SFG; BA 10) bilateally, the anteio and middle potion of the left STG/STS (BA 22), and the ight postcental gyus (BA 43) exhibited stonge activation duing inconguent compaed to conguent peception in AP musicians (see Fig. 4). No stuctue showed an inceased BOLD esponse duing conguent compaed to inconguent peception in AP musicians. In contast to AP musicians, who showed stonge activation only duing inconguent compaed to conguent peception (but not vice vesa), non-ap musicians exhibited stonge activations only fo conguent compaed to inconguent peception. The left supamaginal gyus/stg (BA 40/41), the ight lingual/fusifom gyus (BA 19/37), the cuneus (BA 18/19) and the ceebellum bilateally showed inceased activation fo the peception of the conguent compaed to the inconguent sequences in non-ap musicians. Fo both goups, no functional diffeences wee obseved compaing conguent and inconguent eheasal. Tonal Peception and WM Between AP and Non-AP Musicians The compaison of tonal peception and WM between AP and non-ap musicians was of inteest in the pesent study because a stonge activation of the left STG/STS was expected [Schulze et al., 2009], but no diffeences wee obseved. The complete list of activation diffeences between and within goups fo all conditions is povided in the Suppoting Infomation Table I. DISCUSSION Behavioal Data A bette pefomance fo the conguent, but not the inconguent sequences was obseved fo the AP musicians compaed to the non-ap musicians. Ou behavioal esults theefoe indicate that the vebal labelling of the tones in AP musicians is at least patly automatic, even if this is disadvantageous. Thus, these esults cooboate findings by Miyazaki [2004] and Itoh et al. [2005]. Oveall, AP musicians showed a bette pefomance fo tone sequences (inconguent and conguent togethe) than non-ap musicians, a esult which is consistent with the liteatue [Siegel, 1974; Zatoe et al., 1998]. Futhemoe, ou data did not show a diffeence between musicians with and without AP fo the vebal sequences, indicating that AP musicians do not simply have a bette WM capacity. fmri Data As hypothesized, we obseved a stonge BOLD esponse in the left STG/STS duing vebal peception compaed to tonal peception in non-ap musicians, but not AP musicians. This esult is in accodance with a study [Schulze et al., 2009] that showed a stonge 6

7 Auditoy Stoop and Absolute Pitch TABLE I. Within- and between-goup (AP and non-ap musicians) activation diffeences (vebal and tonal peception/eheasal; inconguent and conguent peception/eheasal) Left hemisphee Right hemisphee Coodinates x, y, z z-value Coodinates x, y, z z-value Coodinates x, y, z z-value Coodinates x, y, z z-value Coodinates x, y, z z-value Coodinates x, y, z z-value Stuctue BA Inteaction contast goup (AP vs. non-ap) condition AP Non-AP Inteaction contast goup (AP vs. non-ap) condition AP Non-AP Vebal > tonal peception PMd 6 32, 6, Anteio STG/STS 22/38 50, 3, , 3, Middle occipital gyus 19 35, 87, , 87, Lingual gyus 18 14, 96, , 99, Vebal > tonal eheasal n.s. Inconguent > conguent peception SFG 9/10 23, 60, , 60, , 57, , 57, STG/STS 22 59, 15, , 15, Supamaginal gyus/stg 40/41 44, 21, , 21, , 18, , 15, Postcental gyus 43 58, 9, , 12, Lingual/fusifom gyus 19/37 32, 57, , 45, , 48, Middle occipital gyus 19 37, 66, Cuneus 18/19 14, 93, , 96, , 90, , 90, Ceebellum 20, 60, , 57, , 54, , 54, , 63, , 60, , 54, , 54, Inconguent > conguent eheasal n.s. In AP o non-ap columns: positive z-values ¼ vebal > tonal o inconguent > conguent; negative z-values ¼ tonal > vebal o conguent > inconguent. All activations ae coected fo multiple compaisons with a significance level of P < Clustes wee obtained using a voxel-wise theshold of P < and an extent theshold of 10 voxels. The statistical analysis fo the contast showing diffeences between AP and non-ap musicians fo the vebal>tonal peception was esticted to the left hemisphee (see Methods). BA, Bodmann aea; PMd, dosolateal pemoto cotex; SFG, supeio fontal gyus; STG, supeio tempoal gyus; STS, supeio tempoal sulcus. 7

