Masamichi Sakagami - Academia.edu (original) (raw)
Papers by Masamichi Sakagami
arXiv (Cornell University), Apr 2, 2021
Proceedings of the National Academy of Sciences of the United States of America, Jun 13, 2017
Behavioral and neuroscientific studies explore two pathways through which internalized social nor... more Behavioral and neuroscientific studies explore two pathways through which internalized social norms promote prosocial behavior. One pathway involves internal control of impulsive selfishness, and the other involves emotion-based prosocial preferences that are translated into behavior when they evade cognitive control for pursuing self-interest. We measured 443 participants' overall prosocial behavior in four economic games. Participants' predispositions [social value orientation (SVO)] were more strongly reflected in their overall game behavior when they made decisions quickly than when they spent a longer time. Prosocially (or selfishly) predisposed participants behaved less prosocially (or less selfishly) when they spent more time in decision making, such that their SVO prosociality yielded limited effects in actual behavior in their slow decisions. The increase (or decrease) in slower decision makers was prominent among consistent prosocials (or proselfs) whose strong pre...
Scientific Reports
Humans form complex societies in which we routinely engage in social decision-making regarding th... more Humans form complex societies in which we routinely engage in social decision-making regarding the allocation of resources among ourselves and others. One dimension that characterizes social decision-making in particular is whether to prioritize self-interest or respect for others—proself or prosocial. What causes this individual difference in social value orientation? Recent developments in the social dual-process theory argue that social decision-making is characterized by its underlying domain-general learning systems: the model-free and model-based systems. In line with this “learning” approach, we propose and experimentally test the hypothesis that differences in social preferences stem from which learning system is dominant in an individual. Here, we used a non-social state transition task that allowed us to assess the balance between model-free/model-based learning and investigate its relation to the social value orientations. The results showed that proselfs depended more on...
Scientific Reports
In vivo calcium imaging with genetically encoded indicators has recently been applied to macaque ... more In vivo calcium imaging with genetically encoded indicators has recently been applied to macaque brains to monitor neural activities from a large population of cells simultaneously. Microendoscopic calcium imaging combined with implantable gradient index lenses captures neural activities from deep brain areas with a compact and convenient setup; however, this has been limited to rodents and marmosets. Here, we developed miniature fluorescent microscopy to image neural activities from the primary visual cortex of behaving macaques. We found tens of clear fluorescent signals from three of the six brain hemispheres. A subset of these neurons showed clear retinotopy and orientation tuning. Moreover, we successfully decoded the stimulus orientation and tracked the cells across days. These results indicate that microendoscopic calcium imaging is feasible and reasonable for investigating neural circuits in the macaque brain by monitoring fluorescent signals from a large number of neurons.
Frontiers in Human Neuroscience, 2019
Oxytocin (OXT) is known to play an important role in trust, whereas the involvement of other pept... more Oxytocin (OXT) is known to play an important role in trust, whereas the involvement of other peptide hormones has not been evaluated. In this study, we focused on microsatellite polymorphisms in the intron of the arginine-vasopressin receptor 1a (AVPR1a) gene and examined whether the association between the repeat lengths in the intron of AVPR1a is associated with trust and reciprocity in humans. Four-hundred and thirty-three participants played the trust game, answered the attitudinal trust question, and their buccal cells were collected. Results showed that men with a short form of AVPR1a tend to send more money to the opponent, even if there is a possibility of being betrayed by the opponent. Additionally, people with a short form of AVPR1a tended to return money to the opponent who trusts them. However, attitudinal trust was not associated with AVPR1a. These results indicate that arginine-vasopressin receptor 1a plays an important role in trust and reciprocal behaviors.
