140 likes | 255 Views
Striate receptive fields. By: Katelyn, Padee , Kaylee , Roger, Lucas, and Rebecca . 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
E N D
Striate receptive fields By: Katelyn, Padee, Kaylee, Roger, Lucas, and Rebecca
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
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
Bar width • The more the bar width matches the receptive field’s size, the faster the neurons fire
Bar Orientation • Orientation affects how fast the neuron fires • If it’s more than 45 degrees off, the neuron doesn’t fire
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.
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
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
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
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
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
Ocular Dominance • Some neurons respond better to light from left eye; some are right-eye dominant
The point is… • Neurons are really picky! • Overall they work together to notice all details of life