8 Schulze et al. Figue 4. Significant diffeences ae shown with blue (A) o ed/yellow tion in non-ap musicians. C Inteaction contast: diffeence (B D) colo-coding using a cluste theshold of P < 0.05, co- inconguent conguent peception has been compaed ected. A Inteaction contast: diffeence vebal tonal was between AP and non-ap musicians. D Stonge activation of compaed between AP and non-ap musicians. B Stonge acti- left STG/STS duing inconguent compaed to conguent pevation of left STG/STS duing vebal compaed to tonal pecep- ception in AP musicians. posteio STS in violinists (compaed to non-violinists) duing listening to music, a egion that is typically associated with the analysis of speech. Because the neual coelates undelying vebal and tonal peception have, to ou knowledge, neve been compaed between AP and non-ap musicians befoe, ou study epots fo the fist time that this well-known vebal tonal diffeence in the left STG/STS is not obseved in AP possessos. Thus, ou findings indicate that vebal and tonal peception stongly ovelap in the left STG/STS in AP musicians, but not in non-ap musicians. This cooboates and extends findings by pevious studies: Schulze et al. [2009] epoted a stonge activation of the left STS in AP musicians compaed to non-ap musicians duing tonal peception. Howeve, the activation obseved in the pesent study is moe anteio than the activation epoted in the pevious study [Schulze et al., 2009]. This discepancy is pesumably due to two aspects. Fist, all tones in the pesent expeiment in contast to Schulze et al. [2009] coesponded to the fequencies of the tones of the Westen musical scale and second, the epoted contasts. While Schulze et al. [2009] compaed only tonal peception between AP and non-ap musicians, the pesent involvement of the left STS in AP musicians duing the peception of tone stimuli, compaed to non-ap musicians. This finding is taken hee to eflect a moe categoical peception in AP musicians based on the following consideations. Humans show a stonge activation of the left anteio and mid-potion of the STG/STS duing the peception of vebal mateial compaed to tones [Binde et al., 2000; Liebenthal et al., 2005]. This stuctue appeas to be impotant in phonemic peception and categoical peception. A moe posteio activation of the left STG/STS exhibited stonge activation afte a taining in which paticipants leaned to peceive stimuli as intelligible speech, compaed to a pe-taining condition in which the same stimuli could not be undestood [Desai et al., 2008; Leech et al., 2009; Mottonen et al., 2006]. Futhemoe, Scott and colleagues [e.g., Scott et al., 2000, 2006] demonstated that the peception of intelligible speech, contasted against the peception of noise-vocoded speech (that contained some phonetic infomation), elicited activations in the left anteio STS. Results by Dick et al. [2010] suggest that the left posteio STS egion is involved in the categoization of auditoy infomation that is elevant fo behavio. This conclusion is based on an inceased activation of the left 8

9 Auditoy Stoop and Absolute Pitch study included a vebal condition. In contast to Schulze et al. [2009], no diffeence in the left STS was obseved in the pesent study when compaing tonal peception between AP and non-ap musicians. This might be due to the smalle goup size in the pesent study. In anothe study speed and accuacy duing a pitch naming task in AP musicians was associated with activation in the left posteio STG [Wilson et al., 2009] and the authos suggested that this finding points to a neuobiological basis of an AP template in the tempoal lobe. These functional diffeences [Schulze et al., 2009; Wilson et al., 2009] wee suppoted by anatomical diffeences between musicians with and without AP: Loui et al. [2010] showed that individuals with AP possess enhanced white matte connectivity between STG and MTG, a neual coelate that might undelie the modified peception in AP musicians. Futhemoe, wheeas Oechslin, Meye et al. [2009] obseved that the ability of AP is associated with diffeent functional esponses to vebal mateial in the tempoal lobe, we did