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Properties of concentration changes of oxyhemoglobin and deoxyhemoglobin in the prefrontal cortex during the tasks of executive functions measured by near infrared spectroscopy
International Congress Series 1232 (2002) 329 – 333
Properties of concentration changes of oxyhemoglobin and deoxyhemoglobin in the prefrontal cortex during the tasks of executive functions measured by near infrared spectroscopy Toshihide Koike a,*, Miyoshi Kumoi a, Takanori Maesako b, Noriyoshi Ichikawa c, Noriyuki Fujiwara c a
Department of Human Development, Faculty of Education, Tokyo Gakugei University, Koganei, Tokyo 184, Japan b Communication and Media Lab., Graduate School of Human Sciences, Osaka University, Yamadaoka, Japan c Hitachi Medical Corporation Ltd., Kashiwa, Japan
Abstract The present study aimed to examine the properties of hemodynamics of prefrontal cortex during a task of executive function by the near infrared (NIR) topography with 24-channels. In the wide regions of prefrontal cortex, increase of [Hb] occurred and then [HbO2] increased. In the restricted areas (2ch, 4ch, 5ch, 7ch and 10ch), responses involve only increase of [HbO2]. The difference of these responses might reflect the distinct activities of the prefrontal cortex, which relate to the executive function. D 2002 Elsevier Science B.V. All rights reserved. Keywords: Prefrontal cortex; Executive function; Near infrared topography
1. Introduction Recently, a near infrared (NIR) spectroscopy has become available, which enables independent measurements of temporal changes in deoxyhemoglobin([Hb]), oxyhemoglobin([HbO2]) and total hemoglobin([T-Hb]) concentration. Because of the advantage of less restriction in measurement, NIR topography is suitable to examine the higher cognitive function, especially executive function.
*
Corresponding author.
0531-5131/02 D 2002 Elsevier Science B.V. All rights reserved. PII: S 0 5 3 1 - 5 1 3 1 ( 0 1 ) 0 0 7 1 4 - 2
330
T. Koike et al. / International Congress Series 1232 (2002) 329–333
It has been widely accepted that the prefrontal cortex plays a major role in the complex aspect of human executive function, such as reasoning, planning and control of memory, but its relationship to the time course of brain functioning has not been fully examined. The present study aimed to examine the properties of hemodynamics of prefrontal cortex during performing a task of executive function.
2. Methods Subjects were three adult persons. Recording device was a 24-channel near infrared topography device (Hitachi Medico). The probes were placed on the prefrontal region. The locations of probes were confirmed by measuring pictures of MRI (Fig. 1). Sampling rate of data acquisition was 100 Hz. Executive functions were evaluated by a task of Tower of Hanoi and a task of memorizing patterns of hand movements. In a task of Tower of Hanoi, four disks were distributed in three pegs as a start state, and a picture of goal state was presented. Subjects were instructed to think steps to attain goal state through transferring disks, one at a time, never placing a large disk on a smaller one. During the period of thinking of 20 s, a subject did not move the disks actually. In a task of memorizing hand movement, five patterns of hand movement were presented sequentially. After the presentation of hand movements, subjects tried to memorize sequences of hand movements.
3. Results Fig. 2 shows traces of [Hb] and [HbO2] in a task of Tower of Hanoi. After the presentation of the task, [Hb] slightly increased and then remarkable increases of [HbO2] occurred in many regions over prefrontal cortex.
Fig. 1. Probe locations over right prefrontal cortex. Numbers indicate measurement locations, which correspond to channels of measurement.
T. Koike et al. / International Congress Series 1232 (2002) 329–333
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Fig. 2. Traces of concentration changes of oxyhemoglobin (thick line) and deoxyhemoglobin (thin line) during a task of Tower of Hanoi. Numbers of channels correspond to the measurement locations in Fig. 1. Dotted lines indicate start time and end time of the task.
In order to evaluate properties of changes of hemodynamics of wider area quantitatively, principal component analysis was applied to traces of [Hb] and [HbO2], respectively, in each hemisphere. As a result, two components were extracted (Table 1).
