Nitric oxide is an important neuromodulator in the brain and is involved in the development of visual system. But it is not clear how nitric oxide and nitric oxide synthase （NOS） are involved in the developing visua...Nitric oxide is an important neuromodulator in the brain and is involved in the development of visual system. But it is not clear how nitric oxide and nitric oxide synthase （NOS） are involved in the developing visual cortex of rodents. Thus we examined the expression of NOS activity in the postnatal developing visual cortex of the golden hamster by using histochemical technique for NADPH-diaphorase （NADPH-d）. A heavily stained NADPH-d band was observed in the neuropil of the visual cortex. This NADPH-d band initially appeared in the cortical plate from the day of birth （P0） to postnatal day 4 （P4）. From P7 to P21, this band was confined to area 17 and migrated to the deeper layers Ill IV and V VI before it eventually disappeared at P28. Such developmental trends of the band correlated well with the process of formation and establishment of the geniculo-cortical projection patterns. Thus, the areal specific development of the band suggests that NOS is closely related to the cortical differentiation and synaptic formation of the primary visual cortex. On the other hand, monocular eye enucleation on P1 could not alter the appearance of this NADPH-d positive band, indicating a non-activity dependant role of NOS. In addition, differences in the laminar distributions and developmental sequence between the heavily and lightly stained NADPH-d positive neurons during development suggest that they play different roles in the development.展开更多
The local visual motion detection mechanism used in the visual systems of primatescan only sense the motion component oriented perpendicularly to the contrast gradient of thebrightness pattern.But the visual system of...The local visual motion detection mechanism used in the visual systems of primatescan only sense the motion component oriented perpendicularly to the contrast gradient of thebrightness pattern.But the visual system of higher animals can adaptively determine the actualdirection of motion through a learning process.In this paper a multilayered feedforward neuralnetwork model for perception of visual motion is presented.This model employs W.Reichardt’selementary motion detectors array and T.Kohonen’s self-organizing feature map.We explored theself-organizing principles for perception of visual motion.The computer simulations show thatthis neural network is able to recognize the true direction of motion through an unsupervisedlearning process.In addition,the neurons with the same or similar motion direction selectivitytend to appear in“functional columns”which seem to be qualitatively similar to the corticalmotion columns observed by electrophysiological and cytohistochemical studies in certain higherareas such as MT.It proves that motion-detection by spatio-temporal coherences,mapping,co-operation,competition,and Hebb rule may be the basic principles for the self-organization ofvisual motion perception networks.展开更多
In this paper the neurocomputation of figure-ground relative motion information in thevisual system of the fly have been investigated in great detail by a combination of quanti-tative behavioural experiments and compu...In this paper the neurocomputation of figure-ground relative motion information in thevisual system of the fly have been investigated in great detail by a combination of quanti-tative behavioural experiments and computational model simulations. Only torque responsesabout the vertical axis of the tethered flying flies (Musca domestica) were determined inthe behavioural experiment. The main results of behavioural experiments are: (i) The dynam-ics of the torque responses depends not only on the phase relationship between figure andbackground motion but also on the oscillation frequency of the figure and ground. (ii) Inall the phase relations tested, the time courses are a characteristic fingerprint of the partic-ular phase relationship. (iii) The variation of the amplitude of the response peaks is an espe-cially sensitive indicator for the variability of figure--ground discrimination behaviour. The main results of computer simulations are: (i) The 'computer fly', the networkmodel of both the SF-system and the LF--system with a two-dimensional array of elementarymovement detectors (EMDs) as the input layer have proved to be sufficient so far to ac-count for the main characteristics of the torque responses of the fly during stimulation withrelative motion under different conditions. (ii) The computer simulations fit the correspond-ing experimental data sufficiently well with respect to their characteristic features underdifferent stimulus conditions. (iii) The time course in computer simulation depends criticallyon the parameters n, q, T and k. The behavioural experimental results together with the computational model simulationscast a new light on an important problem: the strategies underlying the extraction of rela-tive motion information at the level of neural network.展开更多