not obseve diffeences in the tempoal lobe between both goups duing the vebal task. To summaize, the obseved ovelap between vebal and tonal peception in the left STG/STS associated with AP suggests a categoical peception of tones in AP musicians, compaable to vebal peception. Thus, the findings epoted hee suppot the assumption that AP aleady influences peception [Zatoe, 2003]. The second main esult is that inconguent sequences elicited an inceased BOLD esponse in the left anteio STG/STS in AP musicians, but not in non-ap musicians, in a simila egion that was moe stongly involved duing vebal compaed to tonal peception in non-ap musicians but not in AP musician. This indicates that the anteio STG/STS is involved in detecting the inconguencies between tones and tone-names. As aleady discussed above, the middle potion of the STS is involved in phonemic pocessing [e.g., Binde et al., 2000; Liebenthal et al., 2005; Scott et al., 2000, 2006], categoical peception [Liebenthal et al., 2005], and pocessing of intelligible vebal mateial [e.g., Scott et al., 2000, 2006]. Itoh et al. [2005] conducted an EEG study to investigate the auditoy stoop effect in AP and non-ap musicians. They obseved an AP negativity (maximal ove left posteio STG egions, with a peak latency of 150 ms), which was elicited duing both listening and pitch-naming conditions. Notably, this effect was modulated by stimulus inconguency, and the amplitude of this effect was significantly smalle fo inconguent compaed to conguent stimuli. Ou esults togethe with pevious EEG studies [Hiata et al., 1999; Itoh et al., 2005; Wu et al., 2008] cooboate the notion that AP affects tone pocessing as ealy as duing peception. Futhemoe, the pesent fmri study evealed that the left STG/STS in AP musicians might undelie the peception of inconguency duing an auditoy stoop task. In addition, AP musicians, but not non-ap musicians, showed an inceased activation of the supeio fontal gyus (SFG; BA 10), also temed fontopola cotex, duing the peception of inconguent sequences compaed to conguent sequences. The fontopola cotex is known to be involved in a multitude of highe-level cognitive tasks [fo an oveview see Koechlin and Hyafil, 2007], fo example in (i) decision making, especially duing moe unstuctued situations, (ii) the exploation and selection of all possible options and switching back and foth between altenatives, and (iii) solving seveal intenal tasks and integating thei esults. Thus, ou data indicate that fo the AP musicians the inconguent condition inceased the cognitive demand in tems of attention, woking memoy and multitasking, pesumably due to the intenal discepancy of the stimuli [fo an oveview see Gilbet et al., 2006]. The functional diffeence, that is, a stonge involvement of the fontopola cotex duing the peception of inconguent compaed to conguent sequences, togethe with the behavioal esult of a tendency towads a bette pefomance fo conguent compaed to inconguent sequences, suggest that the vebal labelling of tones is at least patly automatic in AP musicians, even if this is disadvantageous. Inteestingly, even though sine wave tones wee used [which ae moe difficult to name than tones played by an instument; see Takeuchi and Hulse, 1993] and although we contolled fo the contou between tones and tone names in the inconguent condition (see Mateials and Methods), a diffeence in bain activation fo non-ap musicians between the inconguent and conguent condition was obseved: The left supamaginal gyus/stg, the ight lingual/fusifom gyus, and bilateally the cuneus and the ceebellum showed inceased activation duing the peception of the conguent compaed to the inconguent sequences. These functional diffeences in non-ap musicians wee supising because (i) non-ap musicians did not show a pefomance diffeence between conguent and inconguent sequences and (ii) non-ap musicians pefomed at chance fo the AP tests. Howeve, it has been poposed that thee ae latent foms of AP [fo an oveview see Vitouch, 2003], which povides a potential explanation fo the obseved activation diffeence