Scientific reports, Jan 7, 2017
Altruistic punishment following social norm violations promotes human cooperation. However, exper... more Altruistic punishment following social norm violations promotes human cooperation. However, experimental evidence indicates that some forms of punishment are spiteful rather than altruistic. Using two types of punishment games and seven non-strategic games, we identified strong behavioural differences between altruistic and spiteful punishers. Altruistic punishers who rejected unfair offers in the ultimatum game and punished norm violators in the third-party punishment game behaved pro-socially in various non-strategic games. Spiteful punishers who rejected unfair offers in the ultimatum game but did not punish norm violators in the third-party punishment game behaved selfishly in non-strategic games. In addition, the left caudate nucleus was larger in spiteful punishers than in altruistic punishers. These findings are in contrast to the previous assumption that altruistic punishers derive pleasure from enforcement of fairness norms, and suggest that spiteful punishers derive pleasu...
Neuroscience Research, 2007
Age-related memory impairment (AMI) is a phenotype of brain aging. The molecular mechanisms under... more Age-related memory impairment (AMI) is a phenotype of brain aging. The molecular mechanisms underlying AMI remain elusive. Given that regulation of lifespan by insulin/insulin-like growth factor signaling (IIS) and intrinsic linkage between AMI and organismal aging, one candidate signaling pathway underlying AMI is IIS. Here, we show that chico, which mediates Drosophila IIS, plays an essential role in olfactory learning and AMI. We found that chico null mutants exhibit learning deficits after olfactory conditioning. In addition, chico null mutation suppresses AMI. In contrast to chico, increasing IIS activity in the mushroom bodies (MBs), structures important for olfactory memory and AMI, causes premature AMI. Inconsistent with previous study, however, chico mutation did not extend female lifespan in our w(CS) genetic background. These results separate the brain aging from the organismal aging and demonstrate a biological role of IIS in the MBs both for learning and for AMI. P1-g48 The relation of the spatial cognition deficit and the hippocampal heterotopic neurons in the prenatal MAM-treated rats
Neuroscience Research, 2011
The prefrontal cortex is credited with contributing to relational reasoning, or the ability to in... more The prefrontal cortex is credited with contributing to relational reasoning, or the ability to integrate multiple acquired associations to generate new relationships. We have recorded single-unit activity from the lateral prefrontal cortex (LPFC) and the striatum while the monkeys performed a sequential paired-association task with asymmetric reward schedule. In the task, the monkeys learned two sequences of associated stimuli: A1-B1-C1 and A2-B2-C2. The asymmetric reward rule was instructed by pairing C1 (or C2) with large (or small) reward block by block. The monkey also learned associations between new stimuli (e.g. N1, N2) and B1 and B2. The new stimuli were presented as the first cue in sequential paired-association trials instead of the old stimuli (A1 and A2). The findings from single-unit activity suggest that the LPFC can use an internal model of category to transfer reward information associated with one stimulus to other stimuli, even to new stimuli that had never been paired with different amount of reward. The striatum only uses direct experience between conditioned stimuli and reward to predict reward. One prediction from this hypothesis is that if the LPFC is inactivated, the monkey still correctly predicts reward for old stimuli through the striatal pathway, but has deficits in predicting reward for new stimuli. We injected muscimol to locally inactivate the LPFC, and also saline into the LPFC as control. In saline sessions, the monkey had significantly higher choice accuracy for new stimuli in large than in small reward trials, but this difference disappeared in muscimol session, consistent with the prediction. Together with single-unit activity data, our results suggest that the LPFC play a critical role in category-based reward inference.
Neuroscience Research, 2007
P3-h1Ø Effect of catechol-O-methylferase (COMT) Val158Met genotype on encoding, maintenance, and ... more P3-h1Ø Effect of catechol-O-methylferase (COMT) Val158Met genotype on encoding, maintenance, and retrieval of visual working memory Hirohito M. Kondo1, Michio Nomura1,2, Makio Kashino1,3,4 1 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
Kagaku tetsugaku, 2009
To survive in changeable circumstances, we have to make appropriate decisions on our behavior. Re... more To survive in changeable circumstances, we have to make appropriate decisions on our behavior. Recent studies have suggested that we have two brain processes to calculate reward values of objects. One is the process coding a specific reward value of a stimulus or event dependent on direct experience. The other enables us to predict reward based on the internal model of given circumstances, including societies, which doesn't necessarily require direct experience. The nigro-striatal network works for the model-free decision and the prefrontal network contributes to the model-based decision. These two networks are cooperative in one occasion and are competitive in another.