Based on quantitative analyses of the response characteristics of visual neurons in the superior colliculus to moving optical bar stimuli, it is demonstrated for the first time that the visual neurons in superior coll...Based on quantitative analyses of the response characteristics of visual neurons in the superior colliculus to moving optical bar stimuli, it is demonstrated for the first time that the visual neurons in superior colliculus of the cat have, to some extent, orientational selectivity. The significance of this selectivity is discussed in reference to its morphological substrate and physiological functions. In addition, both the directional and orientational selectivities in the superior colliculus are relatively weak when compared with those in the primary visual cortex, and the majority of the neurons prefer upward or downward motion in the visual field.展开更多
Although the directionally selective cells in many visual cortical areas are organized in columnar manner, the functional organization of direction selectivity of area VI in the monkey still remains unclear. We quanti...Although the directionally selective cells in many visual cortical areas are organized in columnar manner, the functional organization of direction selectivity of area VI in the monkey still remains unclear. We quantitatively studied the proportion of directionally selective cells, direction selectivity and the functional organization of the striate cortical cells in the monkey and compared those with the cat. The results show that the direction selectivity and directional organization of striate cortical cells in the monkey are significantly weaker than those in the cat, suggesting that the species difference between the two kinds of animal is related to their different anatomic pathways.展开更多
The first Raman spectra of HIV1-HIV2 in human sera and hypericin-induced pho-tosensitive damage of the virus have been obtained.The prominent Raman lines in the spectra are assigned respectively to the carbohydrates o...The first Raman spectra of HIV1-HIV2 in human sera and hypericin-induced pho-tosensitive damage of the virus have been obtained.The prominent Raman lines in the spectra are assigned respectively to the carbohydrates of viral glycoprotein,RNA,protein and lipid.The spectra are dominated by Raman scattering of the carbohydrates.The lines of D-Mannose and N-acetylglucosamine in carbohydrates are obvious and there is aβ-configuration in the anomeric C1 position in D-Mannose.The viral RNA duplexes bound assumes an A-form geometry.The lines of backbone phosphate group,bases(involving interbase hydrogen bonding)and ribose of the RNA are complete and distinct.The secondary structure of the viral protein maintainsα-helix,β-sheet,β-turn and random coil.Its side chains are rich and vary from tryptophan,phenylalanine and“buried”tyrosine;the stable conformation of the S-S bond of gauche-gauche-gauche;the two forms of C-S bonds of gauche and trans;to sulfhydrl group and ionized and unionized carboxyl groups.The viral lipid bilayer molecules are probably in the liquid ordered phase or the gel phase.It was observed that the hypericin-induced photosensitive damage of HIV1-HIV2 in human sera changed various components of HIV1-HIV2 in different degrees:The orderly A-form viral RNA would become a disordered viral RNA.There were a breakage of interbase hydrogen bonds and disruption of vertical base-base stacking interactions.In addition,the groups of ribos and four bases were damaged obviously.A decrease in ordered structure(α-helix andβ-sheet)of viral protein is accompanied by an increase in random coil.The Tyr buried in the three-dimensional structure of protein was damaged,but it was still“buried”and the damage of C-S bond of trans form was stronger.The groups of carbohydrates,including D-Mannos and N-acetyl glucosamine,in viral envelope glycoprotein had also been changed.The hydrophilic C-N bond of choline in viral lipid was damaged,which was the possible binding site to hypericin,whereas the viral lipids bilayers were still probably in the liquid ordered phase or the gel phase.So the space structure of HIV1-HIV2 was damaged under the experimental conditions,which might block viral infection and inhibit its growth and breeding.It is apparent that the laser Raman spectra have provided certain direct evidence at the molecular level for photosensitive damage of HIV1-HIV2.展开更多
The temporal properties of pattern adaptation of relay cells induced by repeated sinusoidal drifting grating were investigated in the dorsal lateral geniculate nucleus (dLGN) of cats. The results showed that the respo...The temporal properties of pattern adaptation of relay cells induced by repeated sinusoidal drifting grating were investigated in the dorsal lateral geniculate nucleus (dLGN) of cats. The results showed that the response amplitude declined and the response latency prolonged when relay cells were pattern-adapted in dLGN, like the similar findings in visual cortex. However, in contrast to the result in cortex, the response phase of relay cells advanced. This implies that an inhibition with relatively long latency may participate in the pattern adaptation of dLGN cells and the adaptation in dLGN may be via a mechanism different from that of visual cortex.展开更多
