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Can we record the valid visual mismatch negativity to a windmill pattern during auditory attention?
International Congress Series 1278 (2005) 401 – 404
www.ics-elsevier.com
Can we record the valid visual mismatch negativity to a windmill pattern during auditory attention? Toshihiko Maekawa*, Yoshinobu Goto, Shozo Tobimatsu Department of Clinical Neurophysiology, Neurological Institute, Graduate School of Medical Sciences, Kyushu University, 3-1-1 Maidashi, Higashiku, Fukuoka 812-8582, Japan
Abstract. The aim of this study was to record valid visual mismatch negativity (V-MMN) to a circular black–white windmill pattern. Seven adults were instructed to pay attention to a story through the earphones. The ratio of the standard (S), deviant (D) and target (T) stimuli was 8:1:1, and they appeared in a random sequence with inter-stimulus interval for 800 ms. The difference among the three stimuli was the number of vanes. ERPs were recorded from 20 sites over the scalp. The number of vanes in each stimulus was systematically changed to observe the relationship among the ERPs to the S, D and T stimuli. P300 was only obtained in response to the T stimulus. A negative potential appeared during the period of 150–300 ms after the stimulus onset by subtracting the ERPs to the S stimulus from those of the D stimulus. This negativity was distributed over the occipitotemporal region. Characteristics of this negativity were similar to those of auditory MMN. V-MMN in our study consisted of early (150–200 ms, MMN1) and late (200–300 ms, MMN2) components. The magnitudes of MMN1 and MMN2 were not altered with varying the D and T stimuli. However, the peak latency of MMN2 was significantly altered with varying the D stimuli, but not MMN1. Therefore, valid V-MMN can be recorded by the windmill patterns during auditory attention. D 2004 Elsevier B.V. All rights reserved. Keywords: Visual mismatch negativity; Pre-attentive processing; Windmill pattern
1. Introduction The strategy of recognition is thought to consist of pre-attentive and attentive stages [1]. Pre-attentive processing has been studied by recording the mismatch negativity (MMN) associated with the detection of stimulus change [2]. MMN is evoked when infrequent * Corresponding author. Tel.: +81 92 642 5543; fax: +81 92 642 5545. E-mail address: [email protected] (T. Maekawa). 0531-5131/ D 2004 Elsevier B.V. All rights reserved. doi:10.1016/j.ics.2004.11.137
402
T. Maekawa et al. / International Congress Series 1278 (2005) 401–404
deviant stimulus (D) is presented within a sequence of common standard (S) stimulus. It is thought to be the product of an automatic process because it is elicited even when attention is directed away from the stimuli. MMN has been applied extensively to the study of the neural events which lead to attentional switching. It has been mainly studied in the auditory system [3], and a few studies on visual MMN (V-MMN) have been reported [4,5]. However, the attention was not carefully monitored in these studies [4,5]. It was uncertain whether the attention was directed away from the D stimulus. Therefore, the aim of this study was to record valid V-MMN to windmill stimulation when attention was directed away from the visual stimuli under full auditory attention. 2. Methods Seven healthy right-handed young adults (2 males and 5 females, 19–29 years) were seated comfortably in a dark room. They were instructed to focus their attention on a story which was delivered through the earphones binaurally, and look at the center of a monitor. A circular black–white windmill pattern with 90% contrast was used as the visual stimulus. Three types of stimuli (S, D and target [T]) were presented in a random order for 200 ms on a 17 inch computer monitor, with inter-stimulus interval for 800 ms. The sequence consisted of S (80%), D (10%) and T (10%) stimuli. To confirm the direction of attention, the accuracy of the questions for the story and reaction time for the target stimuli were evaluated. The number of vanes in each stimulus was systematically changed among the three stimuli. ERPs were recorded from 18 electrodes placed on the scalp according to the international 10–20 system. In addition, two electrodes were placed on bilateral mastoid processes. A reference electrode was placed on the nose tip. Vertical and horizontal electro-oculograms were also monitored. ERPs to each visual stimulus were averaged separately. To counterbalance the signalto-noise ratio between the standard and deviant stimuli, the average numbers of both stimuli were matched. Epochs from 22 to 50 were at least averaged for each subject. VMMN was then obtained by subtracting ERPs to S stimulus from that of D stimulus. To assess the effects of the condition, magnitude (AV_ms) and latency of V-MMN were measured. The statistical analysis was done by three-way analysis of variance (ANOVA) with repeated measures. 