Neurons, Behavior, Data analysis, and Theory, 2021
1The Department of Decoded Neurofeedback, Computational Neuroscience Laboratories, Advanced Telec... more 1The Department of Decoded Neurofeedback, Computational Neuroscience Laboratories, Advanced Telecommunications Research Institute International, Kyoto, Japan 2Institute of Cognitive Neuroscience, University College London, UK 3Medical Research Council Brain Network Dynamics Unit, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, UK 4Wellcome Centre for Integrative Neuroimaging, University of Oxford, FMRIB, John Radcliffe Hospital, Oxford, UK 5Institute for Cognitive Neurodynamics, East China University of Science and Technology, Shanghai, China 6Brain Science Institute, Tamagawa University, Tokyo, Japan 7Department of Psychology, University of Oregon, United States
Associate Editors Masayuki Miura (The University of Tokyo, Japan) Kinichi Nakashima (Kyusyu Unive... more Associate Editors Masayuki Miura (The University of Tokyo, Japan) Kinichi Nakashima (Kyusyu University, Japan) Erin M. Schuman (Max Planck Institute for Brain Research, Germany) Tatsunori Seki (Tokyo Medical University, Japan) Esther T. Stoeckli (University of Zurich, Switzerland) Yumiko Yoshimura (National Institute for Physiological Sciences, Japan) Michisuke Yuzaki (Keio University, Japan) Development/Repair Neuroscience
Communications Biology, 2021
The lateral prefrontal cortex (LPFC) has a strong monosynaptic connection with the caudate nucleu... more The lateral prefrontal cortex (LPFC) has a strong monosynaptic connection with the caudate nucleus (CdN) of the striatum. Previous human MRI studies have suggested that this LPFC-CdN pathway plays an important role in inhibitory control and working memory. We aimed to validate the function of this pathway at a causal level by pathway-selective manipulation of neural activity in non-human primates. To this end, we trained macaque monkeys on a delayed oculomotor response task with reward asymmetry and expressed an inhibitory type of chemogenetic receptors selectively to LPFC neurons that project to the CdN. Ligand administration reduced the inhibitory control of impulsive behavior, as well as the task-related neuronal responses observed in the local field potentials from the LPFC and CdN. These results show that we successfully suppressed pathway-selective neural activity in the macaque brain, and the resulting behavioral changes suggest that the LPFC-CdN pathway is involved in inhibi...
Nature Communications, 2019
Midbrain dopamine neurons are known to encode reward prediction errors (RPE) used to update value... more Midbrain dopamine neurons are known to encode reward prediction errors (RPE) used to update value predictions. Here, we examine whether RPE signals coded by midbrain dopamine neurons are modulated by the cost paid to obtain rewards, by recording from dopamine neurons in awake behaving monkeys during performance of an effortful saccade task. Dopamine neuron responses to cues predicting reward and to the delivery of rewards were increased after the performance of a costly action compared to a less costly action, suggesting that RPEs are enhanced following the performance of a costly action. At the behavioral level, stimulus-reward associations are learned faster after performing a costly action compared to a less costly action. Thus, information about action cost is processed in the dopamine reward system in a manner that amplifies the following dopamine RPE signal, which in turn promotes more rapid learning under situations of high cost.
Journal of Neurophysiology, 2001
The primate brain is equipped with prefrontal circuits for interpreting visual information, but h... more The primate brain is equipped with prefrontal circuits for interpreting visual information, but how these circuits deal with competing stimulus-response (S-R) associations remains unknown. Here we show different types of responses to task-irrelevant visual features in three functionally dissociated groups of primate prefrontal neurons. Two Japanese macaques participated in a go/no-go task in which they had to discriminate either the color or the motion direction of a visual target to make a correct manual response. Prior to the experiment, the monkeys had been trained extensively so that they acquired fixed associations between visual features and required responses (e.g., “green = go”; “downward motion = no-go”). In this design, the monkey was confronted with a visual target from which it had to extract relevant information (e.g., color in the color-discrimination condition) while ignoring irrelevant information (e.g., motion direction in the color-discrimination condition). We rec...
