Configuration Saliency Revealed by Dichoptic Masking

Perception ◽  
1997 ◽  
Vol 26 (1_suppl) ◽  
pp. 95-95
Author(s):  
Y Bonneh ◽  
D Sagi
Keyword(s):  
Correct Response ◽  
Receptive Fields ◽  
Detection Performance ◽  
The Other ◽  
Spatial Integration ◽  
Probe Detection ◽  
Small Rectangle ◽  
Integration Mechanism ◽  
Spatial Configurations ◽  
Visual Filtering

We studied suprathreshold spatial integration by testing the saliency of multi Gabor element configurations in dichoptic masking conditions. Dichoptic presentations allows for a competition between spatially overlapping suprathreshold stimuli that involve nonoverlapping receptive fields in the first stage of visual filtering. Different spatial configurations of Gabor patches (sigma=lambda=0.12 deg) were presented to one eye (target) together with a bandpass noise presented to the other eye (mask). After a short rivalry period (128 ms) in which a dominance of one eye was established, a probe (a randomly positioned small rectangle of reduced contrast in the target) was presented for an additional detection period (80 ms). Probe detection performance was measured (2AFC) by finding the mask contrast leading to 75% correct response. We find that textures of randomly oriented patches are more dominant than uniform textures where the effect decreases and even reverses with decreasing of contrast. For suprathreshold (1-D) contours, however, we find that smooth collinear contours are more dominant than ‘jagged’ ones, regardless of contrast. These findings suggest principles underlying an early lateral integration mechanism based on contrast-dependent inhibitory and excitatory connections. This mechanism could be based on iso-orientation surround (2-D) inhibition and collinear (1-D) facilitation, with inhibition being more effective at high contrasts.

scholarly journals Temporal and spatial integration in the rat SI vibrissa cortex

1985 ◽  
Vol 54 (3) ◽  
pp. 615-635 ◽  
Author(s):  
D. J. Simons
Keyword(s):  
Receptive Fields ◽  
The Other ◽  
Response Suppression ◽  
Mechanical Stimuli ◽  
Spatial Integration ◽  
Inhibitory Effects ◽  
Vertical Electrode ◽  
Electrode Penetration ◽  
Temporal And Spatial ◽  
The Individual

Glass micropipettes were used to record the activity of 124 single units in the somatosensory vibrissa cortex (SI) of 16 rats in response to combined deflections of contralateral vibrissae. Compact multiangular electromechanical stimulators were used to stimulate individual vibrissal hairs alone or in combinations of two or three adjacent whiskers. Each whisker was stimulated independently to produce controlled temporal and spatial patterns of mechanical stimuli. Following displacement of a vibrissa, unit discharges to subsequent deflections of adjacent whiskers are reduced in a time-dependent fashion. Response suppression is strongest at short interdeflection intervals, i.e., 10-20 ms and decreases progressively during the 50-100 ms following the first deflection. In many cases this period also corresponds with a reduction in ongoing unit discharges. Response suppression was not observed for first-order neurons recorded in the trigeminal ganglion of barbiturate-anesthetized rats. In the cortex, the presence and/or degree of response suppression depends on a number of spatial factors. These include 1) the angular direction(s) in which the individual hairs are moved, 2) the sequence in which two whiskers are deflected, that is, which one is deflected first, 3) the particular combination of whiskers stimulated, and 4) the number (2 or 3) of vibrissae comprising the multiwhisker stimulus. Within a vertical electrode penetration, one particular whisker typically elicits the strongest excitatory and inhibitory effects; other, nearby vibrissae elicit variable (or no) excitation or inhibition. Excitatory and inhibitory subregions of a receptive field could thus be distributed asymmetrically around the maximally effective whisker. In these cases, the receptive fields displayed spatial orientations. Quantitative criteria were used to classify 30 cortical units on the basis of the distribution of inhibitory subregions on either side of the maximally effective whisker. Twenty-one of these cells had receptive fields (RFs) with symmetrical inhibitory side regions. Responses of the other nine units were strongly suppressed by a preceding deflection of a vibrissa on one side but relatively unaffected, or even slightly facilitated, by preceding deflection of the whisker on the other side.(ABSTRACT TRUNCATED AT 400 WORDS)

