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Face perception by using topographical NMF
Abstracts / Neuroscience Research 68S (2010) e109–e222
e209
P1-q12 Depletion of CD4-positive T-lymphocytes enhances post-stroke endogenous neurogenesis
P1-q14 Analysis of macroscopic behavior of multi-output node perturbation with eligibility trace
Orie Saino 1 , Akihiko Taguchi 2 , Takayuki Nakagomi 1 , Akiko Doi 1 , Masashi Takata 1 , Shin-ichiro Kashiwamura 1 , Nobutaka Doe 1 , Tomohiro Matsuyama 1
Hiroshi Saito 1 , Kentaro Katahira 1,2,3 , Kazuo Okanoya 2,3 , Masato Okada 1,2,3
1
Institute for Advanced Medical Sciences, Hyogo College of Medicine, Hyogo, Japan 2 Cardiovascular Centor, Osaka, Japan Background and aims: Acute inflammation in the post-stroke period exacerbates neuronal damage and stimulates reparative mechanisms, including neurogenesis. However, only a small fraction of neural stem/progenitor cells (NSPs) survive (Eur J Neurosci, 2009). In this study, we examined the contribution of T-lymphocytes to acute neuronal damage, glial responses, and survival of endogenous NSPs induced by cerebral ischemia, as well as functional recover, using a highly reproducible murine stroke model. Methods: Focal cerebral ischemia was produced by occluding the middle cerebral artery of adult immunocompetent (CB-17) and immunocompromised CB17 (SCID) mice. CD4-, CD8- or CD25-positive T cell population was depleted in immunocompetent mice by intraperitoneal injection of each monoclonal antibody. Then, the measurement of brain volume, immunohistochemistry for nestin, caspase3, BrdU, GFAP and Iba-1, TUNEL assay and behavioral analysis were carried out. Results: In CB-17 mice, a number of CD4+ T cells were infiltrated in the post-ischemic area. Though the expression of astrocytes and microglia within the ischemic area in acute phase of infarction was not different between SCID and CB-17 mice morphologically, SCID mice in chronic phase (28 days after stroke) showed a significantly larger brain volume of ipsilateral hemisphere with reduced apoptosis of NSPs in poststroke area compared with the non-treated- CB-17 mice. Depletion of CD4+ T cells, but not CD8+ T cells, showed similar results. Subsequently, they showed enhanced neurogenesis and improved functional recovery compared with controls. In contrast, depletion of CD25+ T cells resulted in reduced generation of NSPs and impaired functional recovery. Conclution: Our findings demonstrate a key role of CD4-positive T-lymphocytes in regulation of poststroke neurogenesis and indicate a potential novel strategy for cell therapy in repair of the central nervous system after stroke. doi:10.1016/j.neures.2010.07.2494
P1-q13 Face perception by using topographical NMF Yuichiro Nakagawa , Haruo Hosoya Dept of Computer Science, Graduate School of Information Science and Technology, The Univ of Tokyo, Tokyo Recent behavioral and physiological studies have revealed special sensitivies and characteristics in the face recognition function of the primate brain, compared to ordinary object recognition. In this presentation, we attempt to explain such experimental results by using Hosoda et al.’s hierarchical visual model (2009) featuring Topographical Non-negative Matrix Factorization at the top level. We adopt this model since it has successfully reproduced some properties of the primate inferotemporal (IT) cortex (close to the face-related area), where columnar clusters of neurons represent parts of objects and their individual tangential directions represent closely related features. We have trained the model with frontal face images and compared model neurons’ response properties with experimental data. (1) A behavioral experiment revealed that monkeys could identify familiar faces more correctly than unfamiliar ones; analogously, the activity patterns in the model were closer when presented the same person’s faces than when presented different people’s, and, moreover, the activity patterns gradually became more distant as learning progressed when presented different people’s faces. (2) Hasselmo et al. (1989) discovered face-selective neurons whose responses depended on an individual but not on his emotional expressions; we found some populations of model units showing analogous response properties. (3) Bruce et al. (1981) reported on neurons in the superior temporal polysensory area of macaque that are more sensitive to face images than any other stimuli, some influenced by removal of the eyes; we also found analogous model units. (4) Eifuku et al. (2004) found that monkeys trained only with frontal face images showed less performance in recognition of non-frontal views of the same faces; relevantly, after training with frontal faces, the model activity patterns were significantly different between frontal and non-frontal face test images. doi:10.1016/j.neures.2010.07.2495