The Journal of Neuroscience, 2002
PloS one, 2017
Single-unit studies in monkeys have demonstrated that neurons in the prefrontal cortex predict th... more Single-unit studies in monkeys have demonstrated that neurons in the prefrontal cortex predict the reward type, reward amount or reward availability associated with a stimulus. To examine contributions of pyramidal cells and interneurons in reward processing, single-unit activity was extracellularly recorded in prefrontal cortices of four monkeys performing a reward prediction task. Based on their shapes of spike waveforms, prefrontal neurons were classified into broad-spike and narrow-spike units that represented putative pyramidal cells and interneurons, respectively. We mainly observed that narrow-spike neurons showed higher firing rates but less bursty discharges than did broad-spike neurons. Both narrow-spike and broad-spike cells selectively responded to the stimulus, reward and their interaction, and the proportions of each type of selective neurons were similar between the two cell classes. Moreover, the two types of cells displayed equal reliability of reward or stimulus di...
Journal of Neurophysiology, 2002
The lateral prefrontal cortex (LPFC) has been implicated in visuospatial processing, especially w... more The lateral prefrontal cortex (LPFC) has been implicated in visuospatial processing, especially when it is required to hold spatial information during a delay period. It has also been reported that the LPFC receives information about expected reward outcome. However, the interaction between visuospatial processing and reward processing is still unclear because the two types of processing could not be dissociated in conventional delayed response tasks. To examine this, we used a memory-guided saccade task with an asymmetric reward schedule and recorded 228 LPFC neurons. The position of the target cue indicated the spatial location for the following saccade and the color of the target cue indicated the reward outcome for a correct saccade. Activity of LPFC was classified into three main types: S-type activity carried only spatial signals, R-type activity carried only reward signals, and SR-type activity carried both. Therefore only SR-type cells were potentially involved in both visuo...
Proceedings of the National Academy of Sciences of the United States of America, Oct 29, 2016
Distributive justice concerns the moral principles by which we seek to allocate resources fairly ... more Distributive justice concerns the moral principles by which we seek to allocate resources fairly among diverse members of a society. Although the concept of fair allocation is one of the fundamental building blocks for societies, there is no clear consensus on how to achieve "socially just" allocations. Here, we examine neurocognitive commonalities of distributive judgments and risky decisions. We explore the hypothesis that people's allocation decisions for others are closely related to economic decisions for oneself at behavioral, cognitive, and neural levels, via a concern about the minimum, worst-off position. In a series of experiments using attention-monitoring and brain-imaging techniques, we investigated this "maximin" concern (maximizing the minimum possible payoff) via responses in two seemingly disparate tasks: third-party distribution of rewards for others, and choosing gambles for self. The experiments revealed three robust results: (i) participa...
Scientific reports, Jan 15, 2016
Social value orientations (SVOs) are economic preferences for the distribution of resources - pro... more Social value orientations (SVOs) are economic preferences for the distribution of resources - prosocial individuals are more cooperative and egalitarian than are proselfs. Despite the social and economic implications of SVOs, no systematic studies have examined their neural correlates. We investigated the amygdala and dorsolateral prefrontal cortex (DLPFC) structures and functions in prosocials and proselfs by functional magnetic resonance imaging and evaluated cooperative behavior in the Prisoner's Dilemma game. We found for the first time that amygdala volume was larger in prosocials and positively correlated with cooperation, while DLPFC volume was larger in proselfs and negatively correlated with cooperation. Proselfs' decisions were marked by strong DLPFC and weak amygdala activity, and prosocials' decisions were marked by strong amygdala activity, with the DLPFC signal increasing only in defection. Our findings suggest that proselfs' decisions are controlled by...
