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Effect of catechol-O-methylferase (COMT) Val158Met genotype on encoding, maintenance, and retrieval of visual working memory
S230
Abstracts / Neuroscience Research 58S (2007) S1–S244
P3-h1Ø Effect of catechol-O-methylferase (COMT) Val158 Met genotype on encoding, maintenance, and retrieval of visual working memory Hirohito M. Kondo 1 , Michio Nomura 1,2 , Makio Kashino 1,3,4 NTT Communication Science Labs, NTT Corp, Atsugi, Japan; 2 Dept of Psychology, Tokaigakuin Univ, Kakamigahara, Japan; 3 ERATO Shimojo Implicit Brain Function Project, JST, Atsugi, Japan; 4 Grad Sch of Science and Engineering, Tokyo Institute of Technology, Yokohama, Japan
1
COMT is related to the efficiency of prefrontal cortex (PFC) activity. We identified whether polymorphism in the COMT (Val158 Met) gene affects brain activity during encoding, maintenance, or retrieval periods. We recruited 20 healthy participants from 70 adults: Ten were Met carriers and the other ten were Val/Val carriers. They were asked to memorize a visual pattern in the fMRI experiment. Memory accuracy was greater for the Met carriers than for the Val/Val carriers. We found activations in the PFC, anterior cingulate cortex, supramarginal gyrus, parietal areas, and visual areas during encoding period. Signal intensity of the PFC during encoding period was greater for the Val/Val carriers than for the Met carriers. These results suggest that the Met allele leads to more efficient activity in the PFC during encoding of memory than during maintenance and retrieval of it.
P3-h11 Spatial activation patterns of spatial and non-spatial visual information in primate DLPFC Motoaki Nitta, Shintaro Funahashi Human and Environmental Studies, Kyoto University, Japan We investigated how spatial and non-spatial information are represented within DLPFC and how these representations change along the progress of the trial by using three tasks. Each task required monkeys to make a saccade toward a target based on a spatial or non-spatial (color) visual cues. We made expanded flat cortical maps of DLPFC, and plotted the position of each neuron and the magnitude of each single-neuron activity on the expanded flat cortical maps. Although three tasks required monkeys to make a same oculomotor output, we found that spatial activation patterns by color cues were different from that by spatial cues. We also found that those by oculomotor outputs were different from those by visual cues. These result indicated that DLPFC may play a role in integrating various kinds of information to produce particular motor outputs. Research fund: 17300103 to S.F.
P3-h13 The effect of random delay length on prefrontal delayperiod activity during free-choice ODR tasks K. Watanabe, S. Funahashi Department of Cognitive & Behavioral Sciences, Kyoto University, Japan Our previous studies showed that prefrontal directional delay-period activity contributes to the selection of the forthcoming saccade direction during the 3-s delay period in the free-choice ODR task (S-ODR1). In the present study, we introduced a task with variable delay length (1.5, 3 or 4.5 s: S-ODR2). In both tasks, 4 identical visual cues were presented in the cue period. Monkeys were required to make a saccade to any one of 4 directions after the delay. The mean saccade latency and error rates were not affected by the delay length in S-ODR2, suggesting that the monkeys were ready to make saccades before the end of the delay, even in the 1.5-s condition. In concert with the behavioral data, single-trial based analysis of neuron activity showed that the onset latency of delay-period activity in S-ODR2 tended to be shorter than that of S-ODR1. A comparison of delay-period activity between two tasks suggests that directional delay-period activity reflects the selection process of saccade direction in S-ODR tasks. Research funds: KAKENHI (No. 18020016 & 17300103 to SF) (No. 18050592 to KW).
P3-h14 Internal model of the human hand affects object recognition Masazumi Katayama, Taijirou Nakayama, Masaaki Kawaji Department of Human and Artificial Intelligent Systems, University of Fukui, Fukui, Japan In this study, we investigate a relation between an internal model of the human hand and object recognition of graspable tools. Object concepts acquired through motor experience make object recognition possible. Such a mechanism seems to relate to the internal model acquired through motor experience. Thus, we examined whether the novel internal model trained under the condition that changes a displayed hand shape on a monitor affects object concept and/or object recognition. In the first experiment, the internal models were trained under the three conditions: observation, passive movement and active movement. As a result, active movement plays an important role for the learning. For the second experiment, we found that object concept is influenced by the novel internal models, although visual image of a favorite glass is independent from the models. In the third experiment, we ascertained that the novel internal model affects object recognition such a glass. Finally, we conclude that an internal model of the human hand plays an important role for object recognition of graspable tools.
