Fukushima's Selective Attention Model is a model of biological vision system. It has engineering merit of deformation and position shift tolerant recognition and recollection of the recognized object in an input image. Based on this feature, we have proposed a method for hybrid image understanding in which each object is recognized, recollected and segmented sequentially even when the objects are overlapped and occluded. However, parameter setting for the fine object recollection is difficult with the Selective Attention Model and parameters search is necessary to tune the given image. In this paper, we propose a method for the parameter search based on an evaluation of image recollection precision in the hybrid image understanding process. A computer simulation result demonstrates the validity of the proposed method.

抄録全体を表示

It is believed that the hippocampus and the neocortex are involved in several aspects of learning and memory. However, the relationship of the activities between the hippocampus and the neocortex are not well investigated. In the present study, we recorded the response to a sound stimuli in the auditory cortex of the anesthetized guinea pig by voltage sensitive optical recording. And we examined the effect of the hippocampal stimulation on the auditory cortex response by changing the stimulation current intensity. The results showed that the weak stimulation inhibits the auditory responses but the strong stimulation facilitates the responses. It means that the hippocampal activity can produce excitatory or inhibitory potentials, suggesting that it is an important neuronal basis of the memory consolidation process.

抄録全体を表示

In spatial alternation tasks, the same place in different behavioral sequences is represented by different neurons in the rat hippocampus. This indicates that associative memory in the brain solves the memory interference problem at each instance. By assuming that different behavioral sequences are encoded in different continuous attractors, we hypothesize that theta rhythm-dependent activity provides cooperation between external input and retrieval of the behavioral episode. In our computer experiments, these two activities with an appropriate phase difference enable the maintaining of a consistent attractor in accordance with behavior. It suggests neural dynamics for the real-time process of associate memory.

抄録全体を表示

Classical conditioning induced map plasticity in the adult sensory cortex has not been well investigated. In this study, we used voltage sensitive optical recording method to study map changes in the auditory cortex induced by fear conditioning with parining of sound and electric shock. From pair-conditioned group and pseudoconditioned group, the responses were recorded both before and after the conditioning. The result shows that after conditioning, only the response area to CS sound in the pair-condtioned group was increased. This suggests that many neurons in the auditory cortex exhibit a rapid tuning to the CS sound by the fear conditioning.

抄録全体を表示

The modular network SOM (mnSOM) proposed in this paper is a Self-Organizing Map (SOM) in function space, as opposed to the conventional SOM in vector space. Whereas each node of the conventional SOM represents a codebook vector, each unit of mnSOM represents a function (i.e., input-output relationship) which may be a dynamical one. In other words, all nodes of the competitive layer are replaced by some kind of neural networks which may be of a multi-layer perceptron type or a recurrent type. The performance of mnSOM is examined by simulation examples such as one dealing with geology-dependent meteorological changes in Japan, one involving musical scale and one simulating a mass-spring-dashpot system. These results show that the functions acquired by the winner modules are mapped into the 2D lattice with topological continuity, i.e., similar functions are close to each other and desimilar ones are allocated far apart. Moreover, “test functions” whose corresponding input-output data are not used during the training are mapped as “test winner modules” that appear at interpolated locations between “training winner modules”.

抄録全体を表示

Many studies have emphasized simulation theory as a core concept for the mirror neurons that are found in the ventral premotor area (F5) and inferior parietal cortex (PF) of the macaque. Imitation, social cognition, empathy and language are linked to mirror neurons. However, function of mirror neurons in the macaque is still missing, because such cognitive functions are limited or lacking in these monkeys. It is important to discuss these neurons in the aspect of motor function. I would suggest that mirror neurons in area PF might have a roll of monitoring of self generated action. This idea may provide neural correlate of self other distinction.

抄録全体を表示

Current conceptual models of mirror neurons attribute high level functions such as imitation, action understanding and (precursor of) language to mirror neurons. However the number of studies that take a computational viewpoint to realize these proposals is limited. In this article we first present current opinions (`conceptual models') on the mirror neuron function. Then we review the computational models available and explain the strengths and weakness of these models in addressing the mirror neurons. Our meta-analysis underlines the gap between conceptual and computational models and points out the required research effort at both sides to reduce this gap.

抄録全体を表示

人間の原始的な見まね学習の能力は，コミュニケーションとシンボル操作の基本的な機能を司ると言われるが故に，人間の高度な知能の根元であると考えられている．このような考え方を提案するミメシス理論に基づき，隠れマルコフモデルを用いた行動模倣と原始シンボルの創発の統合モデルを提案する．完全に抽象化された世界でのシンボル記述の前段階として，行動の概略記述表現を原始シンボルと定義する．これを隠れマルコフモデルを用いて獲得し，行動認識·生成に応用する手法について説明する．さらに，原始シンボルを組み合わせたり再構成することによって，より上位の複雑な行動パターンを認識·生成するようなシンボル操作のための数理的手法の基礎として幾何学的シンボル操作に注目し，それを可能とする原始シンボル空間の構成法について述べる．

抄録全体を表示