Center for Information and Neural Networks

Suita, Japan

Center for Information and Neural Networks

Suita, Japan
Time filter
Source Type

Noda T.,ATR Computational Neuroscience Labs | Sugimoto N.,Center for Information and Neural Networks | Furukawa J.,Osaka University | Sato M.-A.,Ritsumeikan University | And 2 more authors.
IEEE-RAS International Conference on Humanoid Robots | Year: 2012

In this paper, we introduce our attempt to develop an assistive robot system which can contribute to Brain-Machine Interface (BMI) rehabilitation. For the BMI rehabilitation, we construct a Electroencephalogram(EEG)-Exoskeleton robot system, where the exoskeleton robot is connected to the EEG system so that the users can control the exoskeleton robot by using their brain activities. We use a classification method which considers covariance matrices of measured EEG signals as inputs to decode brain activities. The decoded brain activities are used to control exoskeleton movements. In this study, we consider assisting the stand-up movement which is one of the most frequently appeared movements in daily life and also a standard movement as a rehabilitation training. To assist the stand-up movement, we develop a force control model which takes dynamics of tendon string into account for the pneumatic-electric hybrid actuation system used in our exoskeleton robot. The results show that the exoskeleton robot successfully assisted user stand-up movements, where the assist system was activated by the decoded brain activities. © 2012 IEEE.

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.

Hanay Y.S.,Center for Information and Neural Networks | Gazi V.,Istanbul Kemerburgaz University
Proceedings - International Symposium on Computers and Communications | Year: 2014

This paper proposes a novel algorithm to deploy mobile sensors for maximization of sensing area coverage. The algorithm presented is distributed and robust to errors. Our method is dynamic and based on potential fields. Although some methods using potential fields have been proposed previously, the approach we take here is different in constructing the potential field. In particular, we utilize an entropy-based potential function and use the Newton's iteration to determine the sensor positions. Simulations show that our method is more robust to errors, and less likely to be trapped in local minima compared to some previously proposed methods. © 2014 IEEE.

Iwaki M.,RIKEN | Iwaki M.,Osaka University | Iwane A.H.,RIKEN | Iwane A.H.,Osaka University | And 4 more authors.
Nano Letters | Year: 2015

(Figure Presented). Myosin is a mechano-enzyme that hydrolyzes ATP in order to move unidirectionally along actin filaments. Here we show by single molecule imaging that myosin V motion can be activated by local heat. We constructed a dark-field microscopy that included optical tweezers to monitor 80 nm gold nanoparticles (GNP) bound to single myosin V molecules with nanometer and submillisecond accuracy. We observed 34 nm processive steps along actin filaments like those seen when using 200 nm polystyrene beads (PB) but dwell times (ATPase activity) that were 4.5 times faster. Further, by using DNA nanotechnology (DNA origami) and myosin V as a nanometric thermometer, the temperature gradient surrounding optically trapped GNP could be estimated with nanometer accuracy. We propose our single molecule measurement system should advance quantitative analysis of the thermal control of biological and artificial systems like nanoscale thermal ratchet motors. © 2015 American Chemical Society.

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.

Nakayama D.,University of Tokyo | Baraki Z.,University of Tokyo | Onoue K.,University of Tokyo | Ikegaya Y.,University of Tokyo | And 3 more authors.
Current Biology | Year: 2015

The frontal association cortex (FrA) is implicated in higher brain function [1]. Aberrant FrA activity is likely to be involved in dementia pathology [2-4]. However, the functional circuits both within the FrA and with other regions are unclear. A recent study showed that inactivation of the FrA impairs memory consolidation of an auditory fear conditioning in young mice [5]. In addition, dendritic spine remodeling of FrA neurons is sensitive to paired sensory stimuli that produce associative memory [5]. These findings suggest that the FrA is engaged in neural processes critical to associative learning. Here we characterize stimulus integration in the mouse FrA during associative learning. We experimentally separated contextual fear conditioning into context exposure and shock, and found that memory formation requires protein synthesis associated with both context exposure and shock in the FrA. Both context exposure and shock trigger Arc, an activity-dependent immediate-early gene, expression in the FrA, and a subset of FrA neurons was dually activated by both stimuli. In addition, we found that the FrA receives projections from the perirhinal (PRh) and insular (IC) cortices and basolateral amygdala (BLA), which are implicated in context and shock encoding [6-8]. PRh and IC neurons projecting to the FrA were activated by context exposure and shock, respectively. Arc expression in the FrA associated with context exposure and shock depended on PRh activity and both IC and BLA activities, respectively. These findings indicate that the FrA is engaged in stimulus integration and contributes to memory formation in associative learning. © 2015 Elsevier Ltd. All rights reserved.

Onoue K.,University of Tokyo | Nakayama D.,University of Tokyo | Ikegaya Y.,University of Tokyo | Ikegaya Y.,Center for Information and Neural Networks | And 2 more authors.
Molecular Brain | Year: 2014

Background: Prolonged re-exposure to a fear-eliciting cue in the absence of an aversive event extinguishes the fear response to the cue, and has been clinically used as an exposure therapy. Arc (also known as Arg3.1) is implicated in synaptic and experience-dependent plasticity. Arc is regulated by the transcription factor cAMP response element binding protein, which is upregulated with and necessary for fear extinction. Because Arc expression is also activated with fear extinction, we hypothesized that Arc expression is required for fear extinction. Findings. Extinction training increased the proportion of Arc-labeled cells in the basolateral amygdala (BLA). Arc was transcribed during latter part of extinction training, which is possibly associated with fear extinction, as well as former part of extinction training. Intra-BLA infusions of Arc antisense oligodeoxynucleotide (ODN) before extinction training impaired long-term but not short-term extinction memory. Intra-BLA infusions of Arc antisense ODN 3 h after extinction training had no effect on fear extinction. Conclusion: Our findings demonstrate that Arc is required for long-term extinction of conditioned fear and contribute to the understanding of extinction as a therapeutic manner. © 2014 Onoue et al.; licensee BioMed Central Ltd.

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.

Loading Center for Information and Neural Networks collaborators
Loading Center for Information and Neural Networks collaborators