Humans are highly visual creatures. We rely heavily on visual cues to get and interpret information from the world around us. For example, at least a third of the neurons in our brain cortex are directly or indirectly devoted to processing visual information It shouldn't come as a surprise that so many artistic forms use the visual system as a front door: Painting, sculpture, photography, cinema, architecture. An aesthetic experience occurs when we are in contact with beauty either in nature or in front of a work of art. NEUROAESTHETICS is a discipline that uses neuroscientific techniques to explain the cognitive processes and biological bases of aesthetic experiences. In this field, the visual modality has been widely studied, from the way we perceive the basic elements of a painting until their arrival to our brain centers of memory and emotions where they induce pleasurable feelings or evoke unsuspected memories. Both art and the brain work on the basis of connections. A synapse is the connection space between two neurons and a work of art takes place in the connection space between a creator and a spectator. This is SINAPSIS, Connections between art and your brain I am Fernanda Pérez Gay, I have a PhD in Neuroscience and in this episode of SINASPIS we will talk about the close link between Painting and Visual Perception. Painting and Visual Perception. When we contemplate a painting in a museum we experience various reactions: Astonishment, admiration, sympathy, perplexity, passion ... From a neuroscientific point of view, this raises a central question: How is it that our visual system transforms light patterns into a detailed image capable of making us feel strong emotions? In this episode, we will travel along the visual pathway using art to explain its functioning. As you know, sight begins in the eye when light reflects off of objects and enters the eyeball through the pupil, to be projected onto a tissue that lines the back of the eye: the RETINA The retina is composed of several layers of neurons. The neurons of the outermost layer, fire electrical impulses in response to changes in light, and we call them photoreceptors: Cones and rods. Rods (image on the left) react primarily to contrast and movement and allow us to see in the dark. The activity of cones, on the other hand requires light, and is reponsible for high detail and color vision: It is mostly thanks to our cones that we can appreciate a painting. Have you ever noticed that what is in the center of your visual field is clearer than what is in the periphery? This happens because the cones - which allow us to see in detail - are not evenly distributed throughout the retina. Cones concentrated in the central area of the retina, the "FOVEA", which processes the image more finely, and their number decreases in the periphery where the image is processed in a more complete, but less precise way. In her book "Brain and Vision", Margaret Livingstone suggests that this phenomenon is responsible for one of the greatest puzzles in visual art: the Mona Lisa, painted by Leonardo da Vinci, who at one point appears cheerful and then appears thoughtful or melancholic. Livingstone suggests that this ambiguity can be explained by a conflict between central and peripheral vision When we approach the painting and fix our gaze on Mona Lisa's mouth, the cones of our central vision give us a detailed image, and we do not notice any curve in the outline of her lips. But when we move our gaze to other sides of the painting, the contours of her mouth fade, and a clear smile is more evident. The reason behind this effect is that the few cones in our peripheral vision convey coarser information and do a more general analysis of the image, softening the corners of her lips and making her smile appear. Let's continue with the processing of visual information. Neurons in the retina send signals to the brain through their axons (nerve fibers), organized in the optic nerve, which connects with neurons in the primary visual cortex. located in the occipital lobe. The neuroscientists Hubel and Wiesel won the Nobel Prize by showing that neurons in this area responds to the lines that define the contours of an image. Using electrodes to record the response of neurons in this area they discovered that each one responds to a line with a specific angle or orientation. After being processed in the primary visual cortex, information travels to other areas of the visual cortex specialized in processing different aspects of the image. For example, the areas named V2 and V3 respond to "virtual" lines, those that may arise from a shared edge or contrast with the background even if they are not explicitly drawn. For example, in this optical illusion our brain completes the ambiguous image suggested by the black elements and builds a triangle with imaginary lines. This phenomenon has been extensively explored by artists even since the times of cave paintings. Without knowing brain science, artists had already understood that the elements of a painting can be manipulated in different ways to simulate edges or lines. So far, we described the light's journey from the eye to the visual cortex, where we extract lines and contours. What are the next steps? How is it that these lines turn into objects, portraits or scenes that generate emotions and memories in us? Stay with us in SINAPSIS to continue the journey from the visual cortex to the rest of the brain using artistic