| TITLE | ||||
|---|---|---|---|---|
| Functional coupling of the mediolateral higher motor areas during performance of a dual-task consisting of a main-task and interruption. | ||||
| OBJECT | ||||
| It is poorly understood the mechanism in which multiple cortical areas collaborate in order to orchestrate a goal-directed behavior. The purpose of the present project is to understand this issue from the perspective of the communication in multiple higher motor areas that lie mediolaterally on the frontal lobe. To this aim, we will examine the dynamism of the communication between cortical areas while trained animals perform a dual-task that consists of a main-task and an interrupting task. | ||||
| NAME | AFFILIATION | SPECIALTY | ROLE | |
| Leader | SHIMA, Keisetsu | Tohoku University | Neurophysiology Research | director |
| Collaborator | NAKAJIMA, Toshi | Tohoku University | Neurophysiology | Electrophysiological experiment, analysis of spike data |
| Collaborator | HOSAKA, Ryosuke | Fukuoka University | Applied Mathematics | Analysis of local field potential |
| Collaborator | MUSHIAKE, Hajime | Tohoku University | Neurophysiology | Adviser |
| TITLE | ||||
|---|---|---|---|---|
| Local dynamics of excitatory-inhibitory networks in frontal-lobe areas during emerging behavior in complex environment. | ||||
| OBJECT | ||||
| In order to adapt to ever-changing environment, information processing in the brain should be complex and flexible. We have been analyzing neuronal activities in the prefrontal cortex of monkeys planning and executing complex behavior. In consequence, we have shown that information coded by firing rate of a certain neuronal population shifted dynamically from final- to immediate- goals of behavior and that critical fluctuation of firing preceded the shift of goal representation. In this study, we continue to analyze neuronal activities in the prefrontal cortex of monkeys planning and executing complex behavior. In particular, we try a novel local-attractor plot for each neuronal pair recorded simultaneously. Through such analyses, we will reveal the dynamics of local neuronal networks composed of excitatory and inhibitory neurons, and compare these dynamics between areas of the frontal lobe. Our study will provide the neurophysiological basis for the principles of “hetero brain dynamics” in establishing consistent relationship with complex environment. | ||||
| NAME | AFFILIATION | SPECIALTY | ROLE | |
| Leader | SAKAMOTO, Kazuhiro | Tohoku University | Computational neuroscience and neurophysiology | General planning and execution of this study |
| Collaborator | MUSHIAKE, Hajime | Tohoku University | Neurophysiology | Supervising |
| TITLE | ||||
|---|---|---|---|---|
| Prototype models of intra- and inter- brain heterocommunications using chaos in recurrent neural networks | ||||
| OBJECT | ||||
| Heuristic approaches to functional roles of chaos in brain with use of computer experiments, in particular, about chaotic dynamics introduced into recurrent neural network models with considering the effects of inhibitory neurons. The main topics are (1)functional memory dynamics and chaos, (2)biological control functions and chaos, (3)communication and chaos. The topic (3) is strongly related with intra-brain communications between hetero-fields in brain. Furthermore, (4)hetero-brain communications will be investigated in this research period. | ||||
| NAME | AFFILIATION | SPECIALTY | ROLE | |
| Leader | NARA, Shigetoshi | Okayama University | Neuroscience, Nonlinear Dynamics, Physical Informatics | Research planning, Modeling, Computer experiments, Data processing |
| TITLE | ||||
|---|---|---|---|---|
| Hippocampal mechanisms in rats for spatial coding of self and others | ||||
| OBJECT | ||||
| This project aims to investigate the spatial coding of self versus others in rat hippocampal circuits. Previous research on the cognitive map of the hippocampus has always focused on the spatial mapping of the individual ( "SELF" ) relative to the world. However, if the cognitive map is truly a representation of the world, the neural mechanisms of coding should work equally well in tracking the movements of others. This projects aims to elucidate the commonalities of spatial coding of self-movement versus movement-by-others. The research on spatial coding in rat hippocampus has the advantage of very detailed experimental data, which give very rich opportunities for theoretical work and computational modeling. The work on the mirror system, however, is intrinsically connected to the topic of communication and complex (heterogeneous) systems, and offers very interesting phenomenological observations. Our hypothesis is that rat hippocampal spatial coding might support the transition from auto-coding (the rat’s own spatial position) to hetero-coding (the spatial position of another rat). If the hippocampus truly maintains a cognitive map of the world, this should be the appropriate structure in the brain to find a convergence of auto-and hetero-coding of position. We compare conditions in which the rat itself is moving in complex environments with conditions in which the rat observes another moving in the same environments. Essentially, we examine the equivalent of the mirror system for spatial mapping in rats, through multi-unit recording and recording of local field potentials, particularly in areas CA1 and CA3 of the hippocampus. | ||||