1
Complexity Sci. and Engin, Univ of Tokyo, Tokyo 2 RIKEN BSI 3 JST ERATO OEIP Node perturbation (NP) is a learning rule to adjust a system’s parameters by estimating the average gradient of an objective function. The estimates are computed stochastically from fluctuations of the function value caused by introducing a perturbation into the system’s output. Therefore, NP is applicable for a complex system in which the differential of the objective function cannot be calculated explicitly. As an example, Fiete et al. (2007) proposed that a juvenile songbird’s learning can be explained by a NP-based model. When considering about concrete system, the instruction signal to adjust the parameters is typically delivered after a while. In such a case, it is difficult to distinguishes the relation between the delayed signal and the past events. This is a kind of temporal credit assignment problem; how much does a past event affect the delayed instruction signal. Eligibility trace (ET) is a mechanism that works well with such situation by assigning more eligibility to more contributed past events. In neuroscience, same kind of problem, known as “distal reward problem”, exists. Izhikevich (2007) proposed that the EL is one of essential mechanism to solve the distal reward problem. In previous study, we employed statistical mechanics approach to analyze the macroscopic dynamics of NP with EL where the delivery of instruction signal is delayed. As a result, we obtained the mathematical relationships of the time constant of eligibility trace and the delay of the instruction signal. In this study, we extend our previous model, which consisted of a single output neural network, to multi-output one. This is a case that several networks perform the learning simultaneously according to same instruction signal; this is a kind of spatial credit assignment problem. As a result of the statistical mechanics analysis, we obtained the equations which describe system’s macroscopic behavior and the effect of other networks to one network. doi:10.1016/j.neures.2010.07.2496
P1-q15 Generating mechanisms of MEG and EEG signals at the single cell level in hippocampus and neocortex Shingo Murakami 1,2 , Tongsheng Zhang 3 , Akira Hirose 4 , Yoshio Okada 5 1 Division of Molecular and Cellular Pharmacology, Department of Pharmacology, Graduate School of Medicine, Osaka University 2 Osaka University Center for Advanced Medical Engineering and Informatics, Osaka, Japan 3 New Mexico University Shoool of Medicine, Albuquerque, USA 4 The University of Tokyo Graduate School of Engineering, Department of Electrical Engineering and Information Systems, Tokyo, Japan 5 Department of Neurology, Children’s Hospital Boston, Harvard Medical School, Boston, USA
The genesis of magnetoencephalography (MEG) and electroencephalography (EEG) signals has been re-examined within dramatically changed concepts of the mammalian cellular physiology in the past 20 years in order to provide valuable information in multimodal studies of human brain functions. We developed mathematical models based on the 1991 CA3 model of Roger Traub and Mainen’s neocortex model to explain EEG and MEG generation mechanism in hippocampus and neocortex. Our revised model, taking difference of dendritic diameters or realistic anatomy into account, quantitatively explained the magnitude of the magnetic fields produced by different cell types. In neocortex, the magnitudes of the current dipole moments are clearly different in cell types. The current dipole moment in Layer V pyramidal cell is largest and that in Layer III pyramidal cell is next. The current dipole moments of Layer IV stellate cell and Layer III aspiny cell are smaller than the others. These results indicate that the quantitative estimates can show the possibility that Layer V and Layer III pyramidal cells are important contributors to MEG and EEG signals. doi:10.1016/j.neures.2010.07.2497