between the peception of conguent and inconguent sequences in non-ap musicians. This intepetation was cooboated by the answes of the non-ap musicians given fo the AP questionnaies: Six out of the eight non-ap musicians tested indicated that they can name some tones played by thei instument (such as the tones of the open stings of a sting instument). The supamaginal gyus and the ceebellum, which inteestingly showed inceased activation duing the conguent compaed to the inconguent sequences in non-ap musicians, ae pat of a netwok undelying vebal and tonal WM [Gaab et al., 2003; Gaab and Schlaug, 2003; Hickok et al., 2003; Koelsch et al., 2009; Schulze et al., 2011a]. Ou esults indicate that non-ap musicians elied moe stongly on these classical WM egions duing the 9

10 Schulze et al. conguent compaed to the inconguent condition. Activation in the occipital cotex, which again was moe stongly activated in non-ap musicians duing the conguent condition compaed to the inconguent condition, has been obseved to be involved in the peception of tones and melodies [Belin et al., 1999; Platel et al., 1997; Satoh et al., 2001], and when musicians imagined to play [Meiste et al., 2004] o actually played thei instument [Pasons et al., 2005]. This suggests, togethe with ou esults, that some fom of visual imagey might have played a ole duing peceiving conguent, compaed to inconguent, sequences in non-ap musicians. Because this study was mainly designed to investigate conguent and inconguent peception and eheasal in AP musicians, futue studies ae needed to investigate how conguency influences peception and eheasal of pitch infomation in musicians without absolute pitch. It should be noted that the diffeences obseved between AP and non-ap musicians cannot be due to the fact that Geman was not the native language fo moe of the AP musicians because: (a) the paticipants wee studying music in Gemany and whee fluent Geman speakes, (b) we did not obseve a behavioal diffeence in WM fo vebal mateial between both goups, and (c) no functional diffeence in the left STG/STS was obseved duing vebal peception between AP and non-ap musicians. It has been suggested that thee ae two main auditoy pathways that both poject fom the auditoy cotex [Hickok and Poeppel, 2007; Rauschecke, 1998; Rauschecke and Scott, 2009; Rauschecke and Tian, 2000]: A dosal pathway pojects into the posteio paietal and fontal cotex and is thought to be esponsible fo spatial pocessing [Rauschecke and Scott, 2009] and sensoimoto integation [Hickok and Poeppel, 2007]. A vental what pathway pojects into the anteio tempoal cotex and is involved in the identification of auditoy objects [Hickok and Poeppel, 2007; Rauschecke and Scott, 2009]. Ou finding of an absent functional diffeence between vebal and tonal peception and the stonge activation of the left STG/STS duing inconguent compaed to conguent sequences in AP musicians suggests that the left anteio STG/STS (i.e., pat of the what pathway) is in AP musicians also involved in peceiving (and identifying) tones. It is assumed that the ability of AP does not only influence the peception of tones, but also WM fo tones. Seveal studies [Hantz et al., 1992; Klein et al., 1984; Wayman et al., 1992] epoted a lack, o a eduction, of the P300- ERP in AP musicians in a pitch memoy task. Because the P300 is an electophysiological index fo WM pocesses [Klein et al., 1984], this was taken to eflect that AP musicians update thei WM less fequently (compaed to non- AP musicians) due to intenal tone templates [Zatoe et al., 1998]. Schulze et al. [2009] also obseved a stonge activation of the ight SPL/IPS, possibly indicating a stonge involvement of WM elated aeas in non-ap musicians compaed to non-ap musicians duing a WM task fo tones. Theefoe, we expected diffeences fo tonal WM between AP and non-ap musicians in the pesent study. Howeve, when compaing tonal o vebal WM between AP and non-ap musicians, no diffeences wee obseved. Pehaps the functional diffeences obseved duing tonal peception in ou study also contibuted to a supeio