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Understanding Receptive Fields in Visual Neurons

This article delves into the concept of receptive fields in the visual system, highlighting how each neuron responds to specific patterns of light within particular areas of the retina. It discusses the two main forms of ganglion cells—on-center and off-center—and explains the gradation of responses based on bar width, orientation, and cell type. Key elements such as end-stopping, motion sensitivity, color selectivity, and ocular dominance illustrate the complexity of visual processing. Neurons work collaboratively to help us perceive the intricate details of our surroundings.

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Understanding Receptive Fields in Visual Neurons

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  1. Striate receptive fields By: Katelyn, Padee, Kaylee, Roger, Lucas, and Rebecca

  2. What is a receptive field? • Every neuron in the visual system has a distinctive receptive field: an area of the retina that the cell responds to • There must be a particular pattern of light for the neuron to respond • In the retina, ganglion cells come in two forms, on-center and off-center

  3. Gradation • Receptive fields are not “all-or-nothing” propositions • The cell will probably still respond somewhat if the bar is tilted slightly; it just won’t quite respond at its maximum firing rate • Such response gradation is characteristic of almost all areas of the nervous system

  4. http://sites.sinauer.com/wolfe3e/chap3/striaterfF.htm

  5. Bar width • The more the bar width matches the receptive field’s size, the faster the neurons fire

  6. Bar Orientation • Orientation affects how fast the neuron fires • If it’s more than 45 degrees off, the neuron doesn’t fire

  7. Cell Type • Simple cells respond maximally only when the bar of light is in the center of the cell’s receptive field • Complex cells respond at the same rate across the entire width of the receptive field.

  8. End-stopping • End-stopped: fires neurons fastest when bar of light stops halfway on the receptive field • Non end-stopped: fires neurons fastest when bar of light extends throughout receptive field

  9. Edge detectors • Some respond best when one side of the bar of light is dark • Some receptive fields prefer right and others prefer left sides • Some respond best when both sides of the bar of light are dark

  10. Receptive Field Size • Striate cells vary in the size of their receptive fields—the extent of the area of the visual field to which each cell responds

  11. Motion • Some neurons fire faster when bars are moving across receptive field • Some neurons prefer left, others right • Some neurons respond best when bars do not move

  12. Color • Some neurons are color-selective, responding best to green or red or blue or some other color • Other neurons respond equally well to any light color

  13. Ocular Dominance • Some neurons respond better to light from left eye; some are right-eye dominant

  14. The point is… • Neurons are really picky! • Overall they work together to notice all details of life

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