arXiv (Cornell University), Apr 2, 2021
Proceedings of the National Academy of Sciences of the United States of America, Jun 13, 2017
Behavioral and neuroscientific studies explore two pathways through which internalized social nor... more Behavioral and neuroscientific studies explore two pathways through which internalized social norms promote prosocial behavior. One pathway involves internal control of impulsive selfishness, and the other involves emotion-based prosocial preferences that are translated into behavior when they evade cognitive control for pursuing self-interest. We measured 443 participants' overall prosocial behavior in four economic games. Participants' predispositions [social value orientation (SVO)] were more strongly reflected in their overall game behavior when they made decisions quickly than when they spent a longer time. Prosocially (or selfishly) predisposed participants behaved less prosocially (or less selfishly) when they spent more time in decision making, such that their SVO prosociality yielded limited effects in actual behavior in their slow decisions. The increase (or decrease) in slower decision makers was prominent among consistent prosocials (or proselfs) whose strong pre...
Scientific Reports
Humans form complex societies in which we routinely engage in social decision-making regarding th... more Humans form complex societies in which we routinely engage in social decision-making regarding the allocation of resources among ourselves and others. One dimension that characterizes social decision-making in particular is whether to prioritize self-interest or respect for others—proself or prosocial. What causes this individual difference in social value orientation? Recent developments in the social dual-process theory argue that social decision-making is characterized by its underlying domain-general learning systems: the model-free and model-based systems. In line with this “learning” approach, we propose and experimentally test the hypothesis that differences in social preferences stem from which learning system is dominant in an individual. Here, we used a non-social state transition task that allowed us to assess the balance between model-free/model-based learning and investigate its relation to the social value orientations. The results showed that proselfs depended more on...
Scientific Reports
In vivo calcium imaging with genetically encoded indicators has recently been applied to macaque ... more In vivo calcium imaging with genetically encoded indicators has recently been applied to macaque brains to monitor neural activities from a large population of cells simultaneously. Microendoscopic calcium imaging combined with implantable gradient index lenses captures neural activities from deep brain areas with a compact and convenient setup; however, this has been limited to rodents and marmosets. Here, we developed miniature fluorescent microscopy to image neural activities from the primary visual cortex of behaving macaques. We found tens of clear fluorescent signals from three of the six brain hemispheres. A subset of these neurons showed clear retinotopy and orientation tuning. Moreover, we successfully decoded the stimulus orientation and tracked the cells across days. These results indicate that microendoscopic calcium imaging is feasible and reasonable for investigating neural circuits in the macaque brain by monitoring fluorescent signals from a large number of neurons.
Frontiers in Human Neuroscience, 2019
Oxytocin (OXT) is known to play an important role in trust, whereas the involvement of other pept... more Oxytocin (OXT) is known to play an important role in trust, whereas the involvement of other peptide hormones has not been evaluated. In this study, we focused on microsatellite polymorphisms in the intron of the arginine-vasopressin receptor 1a (AVPR1a) gene and examined whether the association between the repeat lengths in the intron of AVPR1a is associated with trust and reciprocity in humans. Four-hundred and thirty-three participants played the trust game, answered the attitudinal trust question, and their buccal cells were collected. Results showed that men with a short form of AVPR1a tend to send more money to the opponent, even if there is a possibility of being betrayed by the opponent. Additionally, people with a short form of AVPR1a tended to return money to the opponent who trusts them. However, attitudinal trust was not associated with AVPR1a. These results indicate that arginine-vasopressin receptor 1a plays an important role in trust and reciprocal behaviors.