The lesion of nucleus robustus archistriatalis (RA) has no effect on normal short calls in the bramble finch, but affects significantly the temporal and acoustic features of learned long calls.It causes the principal ...The lesion of nucleus robustus archistriatalis (RA) has no effect on normal short calls in the bramble finch, but affects significantly the temporal and acoustic features of learned long calls.It causes the principal frequency of basic sound in monotone long calls to increase 500 cents, and to lose two upper partials. The lesion of RA not only results in the increased sound length of loud-sound and shortened coda of variable-tone long calls by 13.4%-22.1% and 21.2%-24.2% on average, respectively, but also makes the frequency rising coefficient (FRC) of even order partial tone in loud-sound drop 18.5%-25.8% on an average, and the step-up rate decrease 22.7% -24.0% on an average with the increase of frequencies. These results show that the control of temporal and frequency features of learned calls by RA matches to each other. Moreover, the lesion of bilateral RA can confuse the vocal pattern, and the produced long call has the character of both the mono- and variable-tone long calls. The prelude shows rising frequency, and the loud sound is monotone sound.展开更多
This paper concerns certain difficult problems in image processing and perception: neuro-computation of visual motion information. The first part of this paper deals with the spatial physiological integration by the f...This paper concerns certain difficult problems in image processing and perception: neuro-computation of visual motion information. The first part of this paper deals with the spatial physiological integration by the figure-ground discrimination neural network in the visual system of the fly. We have outlined the fundamental organization and algorithms of this neural network, and mainly concentrated on the results of computer simulations of spatial physiological integration. It has been shown that the gain control mechanism , the nonlinearity of synaptic transmission characteristic , the interaction between the two eyes , and the directional selectivity of the pool cells play decisive roles in the spatial physiological integration. In the second part, we have presented a self-organizing neural network for the perception of visual motion by using a retinotopic array of Reichardt's motion detectors and Kohonen's self-organizing maps. It .has been demonstrated by computer simulations that the network is able to learn to solve the ambiguities given by local motion detection mechanism. The resultant self-organized configuration in the output layer is resembling direction selective columns which first appear in area MT of the primate visual system. It has been explored that the spatio-temporal coherences, mapping, cooperation, competition, and Hebb rule are the basic neural principles for visual motion perception.展开更多
High vocal center (HVC) can produce single sound with one or two syllables by the sin-gle-type vocal control pattern in songbirds ruddy bunting (Emberiza rutila). It obviously shows left-side dominance in controlling ...High vocal center (HVC) can produce single sound with one or two syllables by the sin-gle-type vocal control pattern in songbirds ruddy bunting (Emberiza rutila). It obviously shows left-side dominance in controlling double syllables, principal frequency (PF) and increasing sound intensity of the evoked calls. Meanwhile, the complex-type control pattern can produce complex calls with multisyllable, and also shows significant left-side dominance in controlling the number of syllables, tone changing and sound intensity. These indicate that left-side HVC controls higher frequency and complicated sentence structure. The basic vocal center, dorsomedial nucleus of the intercollicular complex (DM), controls the monosyllable sound in songbirds, and shows left-side dominance in controlling both the number of syllable and sound intensity. These results not only provide some direct evidence for left-side dominance in high vocal center, but also indicate that there is some internal connection between the high and basic vocal centers in songbirds.展开更多
The optical recording of three-dimensional(3-D)reconstruction of CA1 pyramidal cells wasderived from the studies on the CA1 region of the hippocampus in adult male Wistar rats.The recordingwas produced by the Confocal...The optical recording of three-dimensional(3-D)reconstruction of CA1 pyramidal cells wasderived from the studies on the CA1 region of the hippocampus in adult male Wistar rats.The recordingwas produced by the Confocal Laser Scan Microscope(LSM-10).The attemption was to outline themorphological neural network of CA1 pyramidal cells organization,following the trail of axo-dendritic connec-tions in 3-D spatial distributions among neurons.The fractal structure of neurons with their dendritic andaxonal trees using fractal algorithm was noticed,and 2—18 simulated cells were obtained using PC-486 comput-er.The simulational cells are similar in morphology to the natural CA1 hippocampal pyramidal cells.There-fore,the exploitation of an advanced neurohistological research technique combining optical recording of theLSM-10 and computer simulation of fractal structure can provide the quantitative fractal structural basis forchaosic dynamics of brain.展开更多
