"When is "now"? What mental representations and neural computations mediate the construction of our perceived present? If seeing starts through the retinal transduction of photons, there is no dedicated sensory receptor for the transduction of time per se; as such, time perception offers a particularly challenging problem to our understanding of human cognition. Indeed, time is a prime example of perceptual construct shaped by the anatomical and dynamical constraints of the nervous system. To clarify the principles and the mental operations underlying time perception, this research proposal focuses on a novel theoretical framework for the understanding of how the human mind affords the temporal experience of ""now"". The empirical work proposed here narrows down the problem to three specific questions which are addressed using psychophysical measures combined with sophisticated brain imaging methods that have excellent temporal resolution, namely magneto- and electro-encephalography (thereafter referred to as MEEG). (i) The first empirical question asks whether our perceptual present reflects the objective present, future or the objective past. Said differently, is the perceived present slightly off with respect to the objective reality? And if so, does it reflect predictive and/or postdictive brain mechanisms? (ii) The second question focuses on the representation of time in the brain. All senses provide latent means to encode temporal information and brain dynamics are likely to convey the raw material for time perception in an amodal form (i.e. independent of sensory modality). The passage from neural dynamics to perceptual abstraction of time is not trivial considering, for instance, the inherent asynchronies of neural processing times. This experiment tests the perception of duration within and across sensory modalities to systematically derive the perceptual resolution afforded by our sense of time. (iii) The third question focuses on tracking the construction of ""now"" by using an illusion resulting from the transformation of veridical temporal properties of events into an explicit temporal construct. An ambitious challenge in this experiment will be to develop a brain classifying/decoding technique using MEEG signals to track the evolution from the veridical encoding of temporal properties to the construction of the illusory percept of time. The goal of this research proposal is to provide a novel approach to the study of time perception. Extension of this work will pave the way to a better understanding of what distinguishes temporal processing impairments from explicit time perception impairments in clinical disorders."

Researcher : Virginie van Wassenhove

Contact :  virginie.van-wassenhove@cea.fr

agreement id : 263584