Scientific reports, Jan 7, 2017
Altruistic punishment following social norm violations promotes human cooperation. However, exper... more Altruistic punishment following social norm violations promotes human cooperation. However, experimental evidence indicates that some forms of punishment are spiteful rather than altruistic. Using two types of punishment games and seven non-strategic games, we identified strong behavioural differences between altruistic and spiteful punishers. Altruistic punishers who rejected unfair offers in the ultimatum game and punished norm violators in the third-party punishment game behaved pro-socially in various non-strategic games. Spiteful punishers who rejected unfair offers in the ultimatum game but did not punish norm violators in the third-party punishment game behaved selfishly in non-strategic games. In addition, the left caudate nucleus was larger in spiteful punishers than in altruistic punishers. These findings are in contrast to the previous assumption that altruistic punishers derive pleasure from enforcement of fairness norms, and suggest that spiteful punishers derive pleasu...
Neuroscience Research, 2007
Age-related memory impairment (AMI) is a phenotype of brain aging. The molecular mechanisms under... more Age-related memory impairment (AMI) is a phenotype of brain aging. The molecular mechanisms underlying AMI remain elusive. Given that regulation of lifespan by insulin/insulin-like growth factor signaling (IIS) and intrinsic linkage between AMI and organismal aging, one candidate signaling pathway underlying AMI is IIS. Here, we show that chico, which mediates Drosophila IIS, plays an essential role in olfactory learning and AMI. We found that chico null mutants exhibit learning deficits after olfactory conditioning. In addition, chico null mutation suppresses AMI. In contrast to chico, increasing IIS activity in the mushroom bodies (MBs), structures important for olfactory memory and AMI, causes premature AMI. Inconsistent with previous study, however, chico mutation did not extend female lifespan in our w(CS) genetic background. These results separate the brain aging from the organismal aging and demonstrate a biological role of IIS in the MBs both for learning and for AMI. P1-g48 The relation of the spatial cognition deficit and the hippocampal heterotopic neurons in the prenatal MAM-treated rats
Neuroscience Research, 2011
The prefrontal cortex is credited with contributing to relational reasoning, or the ability to in... more The prefrontal cortex is credited with contributing to relational reasoning, or the ability to integrate multiple acquired associations to generate new relationships. We have recorded single-unit activity from the lateral prefrontal cortex (LPFC) and the striatum while the monkeys performed a sequential paired-association task with asymmetric reward schedule. In the task, the monkeys learned two sequences of associated stimuli: A1-B1-C1 and A2-B2-C2. The asymmetric reward rule was instructed by pairing C1 (or C2) with large (or small) reward block by block. The monkey also learned associations between new stimuli (e.g. N1, N2) and B1 and B2. The new stimuli were presented as the first cue in sequential paired-association trials instead of the old stimuli (A1 and A2). The findings from single-unit activity suggest that the LPFC can use an internal model of category to transfer reward information associated with one stimulus to other stimuli, even to new stimuli that had never been paired with different amount of reward. The striatum only uses direct experience between conditioned stimuli and reward to predict reward. One prediction from this hypothesis is that if the LPFC is inactivated, the monkey still correctly predicts reward for old stimuli through the striatal pathway, but has deficits in predicting reward for new stimuli. We injected muscimol to locally inactivate the LPFC, and also saline into the LPFC as control. In saline sessions, the monkey had significantly higher choice accuracy for new stimuli in large than in small reward trials, but this difference disappeared in muscimol session, consistent with the prediction. Together with single-unit activity data, our results suggest that the LPFC play a critical role in category-based reward inference.
Neuroscience Research, 2007
P3-h1Ø Effect of catechol-O-methylferase (COMT) Val158Met genotype on encoding, maintenance, and ... more P3-h1Ø Effect of catechol-O-methylferase (COMT) Val158Met genotype on encoding, maintenance, and retrieval of visual working memory Hirohito M. Kondo1, Michio Nomura1,2, Makio Kashino1,3,4 1 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
Kagaku tetsugaku, 2009
To survive in changeable circumstances, we have to make appropriate decisions on our behavior. Re... more To survive in changeable circumstances, we have to make appropriate decisions on our behavior. Recent studies have suggested that we have two brain processes to calculate reward values of objects. One is the process coding a specific reward value of a stimulus or event dependent on direct experience. The other enables us to predict reward based on the internal model of given circumstances, including societies, which doesn't necessarily require direct experience. The nigro-striatal network works for the model-free decision and the prefrontal network contributes to the model-based decision. These two networks are cooperative in one occasion and are competitive in another.