A connection ensemble model (CEM) of local neural circuits in central nervous system(CNS) is proposed in this work.Neuronal interactions are investigated at two levels,i.e.the synaptic con-nection between single neuro...A connection ensemble model (CEM) of local neural circuits in central nervous system(CNS) is proposed in this work.Neuronal interactions are investigated at two levels,i.e.the synaptic con-nection between single neurons and the macro-connections between different neuronal groups.The efficacy ofmacro-connection is quantitatively determined by the efficacies of constituent synapses,and is asymptoticallystable.This model provides a reasonable description for the functional invariance of local neural circuits withstructural diversities,which is a widely observed fact in neurobiology.It is expected that the works in CEMmodel would enrich the current research in neural dynamics.展开更多
In this study, the binding of tau to DNA is investigated by the electrophoretic mobility shift assay. Using polynucleotide as probe, we find that tau bound to double-stranded DNA but not to single-stranded DNA. Fo... In this study, the binding of tau to DNA is investigated by the electrophoretic mobility shift assay. Using polynucleotide as probe, we find that tau bound to double-stranded DNA but not to single-stranded DNA. Formation of tau-polynucleotide complex is interfered at alkaline pH and high concentration of NaC1, but is not affected by dithiothreiotol.……展开更多
The long-term goal of artificial intelligence （AI） is to make machines learn and think like human beings. Due to the high levels of uncertainty and vulnerability in human life and the open-ended nature of problems t...The long-term goal of artificial intelligence （AI） is to make machines learn and think like human beings. Due to the high levels of uncertainty and vulnerability in human life and the open-ended nature of problems that humans are facing, no matter how intelligent machines are, they are unable to completely replace humans. Therefore, it is necessary to introduce human cognitive capabilities or human-like cognitive models into AI systems to develop a new form of AI, that is, hybrid-augmented intelligence. This form of AI or machine intelligence is a feasible and important developing model. Hybrid-augmented intelligence can be divided into two basic models： one is human-in-the-loop augmented intelligence with human-computer collaboration, and the other is cognitive computing based augmented intelligence, in which a cognitive model is embedded in the machine learning system. This survey describes a basic framework for human-computer collaborative hybrid-augmented intelligence, and the basic elements of hybrid-augmented intelligence based on cognitive computing. These elements include intuitive reasoning, causal models, evolution of memory and knowledge, especially the role and basic principles of intuitive reasoning for complex problem solving, and the cognitive learning framework for visual scene understanding based on memory and reasoning. Several typical applications of hybrid-augmented intelligence in related fields are given.展开更多
Neonatal rat cardiomyocytes were subjected to 24 h of hypoxia 95%N2/5%CO2 and 24 h of hypoxia plus 4 h of reoxygenation 95%O2/5%CO2. 24 h of hypoxia increased the levels of NO, --23NO/NO, TBARS and LDH. 24 h of hypoxi...Neonatal rat cardiomyocytes were subjected to 24 h of hypoxia 95%N2/5%CO2 and 24 h of hypoxia plus 4 h of reoxygenation 95%O2/5%CO2. 24 h of hypoxia increased the levels of NO, --23NO/NO, TBARS and LDH. 24 h of hypoxia plus 4 h of reoxygenation decreased the levels of NO, --23NO/NO, but further increased TBARS and LDH. The hypoxia up-regulated the expression of bcl-2, p53 and p21/waf1/cip1 but the reoxygenation down-regulated the expression of bcl-2, and further up-regulated p53 and p21/waf1/cip1. The hypoxia increased cell apoptosis and reoxygena-tion further increased both apoptotic and necrotic cell death. NO, -23NO/NO, TBARS, DNA frag-mentation and cell apoptosis were enhanced by SNP and inhibited by L-NAME respectively. In addition, SOD/catalase down-regulated the expression of p53, p21/wafl/cipl and TBARS but up-regulated bcl-2 and increased indirectly the level of NO, --23NO/NO, and inhibited DNA frag-mentation. The results suggest that hypoxia-induced cell death is associated with the activation of NO, bcl-2 and p53 pathway, while hypoxia-reoxygenation induced cell death via the generation of reactive oxygen species and activation of p53 pathway. The present study clarified that NO may be an initiative signal to apoptotic cell death and the activation of bcl-2, p53 and p21/waf1/cip1 path-way in hypoxic and hypoxia-reoxygenated cardiomyocytes.展开更多