3. Results The average of accuracy for the questions to the story was 96.7%, and that of the detection of T stimulus was 98%. In addition, the N2b-P300 complex was only recorded in response to the T stimulus. These results indicated that the attention of the subjects was mainly directed to the story and T stimulus during the experiment. Interestingly, there was a negative shift between 150 and 300 ms after the stimulus onset in response to the D stimulus compared with that of the S stimulus. This negativity was observed in all subjects in all stimulus conditions. This negative shift was predominantly recorded in the occipital area, being maximum at Oz. Thus, the characteristics of this negative shift were similar to that of previous reported V-MMN [4,5]. V-MMN had two major peaks in the present study. The early V-MMN (MMN1) with
T. Maekawa et al. / International Congress Series 1278 (2005) 401–404
403
Fig. 1. Difference waves in the eight conditions, combining one of the four deviant stimuli (D12, D18, D24 and D30) with one of the two target stimuli (T60 and T0). They were obtained by subtracting ERPs to the S stimulus from those of the D stimulus. The dotted area represents MMN1 while striped area does MMN2. Three-way ANOVA revealed that the peak latency of MMN2 (*) was significantly shorter in the D30 condition than that of the D12 condition. The peak latencies of both MMN1 and MMN2 were shorter in the T60 condition than that of the T0. The magnitude of MMN2 was significantly greater than that of MMN1. Arabic numerals indicate the number of vanes in this figure.
a peak latency between 150 and 200 ms extended from the occipital to the parietal area, while the later (MMN2) with a peak latency of 200–300 ms distributed over the posteriortemporal area. The peak amplitude and latency of N1 were modulated by changing the number of vanes between the S and D stimuli. However, such manipulation did not abolish V-MMN (data not shown). Thus, N1 was an exogenous while V-MMN was endogenous. Fig. 1 shows grand averaged ERPs recorded at Oz. The peak latencies of V-MMN (both MMN1 and MMN2) were shorter in the T stimulus with 60 vanes (T60) than the T stimulus without vanes (T0) ( P=0.032). The peak latency of MMN2 was significantly influenced by deviancy ( P=0.0025). In addition, the magnitude of MMN2 was greater than that of MMN1 ( P=0.0113). 4. Discussion The important findings in this study are: (1) V-MMN appeared during the period of 150–300 ms after the stimulus onset, (2) V-MMN consisted of MMN1 and MMN2 components, and (3) although the magnitudes of MMN1 and MMN2 were not altered with varying the relation between D and T stimuli, the peak latency of MMN2 was influenced by the number of vanes of the D stimulus. Our V-MMN appears to fulfil the criteria of auditory MMN [3] and is comparable with the results of previous V-MMN studies. Therefore, we could record the valid V-MMN by using windmill stimulation during full auditory attention.
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T. Maekawa et al. / International Congress Series 1278 (2005) 401–404
According to the magnetoencephalographic and cortical ERP studies, the cerebral sources of auditory MMN are located in the superior temporal and frontal areas. In this study, MMN1 extended from the occipital area to the parietal area, while MMN2 distributed to the posterior temporal area. These findings suggest that the generator of MMN1 is different from that of MMN2. However, higher spatial equipment will be required for the profound investigation of this issue. Further studies are necessary to elucidate the properties of V-MMN induced by windmill stimulation. Acknowledgements This study was supported in part by Grant-in-Aid for the 21st Century COE Program. References [1] A. Treisman, A. Vieria, A. Hayes, Automaticity and preattentive processing, Am. J. Psychol. 105 (1992) 341 – 362. [2] R. N77t7nen, Event-related potentials and automatic information processing, Attention and Brain Function, Lawrence Erlbaum Associates, Hillsdale, NJ, 1992, pp. 102 – 296. [3] P. Pazo-Alvarez, F. Cadaveria, E. Amenedo, MMN in the visual modality: a review, Biol. Psychol. 63 (2003) 199 – 236. [4] A. Tales, et al., Mismatch negativity in the visual modality, NeuroReport 10 (1999) 3363 – 3367. [5] J.H. Wei, T.C. Chan, Y.J. Luo, A modified oddball paradigm bcross-modal delayed responseQ and the research on mismatch negativity, Brain Res. Bull. 57 (2002) 221 – 230.