Neurons, Behavior, Data analysis, and Theory, 2021
1The Department of Decoded Neurofeedback, Computational Neuroscience Laboratories, Advanced Telec... more 1The Department of Decoded Neurofeedback, Computational Neuroscience Laboratories, Advanced Telecommunications Research Institute International, Kyoto, Japan 2Institute of Cognitive Neuroscience, University College London, UK 3Medical Research Council Brain Network Dynamics Unit, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, UK 4Wellcome Centre for Integrative Neuroimaging, University of Oxford, FMRIB, John Radcliffe Hospital, Oxford, UK 5Institute for Cognitive Neurodynamics, East China University of Science and Technology, Shanghai, China 6Brain Science Institute, Tamagawa University, Tokyo, Japan 7Department of Psychology, University of Oregon, United States
Associate Editors Masayuki Miura (The University of Tokyo, Japan) Kinichi Nakashima (Kyusyu Unive... more Associate Editors Masayuki Miura (The University of Tokyo, Japan) Kinichi Nakashima (Kyusyu University, Japan) Erin M. Schuman (Max Planck Institute for Brain Research, Germany) Tatsunori Seki (Tokyo Medical University, Japan) Esther T. Stoeckli (University of Zurich, Switzerland) Yumiko Yoshimura (National Institute for Physiological Sciences, Japan) Michisuke Yuzaki (Keio University, Japan) Development/Repair Neuroscience
Communications Biology, 2021
The lateral prefrontal cortex (LPFC) has a strong monosynaptic connection with the caudate nucleu... more The lateral prefrontal cortex (LPFC) has a strong monosynaptic connection with the caudate nucleus (CdN) of the striatum. Previous human MRI studies have suggested that this LPFC-CdN pathway plays an important role in inhibitory control and working memory. We aimed to validate the function of this pathway at a causal level by pathway-selective manipulation of neural activity in non-human primates. To this end, we trained macaque monkeys on a delayed oculomotor response task with reward asymmetry and expressed an inhibitory type of chemogenetic receptors selectively to LPFC neurons that project to the CdN. Ligand administration reduced the inhibitory control of impulsive behavior, as well as the task-related neuronal responses observed in the local field potentials from the LPFC and CdN. These results show that we successfully suppressed pathway-selective neural activity in the macaque brain, and the resulting behavioral changes suggest that the LPFC-CdN pathway is involved in inhibi...
Nature Communications, 2019
Midbrain dopamine neurons are known to encode reward prediction errors (RPE) used to update value... more Midbrain dopamine neurons are known to encode reward prediction errors (RPE) used to update value predictions. Here, we examine whether RPE signals coded by midbrain dopamine neurons are modulated by the cost paid to obtain rewards, by recording from dopamine neurons in awake behaving monkeys during performance of an effortful saccade task. Dopamine neuron responses to cues predicting reward and to the delivery of rewards were increased after the performance of a costly action compared to a less costly action, suggesting that RPEs are enhanced following the performance of a costly action. At the behavioral level, stimulus-reward associations are learned faster after performing a costly action compared to a less costly action. Thus, information about action cost is processed in the dopamine reward system in a manner that amplifies the following dopamine RPE signal, which in turn promotes more rapid learning under situations of high cost.
Journal of Neurophysiology, 2001
The primate brain is equipped with prefrontal circuits for interpreting visual information, but h... more The primate brain is equipped with prefrontal circuits for interpreting visual information, but how these circuits deal with competing stimulus-response (S-R) associations remains unknown. Here we show different types of responses to task-irrelevant visual features in three functionally dissociated groups of primate prefrontal neurons. Two Japanese macaques participated in a go/no-go task in which they had to discriminate either the color or the motion direction of a visual target to make a correct manual response. Prior to the experiment, the monkeys had been trained extensively so that they acquired fixed associations between visual features and required responses (e.g., “green = go”; “downward motion = no-go”). In this design, the monkey was confronted with a visual target from which it had to extract relevant information (e.g., color in the color-discrimination condition) while ignoring irrelevant information (e.g., motion direction in the color-discrimination condition). We rec...
