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Your search keyword '"directional selectivity"' showing total 8 results
Start Over Descriptor "directional selectivity" Topic receptive field
8 results on '"directional selectivity"'

2. Comparisons of Visual Properties between Tectal and Thalamic Neurons with Overlapping Receptive Fields in the Pigeon.

Author

Yang, Jin, Zhang, Chuan, and Wang, Shu-Rong

Subjects
*VISUAL evoked response, *NEURONS, *PIGEONS, *DIGITAL mapping, *CELLS, *VISUAL fields
Abstract

The present study is the first attempt to make comparisons of the visual response properties between tectal and thalamic neurons with spatially overlapping receptive fields by using extracellular recording and computer mapping techniques. The results show that in neuronal pairs about 70% of thalamic cells have excitatory receptive field alone, whereas 85% of tectal cells possess an excitatory receptive field surrounded by an inhibitory receptive field. In 70% of pairs the tectal cells are selective for direction of motion different from that which the thalamic cells prefer. Most thalamic cells prefer high speeds (80–160°/s), whereas tectal cells prefer intermediate (40°/s) or low (10–20°/s) speeds. Photergic and scotergic cells exist in the thalamus but not in the tectum. These results provide evidence that tectal and thalamic cells extract different visual information from the same region of the visual field. The functional significance of these differences is discussed. Copyright © 2005 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

Published
2004
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3. Stimulus size selectivity and receptive field organization of ectostriatal neurons in the pigeon.

Author

Gu, Yong, Wang, Yuan, Zhang, Tao, and Wang, Shu-Rong

Subjects
*CELLS, *PIGEONS, *COGNITION, *HOMOLOGY (Biology), *MAMMALS, *VERTEBRATES
Abstract

The avian ectostriatum is the telencephalic recipient zone of the tectofugal pathway, which may be homologous to the colliculo-pulvinar-cortical pathway in mammals. The present paper studies the visual response properties and receptive field organization of ectostriatal cells in pigeons with extracellular recording and computer mapping techniques. The results indicate that 90% of ectostriatal cells prefer forward, downward and upward motion of visual stimuli at velocities in the range of 16–128° s–1. They respond optimally to small stimuli (1–4° visual angle), mostly preferring a target of 2°. Most cells (78.8%) have one excitatory receptive field that usually possesses one or two hotspots, some cells (13.5%) have two excitatory receptive fields each having one or two hotspots, and a few cells (7.7%) have one excitatory receptive field with an unresponsive region in the center. An inhibitory receptive field is not found surrounding the excitatory receptive field in the ectostriatal cells examined. These response properties and receptive field organization may reflect the possible roles of the ectostriatum in stimulus discrimination and visual cognition. [ABSTRACT FROM AUTHOR]

Published
2002
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4. The computation of directional selectivity in the Drosophila OFF motion pathway

Author

Sandro Romani, Eyal Gruntman, and Michael B. Reiser

Subjects
QH301-705.5, Computation, Science, Motion (geometry), Stimulation, Inhibitory postsynaptic potential, General Biochemistry, Genetics and Molecular Biology, Functional studies, Biology (General), Physics, General Immunology and Microbiology, General Neuroscience, Depolarization, General Medicine, Hyperpolarization (biology), Visual motion, ON/OFF, Order (biology), Receptive field, motion vision, directional selectivity, whole cell electrophysiology, Medicine, Drosophila, Biological system, Selectivity, Neuroscience, Excitation
Abstract

The direction of visual motion in Drosophila is computed by separate pathways for moving ON and OFF features. The 4th order neurons T4 (ON) and T5 (OFF) are the first neurons in their respective pathways to extract a directionally selective response from their non-selective inputs. Recent functional studies have found a major role for local inhibition in the generation of directionally selective responses. However, T5 lacks small-field inhibitory inputs. Here we use whole-cell recordings of T5 neurons and find an asymmetric receptive field structure, with fast excitation and persistent, spatially trailing inhibition. We assayed pairwise interactions of local stimulation across the receptive field, and find no active amplification, only passive suppression. We constructed a biophysical model of T5 based on the classic Receptive Field. This model, which lacks active conductances and was tuned only to match non-moving stimuli, accurately predicts responses to complex moving stimuli.

Published
2019

7. A fast stimulus procedure to determine local receptive field properties of motion-sensitive visual interneurons

Author

Roland Hengstenberg and Holger G. Krapp

Subjects
Interneuron, Computer science, Visual interneurons, Motion Perception, Action Potentials, Stimulus (physiology), medicine, Animals, Computer vision, Calliphora erythrocephala, Neurons, Afferent, Directional selectivity, Visual stimulation, business.industry, Optic flow, Diptera, Motion detection, Compound eye, Sensory Systems, Ophthalmology, Electrophysiology, medicine.anatomical_structure, Receptive field, Artificial intelligence, Neuron, Visual system, business, Neuroscience
Abstract

We present a method to determine, within a few seconds, the local preferred direction (LPD) and local motion sensitivity (LMS) in small patches of the receptive fields of wide-held motion-sensitive neurons. This allows us to map, even during intracellular recordings, the distribution of LPD and LMS over the huge receptive fields of neurons sensing self-motions of the animal. Comparisons of the response field of a given neuron with the optic flow fields caused by different movements in space, allows us to specify the particular motion of the animal sensed by that neuron. Copyright (C) 1996 Elsevier Science Ltd.

Published
1997

8. A Competitive gaussian model and linear regression technique for modeling MST neuron receptive field responses for primate perception of self-motion

Author

Robble, Jeffrey

Subjects
Directional selectivity, Medial superior temporal, Receptive field, Rhesus monkey, Self-motion, Visual system
Abstract

This thesis presents a linear regression technique applied to non-linear features extracted from a scaled Gaussian mixture model (SGMM) to describe the receptive field (RF) behavior of neurons in the Medial Superior Temporal region of the brain of Rhesus monkeys which viewed visual stimuli on a projector screen. The stimuli consist of simple and complex combinations of planar, circular, and radial motion and neuron responses were recorded in spikes/second. It is our goal to understand the neuronal responses of the primates to these stimuli and to create a model capable of predicting how the RFs in the primates' neurons respond to novel stimuli simulating the effects of self- motion. The SGMM is trained in stages using a competitive algorithm where a speciated genetic algorithm competes against a custom greedy algorithm. The regions of each subject's visual field which produce the most active neuron responses are identified as hotspot regions for that neuron. We strongly believe that the non-linear interaction between RFs can be explained by the relationship between hotspot and non-hotspot region behavior based on the direction of stimulus motion within each region. Our results show that the SGMM is capable of reasonably modeling and predicting firing rate response values for simple visual stimuli for a moderate number of data points, and that the linear model is capable of very accurately modeling and predicting firing rate response values for more complex stimuli for a small number of data points.

Published
2010

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