Center for Information and Neural Networks

Suita, Japan

Center for Information and Neural Networks

Suita, Japan
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Matsumoto K.,University of Tokyo | Ishikawa T.,University of Tokyo | Matsuki N.,University of Tokyo | Ikegaya Y.,University of Tokyo | Ikegaya Y.,Center for Information and Neural Networks
Frontiers in Neural Circuits | Year: 2013

Cortical microcircuits are nonrandomly wired by neurons. As a natural consequence, spikes emitted by microcircuits are also nonrandomly patterned in time and space. One of the prominent spike organizations is a repetition of fixed patterns of spike series across multiple neurons. However, several questions remain unsolved, including how precisely spike sequences repeat, how the sequences are spatially organized, how many neurons participate in sequences, and how different sequences are functionally linked. To address these questions, we monitored spontaneous spikes of hippocampal CA3 neurons ex vivo using a high-speed functional multineuron calcium imaging technique that allowed us to monitor spikes with millisecond resolution and to record the location of spiking and nonspiking neurons. Multineuronal spike sequences were overrepresented in spontaneous activity compared to the statistical chance level. Approximately 75% of neurons participated in at least one sequence during our observation period. The participants were sparsely dispersed and did not show specific spatial organization. The number of sequences relative to the chance level decreased when larger time frames were used to detect sequences. Thus, sequences were precise at the millisecond level. Sequences often shared common spikes with other sequences; parts of sequences were subsequently relayed by following sequences, generating complex chains of multiple sequences. © 2013 Matsumoto, Ishikawa, Matsuki and Ikegaya.


Mizunuma M.,University of Tokyo | Norimoto H.,University of Tokyo | Tao K.,University of Tokyo | Egawa T.,University of Tokyo | And 10 more authors.
Nature Neuroscience | Year: 2014

Hippocampal sharp waves (SWs)/ripples represent the reactivation of neurons involved in recently acquired memory and are crucial for memory consolidation. By labeling active cells with fluorescent protein under the control of an immediate-early gene promoter, we found that neurons that had been activated while mice explored a novel environment were preferentially reactivated during spontaneous SWs in hippocampal slices in vitro. During SWs, the reactivated neurons received strong excitatory synaptic inputs as opposed to a globally tuned network balance between excitation and inhibition. © 2014 Nature America, Inc. All rights reserved.


Kitanishi T.,Norwegian University of Science and Technology | Ujita S.,University of Tokyo | Fallahnezhad M.,Norwegian University of Science and Technology | Fallahnezhad M.,Nanyang Technological University | And 7 more authors.
Neuron | Year: 2015

Temporally precise neuronal firing phase-locked to gamma oscillations is thought to mediate the dynamic interaction of neuronal populations, which is essential for information processing underlying higher-order functions such as learning and memory. However, the cellular mechanisms determining phase locking remain unclear. By devising a virus-mediated approach to perform multi-tetrode recording from genetically manipulated neurons, we demonstrated that synaptic plasticity dependent on the GluR1 subunit of AMPA (α-amino-3-hydroxy-5-methyl-4-isoxazole propionate) receptor mediates two dynamic changes in neuronal firing in the hippocampal CA1 area during novel experiences: the establishment of phase-locked firing to slow gamma oscillations and the rapid formation of the spatial firing pattern of place cells. The results suggest a series of events potentially underlying the acquisition of new spatial information: slow gamma oscillations, originating from the CA3 area, induce the two GluR1-dependent changes of CA1 neuronal firing, which in turn determine information flow in the hippocampal-entorhinal system. © 2015 Elsevier Inc.


Suzuki S.,RIKEN | Harasawa N.,RIKEN | Ueno K.,RIKEN | Gardner J.L.,RIKEN | And 5 more authors.
Neuron | Year: 2012

A fundamental challenge in social cognition is how humans learn another person@s values to predict their decision-making behavior. This form of learning is often assumed to require simulation of the . other by direct recruitment of one@s own valuation process to model the other@s process. However, the cognitive and neural mechanism of simulation learning is not known. Using behavior, modeling, and fMRI, we show that simulation involves two learning signals in a hierarchical arrangement. A simulated-other@s reward prediction error processed in ventromedial prefrontal cortex mediated simulation by direct recruitment, being identical for valuation of the self and simulated-other. However, direct recruitment was insufficient for learning, and also required observation of the other@s choices to generate a simulated-other@s action prediction error encoded in dorsomedial/dorsolateral prefrontal cortex. These findings show that simulation uses a core prefrontal circuit for modeling the other@s valuation to generate prediction and an adjunct circuit for tracking behavioral variation to refine prediction.


