You are required to post your main discussion question response and at least 2 responses to your peers.
• How is visual information processed in the brain?
• What are the primary areas of the brain responsible for processing visual stimulation?
• Briefly explain the concepts: ocular dominance and orientation columns as studied in the monkey in the video.
Peer Discussion #1: (Chavelys)
Visual Information is primarily processed in the brain through the use of the retina which is relayed through the lateral geniculate nucleus of the thalamus to the main visual cortex which is a thin sheet located in the occipital lobe in the back of the brain. Some primary areas of the brain responsible for processing visual stimulation are the cornea, the lens which adjusts its thickness to focus light on the photoreceptive cells of the retina known as the rods and cones, which then produces neuro impulses. Retina which is the light sensitive membrane in the back of your eyes which is part of the brain which is what passes the conversion of light into the neuronal signals. The central ganglia in the brain is also responsible for the signals sent to the brain from the retina (Kolb,2015). Cells in your visual cortex are known as ocular dominance, there cells are organized in what is known as orientation columns depending on which eye is the dominant eye. In the study done with the monkey, the monkey was using one eye, and that illustrated that the active sites where in different locations depending on the eye the monkey was using (Kolb,2015). This study illustrated higher cortical activity and that primary visual cortex has columns. Changing of the lights on the checker board would lead to neurons becoming more sensitive leading to a dilation of blood vessels and an increase in oxygen levels and if there is a new patter then a new group of cells would activate.
Peer Discussion #2:(Yisel)
The eyes are only one part of the process of the sense of sight. Our visual world begins when light passes through the cornea and the lens of the eye. That image of the visual world is then processed in the retina. The image is then relayed through the lateral geniculate nucleus of the thalamus to the primary visual cortex, a thin sheet of photoreceptors, located in the occipital lobe at the back of the brain. At that point, it works very similar to a camera in that the image on the retina is reversed. Objects that are above the center of the retina project lower, and object that are below the center project higher. The reversed information on the retina, which in fact are electrical signals, are then sent to the optic nerve in the brain which flips the image and that is what we see. The occipital lobe, the smallest of the four lobes, is located near the posterior region of the cerebral cortex, near the back of the skull. The occipital lobe is the primary visual processing center of the brain. Within the occipital region of the brain is the primary visual cortex, which receives visual input from the retina and transforms these signals into images that the brain understands. Other functions of the occipital lobe are visual-spatial processing and movement and color recognition. The occipital lobe processes information very rapidly so that we can make sense of visual information as we are exposed to it. In the video, a monkey looked at a checkerboard with his left eye only and then with his right eye. The video revealed that visual signals are separated into three processing systems: Shape, color, and spatial organization. With the monkey, the two images looked very similar but upon closer inspection, it was revealed that there were differences in what the monkey saw with each eye. There was a slight difference in location between the eyes, having to do with cortical activity. The orientation columns show us that the primary visual cortex is comprised of orientation columns. The lines on the checker board change as the neurons that are sensitive to the orientation columns begin to work. The monkey’s blood vessels became dilated. When the orientation line changes, different cells then become activated. This indicates that with every new orientation line, a new group of cells are activated.
