Taking Flight


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bat in flight

When Dr. Michael Yartsev first got in touch with his soon-to-be mentor Dr. Nachum Ulanovsky, it was because he wanted to inquire about Ulanovsky’s own former PhD adviser, as he was thinking of applying for a PhD position in that adviser’s lab. But when Ulanovsky, a neurobiologist who was then finishing up his postdoc in the US, started talking about his own research and his plans for setting up a lab at the Weizmann Institute, says Yartsev: “I thought ‘this research program is risky, extremely innovative and exciting – which is exactly what I am looking for.’ That is how I became Nachum’s first student.”
Dr. Michael Yartsev
Yartsev, who grew up in Beersheba, completed his BSc and MSc in biomedical engineering at Ben-Gurion University of the Negev. There, he worked on recording the activity of single neurons in the cerebellum of awake, behaviorally active cats. By the time he completed his degrees, he says, he had fallen in love with neuroscience and was looking around for an exciting place to do his PhD. He decided to join Ulanovsky’s group even before the latter returned to Israel. “It just felt so right,” he says.

Ulanovsky works with bats, both in his lab in the Neurobiology Department and in the wild. His lab contains a darkened, soundproofed “bat cave” equipped with visible-range and infrared cameras and microphones that enable him and his team to investigate the bats’ highly developed spatial navigational abilities. The Egyptian fruit bats they work with, says Yartsev, “are extremely intelligent animals and, once they get used to you, they are also pretty friendly...at least most of them.” The key to working with these animals, he found, is to respect the fact that each individual bat has its own unique personality; acknowledging this is the key to getting their cooperation.
Yartsev’s research focused on two specialized classes of cells in the mammalian brain: the place-cells in the hippocampus and grid-cells in the entorhinal cortex. These cells are widely believed to be pivotal for spatial memory and navigation – whether in humans, rodents or any other mammals. While much of this research is done with rats, bats gave Ulanovsky’s group a unique advantage: They enabled the researchers to examine problems similar to those that rodent researchers have been grappling with for a long time, but from a completely different perspective – one that has turned out to be very useful. For example, questions such as the neural mechanisms of 3-D navigation have proved impossible to address using standard animal models.

In their first set of experiments with the bats (published in Nature in 2011), Yartsev and Ulanovsky investigated how the grid cells create a map-like network in the brain. In the process they disproved the most widely accepted class of computational models of grid cells – models that were based solely on rodent experiments. In a second set of experiments (published in Science in 2013), they used tiny, wireless devices to measure the activity of individual neurons in the bats’ brains as they flew around an artificial tree in the lab. Using this innovative technology, the researchers were able, for the first time, to observe how the place cells in the bats’ brains perceive three-dimensional, volumetric space and to answer the question: Do they relate equally to all three axes of space? (The answer is yes, each cell appears to be almost equally sensitive to all the three spatial axes in the room.)  
Dr. Nachum Ulanovsky
In addition to the scientific papers, Yartsev wrote an essay describing their work with bats for studying the neural basis of the mammalian spatial representation system. That essay, which appeared in Science, made him the 2013 grand prize winner for the prestigious Eppendorf and Science Prize for Neurobiology. He also recently received the Donald B. Lindsley Prize in Behavioral Neuroscience from the Society of Neuroscience. Yartsev is the first Israeli student to receive these prestigious prizes.

Admitting to enjoying the recognition his work has received, Yartsev emphasizes that for him the real prize has been the experience and knowledge he gained in the process: “It has truly been an honor and a privilege being Nachum’s first student, and I envy all of those who will be his students in the years to come. Being part of this lab has truly been a wonderful experience.”

At present, Yartsev is a CV Starr Fellow at Princeton University, where he is conducting postdoctoral research in the lab of Prof. Carlos Brody. There he is investigating the neural basis of decision making, including how the brain rapidly routes information to guide choices and how new information is integrated into the process. Along the way he is acquiring new techniques for studying the brain, among them optogenetics – a method for controlling neural circuits with light.

In the future, he intends to return to researching bats. “I plan to use these incredible animals to study how information available in the environment around us guides our actions, choices and decisions,” he says.

Yartsev is married to Liza and they have a five-year-old son, Ariel. They enjoy traveling together, and especially relish new places and new experiences.