In order to understand how neurons communicate with each other, what they do when the brain is thinking, and how memory processes and decision-making are formed, Ranulfo Romo Trujillo, researcher at the Institute of Cellular Physiology (IFC) of the National Autonomous University of Mexico (UNAM) has developed a unique and innovative method now allows studying live brain of rhesus monkeys trained to make decisions and perform actions.
The study also includes the participation of Román Rossi Pool, also researcher at IFC, who works as physicist providing statistical analysis to interpret the data. In a first stage, the work of both researchers, published in the journal Neuron, allowed directly decoding live functioning of neurons populations while making decisions.
Romo, Doctor Honoris Causa by the UNAM and member of the National College of Mexico and a foreign member of the Academy of Sciences of the United States, is currently leading a laboratory where nine scientists from different disciplines (physicians, physicists, mathematicians, biologists and psychologists, among others) design new methods to understand the functioning of the “the most powerful computer we have: the brain.” With very deep statistical methods, they have been able to elucidate what emerges from brain functioning.
Rossi explained that when information enters the brain, does it very homogeneously. “When the most advanced cell areas are recorded, where memory and decisions are made, it begins a great heterogeneity of responses in neurons. In this article we wonder how to gather and make sense of the great heterogeneity of neurons in more advanced brain activities, in order to understand emerging events.” The aim is understand how the brain gathers those signals in an intelligent way, allowing solving the problem.
Romo decided to characterize the individual functioning of neurons, but their responses are so many and so complex in a single brain area, that it was very hard to make sense of how they could be put together so that these complex dynamics emerge. “This is why we now I study populations where neurons have mixed responses, although it is difficult to group them together,” he explained.
The statistical method allows obtaining what is essential, make a synthesis. “It reflects what makes a population of individuals; in this case neurons associated with the thinking of the animal, with its memory, its autobiography, making decisions and reward,” Romo said.
Meanwhile, Rossi indicated that they seek to address at a neuronal scale how this diversity of neurons can be combined in answers that allow understanding what the brain does to solve the problem. “The area of study is the dorsal premotor cortex; a premotor role has been assigned to it, but is involved in more complex cognitive processes,” he said.
Romo said the most interesting part is the thinking. “We are concerned about what precedes the movement, the thought, how actions are elaborated. It is the biology of the thought.” When the monkey is thinking, we can study directly the underlying biological process.
Source: DGCS UNAM