examples. "NEURO-WONDERS" In which areas of a work of art do we fix our gaze for the most time? Does the way we look at this mural by Rufino Tamayo vary between different people? Do children view art the same way as adults? Technological advances in neuroscience gave us the opportunity to learn more about what happens in the brain when we look at a painting. A new technology that allows to study the perception of a work of art are eye-tracking devices. By following and registering our eyes' movements even those that are not easily noticeable, these studies can reveal the course of our gaze on an image which elements we fix first, for how long, and in what order. In collaboration with the Van Gogh Museum, researchers at the University of Vrije in Amsterdam used this technique to study the way children and adults contemplated five paintings by Van Gogh, during 30 seconds, in the museum. Before the subjects' participation, researchers used a statistical software to identify regions of the painting that stood out from their surroundings in terms of color, orientation and contrast. The subjects were then taken to view the paintings in two stages. At first, they left the subjects (adults or children) observe the painting freely. Afterwards they would take a break during which they read them some information on each of the paintings. The study found that the eyes of children in the first stage fixated mostly on visually salient features of the paintings but this pattern changed in the second stage, in which the children fixated their gaze on less salient areas that were connected with the explanation of the painting. In contrast, adults did not show any changes between the two stages of the study:even before the explanation, their gaze was not drawn so significantly to the salient regions of the image. The researchers concluded that children who have less knowledge about art and the world. perceive paintings by their most basic characteristics, although this can change when they receive information. This is an example of the so-called "top-down" processes, in which learning and knowledge can shape our perception. You might intuitively think that the eye works like a camera which picks up signals and projects them onto a "screen" in our brains, in reality, perception is not a simple reproduction of an image, nor a window to the world, but a constructive process, a hypothesis to be constantly verified. As cognitive psychologist Chris Frith wrote “Our perception of the world is a fantasy that coincides with reality. " So... how does the brain construct this fantasy? Let's go back to the point when the visual cortex extracts or completes the contours of an image. After this process, information travels from the primary visual cortex to other areas of the visual cortex specialized in processing of other features of the image. For example, the area V4 processes color perception and the area V5 processes or infers movement Our occipital cortex also has "binocular neurons" that integrate information coming from both eyes: Small differences between the two eyes are interpreted as depth, conveyed through different techniques by many painters. Subsequently, visual information leaves the visual cortex through two pathways the dorsal visual pathway, or the WHERE path, which goes from the occipital lobe to the parietal lobe and is responsible for locating objects in space. More decisive when it comes to looking at a painting is the ventral visual pathway or WHAT path, which goes from the occipital lobe to the temporal lobe, and it is by this path that lines, colors and shapes are integrated to to identify Objects, landscapes, bodies and faces. To complete this task, the brain makes use of past experiences and knowledge, as in the example of the children in the Van Gogh museum. As we have already mentioned, those processes where knowledge shapes perception, are called "top-down" processes Through these processes, the brain looks for the constant elements, extracts the essential characteristics and compares the current image to others encountered in the past. On another note, to appreciate a work of art, the visual system must work together with other brain networks, like those linked to other senses. For example, paints rich in textures, like those of Jackson Pollock, may activate the areas of the brain responsible for touch. After activating networks for different senses, the intensity of the aesthetic experience also depends of the brain's emotional system neurons: the limbic system. This system includes structures that lie deep in the temporal lobe like the hippocampus, which helps in the consolidation of long-term memory and the amygdala, which is activated during strong emotional reactions like fear. Another important structure of the lymbic system is the insular lobe, which is found between the frontal lobe and the temporal lobe, This lobe integrates sensory information into conscious emotional experiences But how is it that the beauty we encounter in a painting is enough to generate in us brain reactions analogous to those we experience when we satisfy our instincts, or when we interact with our loved ones? The explanation is far from simple, and it there is still a long way ahead us to answer it. There is no doubt that brain physiology and neuroimaging give us information on the way we process art, However, and as we mentioned in the episode on Creativity, these technologies and our interpretation of the resulting data, remain