Periodic Reporting for period 2 - HOPLA (Homeostatic Plasticity beyond the critical period)
Reporting period: 2022-11-01 to 2024-04-30
Neuroplasticity is the intrinsic capability of the central nervous system to change in structure or function in response to environmental pressures. This property is fundamental during development to fine-tune our nervous system to the characteristics of the external environment, and throughout life to enable cognition, learning and memory. Plasticity is maximal early during development, and decreases with age at different rates in different brain areas: sensory cortices are thought to lose their plastic potential, whereas higher level brain areas (responsible for learning, memory and cognitive functions) maintain higher plastic potential throughout the lifespan. The classical view is that the sensory brain becomes hard-wired after the temporal window of maximal plasticity called critical period (6-7 years in humans). As a consequence, the ability of our sensory brain to react to injury, sensory loss and to recover from conditions established during development becomes limited in adulthood. Understanding the neural mechanisms underlying visual cortical plasticity is fundamental to develop novel therapeutic strategies in the field of neuro-rehabilitation past the critical period.
Recent findings showed that particular form of neuroplasticity called homeostatic plasticity is relatively preserved beyond the critical period, opening new horizons on adult sensory plasticity. Building on these observations, the objectives of project HOPLA are to unravel the multifaceted nature of sensory neuroplasticity in adult humans, to elucidate the underlying mechanisms and to explore new forms of plasticity. To address these issue, classic behavioural measurements of visual and auditory perception are combined with state-of-the-art neuroimaging techniques and virtual reality environments both in healthy and clinical populations (amblyopic and deaf adults).
Recent findings showed that particular form of neuroplasticity called homeostatic plasticity is relatively preserved beyond the critical period, opening new horizons on adult sensory plasticity. Building on these observations, the objectives of project HOPLA are to unravel the multifaceted nature of sensory neuroplasticity in adult humans, to elucidate the underlying mechanisms and to explore new forms of plasticity. To address these issue, classic behavioural measurements of visual and auditory perception are combined with state-of-the-art neuroimaging techniques and virtual reality environments both in healthy and clinical populations (amblyopic and deaf adults).
During the first half of the project, combining behavioral and neuroimaging techniques, we were able to study different aspects of adult visual plasticity in adult human volunteers. These include: the mutual influence between visual plasticity and non-REM sleep, the interaction between different forms of plasticity (visual plasticity, working memory and motor plasticity) and the interaction between Hebbian and homeostatic plasticity. We also performed important work on establishing the reliability of our techniques in estimating the effect of visual plasticity, which is essential to validate the results of the project.
A lot of effort has finally been put in establishing the international collaborations to perform the ambitious experiments planned for the second half of the project.
The work performed during the first half of the project has been reported in 7 peer-reviewed publications, five flourishing from the project, and two closely related to the project objectives. Our research on the interaction between different forms of plasticity indicates for the first time the existence of a global regulation mechanism for plasticity in the brain, acting across different systems and aimed at preventing excessive instability. The resulting publication has been selected by the editors of the journal as noteworthy for the scientific community, and has been promoted as featured research by the Society of Neuroscience. The results have been disseminated at the major scientific conferences, including the Society for Neuroscience annual meeting, the European Conference of Visual Perception and the Vision Science Society annual meeting. We also organized a scientific workshop at the beginning of the project to disseminate the objective of the project to the community and to gather external collaborators.
A lot of effort has finally been put in establishing the international collaborations to perform the ambitious experiments planned for the second half of the project.
The work performed during the first half of the project has been reported in 7 peer-reviewed publications, five flourishing from the project, and two closely related to the project objectives. Our research on the interaction between different forms of plasticity indicates for the first time the existence of a global regulation mechanism for plasticity in the brain, acting across different systems and aimed at preventing excessive instability. The resulting publication has been selected by the editors of the journal as noteworthy for the scientific community, and has been promoted as featured research by the Society of Neuroscience. The results have been disseminated at the major scientific conferences, including the Society for Neuroscience annual meeting, the European Conference of Visual Perception and the Vision Science Society annual meeting. We also organized a scientific workshop at the beginning of the project to disseminate the objective of the project to the community and to gather external collaborators.
In the second part of the part of the project, which is the most ambitious, we will use state-of-the art neuroimaging techniques (fMRI and Magnetic Resonance Spectroscopy at Ultra-High fields, functional Ultra Sound imaging and EEG), combined with behavioral measurements to investigate the fine neural mechanisms underlying adult visual homeostatic plasticity in typical and clinical populations. We will put a particular emphasis on the role of the balance between excitation and inhibition in the visual cortex for the potentiation of plasticity in patients with amblyopia. We will also use a virtual reality environment to investigate new forms of plasticity in adult humans, with potential clinical applications for neurorehabilitation.