Surprising research from Spain has demonstrated the uniqueness of human consciousness, as a team of scientists say they have shown how the human brain stores memories differently than other species.
Neurons in a human brain record information separate from context, allowing humans to process more complex and abstract information relationships than other species. Dr. Rodrigo Quian Quiroga, group leader of the Neural Mechanisms of Perception and Memory Research Group at the Hospital del Mar Research Institute, led the groundbreaking research into human consciousness.
The Contextual Mind
Previous research on memory storage in rodents and monkeys revealed a strong correlation between context and object. When rats encountered the same object in different locations, their neurons recorded the object differently, activating distinct neural groups for each context. Earlier studies on human memory confirmed that memory-related activity occurs in the hippocampus, but monitoring techniques had not yet determined how individual neurons responded to memory formation and recall.
However, Quian Quiroga’s research found an unexpected deviation from these neural patterns when examining human memory. Their neural responses remained consistent even when participants saw the same person in different locations.
“The basic principle of neuronal coding in humans is the opposite of what has been observed in other species, which has significant implications,” notes Quian Quiroga.
Monitoring Memory
Quian Quiroga worked with nine study participants in the United Kingdom and Argentina. All participants were undergoing treatment for drug-resistant epilepsy, which required monitoring neuron activity using electrode implants.
This method provided a significant advantage, as previous studies on human memory relied on noninvasive fMRI, which monitors general brain activity but cannot distinguish individual neurons. Researchers could monitor neural activity in unprecedented detail by working with participants with precise electrode implants, targeting 737 units in the hippocampus and amygdala.
Testing Recognizable Faces
Researchers showed participants images of over 100 celebrities while monitoring their neural responses. They then identified the two celebrities who triggered the strongest neural activity in each participant.
Participants were presented with two stories featuring the same person in distinct contexts for each selected celebrity. Each participant received four stories in total. Across 21 sessions, researchers displayed images representing when, where, who, and what as a computerized voice narrated the stories. The same image of the celebrity was used both times, while the other three images—representing time, place, and action—varied between stories.
Precise Readings of Human Memory
The high-resolution electrode measurements allowed researchers to pinpoint which groups of hippocampal neurons activated and how they behaved as participants absorbed the stories. The team made a striking discovery: seeing an image of a person and hearing their name elicited the same neural response, regardless of the context in which they appeared.
Neanderthals
Later, when participants were asked to recall the stories in a random order, the same neurons activated just before they mentioned the person’s name—regardless of which story they were recalling. This suggests that information about individuals is stored independently of the context in which they were encountered.
Implications for Human Consciousness
“Memories are stored in a much more abstract manner in humans than other animals. You can think of concepts or anything else in more abstract terms, independent of the context in which you learned them,” explained Quian Quiroga.
“This ability allows us to make much more abstract and complex associations and inferences than if we were forced to think of each concept within a specific, concrete context,” he concluded.
The paper, “Lack of Context Modulation in Human Single Neuron Responses in the Medial Temporal Lobe” appeared on March 12, 2025, in Cell Reports.
Ryan Whalen covers science and technology for The Debrief. He holds an MA in History and a Master of Library and Information Science with a certificate in Data Science. He can be contacted atryan@thedebrief.org, and follow him on Twitter@mdntwvlf.