Why do we see eventually

One of the most ancient brain circuits in evolutionary terms, it is involved in motor control, posture and gait and in the fluid execution of complex sequences of motor movements. Playing the piano, typing, ice dancing or climbing a rock wall—all these activities involve the cerebellum.

It has the brain's most glorious neurons, called Purkinje cells, which possess tendrils that spread like a sea fan coral and harbor complex electrical dynamics. It also has by far the most neurons, about 69 billion most of which are the star-shaped cerebellar granule cells , four times more than in the rest of the brain combined. What happens to consciousness if parts of the cerebellum are lost to a stroke or to the surgeon's knife? Very little! Cerebellar patients complain of several deficits, such as the loss of fluidity of piano playing or keyboard typing but never of losing any aspect of their consciousness.

They hear, see and feel fine, retain a sense of self, recall past events and continue to project themselves into the future. Even being born without a cerebellum does not appreciably affect the conscious experience of the individual. All of the vast cerebellar apparatus is irrelevant to subjective experience. Important hints can be found within its circuitry, which is exceedingly uniform and parallel just as batteries may be connected in parallel.

The cerebellum is almost exclusively a feed-forward circuit: one set of neurons feeds the next, which in turn influences a third set.

There are no complex feedback loops that reverberate with electrical activity passing back and forth. Given the time needed for a conscious perception to develop, most theoreticians infer that it must involve feedback loops within the brain's cavernous circuitry. Moreover, the cerebellum is functionally divided into hundreds or more independent computational modules. Each one operates in parallel, with distinct, nonoverlapping inputs and output, controlling movements of different motor or cognitive systems.

They scarcely interact—another feature held indispensable for consciousness. One important lesson from the spinal cord and the cerebellum is that the genie of consciousness does not just appear when any neural tissue is excited. More is needed. This additional factor is found in the gray matter making up the celebrated cerebral cortex, the outer surface of the brain.

It is a laminated sheet of intricately interconnected nervous tissue, the size and width of a inch pizza. Two of these sheets, highly folded, along with their hundreds of millions of wires—the white matter—are crammed into the skull.

All available evidence implicates neocortical tissue in generating feelings. We can narrow down the seat of consciousness even further. Take, for example, experiments in which different stimuli are presented to the right and the left eyes.

Suppose a picture of Donald Trump is visible only to your left eye and one of Hillary Clinton only to your right eye. We might imagine that you would see some weird superposition of Trump and Clinton. In reality, you will see Trump for a few seconds, after which he will disappear and Clinton will appear, after which she will go away and Trump will reappear. The two images will alternate in a never-ending dance because of what neuroscientists call binocular rivalry. Because your brain is getting an ambiguous input, it cannot decide: Is it Trump, or is it Clinton?

If, at the same time, you are lying inside a magnetic scanner that registers brain activity, experimenters will find that a broad set of cortical regions, collectively known as the posterior hot zone, is active. These are the parietal, occipital and temporal regions in the posterior part of cortex [ see graphic below ] that play the most significant role in tracking what we see.

Curiously, the primary visual cortex that receives and passes on the information streaming up from the eyes does not signal what the subject sees. A similar hierarchy of labor appears to be true of sound and touch: primary auditory and primary somatosensory cortices do not directly contribute to the content of auditory or somatosensory experience. Instead it is the next stages of processing—in the posterior hot zone—that give rise to conscious perception, including the image of Trump or Clinton.

More illuminating are two clinical sources of causal evidence: electrical stimulation of cortical tissue and the study of patients following the loss of specific regions caused by injury or disease. Before removing a brain tumor or the locus of a patient's epileptic seizures, for example, neurosurgeons map the functions of nearby cortical tissue by directly stimulating it with electrodes. Stimulating the posterior hot zone can trigger a diversity of distinct sensations and feelings.

These could be flashes of light, geometric shapes, distortions of faces, auditory or visual hallucinations, a feeling of familiarity or unreality, the urge to move a specific limb, and so on. Stimulating the front of the cortex is a different matter: by and large, it elicits no direct experience. Once the image is clearly focused on the sensitive part of the retina, energy in the light that makes up that image creates an electrical signal.

Nerve impulses can then carry information about that image to the brain through the optic nerve. Other parts of the eye include the aqueous humour , a liquid which sits in a chamber behind the cornea, and the vitreous humour , the clear gel that fills the space between the lens and the retina. The sclera is the white part of the eye, forming an outer layer that protects everything inside, while the choroid is the layer of the eye that lies between the retina and the sclera.

It is made up of layers of blood vessels that nourish the back of the eye. Refractive errors are eye disorders caused by irregularity in the shape of the eye. This makes it difficult for the eyes to focus images clearly, and vision can become blurred and impaired. Short sight myopia and long sight hypermetropia are common conditions, both caused by the cornea and lens not focusing properly on the retina.

Short sight is where the eyeball is elongated or the lens is too thick, causing the image to focus in front of the retina. Long sight is where the eyeball is too short or the lens too thin, causing the image to focus behind the retina. Prescription glasses can help with both long and short sightedness. There could also be deeper, evolutionary reasons for why we are especially prone to see faces.

Human survival depends so heavily on others — whether we need their help, or fear their violence — that we need to react quickly and understand their motives. So the brain may be wired to quickly detect others whenever it can. A more speculative view, according to other researchers, is that a similar mechanism could explain human spirituality. The idea is that the brain, being hard-wired to understand people and their motivations, tries to look for human-like intention in everything around us — be it a thunderstorm, a plague or a terrifying and abstract concept like death.

In a bid to make sense of our fears, we therefore begin to personify them, filling the world with gods and demons. Intriguingly, Tapani Riekki at the University of Helsinki in Finland and colleagues have found that religious people are more likely to see faces in ambiguous photos than atheists.

Whether this is true or not, the strength of our expectations can at least explain why some see the Mother of God in a piece of toast, whereas I see the Queen of Pop. Consider this image, for example.

Do you see Jesus? But perhaps the most common form of pareidolia in the western world is seeing faces in the fronts of cars, Sonja Windhager at the University of Vienna travelled to rural Ethiopia to find out whether people see the same thing. Questioning people on the roadside and in small restaurants, she was initially met with surprise.

Over the past decade, a number of remarkable claims have been made that have disintegrated upon further investigation. Neutrinos don't travel faster-than-light; we haven't found dark matter or sterile neutrinos; cold fusion isn't real; the impossible "reactionless engine" was a failure.

There's a remarkable story here that's all about good science. A much better experiment IceCube followed it up, and ruled out their leading interpretation. It strongly suggested something is amiss with the first experiment, and more science will help us uncover what's truly occurring. For now, based on the scientific evidence we have, parallel Universes will have to remain a science fiction dream. This is a BETA experience. You may opt-out by clicking here. More From Forbes.

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