e209
P1-q12 Depletion of CD4-positive T-lymphocytes enhances post-stroke endogenous neurogenesis
P1-q14 Analysis of macroscopic behavior of multi-output node perturbation with eligibility trace
Orie Saino 1 , Akihiko Taguchi 2 , Takayuki Nakagomi 1 , Akiko Doi 1 , Masashi Takata 1 , Shin-ichiro Kashiwamura 1 , Nobutaka Doe 1 , Tomohiro Matsuyama 1
Hiroshi Saito 1 , Kentaro Katahira 1,2,3 , Kazuo Okanoya 2,3 , Masato Okada 1,2,3
1
Institute for Advanced Medical Sciences, Hyogo College of Medicine, Hyogo, Japan 2 Cardiovascular Centor, Osaka, Japan Background and aims: Acute inflammation in the post-stroke period exacerbates neuronal damage and stimulates reparative mechanisms, including neurogenesis. However, only a small fraction of neural stem/progenitor cells (NSPs) survive (Eur J Neurosci, 2009). In this study, we examined the contribution of T-lymphocytes to acute neuronal damage, glial responses, and survival of endogenous NSPs induced by cerebral ischemia, as well as functional recover, using a highly reproducible murine stroke model. Methods: Focal cerebral ischemia was produced by occluding the middle cerebral artery of adult immunocompetent (CB-17) and immunocompromised CB17 (SCID) mice. CD4-, CD8- or CD25-positive T cell population was depleted in immunocompetent mice by intraperitoneal injection of each monoclonal antibody. Then, the measurement of brain volume, immunohistochemistry for nestin, caspase3, BrdU, GFAP and Iba-1, TUNEL assay and behavioral analysis were carried out. Results: In CB-17 mice, a number of CD4+ T cells were infiltrated in the post-ischemic area. Though the expression of astrocytes and microglia within the ischemic area in acute phase of infarction was not different between SCID and CB-17 mice morphologically, SCID mice in chronic phase (28 days after stroke) showed a significantly larger brain volume of ipsilateral hemisphere with reduced apoptosis of NSPs in poststroke area compared with the non-treated- CB-17 mice. Depletion of CD4+ T cells, but not CD8+ T cells, showed similar results. Subsequently, they showed enhanced neurogenesis and improved functional recovery compared with controls. In contrast, depletion of CD25+ T cells resulted in reduced generation of NSPs and impaired functional recovery. Conclution: Our findings demonstrate a key role of CD4-positive T-lymphocytes in regulation of poststroke neurogenesis and indicate a potential novel strategy for cell therapy in repair of the central nervous system after stroke. doi:10.1016/j.neures.2010.07.2494
P1-q13 Face perception by using topographical NMF Yuichiro Nakagawa , Haruo Hosoya Dept of Computer Science, Graduate School of Information Science and Technology, The Univ of Tokyo, Tokyo Recent behavioral and physiological studies have revealed special sensitivies and characteristics in the face recognition function of the primate brain, compared to ordinary object recognition. In this presentation, we attempt to explain such experimental results by using Hosoda et al.’s hierarchical visual model (2009) featuring Topographical Non-negative Matrix Factorization at the top level. We adopt this model since it has successfully reproduced some properties of the primate inferotemporal (IT) cortex (close to the face-related area), where columnar clusters of neurons represent parts of objects and their individual tangential directions represent closely related features. We have trained the model with frontal face images and compared model neurons’ response properties with experimental data. (1) A behavioral experiment revealed that monkeys could identify familiar faces more correctly than unfamiliar ones; analogously, the activity patterns in the model were closer when presented the same person’s faces than when presented different people’s, and, moreover, the activity patterns gradually became more distant as learning progressed when presented different people’s faces. (2) Hasselmo et al. (1989) discovered face-selective neurons whose responses depended on an individual but not on his emotional expressions; we found some populations of model units showing analogous response properties. (3) Bruce et al. (1981) reported on neurons in the superior temporal polysensory area of macaque that are more sensitive to face images than any other stimuli, some influenced by removal of the eyes; we also found analogous model units. (4) Eifuku et al. (2004) found that monkeys trained only with frontal face images showed less performance in recognition of non-frontal views of the same faces; relevantly, after training with frontal faces, the model activity patterns were significantly different between frontal and non-frontal face test images. doi:10.1016/j.neures.2010.07.2495
