Protopapa, F. | Search bioRxiv

bioRxiv2020

Topographic Connectivity in a Duration Selective Cortico-Cerebellar Network

How does the human brain represent millisecond unit of time? A recent neuroimaging study revealed the existence in the human premotor cortex of a topographic representation of time i.e., neuronal units selectively responsive to specific durations and topographically organized on the cortical surface. By using high resolution functional Magnetic Resonance Images here, we go futher this previous work, showing duration preferences across a wide network of cortical and subcortical brain areas: from cerebellum to primary visual, parietal, premotor and prefrontal cortices. Most importantly, we identify the functional connectivity structure between these different brain areas and their duration selective neural units. The results highlight the role of the cerebellum as the network hub and that of medial premotor cortex as the final stage of duration recognition. Interstingly, when a specific duration is presented, only the communication between the units selective to that duration become particularly "active". These findings identify duration tuning and topographic connectivity as possible mechanisms underlying our capacity of telling time.

neuroscience↗

bioRxiv2018

Chronotopic Maps in Human Medial Premotor Cortex

Time is a fundamental dimension of everyday experiences. We can unmistakably sense its passage and adjust our behavior accordingly. Despite its ubiquity, the neuronal mechanisms underlying the capacity to perceive time remains unclear. Here, in two experiments using ultra-high-field 7-Tesla functional magnetic resonance imaging, we show that in the medial premotor cortex of the human brain, neural units tuned to different durations are orderly mapped in contiguous portions of the cortical surface, so as to form chronomaps. The response of each portion in a chronomap is enhanced by preferred and neighboring durations and suppressed by non-preferred durations represented in distant portions of the map. These findings identify duration-sensitive tuning as a neural mechanism underlying the recognition of time and demonstrate for the first time that the representation of an abstract feature such as time can be instantiated by a topographical arrangement of duration-sensitive neural populations.

neuroscience↗