Biology subjects

Lunghi, C.

Publications and source records attributed to Lunghi, C..

8 recordsLinked to original sources

bioRxiv2024

The environmental impact of pharmaceuticals: an evidence-mapping review of recent data on aquatic concentrations and predictable effects

Pharmaceuticals are recognised among emerging contaminants, particularly in water. They have the potential to alter ecosystem dynamics, with notable examples including hormone-induced feminization of male fish and disruptions to oogenesis in invertebrates. To assess the risk posed by pharmaceuticals, it is essential to understand their amount (via Measured Environmental Concentrations - MEC) and their actual effects on target species (via Predicted No Effect Concentrations - PNEC). Recently, many studies have aimed to collect MEC data from around the world, but a comprehensive overview is still lacking. Thus, the objective of this study is to provide a comprehensive overview by examining recently published literature on MEC data for a wide range of pharmaceuticals. Additionally, to enable risk assessment, this study also reviewed the published literature on PNEC data and integrated it with existing databases. A total of 315 substances were selected for MEC data extraction, with the inclusion of 56 articles. The most frequently monitored locations were Cadiz Bay in Spain (90 samples), the River Thames in the UK (51), and Hrd[e]jovice in the Czech Republic (49). Most MEC samples were collected from surface water (N=325), influent wastewater treatment plants (WWTP) (205), and effluent WWTP (118). Based on PNEC values, risk analysis identified 81 pharmaceuticals as high-risk, with the highest risk values for propranolol (risk quotient [RQ]: 29,450,000), diclofenac (395,920), and 17alpha-ethinylestradiol (95,946). Additionally, the ATC classes with the most high-risk substances were anti-infectives (J), nervous system agents (N), cardiovascular agents (C), antineoplastic agents (L), analgesics (M), and sex hormones (G). The findings of this study highlight the widespread impact of pharmaceuticals across the globe and the involvement of multiple therapeutic classes. To move beyond the current point-in-time overview, which is limited to specific locations and sampling periods, systems for continuous monitoring of pharmaceuticals should be developed. This could involve the creation of resource-efficient methods and the integration of sampling data with estimation models. Furthermore, these results could serve as a starting point for developing and implementing actions to prevent and mitigate the environmental impact of pharmaceuticals.

ecology↗

bioRxiv2022

Motor and Visual Plasticity Interact in Adult Humans

Neuroplasticity is maximal during development and declines in adulthood, especially for sensory cortices. On the contrary, the motor cortex retains plasticity throughout the lifespan. This difference has led to a modular view of plasticity in which different brain regions have their own plasticity mechanisms that do not depend or translate on others. Recent evidence indicates that visual and motor plasticity share common neural mechanisms (e.g. GABAergic inhibition), indicating a possible link between these different forms of plasticity, however the interaction between visual and motor plasticity has never been tested directly. Here we show that when visual and motor plasticity are elicited at the same time in adult humans, visual plasticity is impaired, while motor plasticity is spared. This unilateral interaction between visual and motor plasticity demonstrates a clear link between these two forms of plasticity. We conclude that local neuroplasticity in separate systems might be regulated globally, to preserve overall homeostasis in the brain.

neuroscience↗

bioRxiv2021

Short-term plasticity in the visual thalamus

While there is evidence that the visual cortex retains a potential for plasticity in adulthood, less is known about the subcortical stages of visual processing. Here we asked whether short-term ocular dominance plasticity affects the visual thalamus. We addressed this question in normally sighted adult humans, using ultra-high field (7T) magnetic resonance imaging combined with the paradigm of short-term monocular deprivation. With this approach, we previously demonstrated transient shifts of perceptual eye dominance and ocular dominance in visual cortex (Binda et al., 2018). Here we report evidence for short-term plasticity in the ventral division of the pulvinar (vPulv), where the deprived eye representation was enhanced over the non-deprived eye. This pulvinar plasticity effect was similar as previously seen in visual cortex and it was correlated with the ocular dominance shift measured behaviorally. In contrast, there was no short-term plasticity effect in Lateral Geniculate Nucleus (LGN), where results were reliably different from vPulv, despite their spatial proximity. We conclude that the visual thalamus retains potential for short-term plasticity in adulthood; the plasticity effect differs across thalamic subregions, possibly reflecting differences in their cortical connectivity.

neuroscience↗

bioRxiv2021

Attention cueing in rivalry: insights from pupillometry

We used pupillometry to evaluate the effects of attention cueing on perceptual bi-stability, as reported by adult human observers. Perceptual alternations and pupil diameter were measured during two forms of rivalry, generated by presenting a white and a black disk to the two eyes (binocular rivalry) or splitting the disks between eyes (interocular grouping rivalry). In line with previous studies, we found that subtle pupil size oscillations (about 0.05 mm) tracked alternations between exclusive dominance phases of the black or white disk. These oscillations were larger for perceptually stronger stimuli: presented to the dominant eye or with physically higher luminance contrast. However, cueing of endogenous attention to one of the rivaling percepts did not affect pupil oscillations during exclusive dominance phases. This was in spite of the reliable effects of endogenous attention on perceptual dominance, which shifted in favor of the cued percept by about 10%. The results were comparable for binocular and interocular grouping rivalry. Cueing only had a marginal modulatory effect on pupil size during mixed percepts in binocular rivalry. This may suggest that, rather than acting by modulating perceptual strength, endogenous attention primarily acts during periods of unresolved competition, which is compatible with attention being automatically directed to the rivaling stimuli during periods of exclusive dominance and thereby sustaining perceptual alternations. Significance StatementBinocular rivalry depends on attention. When it is diverted away from the stimuli, perceptual alternations slow down; when it is preferentially directed to one stimulus, perception lingers more on it, consistent with attention enhancing the effective strength of the rivaling stimuli. Here we introduce pupillometry as a means to indirectly track changes in effective stimulus strength. We find that pupil size oscillates, accurately tracking perceived luminance during two forms of rivalry: binocular rivalry and interocular grouping rivalry. Both show robust effects of attention cueing on perceptual dominance, but pupil oscillations during exclusive dominance are unaffected by cueing. This suggests that endogenous attention does not affect perceptual strength during exclusive dominance, though it might do so during transition phases.