Okada K.,Osaka University | Okada K.,Center for Information and Neural Networks | Kobayashi Y.,Osaka University | Kobayashi Y.,Center for Information and Neural Networks | Kobayashi Y.,Japan Science and Technology Agency
Frontiers in Integrative Neuroscience | Year: 2013

The neuromodulators serotonin, acetylcholine, and dopamine have been proposed to play important roles in the execution of movement, control of several forms of attentional behavior, and reinforcement learning. While the response pattern of midbrain dopaminergic neurons and its specific role in reinforcement learning have been revealed, the roles of the other neuromodulators remain elusive. Reportedly, neurons in the dorsal raphe nucleus, one major source of serotonin, continually track the state of expectation of future rewards by showing a correlated response to the start of a behavioral task, reward cue presentation, and reward delivery. Here, we show that neurons in the pedunculopontine tegmental nucleus (PPTN), one major source of acetylcholine, showed similar encoding of the expectation of future rewards by a systematic increase or decrease in tonic activity. We recorded and analyzed PPTN neuronal activity in monkeys during a reward conditioned visually guided saccade task. The firing patterns of many PPTN neurons were tonically increased or decreased throughout the task period. The tonic activity pattern of neurons was correlated with their encoding of the predicted reward value; neurons exhibiting an increase or decrease in tonic activity showed higher or lower activity in the large reward-predicted trials, respectively. Tonic activity and reward-related modulation ended around the time of reward delivery. Additionally, some tonic changes in activity started prior to the appearance of the initial stimulus, and were related to the anticipatory fixational behavior. A partially overlapping population of neurons showed both the initial anticipatory response and subsequent predicted reward value-dependent activity modulation by their systematic increase or decrease of tonic activity. These bi-directional reward- and anticipatory behavior-related modulation patterns are suitable for the presumed role of the PPTN in reward processing and motivational control. © 2013 Okada and Kobayashi.


Winston J.S.,University College London | Vlaev I.,Imperial College London | Vlaev I.,University of Warwick | Vlaev I.,Center for Information and Neural Networks | And 3 more authors.
Journal of Neuroscience | Year: 2014

The valuation of health-related states, including pain, is a critical issue in clinical practice, health economics, and pain neuroscience. Surprisingly the monetary value people associate with pain is highly context-dependent, with participants willing to pay more to avoid medium-level pain when presented in a context of low-intensity, rather than high-intensity, pain. Here, we ask whether context impacts upon the neural representation of pain itself, or alternatively the transformation of pain into valuation-driven behavior. While undergoing fMRI, human participants declared how much money they would be willing to pay to avoid repeated instances of painful cutaneous electrical stimuli delivered to the foot. We also implemented a contextual manipulation that involved presenting medium-level painful stimuli in blocks with either lowor high-level stimuli. We found no evidence of context-dependent activity within a conventional “pain matrix,” where pain-evoked activity reflected absolute stimulus intensity. By contrast, in right lateral orbitofrontal cortex, a strong contextual dependency was evident, and here activity tracked the contextual rank of the pain. The findings are in keeping with an architecture where an absolute pain valuation system and a rank-dependent system interact to influence willing to pay to avoid pain, with context impacting value-based behavior high in a processing hierarchy. This segregated processing hints that distinct neural representations reflect sensory aspects of pain and components that are less directly nociceptive whose integration also guides pain-related actions. A dominance of the latter might account for puzzling phenomena seen in somatization disorders where perceived pain is a dominant driver of behavior. © 2014 Winston et al.


