Fascination on how the brain works never waives for Idan Segev

By Michelle Ponto, Science Writer

The brain and how it works is complex. It weighs only 1.5 kilograms, but inside are 100 billion microchips known as nerves cells.  It’s  how these nerve cells generate everything that we do and feel that has kept Professor Idan Segev captivated with his work for years.

“These microchips connect to each other and generate a huge network of physical elements that eventually generate all of our behaviors, all of our feelings, all of our imagination, all our creativity, all our sadness, everything…I was fascinated already when I was a teenager that there were all these microchips that build a machine that can do all these things,” said Segev.

Segev works at the Hebrew University where he is the head of the department of Neurobiology.  He’s in charge of brain research there, and says the best thing he did when he started was to understand the single cell as a unit of computation. “This was a little difficult to understand because what does it mean to compute? But the nerve cell is a real microchip that receives input from all of its neighbors and from there something wonderful happens,” he said.

Segev says one of his research goals was to understand how a nerve cell functions, and over the years, he has made so many advancements in understanding a nerve cell as a microchip that he is considered one of the leaders when it comes to understanding neurons.  But he’s not done.  Now he and the researchers in his lab want to find the answer to what changes in the brain when we learn.

He says whenever we do something, such as talk to someone or see something, it results in changes in the brain. “I go to a movie, I meet a person or something happens between us and I remember…so what is changing in the brain when I change?” he asks.

Apparently, what is changing is the strength of the connection between the cells. If there are two nerve cells that are connected lightly through synapse, then there is particular chemical connection between those nerve cells.  This chemical connection can change the strength of the connection during experience.

“When I come with a new brain after we discuss something, it’s a group of cells that have become more connected,” Segev explains. “I focused for a long time on this miraculous capability for the connection to change while I’m doing something — and why it doesn’t change when I am not doing something. This is why people say — and they are right when they say this– if I don’t use it, I lose it.”

Segev discovered that if we don’t use the brain, the connection, between the elements, don’t become affected, so we cannot embed new memories. He says this is what happens in Alzheimer’s. The connections are not functioning anymore. And because they cannot change, not only can the person not create new memories, but also the connections become loose and they forget all memories.

“We found an extremely interesting thing about synapse and the rules by which this connection is changing through activity.  The focus is activity. It doesn’t matter if it is running on a beach, solving a puzzle or being engaged in a conversation. These activities are the basis for changing in the brain in terms of connectivity,” he said.

While Segev has come a long way from the years when he was a teenager in understanding how the brain works, codes and changes, his dedication to learning more is still unwavering.

“We are born a blank slate. We don’t know anything, but then suddenly through cell connection, we see face. It’s a wonderful phenomenon and it keeps me fascinated,” he said.