P3-h12 Prefrontal activities under a go/no-go conditional discrimination task
P3-h15 Auditory evoked N1m latency reflects categorical per-
Atsushi Noritake, Masashi Koizumi, Masamichi Sakagami BSRC, Tamagawa University, Tokyo, Japan
Tomomi Mizuochi 1 , Masato Yumoto 2 , Shotaro Karino 3 , Kenji Itoh 4 , Keiko Yamakawa 4 , Kimitaka Kaga 1,3 1 Department of Sensory and Motor Neuroscience, University of Tokyo, Tokyo, Japan; 2 Clinical Laboratory, University of Tokyo, Tokyo, Japan; 3 Otolaryngology, University of Tokyo, Tokyo, Japan; 4 Speech and Cognitive Science, University of Tokyo, Tokyo, Japan
There are two major functions related to attention: selective and divided attention. Although the neuronal basis of selective attention has been investigated systematically [Sakagami, 1994a,b; Sakagami and Tsutsui, 1999], neural underpinning of the divided attention remains unclear. We examined neuronal activity in the lateral prefrontal cortex (LPFC) while the monkey performed a divided attention task – a go/no-go conditional discrimination task that required the monkey to make a go or no-go response depending on the combination of the features present in a random-dot color kinematogram as a cue. The critical features of the kinematogram were color and motion direction and the monkey had to pay attention to the specific combination of these two features to make go/no-go decisions. We found the neurons that showed differential activity for go and no-go stimuli in the wide range of LPFC, but the differential activity in the dorsal part started earlier by 300–400 ms than in the ventral part. These results suggested that the dorsal part of LPFC has more critical role for the go/no-go decision in this task situation.
ception of timbre
To clarify the cortical representation of timbre perception, we recorded neuromagnetic responses to periodic complex sounds with equivalent acoustic parameters except for 2 different fundamental frequencies and 12 different spectral envelopes, which were categorized into vocal, instrumental and linear shapes. We analyzed N1m peak latency and N1m offset latency, which gives first minimal RMS values after the N1m peak. No significant difference was detected in the N1m peak latency across timbre categories, while the offset latency for the instrumental sound was significantly longer than that for the linear sound. These results suggest that the duration of auditory information processing may be affected by the shape of spectral envelopes and this process may be reflected in the duration from the N1m peak to the offset.
Abstracts / Neuroscience Research 58S (2007) S1–S244
P3-h1Ø Effect of catechol-O-methylferase (COMT) Val158 Met genotype on encoding, maintenance, and retrieval of visual working memory Hirohito M. Kondo 1 , Michio Nomura 1,2 , Makio Kashino 1,3,4 NTT Communication Science Labs, NTT Corp, Atsugi, Japan; 2 Dept of Psychology, Tokaigakuin Univ, Kakamigahara, Japan; 3 ERATO Shimojo Implicit Brain Function Project, JST, Atsugi, Japan; 4 Grad Sch of Science and Engineering, Tokyo Institute of Technology, Yokohama, Japan
1
COMT is related to the efficiency of prefrontal cortex (PFC) activity. We identified whether polymorphism in the COMT (Val158 Met) gene affects brain activity during encoding, maintenance, or retrieval periods. We recruited 20 healthy participants from 70 adults: Ten were Met carriers and the other ten were Val/Val carriers. They were asked to memorize a visual pattern in the fMRI experiment. Memory accuracy was greater for the Met carriers than for the Val/Val carriers. We found activations in the PFC, anterior cingulate cortex, supramarginal gyrus, parietal areas, and visual areas during encoding period. Signal intensity of the PFC during encoding period was greater for the Val/Val carriers than for the Met carriers. These results suggest that the Met allele leads to more efficient activity in the PFC during encoding of memory than during maintenance and retrieval of it.
P3-h11 Spatial activation patterns of spatial and non-spatial visual information in primate DLPFC Motoaki Nitta, Shintaro Funahashi Human and Environmental Studies, Kyoto University, Japan We investigated how spatial and non-spatial information are represented within DLPFC and how these representations change along the progress of the trial by using three tasks. Each task required monkeys to make a saccade toward a target based on a spatial or non-spatial (color) visual cues. We made expanded flat cortical maps of DLPFC, and plotted the position of each neuron and the magnitude of each single-neuron activity on the expanded flat cortical maps. Although three tasks required monkeys to make a same oculomotor output, we found that spatial activation patterns by color cues were different from that by spatial cues. We also found that those by oculomotor outputs were different from those by visual cues. These result indicated that DLPFC may play a role in integrating various kinds of information to produce particular motor outputs. Research fund: 17300103 to S.F.
