The brain begins preparing for vision while still in the womb
As early as the 21st week of pregnancy, the visual cortex of the human brain is organized in its basic structure just as it is in adults. The basic framework for future vision thus develops without any prior visual experience.
Published: 07.10.2026
The human brain maps what we see like a map: Points that lie next to one another on the Retina of the Eye are also processed in the brain by adjacent nerve cells. In technical terms, this ordered mapping is called retinotopic organization (from “retina,” the Latin word for the retina). Until now, it was unclear whether the human brain learns this map only through light stimuli after birth or whether it is already established in the womb. A research team led by Professor Michael Artur Skeide from the Institute of Child and Adolescent Psychiatry at the Medical Faculty of Christian-Albrechts-University of Kiel (CAU) and the University Medical Center Schleswig-Holstein (UKSH), Kiel Campus, investigated this question. At the Max Planck Institute for Human Cognitive and Brain Sciences, the researchers developed a method that allowed them to analyze Magnetic resonance imaging (MRI) data from a total of 871 individuals. The study included fetuses from the 21st week of pregnancy onward, as well as newborns, adolescents, and adults. The study has now been published in the journal *Science Advances*.
Retina
The retina is the inner layer of the eye covered with pigment epithelium. The retina is characterized by an inverse (reversed) arrangement: light must first pass through several layers before it hits the photoreceptors (cones and rods). The signals from the photoreceptors are transmitted via the optic nerve to the processing areas of the brain. The reason for the inverse arrangement is the evolutionary development of the retina, which is a protrusion of the brain.
The retina is approximately 0.2 to 0.5 mm thick.
Eye
bulbus oculi
The eye is the sensory organ responsible for perceiving light stimuli – electromagnetic radiation within a specific frequency range. The light visible to humans lies in the range between 380 and 780 nanometers.
Magnetic resonance imaging
Magnetic resonance imaging scanner
A device used by medical professionals for magnetic resonance imaging (MRI). MRI is an imaging technique used to diagnose malformations in various tissues or organs of the body. This method is particularly effective for imaging parts of the body that contain a lot of water. Patients are placed in a tube (scanner) and exposed to a strong magnetic field. However, they are not exposed to X-rays or other forms of ionizing radiation.
The visual map begins to form as early as the 21st week of pregnancy
The analysis shows that two key characteristics of these visual maps are already present in the brain as early as the 21st week of pregnancy. The first of these is eccentricity. This measure indicates how far a point is from the center of the visual field. Second, it concerns the polar angle, which specifies the exact direction within the visual field. Both features can be detected in the visual areas V2 and V3. These are regions of the cerebral Cortex located directly behind the Primary visual cortex (V1) and responsible for the further processing of visual information.
Since unborn babies in the womb do not open their eyes until around the 28th week, and since it is dark inside the uterus, this organization develops without any external visual stimuli. The researchers suspect that spontaneous signals are the cause: Even before birth, the Retina emits regular waves of activity on its own, which gradually wire and structure the visual center in the brain.
“We investigated the fundamental question: Is our visual field, as it is projected onto the eye, already structured this way in the brains of children prenatally—that is, before birth? We can now say: Yes, this is already the case at a very early stage of development,” explains study leader Prof. Dr. Michael Skeide. “The results show that the basic architecture of our Visual system is already in place long before the first light enters the eye.”
Cortex
cortex cerebri
Cortex refers to a collection of neurons, typically in the form of a thin surface. However, it usually refers to the cerebral cortex, the outermost layer of the cerebrum. It is 2.5 mm to 5 mm thick and rich in nerve cells. The cerebral cortex is heavily folded, comparable to a handkerchief in a cup. This creates numerous convolutions (gyri), fissures (fissurae), and sulci. Unfolded, the surface area of the cortex is approximately 1,800cm².
Primary visual cortex
area striata
The part of the occipital lobe whose primary inputs originate from the visual system. According to Brodmann, who originally divided the cerebral cortex into 52 areas in 1909, the primary visual cortex is area 17.
Retina
The retina is the inner layer of the eye covered with pigment epithelium. The retina is characterized by an inverse (reversed) arrangement: light must first pass through several layers before it hits the photoreceptors (cones and rods). The signals from the photoreceptors are transmitted via the optic nerve to the processing areas of the brain. The reason for the inverse arrangement is the evolutionary development of the retina, which is a protrusion of the brain.
The retina is approximately 0.2 to 0.5 mm thick.
