We view the world with our eyes, but we perceive it with our brains
Yasmine El-Shamayleh studies how the brain interprets signals coming from the eye. Using cutting-edge optogenetic tools she explores how brain cells detect shapes and recognize objects. Her research will provide insight into how we make sense of the things we see and has the potential to guide future therapies for visual impairments.Read more about Yasmine El-Shamayleh, PhD >
At a young age, Yasmine El-Shamayleh, PhD, developed a fascination with the eye and the sense of vision. She credits this interest to her father, an ophthalmic surgeon, who taught her about clinical procedures for treating vision impairments.
El-Shamayleh had planned to follow in her father’s footsteps and become an eye doctor. But she had a transformative experience in her first college-level neuroscience course.
“The professor was describing how brain cells analyze information from the eye, and that is when I realized that my attraction to the eye was shortsighted,” said Dr. El-Shamayleh, who is now a principal investigator at Columbia’s Mortimer B. Zuckerman Mind Brain Behavior Institute. “We view the world with our eyes, but we perceive it with our brains.”
El-Shamayleh spent the rest of her college years learning all she could about neuroscience and vision. She decided to dedicate her career to understanding how a region of the brain called the visual cortex processes and interprets signals from the eye.
“I want to understand how the visual cortex enables us to see objects in the world and know what they are,” said Dr. El-Shamayleh, who is also an assistant professor of neuroscience at Columbia’s Vagelos College of Physicians and Surgeons.
In graduate school, Dr. El-Shamayleh studied how brain cells called neurons detect the edge of an object and its texture. In her postdoctoral fellowship, her work shifted to studying how neurons distinguish between two objects based on their shape. The key to this ability lies in signal processing in higher areas of the visual cortex.
“Scientists once thought that higher areas of the visual cortex contain neurons that represent specific objects, like a banana or a car,” she said. “But this would be an inefficient way for the brain to represent objects, as it would require a different neuron for every conceivable object in the world.”
Dr. El-Shamayleh and other scientists now hold an alternative view, where individual neurons represent only a small part of an object. Groups of neurons then work together to represent the full object. This process is analogous to forming words from different combinations of letters.
“We have 26 letters in the English alphabet, and from those 26 letters we can generate thousands of words,” she explained. “We now know that the brain uses a similar process to represent all the different objects in the world. Akin to the letters of the alphabet, higher areas of the visual cortex contain neurons that prefer different parts of objects, either convex or concave. Different combinations of these neurons can be used to represent any object in the world.”
To represent a simple object like a banana, for example, the brain can combine the responses of a neuron that prefers a convex feature on the left side and the responses of another neuron that prefers a concave feature on the right side.To represent a more complex object like a car, the brain can combine the responses of more neurons, with various preferences for convex and concave parts.
Dr. El-Shamayleh’s current research seeks to understand how neurons analyze the shape of objects. Humans and other animals rely on shape information to evaluate objects in the world: to determine what they are, whether we have seen them before or how we might use them. Understanding how the brain analyzes the shape of objects is also important for developing therapeutic strategies for disorders of vision, such as visual agnosia, that affect our perception of shapes and patterns.
This research has recently led her to sharpen her focus and investigate visual processing in the cortex at a deeper level. She now wants to understand how different types of neurons, each with a unique genetic identity, analyze convex and concave parts of objects. To develop insights into these processes, she became an expert in optogenetics. This revolutionary technology uses laser light to manipulate the electrical activity of specific groups of neurons and, as a result, deduce their contribution to vision. To make this shift, however, she had to go back to school.
She enrolled in undergraduate and graduate-level classes in microbiology and genetics. She shadowed experts in biochemistry labs. She even bought Molecular & Cell Biology for Dummies.
Dr. El-Shamayleh believes that her new focus holds promise for deepening our understanding of vision, as well as developing treatments for complex neurological disorders.
“Many diseases of the nervous system, such as epilepsy, schizophrenia and autism, are caused by impaired function of specific types of neurons in the cortex,” she said. “Developing genetic tools that target specific types of neurons could facilitate gene therapeutic approaches to treating these diseases.”
The brain’s most complex abilities, including our perception of visual objects, depend on the electrical pulses sent from neuron to neuron. And while Dr. El -Shamayleh believes in this view, she also believes that a closer examination of the genetic information carried within those neurons is necessary. This new focus is a central component of her work since arriving at Columbia’s Zuckerman Institute in 2019.
“Understanding the inner workings of neurons may be just as critical as understanding the information carried by the electrical pulses transmitted between them,” she said. By combining these two approaches, she hopes to clarify how neurons in the visual cortex enable us to perceive the world.
Prior to coming to Columbia, Dr. El-Shamayleh completed postdoctoral fellowships with Anitha Pasupathy, PhD, and then Gregory D. Horwitz, PhD, at the University of Washington. She earned her Doctorate in Neural Science from the Center for Neural Science at New York University, under the mentorship of J. Anthony Movshon, PhD, and a Bachelors in the Biological Basis of Behavior from the University of Pennsylvania, where she worked in the laboratory of Larry A. Palmer, PhD.