Generally, everything projected by the retina is recognized and formed into a specific image in the occipital lobe. For absolutely healthy people, this proportion works independently and flawlessly, but irreparable consequences can occur with injuries and some illnesses. Sometimes, total blindness can occur. This is the process that happens if there is a damage on the surface of the primary visual cortex. Light signals transmit information to the occipital lobe via nerve endings, which represents a form of irritation or stimuli for the retina.
The nerves then transmit information to the diencephalon , another part of the brain. And diencephalon, in turn, sends information to the primary visual cortex, called the sensory cortex. From the primary sensory cortex, nerve signals are sent to the adjacent areas and are called sensory associative cortex areas. The main function of the occipital lobe is to send signals from the primary visual cortex to the visual associative cortex. The areas described together analyze the visual information observed and retain visual memories.
As already implied, this occurs when the primary visual cortex, whose surface is visible, is damaged. Complete damage to the primary cortex occurs in three cases, as a result of a head injury, as a result of the development of a tumor on the surface of the brain, and finally, yet very rarely, as a consequence of certain congenital anomalies.
Damage to the primary visual cortex leads to a form of central blindness called the Anton's syndrome; patients cannot recognize objects via their sense of sight and are completely unaware of their deficits 2. Epileptic seizures in the area of the occipital lobe cause visual hallucinations, most commonly in the form of dashes and a colored mesh that appears on the contralateral field of view.
Damage of the occipital brain lobe can occur as a result of a head injury, a tumor on the surface of the brain, and certain congenital anomalies. However, focal lesions do not lead to complete loss of vision.
What Happens if the Occipital Lobe is Damaged? The most obvious effect of damage to the occipital lobe is blindness, but occipital lobe damage can have other surprising effects: Epilepsy: Some seizures occur in the occipital lobe, and occipital lobe damage increases vulnerability to seizures. Difficulties with movement: Even if you are still able to move, changes in depth perception and vision can lead to inappropriate movements and difficulty navigating the visual field.
Difficulties perceiving colors, shape, dimension, and size. Difficulty recognizing familiar objects or faces. Hallucinations Inability to recognize or read written words. Inability to detect that an object is moving.
Difficulty reading or writing; for example, the words may appear to move on the page. Difficulty locating objects within the environment, even when you are able to see those objects. Difficulties with fine and gross motor skills, as well as balance. Brain Made Simple. Published September 26, Accessed May 11, Learn More. Rehman A. Neuroanatomy, Occipital Lobe. StatPearls [Internet]. Published July 6, Occipital lobe. Occipital Lobes. Centre For Neuro Skills.
They found that memory impairments were the only area in which patients with isolated occipital lobe damage demonstrated a decline in performance. Only with additional damage to the temporal regions was executive dysfunction witnessed across numerous domains.
They found that differences in cerebral blood flow in the occipital lobe was correlated with depression. After the use of pharmacotherapy, they found that cerebral blood flow increased in the parieto-occipital regions. Tate et al. They found that those with chronic schizophrenia had reduced grey matter outermost area, containing neurons volume in the visual association cortex, suggesting that this area is a cause of some of the visual deficits observed in those with schizophrenia. Olivia has been working as a support worker for adults with learning disabilities in Bristol for the last four years.
Guy-Evans, O. Occipital lobe: definition, functions, and location. Simply Psychology. Binder, D. Surgical treatment of occipital lobe epilepsy. Journal of Neurosurgery, 1 , Neuropsychological functions in idiopathic occipital lobe epilepsy.
Epilepsia, 41 4 , Harward, S. Seizure outcomes in occipital lobe and posterior quadrant epilepsy surgery: a systematic review and meta-analysis. Neurosurgery, 82 3 , Ishizaki, J. International Journal of Geriatric Psychiatry, 23 8 , Jessell, T. Principles of neural science pp. Kandel Eds. New York: Elsevier. Because of this, the process of decoding this information is also very complex.
The primary visual cortex, called Brodmann area 17 or V1, receives information from the retina. It then interprets and transmits information related to space, location, motion, and color of objects in the visual field.
The secondary visual cortex — called Brodmann area 18 and 19 or V2, V3, V4, V5 — receives information from the primary visual cortex. The secondary visual cortex deals with much of the same type of visual information. The ventral stream is one pathway the primary visual cortex uses to send information. It takes information to the temporal lobe, which interprets the information and helps the brain give meaning to objects in the field of vision.
The dorsal stream is the other pathway the primary visual cortex uses to send information. The lateral geniculate bodies take part of the raw information from the outer part of the retina to the visual cortex. The lingula gathers general information about the field of vision from the inside half of the retina. The combination of information from the lateral geniculate bodies and the lingula helps create spatial awareness and gives depth to the visual information.
Although modern science has revealed much about how the occipital lobe reveals the visual world, researchers are still learning new information about the occipital lobe and exactly how it functions.
No section of the brain is truly independent, and this includes the occipital lobe. For example, the occipital lobe takes information from the retina in the eye and translates it into the visual world.
As such, it relies heavily on the eyes themselves. The eyes themselves also have muscles that need controlling. The motor cortex in the brain is responsible for these movements, therefore also playing a role in vision. The temporal and occipital lobes share important interactions, as well. The temporal lobe gives meaning to the interpreted visual information from the occipital lobe.
It also stores the information, to a degree, in the form of memories.
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