pefomance of AP musicians duing the tonal WM task; this issue emains to be specified. SUMMARY AND CONCLUSIONS The data eveal that, in the left STG/STS, neual esouces fo vebal and tonal peception ovelap moe stongly in AP musicians than in non-ap musicians. Likewise, the left anteio STG/STS is involved in the detection of inconguent stimuli duing an auditoy stoop task in AP musicians, but not in non-ap musicians. This is taken to eflect that peceiving and identifying tones involves the what pathway of the auditoy system (of which the anteio STG/STS is pat) in AP musicians. Ou esults also indicate that fist, AP is associated with the categoical peception of tones; second, the left STG/STS is activated in AP musicians only fo the detection of vebal-tonal inconguencies in the auditoy stoop task; and finally, vebal labelling of tones in AP musicians seems to be automatic. Oveall, a unique featue of AP appeas to be the similaity between vebal and tonal peception. ACKNOWLEDGMENTS This wok was suppoted by the Geman Reseach Foundation (Deutsche Foschungsgemeinschaft, gant KO 2266/4-1 awaded to S.K.) and the Max Planck Society. REFERENCES Baddeley AD (2003): Woking memoy: Looking back and looking fowad. Nat Rev Neuosci 4: Belin P, Zatoe RJ, Hoge R, Evans AC, Pike B (1999): Eventelated fmri of the auditoy cotex. Neuoimage 10: Bemudez P, Lech JP, Evans AC, Zatoe RJ (2009): Neuoanatomical coelates of musicianship as evealed by cotical thickness and voxel-based mophomety. Ceeb Cotex 19: Bemudez P, Zatoe RJ (2005): Conditional associative memoy fo musical stimuli in nonmusicians: Implications fo absolute pitch. J Neuosci 25: Bemudez P, Zatoe RJ (2009): The absolute pitch mind continues to eveal itself. J Biol 8:75. Binde JR, Fost JA, Hammeke TA, Bellgowan PS, Spinge JA, Kaufman JN, Possing ET (2000): Human tempoal lobe activation by speech and nonspeech sounds. Ceeb Cotex 10: Dehaene-Lambetz G, Pallie C, Seniclaes W, Spenge-Chaolles L, Jobet A, Dehaene S (2005): Neual coelates of switching fom auditoy to speech peception. Neuoimage 24: Desai R, Liebenthal E, Waldon E, Binde JR (2008): Left posteio tempoal egions ae sensitive to auditoy categoization. J Cogn Neuosci 20:

11 Auditoy Stoop and Absolute Pitch Dick F, Lee HL, Nusbaum H, Pice CJ (2010): Auditoy-moto expetise altes speech selectivity in pofessional musicians and actos. Ceeb Cotex doi: /ceco/bhq166. Foman SD, Cohen JD, Fitzgeald M, Eddy WF, Mintun MA, Noll DC (1995): Impoved assessment of significant activation in functional magnetic esonance imaging (fmri): Use of a cluste-size theshold. Magn Reson Med 33: Fiston KJ, Fletche P, Josephs O, Holmes A, Rugg MD, Tune R (1998): Event-elated fmri: Chaacteizing diffeential esponses. Neuoimage 7: Gaab N, Gase C, Zaehle T, Jancke L, Schlaug G (2003): Functional anatomy of pitch memoy-an fmri study with spase tempoal sampling. Neuoimage 19: Gaab N, Schlaug G (2003): The effect of musicianship on pitch memoy in pefomance matched goups. Neuoepot 14: Gilbet SJ, Spengle S, Simons JS, Steele JD, Lawie SM, Fith CD, Bugess PW (2006): Functional specialization within ostal pefontal cotex (Aea 10): A meta-analysis. J Cogn Neuosci 18: Hall DA, Haggad MP, Akeoyd MA, Palme AR, Summefield AQ, Elliott MR, Guney EM, Bowtell RW (1999): Spase tempoal sampling in auditoy fmri. Hum Bain Mapp 7: Hantz EC, Cumme GC, Wayman JW, Walton JP, Fisina RD (1992): Effects of musical taining and absolute pitch on the neual pocessing of melodic intevals: A P3 event-elated potential study. Music Peception 10: Hickok G, Buchsbaum B, Humphies C, Muftule T (2003): Auditoy-moto inteaction evealed by fmri: Speech, music, and woking memoy in aea Spt. J Cogn Neuosci 15: Hickok G, Poeppel D (2007): The cotical oganization of speech pocessing. Nat Rev Neuosci 8: Hiata Y, Kuiki S, Pantev C (1999): Musicians with absolute pitch show distinct neual activities in the auditoy cotex. Neuoepot 10: Hiose H, Kubota M, Kimua I, Ohsawa M, Yumoto M, Sakakihaa Y (2002): People with absolute pitch pocess tones with poducing P300. Neuosci Lett 330: Itoh K, Suwazono S, Aao