| NAME | AFFILIATION | SPECIALTY | ROLE | |
| Leader | LAUWEREYNS, Johan | Kyushu University | Cognitive neuroscience; behavioral analysis | PI, experimental design, analysis |
| Collaborator | TAKAHASHI, Muneyoshi | Kyushu University | Behavioral neuroscience | Development of experimental set-up, Data collection and analysis |
| TITLE | ||||
|---|---|---|---|---|
| The experimental verification for the dynamical cell assembly induced in the hippocampal neuronal rhythm. | ||||
| OBJECT | ||||
| Memory system is very important for the hetero-brain-communication. In the present project, the dynamical memory sysytem in brain is studied. The dynamical cell assembly (DCA) proposed previously has spatio-temporal pattern of neuronal activity, while there is no experimental evidence for that. There are several rhythms, theta, beta, and gamma rhythms in hippocampus. The rhythms are related to memory system. They are reproduced in vitro hippocampal slices with the application of acetylcholine agonist carbachol. In the generation of beta oscillation, a few neurons fire and the firing propagates in CA3 region. The result suggest DCA may emerge in the generation of the oscillation. The spontaneous DCA will associate with the external signals and become the memory representation. In the present study, we will measure the spatiotemporal pattern induced in the generation of beta oscillation and study whether the pattern will correspond to DCA or not using the several kinds of the stimulus which induces the synaptic long-term potentiation. | ||||
| NAME | AFFILIATION | SPECIALTY | ROLE | |
| Leader | NATSUME, Kiyohisa | Kyushu Institute of Technology | Neurophysiology | Research director, Neurophysiological experiment, and data analysis |
| TITLE | ||||
|---|---|---|---|---|
| Cortical circuit mechanism of top-down or bottom-up shaping of motor command | ||||
| OBJECT | ||||
| We have established a new experimental approach to examine microcircuitry mechanisms of motor information processing in the motor cortex, using multiunit (and juxtacellular) recordings from cortical neurons of head-fixed rats performing a forelimb movement task. In the present study, we are going to explore a cortical circuit mechanism of top-down or bottom-up shaping of motor command. We will examine functional differences in the spike activity of motor cortex neurons between externally-triggered and internally-triggered generation of forelimb movements. In addition, our in vitro experiments using multiphoton laser-scanning microscopy with UV uncaging stimulation will reveal signal coding and processing in hippocampal neurons. The experimental data that we acquire here will be provided for collaborators in theoretical neuroscience. | ||||
| NAME | AFFILIATION | SPECIALTY | ROLE | |
| Leader | ISOMURA, Yoshikazu | Tamagawa University | Neurophysiology | In vivo experiments focusing on signal processing in the motor cortex |
| Collaborator | FUKUSHIMA, Yasuhiro | Kawasaki University of Medical Welfare | Neurophysiology | In vitro experiments focusing on signal processing in the hippocampus |
| TITLE | ||||
|---|---|---|---|---|
| Functional analysis of inhibitory synapses in the microcircuitry of cerebral cortex | ||||
| OBJECT | ||||
| Neurons receive thousands of synaptic inputs onto their dendrites and soma, and spatially and temporally integrate these inputs to produce appropriate output in the form of action potentials generated in axons. We would like to find out the function of inhibitory synapse in the cortical microcircuitry. We analyze inhibitory synapses of a FS basket cell on a pyramidal cell using combined morphological, physiological and modeling method. We hope we can elucidate the fundamental functional mechanism of cortical inhibitory signal. | ||||
| NAME | AFFILIATION | SPECIALTY | ROLE | |
| Leader | KUBOTA, Yoshiyuki | National Institute for Physiological Sciences | Neuroscience | All aspects of this study, including the design of the experiment, collecting and analyzing the data, and writing the manuscript. |