P3-h13 The effect of random delay length on prefrontal delayperiod activity during free-choice ODR tasks K. Watanabe, S. Funahashi Department of Cognitive & Behavioral Sciences, Kyoto University, Japan Our previous studies showed that prefrontal directional delay-period activity contributes to the selection of the forthcoming saccade direction during the 3-s delay period in the free-choice ODR task (S-ODR1). In the present study, we introduced a task with variable delay length (1.5, 3 or 4.5 s: S-ODR2). In both tasks, 4 identical visual cues were presented in the cue period. Monkeys were required to make a saccade to any one of 4 directions after the delay. The mean saccade latency and error rates were not affected by the delay length in S-ODR2, suggesting that the monkeys were ready to make saccades before the end of the delay, even in the 1.5-s condition. In concert with the behavioral data, single-trial based analysis of neuron activity showed that the onset latency of delay-period activity in S-ODR2 tended to be shorter than that of S-ODR1. A comparison of delay-period activity between two tasks suggests that directional delay-period activity reflects the selection process of saccade direction in S-ODR tasks. Research funds: KAKENHI (No. 18020016 & 17300103 to SF) (No. 18050592 to KW).
P3-h14 Internal model of the human hand affects object recognition Masazumi Katayama, Taijirou Nakayama, Masaaki Kawaji Department of Human and Artificial Intelligent Systems, University of Fukui, Fukui, Japan In this study, we investigate a relation between an internal model of the human hand and object recognition of graspable tools. Object concepts acquired through motor experience make object recognition possible. Such a mechanism seems to relate to the internal model acquired through motor experience. Thus, we examined whether the novel internal model trained under the condition that changes a displayed hand shape on a monitor affects object concept and/or object recognition. In the first experiment, the internal models were trained under the three conditions: observation, passive movement and active movement. As a result, active movement plays an important role for the learning. For the second experiment, we found that object concept is influenced by the novel internal models, although visual image of a favorite glass is independent from the models. In the third experiment, we ascertained that the novel internal model affects object recognition such a glass. Finally, we conclude that an internal model of the human hand plays an important role for object recognition of graspable tools.
P3-h12 Prefrontal activities under a go/no-go conditional discrimination task
P3-h15 Auditory evoked N1m latency reflects categorical per-
Atsushi Noritake, Masashi Koizumi, Masamichi Sakagami BSRC, Tamagawa University, Tokyo, Japan
Tomomi Mizuochi 1 , Masato Yumoto 2 , Shotaro Karino 3 , Kenji Itoh 4 , Keiko Yamakawa 4 , Kimitaka Kaga 1,3 1 Department of Sensory and Motor Neuroscience, University of Tokyo, Tokyo, Japan; 2 Clinical Laboratory, University of Tokyo, Tokyo, Japan; 3 Otolaryngology, University of Tokyo, Tokyo, Japan; 4 Speech and Cognitive Science, University of Tokyo, Tokyo, Japan
There are two major functions related to attention: selective and divided attention. Although the neuronal basis of selective attention has been investigated systematically [Sakagami, 1994a,b; Sakagami and Tsutsui, 1999], neural underpinning of the divided attention remains unclear. We examined neuronal activity in the lateral prefrontal cortex (LPFC) while the monkey performed a divided attention task – a go/no-go conditional discrimination task that required the monkey to make a go or no-go response depending on the combination of the features present in a random-dot color kinematogram as a cue. The critical features of the kinematogram were color and motion direction and the monkey had to pay attention to the specific combination of these two features to make go/no-go decisions. We found the neurons that showed differential activity for go and no-go stimuli in the wide range of LPFC, but the differential activity in the dorsal part started earlier by 300–400 ms than in the ventral part. These results suggested that the dorsal part of LPFC has more critical role for the go/no-go decision in this task situation.
ception of timbre
To clarify the cortical representation of timbre perception, we recorded neuromagnetic responses to periodic complex sounds with equivalent acoustic parameters except for 2 different fundamental frequencies and 12 different spectral envelopes, which were categorized into vocal, instrumental and linear shapes. We analyzed N1m peak latency and N1m offset latency, which gives first minimal RMS values after the N1m peak. No significant difference was detected in the N1m peak latency across timbre categories, while the offset latency for the instrumental sound was significantly longer than that for the linear sound. These results suggest that the duration of auditory information processing may be affected by the shape of spectral envelopes and this process may be reflected in the duration from the N1m peak to the offset.