Visual system
The visual system is the part of the nervous system that processes visual information. It primarily comprises the eye, the optic nerve, the optic chiasm, the optic tract, the lateral geniculate nucleus, the optic radiation, the primary visual cortex, and the visual association cortices.
How the Measurement Works in the Womb
For the study, the researchers used publicly available data from the “Human Connectome Project.” They analyzed functional MRI (fMRI) data from fetuses, newborns, children, and young adults. fMRI measures the hemodynamic response—that is, blood flow in the brain—to identify active regions. Adults in an MRI scanner are usually shown moving dots or patterns on a screen to map the Visual cortex This is not possible for unborn babies in the womb. Therefore, the research team used data from what is known as resting-state fMRI (Functional magnetic resonance imaging at rest). This method measures minute, spontaneous changes in blood flow in the brain while the person is not performing a specific task or is asleep.
Using a mathematical method, the researchers determined the strength of the resting-state signals linking the Primary visual cortex (V1) to the adjacent areas (V2 and V3). By comparing this functional connection with retinotopic maps from adults, the internal map of the visual Cortex can also be reconstructed in fetuses.
Visual cortex
The visual cortex refers to the areas of the occipital lobe that are involved in processing visual information. These include the primary visual cortex and the associative visual cortices V1 to V5. According to Brodmann, the visual cortex comprises areas 17, 18, and 19.
Functional magnetic resonance imaging
Functional magnetic resonance imaging (fMRI) is a modification of MRI that allows brain activity to be measured indirectly via regional blood flow and oxygen consumption. BOLD (blood oxygen level dependent) contrast is often used, which exploits differences in the magnetic behavior of oxygen-rich and oxygen-poor blood. An increase in the BOLD signal indicates increased neural activity. fMRI provides good spatial resolution and allows detailed conclusions to be drawn about the activity of specific areas of the brain, while the temporal resolution is in the range of seconds.
Primary visual cortex
area striata
The part of the occipital lobe whose primary inputs originate from the visual system. According to Brodmann, who originally divided the cerebral cortex into 52 areas in 1909, the primary visual cortex is area 17.
Cortex
cortex cerebri
Cortex refers to a collection of neurons, typically in the form of a thin surface. However, it usually refers to the cerebral cortex, the outermost layer of the cerebrum. It is 2.5 mm to 5 mm thick and rich in nerve cells. The cerebral cortex is heavily folded, comparable to a handkerchief in a cup. This creates numerous convolutions (gyri), fissures (fissurae), and sulci. Unfolded, the surface area of the cortex is approximately 1,800cm².
Implications for Medicine and Basic Research
The findings are currently based on average values from several hundred children in order to make the weak signal from fetuses statistically detectable on MRI at all. For clinical applications, such as the early detection of visual impairments, a reliable analysis of individual brains is required. “The next scientific step is to develop methods that allow us to reconstruct these Retinal maps in the brain on an individual level. Only when we succeed in doing so will the method be usable to examine, on a case-by-case basis, how the visual areas in the brain have developed,” says Skeide.
The study shows only the basic spatial organization. How brightness, shapes, or object recognition develop in the brain remains an open question. “Newborns, for example, can already distinguish faces shortly after birth,” emphasizes the expert on early childhood brain development. “We find it very interesting how this is possible so early on. For this to happen, more must occur prenatally than just the basic processes we have described.” Future studies will aim to clarify whether the Perception of shapes and objects is also pre-programmed in the brain before birth.
Retinal
A chemical synthesized from vitamin A. Together with opsin, it forms rhodopsin.
Perception
The term describes the complex process of gathering and processing information from stimuli in the environment and from the internal states of a living being. The brain combines the information, which is perceived partly consciously and partly unconsciously, into a subjectively meaningful overall impression. If the data it receives from the sensory organs is insufficient for this, it supplements it with empirical values. This can lead to misinterpretations and explains why we succumb to optical illusions or fall for magic tricks.
Original publication
So-Hyeon Yoo, Anne-Sophie Kieslinger, Michael A. Skeide; Population connective field modeling reveals proto-retinotopic Visual cortex organization in the prenatal human brain. Science Advances
Source
Visual cortex
The visual cortex refers to the areas of the occipital lobe that are involved in processing visual information. These include the primary visual cortex and the associative visual cortices V1 to V5. According to Brodmann, the visual cortex comprises areas 17, 18, and 19.
