Periodic Reporting for period 4 - PUPILTRAITS (Biomarkers of individual differences in human cortical visual processing)
Reporting period: 2023-09-01 to 2024-08-31
Perception is not a record of reality; it is best described as an inference, where incomplete sensory data is interpreted in the light of its spatiotemporal context. Since the context varies depending on the history of stimulation, our inferences often varies, both between and within individuals. Understanding how complex ideas like inference and context map onto the activity of neurons is one of the main goals of neuroscience. Understanding how these vary across persons could mark a key step towards characterising each person’s style of information processing – the first step towards communicating and interacting. And understanding whether and how information processing varies within individuals, time locked to metabolic changes, has the potential to elucidate the much-discussed links between brain and gut function. Project PUPILTRAITS addresses these questions using the visual system as a model, taking advantage of the in-depth physiological knowledge and the established methods for quantifying visual perception (psychophysics, and ultra-high field functional Magnetic Resonance) and combining them with an innovative technique, that tracks perceptual processing through variations of the diameter of our eye-pupils.
By taking advantage of the diverse expertise of the PUPILTRAITS team members, we were able to apply a variety of non-invasive techniques (pupillometry and eye-tracking, psychophysics, MRI, EEG) to the study of human participants of different ages and clinical profiles.
Using neuroimaging, we gained fundamental insight into the mechanisms through which sensory signals are evaluated against their context. Using neuroimaging and psychophysical techniques, we gathered evidence that the metabolic state (both in the long and short-term, as in obesity and overnight fasting) impacts fundamental functions of the visual system, including its plasticity. Using pupillometry, we were able to show a tight relationship between performance (specifically, the way contextual information influences perception) and Autistic Traits, supporting the notion that individual styles of information-processing can be indexed through pupil-size: a simple, objective, and quantitative measure. The area of applicability of this technique is rapidly growing, as we (and other teams) expose the normed relationship between changes in pupil diameter and information processing in the brain. We demonstrated this in a variety of domains: perception, attention, and cognition. And we applied this technique in both neurotypical individuals and in autistic children, marking a first step towards assessing the applicative potential of the pupillometric technique for clinical evaluations.
The work we performed has been reported in 43 peer-reviewed publications. Of these, 26 publications constitute the core of the project; 8 are in the top 25% most cited worldwide (hosted in generalist journals like Nature Communications, Current Biology and eLife) leading to a project H-index of 9. Our research was presented to the scientific community at the main international conferences of the field (including The Vision Sciences Society annual meeting, the European Conference of Visual Perception, International Society for Magnetic Resonance in Medicine). It was disseminated in public events (e.g. the Researchers’ Bright Night), communicated through several press-releases and a full article in the journal “eXL”, an outreach effort directed towards the industrial and commercial community. Moreover, I had the unique opportunity to showcase this research during the opening ceremony of the 2021-22 Academic Year of the University of Pisa, in the presence of the President of the Republic and the Ministry of University and Research.
Using neuroimaging, we gained fundamental insight into the mechanisms through which sensory signals are evaluated against their context. Using neuroimaging and psychophysical techniques, we gathered evidence that the metabolic state (both in the long and short-term, as in obesity and overnight fasting) impacts fundamental functions of the visual system, including its plasticity. Using pupillometry, we were able to show a tight relationship between performance (specifically, the way contextual information influences perception) and Autistic Traits, supporting the notion that individual styles of information-processing can be indexed through pupil-size: a simple, objective, and quantitative measure. The area of applicability of this technique is rapidly growing, as we (and other teams) expose the normed relationship between changes in pupil diameter and information processing in the brain. We demonstrated this in a variety of domains: perception, attention, and cognition. And we applied this technique in both neurotypical individuals and in autistic children, marking a first step towards assessing the applicative potential of the pupillometric technique for clinical evaluations.
The work we performed has been reported in 43 peer-reviewed publications. Of these, 26 publications constitute the core of the project; 8 are in the top 25% most cited worldwide (hosted in generalist journals like Nature Communications, Current Biology and eLife) leading to a project H-index of 9. Our research was presented to the scientific community at the main international conferences of the field (including The Vision Sciences Society annual meeting, the European Conference of Visual Perception, International Society for Magnetic Resonance in Medicine). It was disseminated in public events (e.g. the Researchers’ Bright Night), communicated through several press-releases and a full article in the journal “eXL”, an outreach effort directed towards the industrial and commercial community. Moreover, I had the unique opportunity to showcase this research during the opening ceremony of the 2021-22 Academic Year of the University of Pisa, in the presence of the President of the Republic and the Ministry of University and Research.
The project went beyond expectations for the number of its outputs and their impact on the scientific community. We have shown that visual perception reveals fundamental axes of variability within and across individuals. We have demonstrated that this variability affects visual processing since the earliest possible stage, when light enters the eye through the eye-pupil. This provides a strong foundation for using pupil-size measurements to make inferences on information processing and its idiosyncrasies, with strong clinical relevance particularly in the study of Autistic Spectrum Disorders.