limited when facing subjective and complex phenomena such as artistic appreciation. One way to work around these limitations is to get involved in multidisciplinary work teams, which include the participation of artists, physiologists, psychologists, engineers, anthropologists ... even physicists and mathematicians. A good example of this type of collaboration is the work team of Dr. Francisco Fernández de Miguel, Mexican researcher at the Institute of Cellular Physiology who is leading a project to study the response of our brain to beauty and violence. "HUNTING FOR ANSWERS" Our "Art and Brain" project that we are developing at the Institute of Cellular Physiology and in the Center for Complexity Sciences we are interested in fundamental phenomena of our perception of art, in particular, of our perception of visual art. Fo this purpose, we study the perception of pre-Hispanic murals which interestingly address issues of art perception still relevant in this century In this study, we first did a validation of the subjective accounts of the perception of these murals in different groups of people. For this purpose, we use "semantic networks": The subject is asked to tell us what type of emotions these paintings generate in them. In this stage, psychologists are fundamental. In addition, the artists in the team help us modify the paintings. by changing their colors and shapes to analyze the role of each variable in our perception. In a second stage, we record these people's brain responses when viewing these mural paintings. We use "electroencephalography" to record the responses of several electrodes that correspond to different areas of the brain to see which zones activate and which zones inactivate. The project has been very generous because, eventhough we study abstract concepts which characterize artistic thought, with the application of concrete procedures -which characterize scientific thought- we select the particular questions of our interest and build paradigms that give "binary" answers (yes or no) on the fundamental processes of perception. One of our questions was, for example, how violence and beauty overlap in the art of Cacaxtla murals. Why do we find them so beautiful to watch if they are composed of images with human sacrifices, blood, entrails coming out, and you don't see them in a first impression. Through modifying these murals and recording brain activity we have found, for example, differences in perception related to gender: Women's data show that they are more reactive to violence and with more consistency and reproducibility. This makes us wonder: Where do these differences come from? Since we were kids? How do these differences emerge in childhood? Are these cultural or innate differences? And what we have found in children is surprising Girls are much more structured and concrete in their responses (in the semantic networks task) and they give answers that are more similar to each other while boys have more scattered and diverse responses, thus confirming the differences in perception from a very young age. I want to end this presentation with a reflection: The type of knowledge we are acquiring, even if it does not come from philosophy but rather from physiology has the advantage of being, in principle, neutral but its application has risks, it can be used, for example, for marketing strategies, with ideologization purposes or to sell us products and ultimately, to deprive us of our freedoms. So this is the moment when philosophy, ethics, jurisprudence and science can work together to regulate the use of overflowing knowledge emerging from studies on the nervous system. As we have learned, the study of visual perception is intimately related to the art of painting When we visit a museum, we immerse ourselves in works that exhibit all the characteristics studied by vision neuroscientists shape, color, depth, texture contrast, movement, etcetera. This is why neuroscientist Margaret Livingston postulates that “Each aspect of our vision is illustrated with examples of painters who have mastered the means of fooling it” “The brain,” wrote Emily Dickinson, “is wider than the sky”. "Put them side by side: The one the other will contain. With ease" We invite you to keep navigating between the wonderful clouds of the brain by following us on our social networks: By subscribing to our Youtube channel, and waiting for the next episodes of SINAPSIS: Connections between art... ... and your brain. Credits: Original idea, research, script and host: Dr. Fernanda Pérez-Gay Juárez // Production:Ivan Méndez Rivera // Production assistants:Luis Ángel Pérez Córdova, Miguel Ángel Cañedo Zavaleta. Editing, post-production and illustration: Rodrigo Pérez-Grovas Álvarez. // Communication assistant: Ana Laura Pérez Flores. Invited scientist: Dr. Francisco Fernández de Miguel // Brain dissections: Dr. Julio Caesar Pérez Acknowledgments: Faculty of Medicine, National Autonomous University of Mexico, Museum of Anthropology, National Institute of Anthropology and History (INAH) Music: -Original compositions by Manuel Velázquez -Album Into Madness -Scott Holmes, André Codeman, Dee Yan-Jey English translation Fernanda Pérez-Gay ** Funded by the Fonds de Recherche de Québec Original Project Funding: FONCA (Mexico Council for the Arts), Secretariat of Culture ACT Program - Arte, Ciencia y Tecnologías (Art, Science and Technologies). SINAPSIS: Conexiones entre el Arte y tu Cerebro. Mexico City, Mexico, 2019