www.ics-elsevier.com
Can we record the valid visual mismatch negativity to a windmill pattern during auditory attention? Toshihiko Maekawa*, Yoshinobu Goto, Shozo Tobimatsu Department of Clinical Neurophysiology, Neurological Institute, Graduate School of Medical Sciences, Kyushu University, 3-1-1 Maidashi, Higashiku, Fukuoka 812-8582, Japan
Abstract. The aim of this study was to record valid visual mismatch negativity (V-MMN) to a circular black–white windmill pattern. Seven adults were instructed to pay attention to a story through the earphones. The ratio of the standard (S), deviant (D) and target (T) stimuli was 8:1:1, and they appeared in a random sequence with inter-stimulus interval for 800 ms. The difference among the three stimuli was the number of vanes. ERPs were recorded from 20 sites over the scalp. The number of vanes in each stimulus was systematically changed to observe the relationship among the ERPs to the S, D and T stimuli. P300 was only obtained in response to the T stimulus. A negative potential appeared during the period of 150–300 ms after the stimulus onset by subtracting the ERPs to the S stimulus from those of the D stimulus. This negativity was distributed over the occipitotemporal region. Characteristics of this negativity were similar to those of auditory MMN. V-MMN in our study consisted of early (150–200 ms, MMN1) and late (200–300 ms, MMN2) components. The magnitudes of MMN1 and MMN2 were not altered with varying the D and T stimuli. However, the peak latency of MMN2 was significantly altered with varying the D stimuli, but not MMN1. Therefore, valid V-MMN can be recorded by the windmill patterns during auditory attention. D 2004 Elsevier B.V. All rights reserved. Keywords: Visual mismatch negativity; Pre-attentive processing; Windmill pattern
1. Introduction The strategy of recognition is thought to consist of pre-attentive and attentive stages [1]. Pre-attentive processing has been studied by recording the mismatch negativity (MMN) associated with the detection of stimulus change [2]. MMN is evoked when infrequent * Corresponding author. Tel.: +81 92 642 5543; fax: +81 92 642 5545. E-mail address: [email protected] (T. Maekawa). 0531-5131/ D 2004 Elsevier B.V. All rights reserved. doi:10.1016/j.ics.2004.11.137
402
T. Maekawa et al. / International Congress Series 1278 (2005) 401–404
deviant stimulus (D) is presented within a sequence of common standard (S) stimulus. It is thought to be the product of an automatic process because it is elicited even when attention is directed away from the stimuli. MMN has been applied extensively to the study of the neural events which lead to attentional switching. It has been mainly studied in the auditory system [3], and a few studies on visual MMN (V-MMN) have been reported [4,5]. However, the attention was not carefully monitored in these studies [4,5]. It was uncertain whether the attention was directed away from the D stimulus. Therefore, the aim of this study was to record valid V-MMN to windmill stimulation when attention was directed away from the visual stimuli under full auditory attention. 2. Methods Seven healthy right-handed young adults (2 males and 5 females, 19–29 years) were seated comfortably in a dark room. They were instructed to focus their attention on a story which was delivered through the earphones binaurally, and look at the center of a monitor. A circular black–white windmill pattern with 90% contrast was used as the visual stimulus. Three types of stimuli (S, D and target [T]) were presented in a random order for 200 ms on a 17 inch computer monitor, with inter-stimulus interval for 800 ms. The sequence consisted of S (80%), D (10%) and T (10%) stimuli. To confirm the direction of attention, the accuracy of the questions for the story and reaction time for the target stimuli were evaluated. The number of vanes in each stimulus was systematically changed among the three stimuli. ERPs were recorded from 18 electrodes placed on the scalp according to the international 10–20 system. In addition, two electrodes were placed on bilateral mastoid processes. A reference electrode was placed on the nose tip. Vertical and horizontal electro-oculograms were also monitored. ERPs to each visual stimulus were averaged separately. To counterbalance the signalto-noise ratio between the standard and deviant stimuli, the average numbers of both stimuli were matched. Epochs from 22 to 50 were at least averaged for each subject. VMMN was then obtained by subtracting ERPs to S stimulus from that of D stimulus. To assess the effects of the condition, magnitude (AV_ms) and latency of V-MMN were measured. The statistical analysis was done by three-way analysis of variance (ANOVA) with repeated measures. 