Periodic Reporting for period 2 - TIMECODE (How does the brain code time?)
Período documentado: 2022-03-01 hasta 2023-08-31
Does the brain have an internal clock? How come “a watched pot never boils?” Time perception is a distinct area of study that attempts to characterize what exactly it means to perceive the passage of time, and how our sensory and motor systems alter our perception of elapsed time. Although numerous studies have addressed this enigmatic topic, our understanding of how timing is coded in the brain remains relatively limited, and we still do not know of a single organ or part of the brain that serves as an “internal clock.” The EU-funded TIMECODE project takes a holistic approach based on the hypothesis that time perception integrates local and global representations of timing by means of coordinated rhythmic activity. In other words, our subjective experience of time results from a shared effort between sensory cortices engaged in perceptual processing and a brain-wide “central clock.” The hypothesized interaction between these two brain areas is putatively driven by synchronized neural oscillations. Combining behavioral and physiological studies of human and non-human primates, together with computational tools, the team plans to shed light on the underlying neural substrates and the resulting cognitive perception of timing in the brain.
Despite the ubiquity of time in our daily lives and activities, our understanding of the neural mechanisms enabling us to measure time duration is very limited. We measured the electrical field produced by the brain as individuals performed a task in which they judged the duration of a visual or tactile event. Was the event short? Or did it seem long? We found a neural signature that reflects the elapsed time perceived by our participants as they made their temporal decisions. This finding provides a breakthrough in our ability to track the neural dynamics of interval timing, and gives insight into a cognitive process that is as elusive as it is basic to our daily experience. TIMECODE also investigates which aspects of motor production - from force exertion to complex movements - play an integral role in timing. For this, we have constructed a novel experimental platform that permits users to engage in full body interactions using a free-flowing range of movements.
One candidate brain area that might serve as a “central clock,” and which has previously been associated with timing, is the basal ganglia (BG). As part of TIMECODE, we will be measuring brain activity from the scalp in concert with measurements from within the brain, from the BG. Patients who suffer from Parkinson’s disease (as well as other neuropathologies) routinely have electrodes implanted to their BG. Such electrodes are designed to generate a therapeutic intervention but can also provide neural recordings from the site of implantation. We look forward to welcoming to our research program patients who volunteer to partake in our research on time perception. Through these measurements of BG activity, in concert with noninvasive scalp measurements, we hope to be able to shed light on the network dynamics that underlie time perception. We will also apply machine learning algorithms and other computational models to test whether individuals’ elapsed sense of time is represented in different brain regions.