Writing in Aphasia Rehabilitation: Cursive vs Manuscript

1976 ◽  
Vol 41 (4) ◽  
pp. 523-529 ◽  
Author(s):  
Daniel R. Boone ◽  
Harold M. Friedman
Keyword(s):  
Correct Response ◽  
The Other ◽  
Read Aloud ◽  
Writing Style ◽  
Reading And Writing ◽  
Manual Responses ◽  
Significant Difference ◽  
Written Form ◽  
The Individual ◽  
Read Number

Reading and writing performance was observed in 30 adult aphasic patients to determine whether there was a significant difference when stimuli and manual responses were varied in the written form: cursive versus manuscript. Patients were asked to read aloud 10 words written cursively and 10 words written in manuscript form. They were then asked to write on dictation 10 word responses using cursive writing and 10 words using manuscript writing. Number of words correctly read, number of words correctly written, and number of letters correctly written in the proper sequence were tallied for both cursive and manuscript writing tasks for each patient. Results indicated no significant difference in correct response between cursive and manuscript writing style for these aphasic patients as a group; however, it was noted that individual patients varied widely in their success using one writing form over the other. It appeared that since neither writing form showed better facilitation of performance, the writing style used should be determined according to the individual patient’s own preference and best performance.

The Restructuring of the Automobile Industry in the USA

1992 ◽  
Vol 24 (6) ◽  
pp. 833-852 ◽  
Author(s):  
R D Bingham ◽  
K K Sunmonu
Keyword(s):  
Automobile Industry ◽  
The Other ◽  
Cycle Phase ◽  
Economic Downturn ◽  
Mature Phase ◽  
The Us ◽  
Two Systems ◽  
Spatial Configurations ◽  
The Usa

In this paper, the changes in the US automobile industry which have occurred over the 1979–86 economic downturn and recovery are examined within the framework of Markusen's profit-cycle theory. When viewing the automobile indusltry as a whole, some of the findings support the profit-cycle theory and others do not. The theory is supported, however, within the context of two distinct automobile industries in the USA—one ‘Fordist’ and the other a Japanese ‘post-Fordist’ system. The Fordist system is entering the negative profit-cycle phase and the post-Fordist system is in the mature phase. The two systems have very different spatial configurations and are likely to have very different economic futures.

Mutational analysis of patterning of oral structures in Tetrahymena

Development ◽  
1984 ◽  
Vol 82 (1) ◽  
pp. 67-95
Author(s):  
Joseph Frankel ◽  
E. Marlo Nelsen ◽  
Julita Bakowska ◽  
Leslie M. Jenkins
Keyword(s):  
Mutational Analysis ◽  
Tetrahymena Thermophila ◽  
The State ◽  
The Other ◽  
Basal Bodies ◽  
Ciliated Protozoan ◽  
Vertebrate Limb ◽  
Spatial Configurations ◽  
Oral Development ◽  
Mutant Cells

The ciliary arrays of the oral apparatus of the ciliated protozoan Tetrahymena thermophila each have their own unique ‘pattern signature’, which varies little so long as the number of arrays remains the same. In this study, we analyse the consequence of increases in the number of these arrays (membranelles) brought about by certain mutations. In oral apparatuses of mutant cells, the addition of a membranelle is associated with specific alterations in at least one of the other membranelles. The features that are altered include the relative lengths of membranelles, the state of ciliation of basal bodies located at specific positions within these membranelles, and the spatial configurations resulting from displacement of ciliary units during late oral development. The final organization of each membranelle depends upon its relativeposition along the length of the oral apparatus. This indicates that the membranelles are not individually ‘named’ by the organism, and suggests that the unit of pattern organizationis the membranelle field as a whole. In the Discussion, we consider means for testing whether thesame underlying idea might also apply to multicellular systems, such as the vertebrate limb, in which spatially ordered differences appear to be superimposed upon a fundamental repeating pattern.