Table1 Matrix of factor loading Deoxyhemoglobin (right) 1 1ch 2ch 3ch 4ch 5ch 6ch 7ch 8ch 9ch 10ch 11ch 12ch
0.99 0.35 0.97 0.76 0.32 0.944 0.87 0.53 0.98 0.67 0.92 0.99
Oxyhemoglobin (right) 2
1
2
1.1e 03 0.91 7.9e 02 0.46 0.89 0.30 0.39 0.81 0.19 0.70 3.9 2.43e 02
0.93 0.75 0.97 0.98 0.51 0.92 0.32 0.96 0.97 0.73 0.98 0.99
0.28 4.08e 02 0.12 4.7e 02 0.82 0.37 0.91 0.17 0.23 0.63 0.14 8.9e 02
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T. Koike et al. / International Congress Series 1232 (2002) 329–333
Regarding [Hb], the principal component 1 related to the activities of wider regions of right prefrontal cortex, and the principal component 2 related to the activities of restricted regions (2ch, 4ch, 5ch, 7ch and 10ch). Cumulative proportions of components 1 and 2 were 0.94 and 0.92, respectively. Almost the same relationship was found between principal components and regions of left prefrontal cortex. Fig. 3 shows traces of component score of each principal component. As for principal components 1 (filled circles) of [Hb], the maximum values were observed at about 5 s after the presentation of the task in both hemispheres. The maximum values of [HbO2] were observed at about 7 s, which indicated that concentration of oxyhemoglobin increased after the maximum increase of deoxyhemoglobin. As for principal components 2 (open circles), [HbO2] did not show increase after the presentation of the task, while [HbO2] had the maximum peak after the presentation of the task. This response pattern was observed in the restricted regions. The same patterns of changes were observed in a task of memorizing hand movements.
Fig. 3. Traces of component scores of each principal component. Filled circles indicate component scores of principal component 1. Open circles indicate those of principal component 2. Point numbers (abscissa) of 6 and 15 indicate start time and end time of the task, respectively.
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4. Discussion The above results indicate that the different process of responses might occur during the task, which needs executive function. In the wide regions, responses involve increase of [Hb] as well as [HbO2]. In the restricted areas (2ch, 4ch, 5ch, 7ch and 10ch), responses involve only increase of [HbO2]. These differences might reflect the distinct activities of the prefrontal cortex, which relate to the executive function. Since multiple processes constitute executive function, further research is needed to find the fundamental process, which is responsible for the above-described hemodynamic responses.
Properties of concentration changes of oxyhemoglobin and deoxyhemoglobin in the prefrontal cortex during the tasks of executive functions measured by near infrared spectroscopy Toshihide Koike a,*, Miyoshi Kumoi a, Takanori Maesako b, Noriyoshi Ichikawa c, Noriyuki Fujiwara c a
Department of Human Development, Faculty of Education, Tokyo Gakugei University, Koganei, Tokyo 184, Japan b Communication and Media Lab., Graduate School of Human Sciences, Osaka University, Yamadaoka, Japan c Hitachi Medical Corporation Ltd., Kashiwa, Japan
Abstract The present study aimed to examine the properties of hemodynamics of prefrontal cortex during a task of executive function by the near infrared (NIR) topography with 24-channels. In the wide regions of prefrontal cortex, increase of [Hb] occurred and then [HbO2] increased. In the restricted areas (2ch, 4ch, 5ch, 7ch and 10ch), responses involve only increase of [HbO2]. The difference of these responses might reflect the distinct activities of the prefrontal cortex, which relate to the executive function. D 2002 Elsevier Science B.V. All rights reserved. Keywords: Prefrontal cortex; Executive function; Near infrared topography
1. Introduction Recently, a near infrared (NIR) spectroscopy has become available, which enables independent measurements of temporal changes in deoxyhemoglobin([Hb]), oxyhemoglobin([HbO2]) and total hemoglobin([T-Hb]) concentration. Because of the advantage of less restriction in measurement, NIR topography is suitable to examine the higher cognitive function, especially executive function.
*
Corresponding author.
0531-5131/02 D 2002 Elsevier Science B.V. All rights reserved. PII: S 0 5 3 1 - 5 1 3 1 ( 0 1 ) 0 0 7 1 4 - 2
330
T. Koike et al. / International Congress Series 1232 (2002) 329–333
It has been widely accepted that the prefrontal cortex plays a major role in the complex aspect of human executive function, such as reasoning, planning and control of memory, but its relationship to the time course of brain functioning has not been fully examined. The present study aimed to examine the properties of hemodynamics of prefrontal cortex during performing a task of executive function.