neuroscience↗

bioRxiv2021

Sleep Slow Oscillations and Spindles encode ocular dominance plasticity and promote its consolidation in adult humans

Sleep and plasticity are highly interrelated, as sleep slow oscillations and sleep spindles are associated with consolidation of Hebbian-based processes. However, in adult humans, visual cortical plasticity is mainly sustained by homeostatic mechanisms, for which the role of sleep is still largely unknown. Here we demonstrate that non-REM sleep stabilizes homeostatic plasticity of ocular dominance induced in adult humans by short-term monocular deprivation: the counter intuitive and otherwise transient boost of the deprived eye was preserved at the morning awakening (>6 hours after deprivation). Subjects exhibiting a stronger boost of the deprived eye after sleep had increased sleep spindle density in frontopolar electrodes, suggesting the involvement of distributed processes. Crucially, the individual susceptibility to visual homeostatic plasticity soon after deprivation correlated with the changes in sleep slow oscillations and spindle power in occipital sites, consistent with a modulation in early occipital visual cortex.

neuroscience↗

bioRxiv2020

GABAergic inhibition in the human visual cortex relates to eye dominance

Our binocular world is seamlessly assembled from two retinal images that remain segregated until the cerebral cortex. Despite the coherence of this input, there is often an imbalance between the strength of these connections in the brain. Eye dominance provides a measure of the perceptual dominance of one eye over the other. Theoretical models suggest that eye dominance is related to reciprocal inhibition between monocular units in the primary visual cortex, the first location where the binocular input is combined. As the specific inhibitory interactions in the binocular visual system critically depend on the presence of visual input, we sought to test the role of inhibition by measuring the concentrations of inhibitory (GABA) neurotransmitters during monocular visual stimulation of the dominant and the non-dominant eye. GABA-levels were acquired in V1 using a combined functional magnetic resonance imaging (fMRI) and magnetic resonance spectroscopy (MRS) sequence on a 7-Tesla MRI scanner. Individuals with stronger eye dominance had a greater difference in GABAergic inhibition between the eyes. This relationship was present only when the visual system was actively processing sensory input and was not present at rest. We provide the first evidence that imbalances in GABA levels during ongoing sensory processing are related to eye dominance in the human visual cortex. This provides strong support to the view that intracortical inhibition underlies normal eye dominance. SIGNIFICANCE STATEMENTWhat we see is shaped by excitation and inhibition in our brain. We investigated how eye dominance, the perceptual preference of one eyes input over the other, is related to levels of inhibitory neurotransmitter GABA during monocular visual stimulation. GABAergic inhibition is related to eye dominance, but only when the visual system is actively processing sensory input. This provides key support for the view that imbalances in visual competition that are observed in the normal visual system arise from an inability of GABA signalling to suppress the stronger sensory representation.

neuroscience↗

bioRxiv2018

A new counter-intuitive therapy for adult amblyopia

Visual cortex plasticity is high during a critical period of early postnatal development, but rapidly diminishes with the transition to adulthood. Accordingly, visual disorders such as amblyopia (lazy eye), can be treated early in life by long-term occlusion of the non-amblyopic eye, but may become irreversible in adults, because of the decline in brain plasticity. Here we show that a novel counter-intuitive approach can promote the recovery of visual function in adult amblyopic patients: short-term occlusion of the amblyopic (not the fellow) eye, combined with physical exercise (cycling). After six brief (2h) training sessions, visual acuity improved in all ten patients (0.15{+/-}0.02 LogMar), and six of them also recovered stereopsis. The improvement was preserved for up to one year after training. A control experiment revealed that physical activity was crucial for the recovery of visual acuity and stereopsis. Thus, we propose a non-invasive therapeutic strategy for adult human amblyopia based an inverse-occlusion and physical exercise procedure.

neuroscience↗

bioRxiv2018

Short-term plasticity of 7T BOLD ocular dominance and spatial frequency representation in adult human primary visual cortex

Visual cortex, particularly V1, is considered to be resilient to plastic changes in adults. In particular, ocular dominance is assumed to be hard-wired after the end of the critical period. We show that short-term (2h) monocular deprivation in adult humans boosts the BOLD response to the deprived eye, changing ocular dominance of V1 vertices, consistently with homeostatic plasticity. The boost is strongest in V1, present in V2, V3 & V4 but absent in V3a and MT. Assessment of spatial frequency tuning in V1 by a population Receptive-Field technique shows that deprivation primarily boosts high spatial frequencies, consistent with a primary involvement of the parvocellular pathway. Crucially, the V1 deprivation effect correlates across participants with the perceptual increase of the deprived eye dominance assessed with binocular rivalry, suggesting a common origin. Our results demonstrate that visual cortex, particularly the ventral pathway, retains a high potential for homeostatic plasticity in the human adult.

neuroscience↗