Scientists across various fields agree on one thing: the human brain, weighing an average of 1,350 grams, is the most complex object known in the universe. This 'warm porridge' of neurons continuously provides us with an internal representation of the external world, navigating both space and time.
Since the cognitive revolution of the late 1950s, significant breakthroughs have been made regarding spatial perception. In 1948, psychologist Edward Tolman proposed the existence of a 'cognitive map' in the hippocampus, a brain structure crucial for memory and navigation. By the early 1970s, neuroscientist John O'Keefe identified 'place cells' in the hippocampus, which activate only when an animal is in a specific location, indicating a mental representation of space.
These discoveries earned O'Keefe, alongside Norwegian neuroscientists May-Britt and Edvard Moser, the Nobel Prize in Physiology or Medicine in 2014.
However, the understanding of time remains elusive. The 'Chronology' project, led by researchers Virginie van Wassenhove (CEA), Brice Bathellier (CNRS), Srdjan Ostojic (ENS), and Mehrdad Jazayeri (MIT), aims to explore how the brain represents time. Funded with €10 million from the European Research Council, the project will begin next year and will take several years to yield results.
The researchers aim to discover whether the brain uses a cognitive map for temporal navigation similar to that used for spatial navigation. Van Wassenhove explains, 'We seek to test the hypothesis that the brain constructs a cognitive map for representing the elusive fourth dimension.'
Interestingly, while cognitive psychology confirms that spatial navigation relies on visual perception, the sensory equivalent for our perception of time remains unclear. Additionally, humans uniquely possess the ability to 'travel' through time, envisioning future scenarios, unlike other conscious beings.
In 2021, a Franco-Dutch team published findings in the 'Journal of Neuroscience,' revealing 'time cells' in the human hippocampus, which activate sequentially to encode the order of events. This suggests that even in the absence of external stimuli, these neurons can represent the passage of time based solely on internal experiences.
As Emily Dickinson wrote, the brain is indeed 'greater than the sky'; despite its size, our understanding of it is still far from complete.