H, Miyazaki K, Nakada T (2005): Electophysiological coelates of absolute pitch and elative pitch. Ceeb Cotex 15: Jancke L, Wustenbeg T, Schulze K, Heinze HJ (2002): Asymmetic hemodynamic esponses of the human auditoy cotex to monaual and binaual stimulation. Hea Res 170: Keenan JP, Thangaaj V, Halpen AR, Schlaug G (2001): Absolute pitch and planum tempoale. Neuoimage 14: Klein M, Coles MGH, Donchin E (1984): People with absolute pitch pocess tones without poducing a P300. Science 223: Koechlin E, Hyafil A (2007): Anteio pefontal function and the limits of human decision-making. Science 318: Koelsch S, Schulze K, Sammle D, Fitz T, Mulle K, Gube O. (2009).Functional achitectue of vebal and tonal woking memoy: An FMRI study. Hum Bain Mapp 30: Leech R, Holt LL, Devlin JT, Dick F (2009): Expetise with atificial nonspeech sounds ecuits speech-sensitive cotical egions. J Neuosci 29: Liebenthal E, Binde JR, Spitze SM, Possing ET, Medle DA (2005): Neual substates of phonemic peception. Ceeb Cotex 15: Lohmann G, Mulle K, Bosch V, Mentzel H, Hessle S, Chen L, Zysset S, von Camon DY (2001): LIPSIA a new softwae system fo the evaluation of functional magnetic esonance images of the human bain. Comput Med Imaging Gaph 25: Lohmann G, Neumann J, Muelle K, Lepsien J, Tune R (2008): The multiple compaison poblem in fmri a new method based on anatomical pios. In: Poceedings of the Fist Wokshop on Analysis of Functional Medical Images. In 11th Intenational Confeence on Medical Image Computing and Compute Assisted Intevention (MICCAI) (New Yok City). Loui P, Li HC, Hohmann A, Schlaug G (2010): Enhanced cotical connectivity in absolute pitch musicians: A model fo local hypeconnectivity. J Cogn Neuosci 23: Ludes E, Gase C, Jancke L, Schlaug G (2004): A voxel-based appoach to gay matte asymmeties. Neuoimage 22: Luo H, Husain FT, Howitz B, Poeppel D (2005): Discimination and categoization of speech and non-speech sounds in an MEG delayed-match-to-sample study. Neuoimage 28: Meiste IG, Kings T, Foltys H, Booojedi B, Mulle M, Toppe R, Thon A (2004): Playing piano in the mind-an fmri study on music imagey and pefomance in pianists. Bain Res Cogn Bain Res 19: Miyazaki K.1988.Musical pitch identification by absolute pitch possessos. Pecept Psychophys 44: Miyazaki K (2004): The Auditoy Stoop Intefeence and the Ielevant Speech/Pitch Effect: Absolute-Pitch Listenes Can t Suppess Pitch Labeling. summay?doi Mottonen R, Calvet GA, Jaaskelainen IP, Matthews PM, Thesen T, Tuomainen J, Sams M (2006): Peceiving identical sounds as speech o non-speech modulates activity in the left posteio supeio tempoal sulcus. Neuoimage 30: Oechslin MS, Imfeld A, Loenneke T, Meye M, Jancke L (2009): The plasticity of the supeio longitudinal fasciculus as a function of musical expetise: A diffusion tenso imaging study. Font Hum Neuosci 3:76. Oechslin MS, Meye M, Jancke L (2009): Absolute pitch Functional evidence of speech-elevant auditoy acuity. Ceeb Cotex 20: Ohnishi T, Matsuda H, Asada T, Auga M, Hiakata M, Nishikawa M, Katoh A, Imabayashi E (2001): Functional anatomy of musical peception in musicians. Ceeb Cotex 11: Oldfield R C (1971): The assessment and analysis of handedness: The Edinbugh inventoy. Neuopsychologia 9: Pasons LM, Segent J, Hodges DA, Fox PT (2005): The bain basis of piano pefomance. Neuopsychologia 43: Platel H, Pice C, Baon JC, Wise R, Lambet J, Fackowiak RS, Lechevalie B, Eustache F (1997): The stuctual components of music peception. A functional anatomical study. Bain 120: Rakowski A (1993): Categoical peception in absolute pitch. Ach Acoust 18: Rauschecke JP (1998): Cotical pocessing of complex sounds. Cu Opin Neuobiol 8: Rauschecke JP, Scott SK (2009): Maps and steams in the auditoy cotex: Nonhuman pimates illuminate human speech pocessing. Nat Neuosci 12: Rauschecke JP, Tian B (2000): Mechanisms and steams fo pocessing of what and whee in auditoy cotex. Poc Natl Acad Sci USA 97: Satoh M, Takeda K, Nagata K, Hatazawa J, Kuzuhaa S (2001): Activated bain egions in musicians duing an ensemble: A PET study. Bain Res Cogn Bain Res 12: