All cases of blindsight require some damage to the primary visual cortex (V1) with similar conceptually to previously described conscious/automatic processing the relationship of awareness, attention, consciousness, memory, and mood. Scientists who study consciousness examine the relationship between stated perception blindsight, anosognosia, brainwaves during sleep, and altered states of . Much of what is stored in the unconscious is thought to be unpleasant or. ples of unconscious perception, such as blindsight.2 Patients with blindsight are able to .. connection between consciousness and demonstrative thought even.
Given these observations, it is possible to infer that one dimension of consciousness is simply the act of being aware. Unlike the driving scenario however, Blindsight patients cannot intentionally shift their attention. The neurological pathway through the superior colliculus could be exploited through training to aid in day to day navigation for cortex-based vision loss suffers. With time and practice people with these injuries may learn to use these pathways and reduce reliance on other aid such as a cane or guide dog but also possibly gain some conscious vision too.
S Ramachandran of the same name. The program was televised on the BBC and focuses on the phenomena of blindsight. It features expert analysis by Dr.
Ramachandran, a renowned neurologist and leader in research surrounding visual perception and neurology, whose insightful and credible inputs ensure the program remains reliable but also to the point. The documentary tries to focus on reaching the general population which is evident as the program was broadcasted on the BBC.
The aim of the program is to be both informative and entertaining but at the same time simplistic with its explanations of the topic. Individuals with a vested interest in neurology would benefit far greater from viewing this documentary as it is more appealing and also those familiar with the work of Ramachandran.
Insights from Dr Blakemore, a neurobiologist specialising in vision, and the focus patient Graham enable the documentary to explain efficiently and appropriately the impairment of blindsight to the wider audience. Therefore it was easy to determine that the content of the media item would be credible. The excerpt follows the patient Graham, who although is clinically blind on his right side, is able to describe movements in his impaired visual field.
Throughout the excerpt we are able to experience and identify the difficulties Graham has faced with his impairment in everyday life.Binocular Rivalry — Competition, Connection, and Consciousness
The program then becomes intriguing by coinciding a visual test conducted on Graham. The task involved different menial tasks that involve the patient identifying the direction of an object on a computer screen in his impaired visual field. What is even more astounding is that Graham is able to guess the direction more correctly then if by random chance. From this the audience is able to witness first-hand the mystery of the blindsight condition.
The utilisation of language within the excerpt is crucial to the documentary reaching its wider audience. The animated Ramachandran enthusiastically draws people in with his explanations using layman terms but at the same time intrigues the audience by encouraging self-thought processing.
Statements from Dr Blakemore help to emphasise the extraordinary behaviour individuals with blindsight exhibit and the potential it has to unlock previously unexplained occurrences involving the brain. The limitations of the documentary include neglecting previous research into blindsight. It ignores efforts made by profound neurologists and predominantly focuses on the theory proposed by Ramachandran.
Within the documentary, Ramachandran suggests within our brain there are two visual pathways working in parallel.
Blindsight - Wikipedia
The prominent more recognised pathway is considered to be an evolutionary adaptation by where visual information is received via the eyeball and transferred to the thalamus. Ramanchandran further explains that the second pathway constitutes reflexive behaviour, therefore accentuating his theory on blindsight by where both pathways are interrupted but it is the second pathway that enables a person who experiences blindsight to recognise movements in their otherwise impaired visual field.
This means that although damage to the V1 cortex has occurred small areas are still functioning hence contributing to the individuals residual vision. Overall the excerpt is informative and entertaining while still holding true to its neurological background. In regards to aim of the program, in reaching its target audience, it has conducted this successfully by providing an adequate and engaging explanation to blindsight.
However, as a research tool its inability to connect with other research conducted on blindsight limits the usefulness and validity of this program. This is due to the vast array of theories proposed on blindsight without a clear understanding still to be found.
Through this a response can be elicited from the neurological world and those with previous knowledge on the topic to debate and then potentially define, through collective reasoning, an appropriate definition of blindsight. Or Weiskrantz and Warrington would present a single line on the screen, and Daniel had to decide whether it was horizontal or vertical.