Primary information processing of the vertebrate visual system can be considered as an image information processing system with multi-input-output. The input is a distribution of light intensity projected on the retin...Primary information processing of the vertebrate visual system can be considered as an image information processing system with multi-input-output. The input is a distribution of light intensity projected on the retina and the output represents the response of neural cells at a spatial location and time at a certain level in visual pathways. With the viewpoint of system analysis, properties of the system can be described by a weight展开更多
基金the Fundamental Research Funds for the Central Universities,No.21609101the National Basic Research Program of China (973 Program),No.2011CB707501
文摘Nitric oxide is an important neuromodulator in the brain and is involved in the development of visual system. But it is not clear how nitric oxide and nitric oxide synthase （NOS） are involved in the developing visual cortex of rodents. Thus we examined the expression of NOS activity in the postnatal developing visual cortex of the golden hamster by using histochemical technique for NADPH-diaphorase （NADPH-d）. A heavily stained NADPH-d band was observed in the neuropil of the visual cortex. This NADPH-d band initially appeared in the cortical plate from the day of birth （P0） to postnatal day 4 （P4）. From P7 to P21, this band was confined to area 17 and migrated to the deeper layers Ill IV and V VI before it eventually disappeared at P28. Such developmental trends of the band correlated well with the process of formation and establishment of the geniculo-cortical projection patterns. Thus, the areal specific development of the band suggests that NOS is closely related to the cortical differentiation and synaptic formation of the primary visual cortex. On the other hand, monocular eye enucleation on P1 could not alter the appearance of this NADPH-d positive band, indicating a non-activity dependant role of NOS. In addition, differences in the laminar distributions and developmental sequence between the heavily and lightly stained NADPH-d positive neurons during development suggest that they play different roles in the development.
基金Supported in part by the National Natural Science Foundation of China National Laboratory of Pattern Recognition,Institute of Automation,Academia Sinica.
文摘The local visual motion detection mechanism used in the visual systems of primatescan only sense the motion component oriented perpendicularly to the contrast gradient of thebrightness pattern.But the visual system of higher animals can adaptively determine the actualdirection of motion through a learning process.In this paper a multilayered feedforward neuralnetwork model for perception of visual motion is presented.This model employs W.Reichardt’selementary motion detectors array and T.Kohonen’s self-organizing feature map.We explored theself-organizing principles for perception of visual motion.The computer simulations show thatthis neural network is able to recognize the true direction of motion through an unsupervisedlearning process.In addition,the neurons with the same or similar motion direction selectivitytend to appear in“functional columns”which seem to be qualitatively similar to the corticalmotion columns observed by electrophysiological and cytohistochemical studies in certain higherareas such as MT.It proves that motion-detection by spatio-temporal coherences,mapping,co-operation,competition,and Hebb rule may be the basic principles for the self-organization ofvisual motion perception networks.
基金Project supported by the National Natural Science Foundation of China.
文摘In this paper the neurocomputation of figure-ground relative motion information in thevisual system of the fly have been investigated in great detail by a combination of quanti-tative behavioural experiments and computational model simulations. Only torque responsesabout the vertical axis of the tethered flying flies (Musca domestica) were determined inthe behavioural experiment. The main results of behavioural experiments are: (i) The dynam-ics of the torque responses depends not only on the phase relationship between figure andbackground motion but also on the oscillation frequency of the figure and ground. (ii) Inall the phase relations tested, the time courses are a characteristic fingerprint of the partic-ular phase relationship. (iii) The variation of the amplitude of the response peaks is an espe-cially sensitive indicator for the variability of figure--ground discrimination behaviour. The main results of computer simulations are: (i) The 'computer fly', the networkmodel of both the SF-system and the LF--system with a two-dimensional array of elementarymovement detectors (EMDs) as the input layer have proved to be sufficient so far to ac-count for the main characteristics of the torque responses of the fly during stimulation withrelative motion under different conditions. (ii) The computer simulations fit the correspond-ing experimental data sufficiently well with respect to their characteristic features underdifferent stimulus conditions. (iii) The time course in computer simulation depends criticallyon the parameters n, q, T and k. The behavioural experimental results together with the computational model simulationscast a new light on an important problem: the strategies underlying the extraction of rela-tive motion information at the level of neural network.
