Dezso NEMETH : following the voice of the implicit

Dezso Nemeth, a specialist in implicit memory, is developing an approach where theoretical psychology meets experimentation. In this way, he reveals mechanisms that are essential to our cognitive processes and which are inherently difficult to explain.

Dezso Nemeth didn’t come to Lyon by chance. As the son of a Sorbonne-trained French teacher, he grew up surrounded by French culture. While he still finds it difficult to learn the language, France clearly has a special place in his heart.

Is it safe to say that his subconscious led him to the Gallic capital? He probably wouldn’t dismiss the idea. For Dezso, discovering Freud and reading about his theories during his high-school years in Hungary gave him a taste for neuroscience.

But in the age of neurotechnology, these 19th-century theories are no longer something to be simply mulled over, and so he decided to enter the field of experimental psychology. “I wanted evidence-based psychology,” he says, borrowing from the term evidence-based medicine. This approach has been using scientific logic to measure progress and evaluate practices since the end of the 20th century.

In 2005, he defended a doctoral thesis on the relationship between memory and language at the Eotvos Lorand University in Budapest. This subject is not without Freudian influence: it touches on the idea of implicit memory. This field of study focuses on explaining learning that is difficult to pinpoint, even though it is experienced by everyone. “It can be a sport, such as cycling, or a native language... This field covers all types of learning that are not based on explicit rules,” says the researcher.

Dezso Nemeth’s research combines behavioral methods from experimental psychology (such as gaze tracking) and brain activity measurements (EEG or MRI). He completed his theoretical and technical studies in the United States. While teaching psychology at universities in Hungary, the young researcher studied cognitive neuroscience at Georgetown University (Washington, D.C.), and also learned how to use and read functional MRIs, a state-of-the-art brain imaging technique, at the University of Texas at Austin. Back in Hungary, with a comfortable teaching position in Budapest, he was looking for a change.

“I’m 44 years old. Maybe I’m having a midlife crisis,” he says playfully. “I needed something new. Change improves creativity,” he says, this time a little more seriously. His personality seems to combine a sense of humor with discipline.

That being said, his decision to apply for the IDEXLYON Fellowships’ call for projects was by no means impulsive. He was drawn in by the high-quality scientific environment of the Lyon Neuroscience Research Center [Centre de Recherche en Neurosciences de Lyon], located at the Le Vinatier Hospital of reference for psychiatry and mental health care [Centre hospitalier du Vinatier, établissement lyonnais référent en psychiatrie et santé mentale] in Bron, where he has just set up his team.

“It’s just fantastic! This Neurocampus has everything, from patient medical services to basic research units,” he says enthusiastically. This combination is very important for his field, where access to patients is crucial.

It means that Dezso Nemeth can initiate a series of experiments with volunteers awaiting surgery for severe epilepsy. A few days before the operation, doctors place an implant in the patient’s brain. This allows them to pinpoint the exact location of the areas involved in triggering the seizures. This technique is used by surgeons to avoid damaging healthy brain tissue. It is also of great use to neurobiologists.
“Volunteer patients can perform memory tasks for us during this time and, using their implant, we can study brain activity with unprecedented precision,” explains the psychologist.

Not only will this type of test help researchers identify the areas of the brain involved in Implicit Cognition, but it will also give them a better understanding of how they interact. “You see, there’s not just one memory in our brain, but a number of different memory systems. Each one is linked to a type of task or situation,” adds Dezso Nemeth. “During the last 20 years, we have discovered that these different memory structures work through both cooperative and competitive processes.” For example, when performing a task or learning, some parts of the brain will work together while others will be tuned out. For instance, the prefrontal cortex, the locus of decision-making and general executive function, plays a very important role in explicit learning, especially in directing attention of the subject. But it plays a much smaller role when it comes to implicit learning.

The work of Dezso Nemeth and his team focuses on understanding how the different brain structures work and interact during implicit learning processes. This approach could provide insight into pathological situations, such as autism spectrum disorders or schizophrenia, but also help develop strategies to support this type of learning. It’s only a matter of time before Dezso Nemeth can put his research into practice, perhaps to improve his French!

Written by Agnès Vernet, for the Université de Lyon | May 2020