3. Results The average of accuracy for the questions to the story was 96.7%, and that of the detection of T stimulus was 98%. In addition, the N2b-P300 complex was only recorded in response to the T stimulus. These results indicated that the attention of the subjects was mainly directed to the story and T stimulus during the experiment. Interestingly, there was a negative shift between 150 and 300 ms after the stimulus onset in response to the D stimulus compared with that of the S stimulus. This negativity was observed in all subjects in all stimulus conditions. This negative shift was predominantly recorded in the occipital area, being maximum at Oz. Thus, the characteristics of this negative shift were similar to that of previous reported V-MMN [4,5]. V-MMN had two major peaks in the present study. The early V-MMN (MMN1) with
T. Maekawa et al. / International Congress Series 1278 (2005) 401–404
403
Fig. 1. Difference waves in the eight conditions, combining one of the four deviant stimuli (D12, D18, D24 and D30) with one of the two target stimuli (T60 and T0). They were obtained by subtracting ERPs to the S stimulus from those of the D stimulus. The dotted area represents MMN1 while striped area does MMN2. Three-way ANOVA revealed that the peak latency of MMN2 (*) was significantly shorter in the D30 condition than that of the D12 condition. The peak latencies of both MMN1 and MMN2 were shorter in the T60 condition than that of the T0. The magnitude of MMN2 was significantly greater than that of MMN1. Arabic numerals indicate the number of vanes in this figure.
a peak latency between 150 and 200 ms extended from the occipital to the parietal area, while the later (MMN2) with a peak latency of 200–300 ms distributed over the posteriortemporal area. The peak amplitude and latency of N1 were modulated by changing the number of vanes between the S and D stimuli. However, such manipulation did not abolish V-MMN (data not shown). Thus, N1 was an exogenous while V-MMN was endogenous. Fig. 1 shows grand averaged ERPs recorded at Oz. The peak latencies of V-MMN (both MMN1 and MMN2) were shorter in the T stimulus with 60 vanes (T60) than the T stimulus without vanes (T0) ( P=0.032). The peak latency of MMN2 was significantly influenced by deviancy ( P=0.0025). In addition, the magnitude of MMN2 was greater than that of MMN1 ( P=0.0113). 4. Discussion The important findings in this study are: (1) V-MMN appeared during the period of 150–300 ms after the stimulus onset, (2) V-MMN consisted of MMN1 and MMN2 components, and (3) although the magnitudes of MMN1 and MMN2 were not altered with varying the relation between D and T stimuli, the peak latency of MMN2 was influenced by the number of vanes of the D stimulus. Our V-MMN appears to fulfil the criteria of auditory MMN [3] and is comparable with the results of previous V-MMN studies. Therefore, we could record the valid V-MMN by using windmill stimulation during full auditory attention.
404
T. Maekawa et al. / International Congress Series 1278 (2005) 401–404
According to the magnetoencephalographic and cortical ERP studies, the cerebral sources of auditory MMN are located in the superior temporal and frontal areas. In this study, MMN1 extended from the occipital area to the parietal area, while MMN2 distributed to the posterior temporal area. These findings suggest that the generator of MMN1 is different from that of MMN2. However, higher spatial equipment will be required for the profound investigation of this issue. Further studies are necessary to elucidate the properties of V-MMN induced by windmill stimulation. Acknowledgements This study was supported in part by Grant-in-Aid for the 21st Century COE Program. References [1] A. Treisman, A. Vieria, A. Hayes, Automaticity and preattentive processing, Am. J. Psychol. 105 (1992) 341 – 362. [2] R. N77t7nen, Event-related potentials and automatic information processing, Attention and Brain Function, Lawrence Erlbaum Associates, Hillsdale, NJ, 1992, pp. 102 – 296. [3] P. Pazo-Alvarez, F. Cadaveria, E. Amenedo, MMN in the visual modality: a review, Biol. Psychol. 63 (2003) 199 – 236. [4] A. Tales, et al., Mismatch negativity in the visual modality, NeuroReport 10 (1999) 3363 – 3367. [5] J.H. Wei, T.C. Chan, Y.J. Luo, A modified oddball paradigm bcross-modal delayed responseQ and the research on mismatch negativity, Brain Res. Bull. 57 (2002) 221 – 230.