基金Project supported by the National Natural Science Foundation of China and the Chinese Academy of Sciences.
文摘Based on quantitative analyses of the response characteristics of visual neurons in the superior colliculus to moving optical bar stimuli, it is demonstrated for the first time that the visual neurons in superior colliculus of the cat have, to some extent, orientational selectivity. The significance of this selectivity is discussed in reference to its morphological substrate and physiological functions. In addition, both the directional and orientational selectivities in the superior colliculus are relatively weak when compared with those in the primary visual cortex, and the majority of the neurons prefer upward or downward motion in the visual field.
文摘Although the directionally selective cells in many visual cortical areas are organized in columnar manner, the functional organization of direction selectivity of area VI in the monkey still remains unclear. We quantitatively studied the proportion of directionally selective cells, direction selectivity and the functional organization of the striate cortical cells in the monkey and compared those with the cat. The results show that the direction selectivity and directional organization of striate cortical cells in the monkey are significantly weaker than those in the cat, suggesting that the species difference between the two kinds of animal is related to their different anatomic pathways.
基金This work was supported by the National Natural Science Foundation of China(Grant No.39570189).
文摘The first Raman spectra of HIV1-HIV2 in human sera and hypericin-induced pho-tosensitive damage of the virus have been obtained.The prominent Raman lines in the spectra are assigned respectively to the carbohydrates of viral glycoprotein,RNA,protein and lipid.The spectra are dominated by Raman scattering of the carbohydrates.The lines of D-Mannose and N-acetylglucosamine in carbohydrates are obvious and there is aβ-configuration in the anomeric C1 position in D-Mannose.The viral RNA duplexes bound assumes an A-form geometry.The lines of backbone phosphate group,bases(involving interbase hydrogen bonding)and ribose of the RNA are complete and distinct.The secondary structure of the viral protein maintainsα-helix,β-sheet,β-turn and random coil.Its side chains are rich and vary from tryptophan,phenylalanine and“buried”tyrosine;the stable conformation of the S-S bond of gauche-gauche-gauche;the two forms of C-S bonds of gauche and trans;to sulfhydrl group and ionized and unionized carboxyl groups.The viral lipid bilayer molecules are probably in the liquid ordered phase or the gel phase.It was observed that the hypericin-induced photosensitive damage of HIV1-HIV2 in human sera changed various components of HIV1-HIV2 in different degrees:The orderly A-form viral RNA would become a disordered viral RNA.There were a breakage of interbase hydrogen bonds and disruption of vertical base-base stacking interactions.In addition,the groups of ribos and four bases were damaged obviously.A decrease in ordered structure(α-helix andβ-sheet)of viral protein is accompanied by an increase in random coil.The Tyr buried in the three-dimensional structure of protein was damaged,but it was still“buried”and the damage of C-S bond of trans form was stronger.The groups of carbohydrates,including D-Mannos and N-acetyl glucosamine,in viral envelope glycoprotein had also been changed.The hydrophilic C-N bond of choline in viral lipid was damaged,which was the possible binding site to hypericin,whereas the viral lipids bilayers were still probably in the liquid ordered phase or the gel phase.So the space structure of HIV1-HIV2 was damaged under the experimental conditions,which might block viral infection and inhibit its growth and breeding.It is apparent that the laser Raman spectra have provided certain direct evidence at the molecular level for photosensitive damage of HIV1-HIV2.
基金the National NaturalScience Foundation of China (Grant Nos. 97908003 and 30070257) the Foundation of the Chinese Academy of Sciences (Grant No. 39893340-03).
文摘The temporal properties of pattern adaptation of relay cells induced by repeated sinusoidal drifting grating were investigated in the dorsal lateral geniculate nucleus (dLGN) of cats. The results showed that the response amplitude declined and the response latency prolonged when relay cells were pattern-adapted in dLGN, like the similar findings in visual cortex. However, in contrast to the result in cortex, the response phase of relay cells advanced. This implies that an inhibition with relatively long latency may participate in the pattern adaptation of dLGN cells and the adaptation in dLGN may be via a mechanism different from that of visual cortex.
