Apparent Movements Induced by Luminance Modulations: A Model Study

Perception ◽  
1988 ◽  
Vol 17 (5) ◽  
pp. 667-679 ◽  
Author(s):  
Henk A K Mastebroek ◽  
Willem H Zaagman
Keyword(s):  
Receptive Field ◽  
Stimulus Pattern ◽  
Input Output ◽  
Zero Crossings ◽  
Model Study ◽  
Illusory Movement ◽  
Dimensional Distribution ◽  
Full Analysis ◽  
Spatial Derivatives ◽  
Visual Percept

When the receptive-field profiles of the different units in the primary visual cortex are described by a series of different functions which are given by a Gaussian distribution and its first, second, and so on, spatial derivatives, a full analysis of the input—output processing of these units (under the assumption of linearity for small signals) can be achieved for a wide variety of optical stimuli consisting of closely adjacent fields modulated independently in intensity. Once the input—output relationship for one particular unit has been obtained, it is possible to calculate in a straightforward manner the spatial representation of the stimulus pattern in a two-dimensional distribution of such units. Investigations are reported into how a stimulus pattern (a dark or bright bar between two fields modulated in illuminance) is represented in a hierarchical structure of such layers of units, each layer containing just one type of receptive-field profile from the Gaussian family of derivatives. It is shown that if a visual percept is associated with the behaviour of the extrema or zero-crossings of the representations in the first few layers of such an architecture, a complete description can be given of the experimental results obtained by Gregory and Heard in their psychophysical experiments on illusory movement perception induced by luminance intensity modulations.

Biohydrogen development in United States and in China: An input–output model study

2011 ◽  
Vol 36 (21) ◽  
pp. 14238-14244 ◽  
Author(s):  
Duu-Hwa Lee ◽  
Duu-Jong Lee ◽  
Ling-Hui Chiu
Keyword(s):  
United States ◽  
Input Output ◽  
Model Study

Hebbian Network of Self-Organizing Receptive Field Neurons as Associative Incremental Learner

2015 ◽  
Vol 14 (04) ◽  
pp. 1550023 ◽  
Author(s):  
Tarek Najjar ◽  
Osamu Hasegawa
Keyword(s):  
Receptive Field ◽  
Receptive Fields ◽  
Data Representation ◽  
Training Data ◽  
Internal Dynamic ◽  
Input Output ◽  
Learning Mechanism ◽  
Hebbian Plasticity ◽  
Data Points ◽  
Self Organizing

Associative learning plays a major role in the formation of the internal dynamic engine of an adaptive system or a cognitive robot. Interaction with the environment can provide a sparse and discrete set of sample correlations of input–output incidences. These incidences of associative data points can provide useful hints for capturing underlying mechanisms that govern the system’s behavioral dynamics. In many approaches to solving this problem, of learning system’s input–output relation, a set of previously prepared data points need to be presented to the learning mechanism, as a training data, before a useful estimations can be obtained. Besides data-coding is usually based on symbolic or nonimplicit representation schemes. In this paper, we propose an incremental learning mechanism that can bootstrap from a state of complete ignorance of any representative sample associations. Besides, the proposed system provides a novel mechanism for data representation in nonlinear manner through the fusion of self-organizing maps and Gaussian receptive fields. Our architecture is based solely on cortically-inspired techniques of coding and learning as: Hebbian plasticity and adaptive populations of neural circuitry for stimuli representation. We define a neural network that captures the problem’s data space components using emergent arrangement of receptive field neurons that self-organize incrementally in response to sparse experiences of system–environment interactions. These learned components are correlated using a process of Hebbian plasticity that relates major components of input space to those of the output space. The viability of the proposed mechanism is demonstrated through multiple experimental setups from real-world regression and robotic arm sensory-motor learning problems.

scholarly journals Synaptic and intrinsic mechanisms underlying development of cortical direction selectivity

eLife ◽  
2020 ◽  
Vol 9 ◽  
Author(s):  
Arani Roy ◽  
Jason J Osik ◽  
Benyamin Meschede-Krasa ◽  
Wesley T Alford ◽  
Daniel P Leman ◽  
...  
Keyword(s):  
Receptive Field ◽  
Receptive Fields ◽  
Direction Selectivity ◽  
Developmental Changes ◽  
Input Output ◽  
Intrinsic Properties ◽  
Synaptic Inputs ◽  
Spike Threshold ◽  
Eye Opening ◽  
Spatiotemporal Receptive Fields

Modifications of synaptic inputs and cell-intrinsic properties both contribute to neuronal plasticity and development. To better understand these mechanisms, we undertook an intracellular analysis of the development of direction selectivity in the ferret visual cortex, which occurs rapidly over a few days after eye opening. We found strong evidence of developmental changes in linear spatiotemporal receptive fields of simple cells, implying alterations in circuit inputs. Further, this receptive field plasticity was accompanied by increases in near-spike-threshold excitability and input-output gain that resulted in dramatically increased spiking responses in the experienced state. Increases in subthreshold membrane responses induced by the receptive field plasticity and the increased input-output spiking gain were both necessary to explain the elevated firing rates in experienced ferrets. These results demonstrate that cortical direction selectivity develops through a combination of plasticity in inputs and in cell-intrinsic properties.