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View image of Credit: And over the following decades, the condition has come to answer some fundamental questions about the human mind. Just how many of our decisions occur out of our awareness, even when we have the illusion of control? And if the conscious mind is not needed to direct our actions, then what is its purpose? Daniel, whose name has been changed for this article and is known in the literature simply as DB, offered some of the first clues. The participant is still perceiving, but they lack awareness of perception.
Of particular interest has been the fact that they can sense emotion: Getty Images Besides mirroring expressions, they also show physiological signs of stress when they see a picture of a frightened face.
It might be helpful to notice if they are in danger, for instance. Unlike Daniel, he was blind across the whole of his visual field, and normally walked with a white cane. But the team took away his cane and then loaded a corridor with furniture that might potentially trip him up, before asking him make his way to the other side. You can watch it for yourself, on the video below. View image of This video is no longer available Importantly, the participant claimed that not only was he not aware of having seen anything; he was not even aware of having moved out of the way of the objects.
He insisted he had just walked straight down the hallway. It was like seeing a black shadow moving against a completely black background Only in very rare circumstances do they come close to being aware of what they are seeing. But even then, he could not describe the content itself, meaning that his experience lacked almost everything we would normally associate with vision. Researchers eventually began to notice that TN exhibited signs of blindsight and in decided to test their theory.
They took TN into a hallway and asked him to walk through it without using the cane he always carried after having the strokes. TN was not aware at the time, but the researchers had placed various obstacles in the hallway to test if he could avoid them without conscious use of his sight.
To the researchers' delight, he moved around every obstacle with ease, at one point even pressing himself up against the wall to squeeze past a trashcan placed in his way. After navigating through the hallway, TN reported that he was just walking the way he wanted to, not because he knew anything was there. The girl's grandfather, Mr. The doctor helped Mr. The doctor then asked, "Mr. Keep looking that way, and don't move your eyes or turn your head. I know that you can see a little bit straight ahead of you, and I don't want you to use that piece of vision for what I'm going to ask you to do.
Blindsight and Consciousness
Now, I'd like you to reach out with your right hand [and] point to what I'm holding. J then shrugged and pointed, and was surprised when his finger encountered the end of the cane which the doctor was pointing toward him. The doctor then turned the cane around so that the handle side was pointing towards Mr.
He then asked for Mr. After this, the doctor said, "Good. Now put your hand down, please. The doctor then asked Mr. This case study shows that—although on a conscious level Mr. Please review the contents of the section and add the appropriate references if you can. Unsourced or poorly sourced material may be challenged and removed. August Visual processing in the brain goes through a series of stages. Destruction of the primary visual cortex leads to blindness in the part of the visual field that corresponds to the damaged cortical representation.
The area of blindness — known as a scotoma — is in the visual field opposite the damaged hemisphere and can vary from a small area up to the entire hemifield. Visual processing occurs in the brain in a hierarchical series of stages with much crosstalk and feedback between areas.
neur - Blindsight
The route from the retina through V1 is not the only visual pathway into the cortex, though it is by far the largest; it is commonly thought that the residual performance of people exhibiting blindsight is due to preserved pathways into the extrastriate cortex that bypass V1. What is surprising is that activity in these extrastriate areas is apparently insufficient to support visual awareness in the absence of V1.
To put it in a more complex way, recent physiological findings suggest that visual processing takes place along several independent, parallel pathways. One system processes information about shape, one about color, and one about movement, location and spatial organization.
This information moves through an area of the brain called the lateral geniculate nucleuslocated in the thalamusand on to be processed in the primary visual cortex, area V1 also known as the striate cortex because of its striped appearance. People with damage to V1 report no conscious vision, no visual imagery, and no visual images in their dreams.
However, some of these people still experience the blindsight phenomenon,  though this too is controversial, with some studies showing a limited amount of consciousness without V1 or projections relating to it. Relevant discussion may be found on the talk page.
The cells in these layers behave like that of M-retinal ganglion cells, are most sensitive to movement of visual stimuli and have large centre-surround receptive fields.