2. Methods Subjects were three adult persons. Recording device was a 24-channel near infrared topography device (Hitachi Medico). The probes were placed on the prefrontal region. The locations of probes were confirmed by measuring pictures of MRI (Fig. 1). Sampling rate of data acquisition was 100 Hz. Executive functions were evaluated by a task of Tower of Hanoi and a task of memorizing patterns of hand movements. In a task of Tower of Hanoi, four disks were distributed in three pegs as a start state, and a picture of goal state was presented. Subjects were instructed to think steps to attain goal state through transferring disks, one at a time, never placing a large disk on a smaller one. During the period of thinking of 20 s, a subject did not move the disks actually. In a task of memorizing hand movement, five patterns of hand movement were presented sequentially. After the presentation of hand movements, subjects tried to memorize sequences of hand movements.
3. Results Fig. 2 shows traces of [Hb] and [HbO2] in a task of Tower of Hanoi. After the presentation of the task, [Hb] slightly increased and then remarkable increases of [HbO2] occurred in many regions over prefrontal cortex.
Fig. 1. Probe locations over right prefrontal cortex. Numbers indicate measurement locations, which correspond to channels of measurement.
T. Koike et al. / International Congress Series 1232 (2002) 329–333
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Fig. 2. Traces of concentration changes of oxyhemoglobin (thick line) and deoxyhemoglobin (thin line) during a task of Tower of Hanoi. Numbers of channels correspond to the measurement locations in Fig. 1. Dotted lines indicate start time and end time of the task.
In order to evaluate properties of changes of hemodynamics of wider area quantitatively, principal component analysis was applied to traces of [Hb] and [HbO2], respectively, in each hemisphere. As a result, two components were extracted (Table 1).
Table1 Matrix of factor loading Deoxyhemoglobin (right) 1 1ch 2ch 3ch 4ch 5ch 6ch 7ch 8ch 9ch 10ch 11ch 12ch
0.99 0.35 0.97 0.76 0.32 0.944 0.87 0.53 0.98 0.67 0.92 0.99
Oxyhemoglobin (right) 2
1
2
1.1e 03 0.91 7.9e 02 0.46 0.89 0.30 0.39 0.81 0.19 0.70 3.9 2.43e 02
0.93 0.75 0.97 0.98 0.51 0.92 0.32 0.96 0.97 0.73 0.98 0.99
0.28 4.08e 02 0.12 4.7e 02 0.82 0.37 0.91 0.17 0.23 0.63 0.14 8.9e 02
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T. Koike et al. / International Congress Series 1232 (2002) 329–333
Regarding [Hb], the principal component 1 related to the activities of wider regions of right prefrontal cortex, and the principal component 2 related to the activities of restricted regions (2ch, 4ch, 5ch, 7ch and 10ch). Cumulative proportions of components 1 and 2 were 0.94 and 0.92, respectively. Almost the same relationship was found between principal components and regions of left prefrontal cortex. Fig. 3 shows traces of component score of each principal component. As for principal components 1 (filled circles) of [Hb], the maximum values were observed at about 5 s after the presentation of the task in both hemispheres. The maximum values of [HbO2] were observed at about 7 s, which indicated that concentration of oxyhemoglobin increased after the maximum increase of deoxyhemoglobin. As for principal components 2 (open circles), [HbO2] did not show increase after the presentation of the task, while [HbO2] had the maximum peak after the presentation of the task. This response pattern was observed in the restricted regions. The same patterns of changes were observed in a task of memorizing hand movements.
Fig. 3. Traces of component scores of each principal component. Filled circles indicate component scores of principal component 1. Open circles indicate those of principal component 2. Point numbers (abscissa) of 6 and 15 indicate start time and end time of the task, respectively.
T. Koike et al. / International Congress Series 1232 (2002) 329–333
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4. Discussion The above results indicate that the different process of responses might occur during the task, which needs executive function. In the wide regions, responses involve increase of [Hb] as well as [HbO2]. In the restricted areas (2ch, 4ch, 5ch, 7ch and 10ch), responses involve only increase of [HbO2]. These differences might reflect the distinct activities of the prefrontal cortex, which relate to the executive function. Since multiple processes constitute executive function, further research is needed to find the fundamental process, which is responsible for the above-described hemodynamic responses.