Imagine a swarm of fireflies, flickering lights on and off in the nighttime space. How does the human brain process and integrate information about duration and spatial position enabling this vision? This was the question addressed by Valeria Centanino, Gianfranco Fortunato, and Domenica Bueti from SISSA’s Cognitive Neuroscience group in their research published in Nature Communications.
The study highlights the existence of a functional hierarchy in the human cerebral cortex, where posterior areas—those that first receive visual information—process space and time together. In contrast, in parietal areas and even more so in frontal areas, engaged later in information processing, space and time gradually separate.
Moreover, the way time is encoded differs across these brain regions. In the occipital areas, where space and time are processed together, time is encoded in the activity of the same neural population, which becomes proportionally more active the longer the duration. In parietal and frontal areas, instead, where the link between space and time becomes progressively weaker and eventually disappears, time is encoded by distinct neural populations, each of them responding selectively to specific durations. In the parietal areas, in an intermediate position of this hierarchy, there is a coexistence of duration coding mechanisms and time and space are either processed toghether or independently.