When a newborn baby opens her eyes, she doesn’t see well at all. You the parent are a kind of blurry shape of light and dark. Soon her vision comes online. Baby starts recognizing you and you can see it in her eyes.
After that baby looks beyond you and that flash of recognition fades. She even can’t make out what its outside the window. Its another blurry world of shapes and light. Within few months, she can see trees which are outside. After that her entire world comes into focus.
Brain Sensations: As Baby tries to see the World:
UNC School of Medicine Scientists has found more clues regarding what happens inside the brain of baby mammals as they try to make visual sense of the world.
Study which was conducted in mice and published in the journal Nature Neuroscience is a part of the ongoing project in the lab of Spencer Smith, PhD and assistant professor of cell biology and Physiology.
They were trying to map the functions of the brain areas which are playing crucial roles in vision. Proper function of these areas are quite critical for the case of vision restoration.
Smith adding on the same says, “There’s this remarkable biological operation that plays out during development. Early on, there are genetic programs and chemical pathways that position cells in the brain and help wire up a ‘rough draft’ of the circuitry. Later, after birth, this circuitry is actively sculpted by visual experience: simply looking around our world helps developing brains wire up the most sophisticated visual processing circuitry the world has ever known. Even the best supercomputers and our latest algorithms still can’t compete with the visual processing abilities of humans and animals. We want to know how neural circuitry does this.”
If cures for the case of partial or entire blindness, it can be developed via gene therapy or retinal implants. Researchers will then require to understand the totality of visual brain circuitry for ensuring people to recover useful visual function.
Effect Over Eyes:
Smith further adding to the same says, “Most work on restoring vision has focused on the retina and the primary visual cortex. Less work has explored the development of the higher visual areas of the brain, and their potential for recovery from early deficits. I want to understand how these higher visual areas develop. We need to know the critical time windows during which vision should be restored, and what occurs during these windows to ensure proper circuit development.”
For understanding the potential challenges that vision restoration later in life might entail lets take the case of bilateral cataracts.
It is when lenses of both the eyes are cloudy and vision is severely limited. In the case of developed countries, its quite common for having such cataracts being surgically removed during early part of the life.
Smith says, “But in less developed, rural parts of the world, people often don’t get to a clinic until they are teens or older. They’ve gone through life seeing light and dark, fuzzy things. That’s about it. When they have the cataracts removed, they recover a large amount of visual function, but it is not complete. They can learn to read and recognize their friends. But they have great difficulty perceiving some types of visual motion.”
Effect on Mice:
There were two sub-networks of visual circuitry which were called ventral and dorsal streams. Later these is important for the case of motion perception.
Smith wanted to know if visual experience is particularly essential for the case of proper development of dorsal stream and what could be changing at the individual neuron level during early development.
For exploration of these questions, Smith and his UNC colleagues has conducted hundreds of painstaking, time-consuming experiments.
Over the essence, his lab is reverse engineering complicated brain circuitry with the help of specialized two-photon imaging systems.
In series of experiments, Smith’s team reared mice in complete darkness for several weeks. Even the daily aid was done in darkness by night-vision goggles.
By use of these imaging systems and precision surgical methods, Smith and colleagues could possibly view areas of the brain with neuron-level resolution.
They have showed that the ventral visual stream in mice did indeed come online immediately with the neurons living as the mice responded to visual stimuli. But dorsal stream didn’t.