基金the National Natural Science Foundation of China (Grant No. 39570195) and Outstanding Youth Foundation of Ministry of Education of China.
文摘The lesion of nucleus robustus archistriatalis (RA) has no effect on normal short calls in the bramble finch, but affects significantly the temporal and acoustic features of learned long calls.It causes the principal frequency of basic sound in monotone long calls to increase 500 cents, and to lose two upper partials. The lesion of RA not only results in the increased sound length of loud-sound and shortened coda of variable-tone long calls by 13.4%-22.1% and 21.2%-24.2% on average, respectively, but also makes the frequency rising coefficient (FRC) of even order partial tone in loud-sound drop 18.5%-25.8% on an average, and the step-up rate decrease 22.7% -24.0% on an average with the increase of frequencies. These results show that the control of temporal and frequency features of learned calls by RA matches to each other. Moreover, the lesion of bilateral RA can confuse the vocal pattern, and the produced long call has the character of both the mono- and variable-tone long calls. The prelude shows rising frequency, and the loud sound is monotone sound.
基金Project supported by the National Natural Science Foundation of China.
文摘This paper concerns certain difficult problems in image processing and perception: neuro-computation of visual motion information. The first part of this paper deals with the spatial physiological integration by the figure-ground discrimination neural network in the visual system of the fly. We have outlined the fundamental organization and algorithms of this neural network, and mainly concentrated on the results of computer simulations of spatial physiological integration. It has been shown that the gain control mechanism , the nonlinearity of synaptic transmission characteristic , the interaction between the two eyes , and the directional selectivity of the pool cells play decisive roles in the spatial physiological integration. In the second part, we have presented a self-organizing neural network for the perception of visual motion by using a retinotopic array of Reichardt's motion detectors and Kohonen's self-organizing maps. It .has been demonstrated by computer simulations that the network is able to learn to solve the ambiguities given by local motion detection mechanism. The resultant self-organized configuration in the output layer is resembling direction selective columns which first appear in area MT of the primate visual system. It has been explored that the spatio-temporal coherences, mapping, cooperation, competition, and Hebb rule are the basic neural principles for visual motion perception.
基金supported by the National Natural Science Foundation of China(Grant No.39570195)Outstanding Youth Foundation of Ministry of Education of China,Science and Technology Research Project of Ministry of Education of China(Grant No.01062)Laboratory of Visual Information Processing Foundation of the Chinese Academy of Sciences.
文摘High vocal center (HVC) can produce single sound with one or two syllables by the sin-gle-type vocal control pattern in songbirds ruddy bunting (Emberiza rutila). It obviously shows left-side dominance in controlling double syllables, principal frequency (PF) and increasing sound intensity of the evoked calls. Meanwhile, the complex-type control pattern can produce complex calls with multisyllable, and also shows significant left-side dominance in controlling the number of syllables, tone changing and sound intensity. These indicate that left-side HVC controls higher frequency and complicated sentence structure. The basic vocal center, dorsomedial nucleus of the intercollicular complex (DM), controls the monosyllable sound in songbirds, and shows left-side dominance in controlling both the number of syllable and sound intensity. These results not only provide some direct evidence for left-side dominance in high vocal center, but also indicate that there is some internal connection between the high and basic vocal centers in songbirds.
基金the National Natural Science Foundation of ChinaLaboratory of Visual Information Processing,Institute of Biophysics,Chinese Academy of Sciences
文摘The optical recording of three-dimensional(3-D)reconstruction of CA1 pyramidal cells wasderived from the studies on the CA1 region of the hippocampus in adult male Wistar rats.The recordingwas produced by the Confocal Laser Scan Microscope(LSM-10).The attemption was to outline themorphological neural network of CA1 pyramidal cells organization,following the trail of axo-dendritic connec-tions in 3-D spatial distributions among neurons.The fractal structure of neurons with their dendritic andaxonal trees using fractal algorithm was noticed,and 2—18 simulated cells were obtained using PC-486 comput-er.The simulational cells are similar in morphology to the natural CA1 hippocampal pyramidal cells.There-fore,the exploitation of an advanced neurohistological research technique combining optical recording of theLSM-10 and computer simulation of fractal structure can provide the quantitative fractal structural basis forchaosic dynamics of brain.