The Journal of Neuroscience, 2002
PloS one, 2017
Single-unit studies in monkeys have demonstrated that neurons in the prefrontal cortex predict th... more Single-unit studies in monkeys have demonstrated that neurons in the prefrontal cortex predict the reward type, reward amount or reward availability associated with a stimulus. To examine contributions of pyramidal cells and interneurons in reward processing, single-unit activity was extracellularly recorded in prefrontal cortices of four monkeys performing a reward prediction task. Based on their shapes of spike waveforms, prefrontal neurons were classified into broad-spike and narrow-spike units that represented putative pyramidal cells and interneurons, respectively. We mainly observed that narrow-spike neurons showed higher firing rates but less bursty discharges than did broad-spike neurons. Both narrow-spike and broad-spike cells selectively responded to the stimulus, reward and their interaction, and the proportions of each type of selective neurons were similar between the two cell classes. Moreover, the two types of cells displayed equal reliability of reward or stimulus di...
Journal of Neurophysiology, 2002
The lateral prefrontal cortex (LPFC) has been implicated in visuospatial processing, especially w... more The lateral prefrontal cortex (LPFC) has been implicated in visuospatial processing, especially when it is required to hold spatial information during a delay period. It has also been reported that the LPFC receives information about expected reward outcome. However, the interaction between visuospatial processing and reward processing is still unclear because the two types of processing could not be dissociated in conventional delayed response tasks. To examine this, we used a memory-guided saccade task with an asymmetric reward schedule and recorded 228 LPFC neurons. The position of the target cue indicated the spatial location for the following saccade and the color of the target cue indicated the reward outcome for a correct saccade. Activity of LPFC was classified into three main types: S-type activity carried only spatial signals, R-type activity carried only reward signals, and SR-type activity carried both. Therefore only SR-type cells were potentially involved in both visuo...
Proceedings of the National Academy of Sciences of the United States of America, Oct 29, 2016
Distributive justice concerns the moral principles by which we seek to allocate resources fairly ... more Distributive justice concerns the moral principles by which we seek to allocate resources fairly among diverse members of a society. Although the concept of fair allocation is one of the fundamental building blocks for societies, there is no clear consensus on how to achieve "socially just" allocations. Here, we examine neurocognitive commonalities of distributive judgments and risky decisions. We explore the hypothesis that people's allocation decisions for others are closely related to economic decisions for oneself at behavioral, cognitive, and neural levels, via a concern about the minimum, worst-off position. In a series of experiments using attention-monitoring and brain-imaging techniques, we investigated this "maximin" concern (maximizing the minimum possible payoff) via responses in two seemingly disparate tasks: third-party distribution of rewards for others, and choosing gambles for self. The experiments revealed three robust results: (i) participa...
Scientific reports, Jan 15, 2016
Social value orientations (SVOs) are economic preferences for the distribution of resources - pro... more Social value orientations (SVOs) are economic preferences for the distribution of resources - prosocial individuals are more cooperative and egalitarian than are proselfs. Despite the social and economic implications of SVOs, no systematic studies have examined their neural correlates. We investigated the amygdala and dorsolateral prefrontal cortex (DLPFC) structures and functions in prosocials and proselfs by functional magnetic resonance imaging and evaluated cooperative behavior in the Prisoner's Dilemma game. We found for the first time that amygdala volume was larger in prosocials and positively correlated with cooperation, while DLPFC volume was larger in proselfs and negatively correlated with cooperation. Proselfs' decisions were marked by strong DLPFC and weak amygdala activity, and prosocials' decisions were marked by strong amygdala activity, with the DLPFC signal increasing only in defection. Our findings suggest that proselfs' decisions are controlled by...