Synaptic Actions of Oesophageal Proprioceptors in the Mollusc, Philine

1981 ◽  
Vol 94 (1) ◽  
pp. 95-104
Author(s):  
J. N. SIGGER ◽  
D. A. DORSETT
Keyword(s):  
Receptive Fields ◽  
Large Cell ◽  
The Other ◽  
Small Cells ◽  
Sensory Cells ◽  
Periodic Activity ◽  
Buccal Ganglia ◽  
Excitatory Synaptic Input ◽  
Feeding Cycle ◽  
Protraction Phase

The buccal ganglia of Philine each contain a group of mechanoreceptors, consisting of 1 large and 3 small cells, with receptive fields in the oesophagus. Synaptic contacts occur between the receptors; the large cell providing an EIPSP input to its contralateral partner and to the two groups of smaller receptors. The small receptors make weak excitatory contacts with both the large receptors. The sensory cells synapse with other buccal motoneurones and interneurones, some of which show periodic activity associated with the feeding movements. Protraction phase neurones are divisible into two groups, one of which receives EPSPs from the receptors, while the other group receives IPSPs. Retraction phase neurones receive a biphasic EIPSP. The receptors provide excitatory synaptic input to a pair of interneurones which ‘gate’ the feeding cycle. A third class of neurones which are not rhythmically active during feeding receive a predominantly inhibitory EIPSP.

scholarly journals Detection of Micro-Defects on Irregular Reflective Surfaces Based on Improved Faster R-CNN

Sensors ◽  
2019 ◽  
Vol 19 (22) ◽  
pp. 5000 ◽  
Author(s):  
Zhuangzhuang Zhou ◽  
Qinghua Lu ◽  
Zhifeng Wang ◽  
Haojie Huang
Keyword(s):  
Specular Reflection ◽  
Receptive Fields ◽  
Ground Truth ◽  
Detection Performance ◽  
Support Vector ◽  
Detection Accuracy ◽  
Irregular Surfaces ◽  
Detection Algorithms ◽  
Proposed Model ◽  
Improved Model

The detection of defects on irregular surfaces with specular reflection characteristics is an important part of the production process of sanitary equipment. Currently, defect detection algorithms for most irregular surfaces rely on the handcrafted extraction of shallow features, and the ability to recognize these defects is limited. To improve the detection accuracy of micro-defects on irregular surfaces in an industrial environment, we propose an improved Faster R-CNN model. Considering the variety of defect shapes and sizes, we selected the K-Means algorithm to generate the aspect ratio of the anchor box according to the size of the ground truth, and the feature matrices are fused with different receptive fields to improve the detection performance of the model. The experimental results show that the recognition accuracy of the improved model is 94.6% on a collected ceramic dataset. Compared with SVM (Support Vector Machine) and other deep learning-based models, the proposed model has better detection performance and robustness to illumination, which proves the practicability and effectiveness of the proposed method.

Spatial representations of self and other in the hippocampus

Science ◽  
2018 ◽  
Vol 359 (6372) ◽  
pp. 213-218 ◽  
Author(s):  
Teruko Danjo ◽  
Taro Toyoizumi ◽  
Shigeyoshi Fujisawa
Keyword(s):  
Receptive Fields ◽  
Pyramidal Cells ◽  
Spatial Location ◽  
The Self ◽  
The Other ◽  
Spatial Representations ◽  
Self And Other ◽  
Ca1 Pyramidal Cells ◽  
Ca1 Region ◽  
Reward Information

An animal’s awareness of its location in space depends on the activity of place cells in the hippocampus. How the brain encodes the spatial position of others has not yet been identified. We investigated neuronal representations of other animals’ locations in the dorsal CA1 region of the hippocampus with an observational T-maze task in which one rat was required to observe another rat’s trajectory to successfully retrieve a reward. Information reflecting the spatial location of both the self and the other was jointly and discretely encoded by CA1 pyramidal cells in the observer rat. A subset of CA1 pyramidal cells exhibited spatial receptive fields that were identical for the self and the other. These findings demonstrate that hippocampal spatial representations include dimensions for both self and nonself.