文摘A connection ensemble model (CEM) of local neural circuits in central nervous system(CNS) is proposed in this work.Neuronal interactions are investigated at two levels,i.e.the synaptic con-nection between single neurons and the macro-connections between different neuronal groups.The efficacy ofmacro-connection is quantitatively determined by the efficacies of constituent synapses,and is asymptoticallystable.This model provides a reasonable description for the functional invariance of local neural circuits withstructural diversities,which is a widely observed fact in neurobiology.It is expected that the works in CEMmodel would enrich the current research in neural dynamics.
文摘 In this study, the binding of tau to DNA is investigated by the electrophoretic mobility shift assay. Using polynucleotide as probe, we find that tau bound to double-stranded DNA but not to single-stranded DNA. Formation of tau-polynucleotide complex is interfered at alkaline pH and high concentration of NaC1, but is not affected by dithiothreiotol.……
基金Project supported by the Chinese Academy of Engi- neering, the National Natural Science Foundation of China （No. L1522023）, the National Basic Research Program （973） of China （No. 2015CB351703）, and the National Key Research and Development Plan （Nos. 2016YFB1001004 and 2016YFB1000903）
文摘The long-term goal of artificial intelligence （AI） is to make machines learn and think like human beings. Due to the high levels of uncertainty and vulnerability in human life and the open-ended nature of problems that humans are facing, no matter how intelligent machines are, they are unable to completely replace humans. Therefore, it is necessary to introduce human cognitive capabilities or human-like cognitive models into AI systems to develop a new form of AI, that is, hybrid-augmented intelligence. This form of AI or machine intelligence is a feasible and important developing model. Hybrid-augmented intelligence can be divided into two basic models： one is human-in-the-loop augmented intelligence with human-computer collaboration, and the other is cognitive computing based augmented intelligence, in which a cognitive model is embedded in the machine learning system. This survey describes a basic framework for human-computer collaborative hybrid-augmented intelligence, and the basic elements of hybrid-augmented intelligence based on cognitive computing. These elements include intuitive reasoning, causal models, evolution of memory and knowledge, especially the role and basic principles of intuitive reasoning for complex problem solving, and the cognitive learning framework for visual scene understanding based on memory and reasoning. Several typical applications of hybrid-augmented intelligence in related fields are given.
基金the Guangdong Natural Science Foundation and National Natural Science Foundation of China (Grant No. 29935080).
文摘Neonatal rat cardiomyocytes were subjected to 24 h of hypoxia 95%N2/5%CO2 and 24 h of hypoxia plus 4 h of reoxygenation 95%O2/5%CO2. 24 h of hypoxia increased the levels of NO, --23NO/NO, TBARS and LDH. 24 h of hypoxia plus 4 h of reoxygenation decreased the levels of NO, --23NO/NO, but further increased TBARS and LDH. The hypoxia up-regulated the expression of bcl-2, p53 and p21/waf1/cip1 but the reoxygenation down-regulated the expression of bcl-2, and further up-regulated p53 and p21/waf1/cip1. The hypoxia increased cell apoptosis and reoxygena-tion further increased both apoptotic and necrotic cell death. NO, -23NO/NO, TBARS, DNA frag-mentation and cell apoptosis were enhanced by SNP and inhibited by L-NAME respectively. In addition, SOD/catalase down-regulated the expression of p53, p21/wafl/cipl and TBARS but up-regulated bcl-2 and increased indirectly the level of NO, --23NO/NO, and inhibited DNA frag-mentation. The results suggest that hypoxia-induced cell death is associated with the activation of NO, bcl-2 and p53 pathway, while hypoxia-reoxygenation induced cell death via the generation of reactive oxygen species and activation of p53 pathway. The present study clarified that NO may be an initiative signal to apoptotic cell death and the activation of bcl-2, p53 and p21/waf1/cip1 path-way in hypoxic and hypoxia-reoxygenated cardiomyocytes.
文摘Primary information processing of the vertebrate visual system can be considered as an image information processing system with multi-input-output. The input is a distribution of light intensity projected on the retina and the output represents the response of neural cells at a spatial location and time at a certain level in visual pathways. With the viewpoint of system analysis, properties of the system can be described by a weight