3-Dimensional immunolabeling and in situ hybridization detection using fluorescence photooxidation and intermediate-voltage Electron Microscopy

1994 ◽  
Vol 52 ◽  
pp. 164-165
Author(s):  
Thomas J. Deerinck ◽  
Maryann E. Martone ◽  
Varda Lev-Ram ◽  
David P. L. Green ◽  
Roger Y. Tsien ◽  
...  
Keyword(s):  
Laser Scanning ◽  
Reactive Oxygen ◽  
Confocal Laser Scanning Microscope ◽  
Fluorescent Dye ◽  
Confocal Laser ◽  
3 Dimensional ◽  
Voltage Electron ◽  
Dimensional Distribution ◽  
Electron Microscopes ◽  
New Generation

The confocal laser scanning microscope has become a powerful tool in the study of the 3-dimensional distribution of proteins and specific nucleic acid sequences in cells and tissues. This is also proving to be true for a new generation of high contrast intermediate voltage electron microscopes (IVEM). Until recently, the number of labeling techniques that could be employed to allow examination of the same sample with both confocal and IVEM was rather limited. One method that can be used to take full advantage of these two technologies is fluorescence photooxidation. Specimens are labeled by a fluorescent dye and viewed with confocal microscopy followed by fluorescence photooxidation of diaminobenzidine (DAB). In this technique, a fluorescent dye is used to photooxidize DAB into an osmiophilic reaction product that can be subsequently visualized with the electron microscope. The precise reaction mechanism by which the photooxidation occurs is not known but evidence suggests that the radiationless transfer of energy from the excited-state dye molecule undergoing the phenomenon of intersystem crossing leads to the formation of reactive oxygen species such as singlet oxygen. It is this reactive oxygen that is likely crucial in the photooxidation of DAB.

Three-dimensional distribution of ribulose-1, 5-bisphosphate carboxylase/oxygemase during the early development of proplastids in dark-grown Euglena cells transferred to an inorganic medium

1990 ◽  
Vol 48 (3) ◽  
pp. 906-907
Author(s):  
Tomoko Ehara ◽  
Shuji Sumida ◽  
Tetsuaki Osafune ◽  
Eiji Hase
Keyword(s):  
Cell Suspension ◽  
Euglena Gracilis ◽  
Carbon Materials ◽  
Three Dimensional ◽  
Peripheral Region ◽  
Plastid Development ◽  
Bisphosphate Carboxylase ◽  
Inorganic Medium ◽  
Ribulose 1 ◽  
Dimensional Distribution

As shown previously, Euglena cells grown in Hutner’s medium in the dark without agitation accumulate wax as well as paramylum, and contain proplastids showing no internal structure except for a single prothylakoid existing close to the envelope. When the cells are transferred to an inorganic medium containing ammonium salt and the cell suspension is aerated in the dark, the wax was oxidatively metabolized, providing carbon materials and energy 23 for some dark processes of plastid development. Under these conditions, pyrenoid-like structures (called “pro-pyrenoids”) are formed at the sites adjacent to the prolamel larbodies (PLB) localized in the peripheral region of the proplastid. The single prothylakoid becomes paired with a newly formed prothylakoid, and a part of the paired prothylakoids is extended, with foldings, in to the “propyrenoid”. In this study, we observed a concentration of RuBisCO in the “propyrenoid” of Euglena gracilis strain Z using immunoelectron microscopy.

Social Desirability in Personality Inventories

2014 ◽  
Vol 35 (3) ◽  
pp. 144-157 ◽  
Author(s):  
Martin Bäckström ◽  
Fredrik Björklund
Keyword(s):  
Social Desirability ◽  
Big Five ◽  
Work Performance ◽  
Factor Model ◽  
Five Factor Model ◽  
Peer Ratings ◽  
Personality Inventories ◽  
Model Study ◽  
The Difference ◽  
New Variables

The difference between evaluatively loaded and evaluatively neutralized five-factor inventory items was used to create new variables, one for each factor in the five-factor model. Study 1 showed that these variables can be represented in terms of a general evaluative factor which is related to social desirability measures and indicated that the factor may equally well be represented as separate from the Big Five as superordinate to them. Study 2 revealed an evaluative factor in self-ratings and peer ratings of the Big Five, but the evaluative factor in self-reports did not correlate with such a factor in ratings by peers. In Study 3 the evaluative factor contributed above the Big Five in predicting work performance, indicating a substance component. The results are discussed in relation to measurement issues and self-serving biases.

Input-Output in Personnel Management

1970 ◽  
Vol 15 (2) ◽  
pp. 115, 118
Author(s):  
WILLIAM E. COLEMAN
Keyword(s):  
Personnel Management ◽  
Input Output
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