Haruno M.,Center for Information and Neural Networks | Haruno M.,Japan Science and Technology Agency | Kimura M.,Tamagawa University | Frith C.D.,University College London | Frith C.D.,University of Aarhus
Journal of Cognitive Neuroscience | Year: 2014

Much decision-making requires balancing benefits to the self with benefits to the group. There are marked individual differences in this balance such that individualists tend to favor themselves whereas prosocials tend to favor the group. Understanding the mechanisms underlying this difference has important implications for society and its institutions. Using behavioral and fMRI data collected during the performance of the ultimatum game, we show that individual differences in social preferences for resource allocation, so-called "social value orientation," is linked with activity in the nucleus accumbens and amygdala elicited by inequity, rather than activity in insula, ACC, and dorsolateral pFC. Importantly, the presence of cognitive load made prosocials behave more prosocially and individualists more individualistically, suggesting that social value orientation is driven more by intuition than reflection. In parallel, activity in the nucleus accumbens and amygdala, in response to inequity, tracked this behavioral pattern of prosocials and individualists. In addition, we conducted an impunity game experiment with different participants where they could not punish unfair behavior and found that the inequity-correlated activity seen in prosocials during the ultimatum game disappeared. This result suggests that the accumbens and amygdala activity of prosocials encodes "outcome-oriented emotion" designed to change situations (i.e., achieve equity or punish). Together, our results suggest a pivotal contribution of the nucleus accumbens and amygdala to individual differences in sociality. © 2014 Massachusetts Institute of Technology.


Sasaki T.,University of Tokyo | Matsuki N.,University of Tokyo | Ikegaya Y.,University of Tokyo | Ikegaya Y.,Center for Information and Neural Networks
European Journal of Neuroscience | Year: 2014

Neuronal firing sequences that occur during behavioral tasks are precisely reactivated in the neocortex and the hippocampus during rest and sleep. These precise firing sequences are likely to reflect latent memory traces, and their reactivation is believed to be essential for memory consolidation and working memory maintenance. However, how the organized repeating patterns emerge through the coordinated interplay of distinct types of neurons remains unclear. In this study, we monitored ongoing spatiotemporal firing patterns using a multi-neuron calcium imaging technique and examined how the activity of individual neurons is associated with repeated ensembles in hippocampal slice cultures. To determine the cell types of the imaged neurons, we applied an optical synapse mapping method that identifies network connectivity among dozens of neurons. We observed that inhibitory interneurons exhibited an increase in their firing rates prior to the onset of repeating sequences, while the overall activity level of excitatory neurons remained unchanged. A specific repeating sequence emerged preferentially after the firing of a specific interneuron that was located close to the neuron first activated in the sequence. The times of repeating sequences could be more precisely predicted based on the activity patterns of inhibitory cells than excitatory cells. In line with these observations, stimulation of a single interneuron could trigger the emergence of repeating sequences. These findings provide a conceptual framework that interneurons serve as a key regulator of initiating sequential spike activity. © 2014 Federation of European Neuroscience Societies and John Wiley & Sons Ltd.


Nakayama D.,University of Tokyo | Iwata H.,University of Tokyo | Teshirogi C.,University of Tokyo | Ikegaya Y.,University of Tokyo | And 3 more authors.
Journal of Neuroscience | Year: 2015

Fear memories typically persist for long time periods, and persistent fear memories contribute to post-traumatic stress disorder. However, little is known about the cellular and synaptic mechanisms that perpetuate long-term memories. Here, we find that mouse hippocampal CA1 neurons exhibit biphasic Arc (also known as Arg3.1) elevations after fear experience and that the late Arc expression regulates the perpetuation of fear memoires. An early Arc increase returned to the baseline after 6 h, followed by a second Arc increase after 12 h in the same neuronal sub population; these elevations occurred via distinct mechanisms. Antisense-induced blockade of late Arc expression disrupted memory persistence but not formation. Moreover, prolonged fear memories were associated with the delayed, specific elimination of den dritic spines and the reactivation of neuronal ensembles formed during fear experience, both of which required late Arc expression. We propose that late Arc expression refines functional circuits in a delayed fashion to prolong fear memory. © 2015 the authors.


Zhang S.,Center for Information and Neural Networks | Seymour B.,Center for Information and Neural Networks | Seymour B.,University of Cambridge
Current Biology | Year: 2014

Technology developed for chronic pain management has been fast evolving and offers new stand-alone prospects for the diagnosis and treatment of pain, rather than simply addressing the limitations of pharmacology-based approaches. There are two central challenges to be tackled: developing objective measures that capture the subjectivity of pain experience, and providing technology-based interventions that offer new approaches for pain management. Here we highlight recent developments that hold promise in addressing both of these challenges. © 2014 Elsevier Ltd. All rights reserved.

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