retina

Examples of retina in the following topics:

• Perceiving Motion

  • First-order motion perception occurs through specialized neurons located in the retina, which track motion through luminance.
  • An object must be directly in front of the retina, with motion perpendicular to the retina, in order to be perceived as moving.
  • The motion-sensing neurons detect a change in luminance at one point on the retina and correlate it with a change in luminance at a neighboring point on the retina after a short delay.
  • Second-order motion perception occurs by examining the changes in an objects' position over time through feature tracking on the retina.

• Perceiving Depth, Distance, and Size

  • Visual stimuli enter as light through the photoreceptors in the retina, where they are changed into neural impulses.
  • When an image is projected onto a single retina, cues about the relative size of the object compared to other objects are obtained.
  • Depth perception relies on the convergence of both eyes upon a single object, the relative differences between the shape and size of the images on each retina, the relative size of objects in relation to each other, and other cues such as texture and constancy.
  • This is useful when you cross the street: as you watch a car come toward you, your brain uses the change in size projected on your retina to determine how far away it is.

• Vision: The Visual System, the Eye, and Color Vision

  • the retina, which allows us to piece images together and includes cones and rods.
  • Together with the cornea, the lens adjusts the focal length of the image being seen onto the back of the eye, the retina.
  • Visual reception occurs at the retina where photoreceptor cells called cones and rods give an image color and shadow.
  • Visual stimulus transduction happens in the retina.
  • This density map shows the retina, which is made up of cones and rods.

• Perceptual Constancy

  • Within a certain range, people's perception of a particular object's size will not change, regardless of changes in distance or size change on the retina.
  • This happens when we watch a door open: the actual image on our retinas is different each time the door swings in either direction, but we perceive it as being the same door made of the same shapes.
  • This form of perceptual constancy allows us to perceive that the door is made of the same shapes despite different images being delivered to our retinae.

• Circadian Rhythms

  • The retina of the eye contains photoreceptors (rods for seeing at night, and cones for distinguishing colors), which are used for conventional vision.
  • But the retina also contains specialized ganglion cells, which are photosensitive and project directly to the SCN, where they help in the entrainment of this master circadian clock.

• Mechanics of the Action Potential

  • For example, changes in electrical synapses in the retina are seen during light and dark adaptations of the retina.

• Introduction to Sensation

  • Rod and cone receptors in the retina of the eye perceive light; cilia in the ear perceive sound; chemical receptors in the nasal cavities and mouth perceive smell and taste; and muscle spindles, as well as pressure, vibration, heat and pain receptors in the skin, perceive the many sensations of touch.

• Cerebral Hemispheres and Lobes of the Brain

  • The visual cortex receives raw sensory information through sensors in the retina of the eyes, which is then conveyed through the optic tracts to the visual cortex.

• Introducing the Perception Process

  • When you open your eyes, you do not need to tell your brain to interpret the light falling onto your retinas from the object in front of you as "computer" because this has happened unconsciously.