Two-point touch discrimination depends on the perceived length of the arm

2012 ◽  
Vol 25 (0) ◽  
pp. 126
Author(s):  
Laurence R. Harris ◽  
Sarah D’Amour ◽  
Lisa M. Pritchett
Keyword(s):  
Body Size ◽  
Psychometric Function ◽  
Correct Response ◽  
Tactile Stimulation ◽  
Receptive Fields ◽  
Discrimination Threshold ◽  
Separate Experiment ◽  
Tendon Vibration ◽  
Threshold Distance

Two-point discrimination threshold depends on the number and size of receptive fields between the touches. But what determines the size of the receptive fields? Are they anatomically fixed? Or are they related to perceived body size? To answer this question we manipulated perceived arm length using the Pinocchio illusion. The test arm was held at the wrist and the holding arm was made to feel perceptually more extended than it was by applying vibration to the tendon of the biceps (cf. de Vignemont et al., 2005). For control trials the holding arm was vibrated elsewhere. An array of tactors, separated by 3 cm, was placed on the upper surface of the arm and covered with a cloth. Vibro-tactile stimulation was applied to either one or two tactors in two periods. Subjects identified which period contained two stimuli. A psychometric function was drawn through the probability of correct response as a function of tactor separation to determine the threshold distance. In a separate experiment, subjects estimated the perceived location of each tactor against a scale laid on top of the cloth. The estimated locations of the tactors on the tested arm were displaced by tendon vibration of the holding arm compatible with a perceptual lengthening of the arm. The threshold for two-touch discrimination was significantly increased from 4.5 (±0.6) cm with no tendon stimulation to 5.7 (±0.5) cm when the arm was perceptually extended. We conclude that two-point touch discrimination depends on the size of central receptive fields that become larger when the arm is perceptually lengthened.

Structured Pyramidal Neural Networks

2018 ◽  
Vol 28 (05) ◽  
pp. 1750021 ◽  
Author(s):  
Alessandra M. Soares ◽  
Bruno J. T. Fernandes ◽  
Carmelo J. A. Bastos-Filho
Keyword(s):  
Neural Network ◽  
Neural Networks ◽  
Processing Time ◽  
Receptive Fields ◽  
Memory Capacity ◽  
The Other ◽  
Support Vector ◽  
Proposed Model ◽  
Novel Method ◽  
Original Approach

The Pyramidal Neural Networks (PNN) are an example of a successful recently proposed model inspired by the human visual system and deep learning theory. PNNs are applied to computer vision and based on the concept of receptive fields. This paper proposes a variation of PNN, named here as Structured Pyramidal Neural Network (SPNN). SPNN has self-adaptive variable receptive fields, while the original PNNs rely on the same size for the fields of all neurons, which limits the model since it is not possible to put more computing resources in a particular region of the image. Another limitation of the original approach is the need to define values for a reasonable number of parameters, which can turn difficult the application of PNNs in contexts in which the user does not have experience. On the other hand, SPNN has a fewer number of parameters. Its structure is determined using a novel method with Delaunay Triangulation and k-means clustering. SPNN achieved better results than PNNs and similar performance when compared to Convolutional Neural Network (CNN) and Support Vector Machine (SVM), but using lower memory capacity and processing time.

scholarly journals Processing of mechanosensory signals in local reflex pathways of the locust

1989 ◽  
Vol 146 (1) ◽  
pp. 209-227 ◽  
Author(s):  
M. Burrows
Keyword(s):  
Receptive Fields ◽  
Sensory Information ◽  
Afferent Input ◽  
The Other ◽  
Reflex Pathways ◽  
Motor Neurones ◽  
The Central Nervous System ◽  
Local Reflex ◽  
Spiking Local Interneurones ◽  
The Stability

The processing of mechanosensory signals responsible for the reflex adjustment of the posture or movement of the legs of the locust is described in terms of the actions and connections of identified neurones. Signals can be followed from the major classes of exteroceptors of a leg, through their various integrative stages in the central nervous system to their emergence as specific patterns in known motor neurones. Particular emphasis is placed on the integrative roles of two classes of local interneurones. The spiking local interneurones map the leg as a series of overlapping receptive fields and reverse the sign of the afferent input. The nonspiking local interneurones control the output of the motor neurones by the graded release of chemical transmitter and can adjust the gain of a local reflex depending on the position and movements of the joints of that leg. The reflex movements of one leg must not impair the stability of the animal and must therefore be influenced by events at the other legs. Populations of intersegmental interneurones convey sensory information from one segment to another to ensure such coordination. These interneurones do not produce stereotyped intersegmental reflexes but, instead, alter the performance of a local reflex in a distant leg by making synaptic connections with nonspiking local interneurones. These connections change the effectiveness of the outputs to the motor neurones and consequently the local reflex. The local interneurones therefore play a crucial role both in the production of local reflexes and in the integration of these actions with the movements of the other legs.

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