For the First Time, Possible Bases of Human Intelligence Observed

A study led by Dr. Rodrigo Quian Quiroga, coordinator of the Neural Mechanisms of Perception and Memory Research Group at the Hospital del Mar Research Institute, has allowed scientists to observe for the first time how the neurons in our brain store memories. In a study published in Cell Reports, they confirmed that these neurons can distinguish objects or people independently of their context, enabling the establishment of superior and abstract relationships, which form the basis of human intelligence.

This is the first time a study has observed this neuronal behavior in humans. Until now, studies conducted on animals showed significant differences in the encoding of concepts (whether a specific place, object, etc.) when the context was changed. For example, neurons responded very differently if a rat encountered an object in one location versus another. Thus, it was believed that these memories were stored in different groups of neurons. The study led by Dr. Quian Quiroga has provided "surprising responses" that contradict what was previously published, as neuronal responses to a given concept remain the same when the context changes, such as when recalling having seen a person in one place or another. "The basic principle of neuronal encoding in humans is the opposite of what has been observed in other species, which has important consequences," states Dr. Quian Quiroga.

Data from Individual Neurons

The study included data from nine patients in Argentina and the United Kingdom with treatment-resistant epilepsy, who had electrodes implanted to control the functioning of specific neuron groups individually. This allowed precise recordings of their responses, unlike previous studies in humans, which were based on magnetic resonance imaging and could not differentiate individual neurons.

The patients were told two stories, both involving the same person, in different contexts, with the aid of images. Monitoring revealed which neuron groups were activated. Specifically, it was found that the response to the image of the person was the same, activating the same group of neurons in both stories. Additionally, when the patients told the stories themselves, it was observed that just seconds before referring to the protagonist, those neurons were already activated in the same way for both stories.

"Memories are stored in a much more abstract manner in humans than in other animals. You can think of concepts, or anything, in more abstract terms, independent of the context in which you learned them," explains Dr. Quian Quiroga, noting that this may represent the "basis of human intelligence." "This allows us to make associations and inferences that are much more abstract and complex than if we were forced to think of each concept in a specific context," he adds. In other words, humans can decontextualize their memories to create more abstract thinking.