Question

1. Explain how the human body translates visual input into signals to which the brain attaches meaning (i.e., the entire process of converting physical sensation into something the brain can interpret and perceive).
2.Explain touch deprivation or “skin hunger” and why we need to be aware of it. What is the connection between “the hole” student prisoners were placed in and its relation to touch deprivation?

Answer 1

• 1.In the human visual system, the eye receives physical stimuli in the form of light and sends those stimuli as electrical signals to the brain, which interprets the signals as images.
  
• The human visual system gives our bodies the ability to see our physical environment. The system requires communication between its major sensory organ (the eye) and the core of the central nervous system (the brain) to interpret external stimuli (light waves) as images.
• All vision is based on the perception of electromagnetic rays. These rays pass through the cornea in the form of light; the cornea focuses the rays as they enter the eye through the pupil, the black aperture at the front of the eye.
• The pupil acts as a gatekeeper, allowing as much or as little light to enter as is necessary to see an image properly. The pigmented area around the pupil is the iris.
• Along with supplying a person’s eye color, the iris is responsible for acting as the pupil’s stop, or sphincter. Two layers of iris muscles contract or dilate the pupil to change the amount of light that enters the eye.
• Behind the pupil is the lens, which is similar in shape and function to a camera lens. 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. The image is transduced into neural impulses and then transferred through the optic nerve to the rest of the brain for processing.
• The optic nerves convey signals from the retinas first to two structures called the lateral geniculate bodies, which reside in the thalamus, a part of the brain that functions as a relay station for sensory messages arriving from all parts of the body.
• From there the signals proceed to a region of the brain at the back of the skull, the primary visual cortex, also known as V1.
• They then feed into a second processing area, called V2, and branch out to a series of other, higher centers, dozens, perhaps with each one carrying out a specialized function, such as detecting color, detail, depth, movement, or shape or recognizing faces.
• The visual cortex in the brain interprets the image to extract form, meaning, memory, and context.
• The left hemisphere of the brain processes visual images from the right-hand side of space, or the right visual field, and the right hemisphere processes visual images from the left-hand side of space, or the left visual field.
• The optic chiasm is a complicated crossover of optic nerve fibers behind the eyes at the bottom of the brain, allowing the right eye to “wire” to the left neural hemisphere and the left eye to “wire” to the right hemisphere. This allows the visual cortex to receive the same visual field from both eyes.
• Cones are for color vision and rods are for shadows and light differences. The front of your eye has many more cones than rods, while the sides have more rods than cones; for this reason, your peripheral vision is sharper than your direct vision in the darkness, but your peripheral vision is also in black and white.Cones perceive color and rods perceive shadow in images.
• Color vision is a critical component of human vision and plays an important role in both perception and communication. Color sensors are found within cones, which respond to relatively broad color bands in the three basic regions of red, green, and blue (RGB).
• Depth perception refers to our ability to see the world in three dimensions. With this ability, we can interact with the physical world by accurately gauging the distance to a given object.
• While depth perception is often attributed to binocular vision (vision from two eyes), it also relies heavily on monocular cues (cues from only one eye) to function properly.
• Due to time limit,remaining questions can be asked as another question,they will be answered,thankyou for your cooperation.