1
Complexity Sci. and Engin, Univ of Tokyo, Tokyo 2 RIKEN BSI 3 JST ERATO OEIP Node perturbation (NP) is a learning rule to adjust a system’s parameters by estimating the average gradient of an objective function. The estimates are computed stochastically from fluctuations of the function value caused by introducing a perturbation into the system’s output. Therefore, NP is applicable for a complex system in which the differential of the objective function cannot be calculated explicitly. As an example, Fiete et al. (2007) proposed that a juvenile songbird’s learning can be explained by a NP-based model. When considering about concrete system, the instruction signal to adjust the parameters is typically delivered after a while. In such a case, it is difficult to distinguishes the relation between the delayed signal and the past events. This is a kind of temporal credit assignment problem; how much does a past event affect the delayed instruction signal. Eligibility trace (ET) is a mechanism that works well with such situation by assigning more eligibility to more contributed past events. In neuroscience, same kind of problem, known as “distal reward problem”, exists. Izhikevich (2007) proposed that the EL is one of essential mechanism to solve the distal reward problem. In previous study, we employed statistical mechanics approach to analyze the macroscopic dynamics of NP with EL where the delivery of instruction signal is delayed. As a result, we obtained the mathematical relationships of the time constant of eligibility trace and the delay of the instruction signal. In this study, we extend our previous model, which consisted of a single output neural network, to multi-output one. This is a case that several networks perform the learning simultaneously according to same instruction signal; this is a kind of spatial credit assignment problem. As a result of the statistical mechanics analysis, we obtained the equations which describe system’s macroscopic behavior and the effect of other networks to one network. doi:10.1016/j.neures.2010.07.2496
P1-q15 Generating mechanisms of MEG and EEG signals at the single cell level in hippocampus and neocortex Shingo Murakami 1,2 , Tongsheng Zhang 3 , Akira Hirose 4 , Yoshio Okada 5 1 Division of Molecular and Cellular Pharmacology, Department of Pharmacology, Graduate School of Medicine, Osaka University 2 Osaka University Center for Advanced Medical Engineering and Informatics, Osaka, Japan 3 New Mexico University Shoool of Medicine, Albuquerque, USA 4 The University of Tokyo Graduate School of Engineering, Department of Electrical Engineering and Information Systems, Tokyo, Japan 5 Department of Neurology, Children’s Hospital Boston, Harvard Medical School, Boston, USA
The genesis of magnetoencephalography (MEG) and electroencephalography (EEG) signals has been re-examined within dramatically changed concepts of the mammalian cellular physiology in the past 20 years in order to provide valuable information in multimodal studies of human brain functions. We developed mathematical models based on the 1991 CA3 model of Roger Traub and Mainen’s neocortex model to explain EEG and MEG generation mechanism in hippocampus and neocortex. Our revised model, taking difference of dendritic diameters or realistic anatomy into account, quantitatively explained the magnitude of the magnetic fields produced by different cell types. In neocortex, the magnitudes of the current dipole moments are clearly different in cell types. The current dipole moment in Layer V pyramidal cell is largest and that in Layer III pyramidal cell is next. The current dipole moments of Layer IV stellate cell and Layer III aspiny cell are smaller than the others. These results indicate that the quantitative estimates can show the possibility that Layer V and Layer III pyramidal cells are important contributors to MEG and EEG signals. doi:10.1016/j.neures.2010.07.2497