When a newborn mammal opens its eyes for the first time, it can already visually understand the world around it. But how does this happen before they have experienced the sight?
A new Yale study suggests that, in a sense, mammals dream of the world they are about to experience even before they are born.
Writing in the last issue of Science, a team led by Michael crairWilliam Ziegler III professor of neuroscience and professor of ophthalmology and visual sciences at Yale, describes waves of activity emanating from the neonatal retina in mice before their eyes open.
This activity disappears shortly after birth and is replaced by a more mature network of neural transmissions of visual stimuli to the brain, where the information is further encoded and stored.
“At first glance, mammals are capable of quite sophisticated behavior, “said Crair, lead author of the study, who is also vice chancellor for research at Yale.” But how are the circuits formed that allow us to perceive movement and navigate the world? It turns out that we are born capable of many of these behaviors, at least in a rudimentary way. “
In the study, Crair’s team, led by Yale graduate students Xinxin Ge and Kathy Zhang, explored the origins of these waves of activity. By imaging the brains of mice shortly after birth, but before their eyes were opened, the Yale team discovered that these retinal waves flow in a pattern that mimics the activity that would occur if the animal moved through the environment. ..
“This early sleep-like activity makes evolutionary sense because it allows a mouse to anticipate what it will experience after opening its eyes and be ready to respond immediately to environmental threats, ”Crair said.
Going further, the Yale team He also investigated cells and circuits. responsible for propagating retinal waves that mimic forward movement in newborn mice.
They found that blocking the function of amacrine star cells, which are cells in the retina that release neurotransmitters, prevents waves from flowing in the direction that mimics forward motion. This, in turn, affects the development of the mouse’s ability to respond to visual movement after birth.
Interestingly, within the adult mouse retina, these same cells play a crucial role in a more sophisticated motion-sensing circuitry that allows them to respond to environmental signals.
Mice, of course, differ from humans in their ability to quickly navigate their environment shortly after birth. However, human babies can also detect objects and identify movements immediately, such as a finger moving across their field of vision, suggesting that their visual system was also ready before birth.
“These brain circuits are self-organizing at birth and some of the early teachings are already done, ”Crair said. “It’s like dreaming about what you are going to see even before you open your eyes.”
(CLOCK the Yale video for this story below).
Source: Yale university
SEND this dreamy investigation to your friends on social media …