Novel functional imaging approaches for investigating brain plasticity in multiple sclerosis and Parkinson\u2019s disease: from research to clinical applications

Neuronal plasticity, as the capacity of the brain to respond to external demands or to injury, has emerged as a crucial mechanism to preserve, at least in part, an adequate behavioral functioning after an injury and as the process underlying improvements in disability during rehabilitation. Brain plasticity can be detected with both structural and functional magnetic resonance imaging and more and more processing techniques have been developed to better capture the occurring changes and to better define the potential plasticity. Gait and balance are affected in patients with multiple sclerosis since the early stages of the disease with sensory deficits playing a major role in determining both balance and gait impairment. Moreover, gait disorders are one of the major causes of disability in patients with Parkinson\u2019s disease, in particular if suffering from freezing of gait. With this work we aimed at i) investigating the functional reorganization occurring in multiple sclerosis at both early and late stages of the disease, ii) characterizing the functional pattern underlying sensory impairment in patients with early multiple sclerosis and iii) verifying the neural correlates of action observation of gait in patients with Parkinson\u2019s disease. These different studies fit into a larger framework where neuroimaging techniques, in particular functional imaging, would support the clinicians in identifying tailored rehabilitation treatments and the patients who would better benefit from them. We found that patients with early multiple sclerosis showed a higher brain functional flexibility, expressed in terms of blood oxygen level dependent signal variability, which correlated to clinical disability, representing a possible compensatory mechanism. In patients with early multiple sclerosis we also observed subtle position sense deficits, not detectable with a standard neurological examination, and which affected still standing balance. Moreover, these deficits were related to a structural damage at the level of the corpus callosum and to functional activity patterns mainly involving the frontoparietal regions. On the contrary, patients with multiple sclerosis at the progressive stages presented with more subtle changes in the resting state functional connectivity which, nonetheless, were related to clinical disability. Lastly, the presence of freezing of gait in patients with Parkinson disease influenced the neural activation underpinning the action observation of walking. Altogether, these results offer an better insight into the pathophysiological mechanisms underlying disability in patients with multiple sclerosis and constitute a groundwork for the enhancement of rehabilitation protocols to improve gait and balance in both multiple sclerosis and Parkinson\u2019s disease, supporting the embracing of new strategies such as sensory integration and action observation training

Cerebellum and neurodegenerative diseases: Beyond conventional magnetic resonance imaging

The cerebellum plays a key role in movement control and in cognition and cerebellar involvement is described in several neurodegenerative diseases. While conventional magnetic resonance imaging (MRI) is widely used for brain and cerebellar morphologic evaluation, advanced MRI techniques allow the investigation of cerebellar microstructural and functional characteristics. Volumetry, voxel-based morphometry, diffusion MRI based fiber tractography, resting state and task related functional MRI, perfusion, and proton MR spectroscopy are among the most common techniques applied to the study of cerebellum. In the present review, after providing a brief description of each technique's advantages and limitations, we focus on their application to the study of cerebellar injury in major neurodegenerative diseases, such as multiple sclerosis, Parkinson's and Alzheimer's disease and hereditary ataxia. A brief introduction to the pathological substrate of cerebellar involvement is provided for each disease, followed by the review of MRI studies exploring structural and functional cerebellar abnormalities and by a discussion of the clinical relevance of MRI measures of cerebellar damage in terms of both clinical status and cognitive performance

Motor imagery as a function of disease severity in multiple sclerosis: An fMRI study

Motor imagery (MI) is defined as mental execution without any actual movement. While healthy adults usually show temporal equivalence, i.e., isochrony, between the mental simulation of an action and its actual performance, neurological disorders are associated with anisochrony. Unlike in patients with stroke and Parkinson disease, only a few studies have investigated differences of MI ability in multiple sclerosis (MS). However, the relationship among disease severity, anisochrony and brain activation patterns during MI has not been investigated yet. Here, we propose to investigate MI in MS patients using fMRI during a behavioral task executed with dominant/non-dominant hand and to evaluate whether anisochrony is associated with disease severity. Thirty-seven right-handed MS patients, 17 with clinically isolated syndrome (CIS) suggestive of MS and 20 with relapsing-remitting MS (RR-MS) and 20 right-handed healthy controls (HC) underwent fMRI during a motor task consisting in the actual or imaged movement of squeezing a foam ball with the dominant and non-dominant hand. The same tasks were performed outside the MRI room to record the number of actual and imagined ball squeezes, and calculate an Index of performance (IP) based on the ratio between actual and imagined movements. IP showed that a progressive loss of ability in simulating actions (i.e., anisochrony) more pronounced for non-dominant hand, was found as function of the disease course. Moreover, anisochrony was associated with activation of occipito-parieto-frontal areas that were more extensive at the early stages of the disease, probably in order to counteract the changes due to MS. However, the neural engagement of compensatory brain areas becomes more difficult with more challenging tasks, i.e., dominant vs. non-dominant hand, with a consequent deficit in behavioral performance. These results show a strict association between MI performance and disease severity, suggesting that, at early stages of the disease, anisochrony in MI could be considered as surrogate behavioral marker of MS severity

Relationship between retinal inner nuclear layer, age, and disease activity in progressive MS

ObjectiveTo investigate whether inner nuclear layer (INL) thickness as assessed with optical coherence tomography differs between patients with progressive MS (P-MS) according to age and disease activity.MethodsIn this retrospective longitudinal analysis, differences in terms of peripapillary retinal nerve fiber layer (pRNFL), ganglion cell layer + inner plexiform layer (GCIPL), INL and T1/T2 lesion volumes (T1LV/T2LV) were assessed between 84 patients with P-MS and 36 sex- and age-matched healthy controls (HCs) and between patients stratified according to age (cut-off: 51 years) and evidence of clinical/MRI activity in the previous 12 monthsResultspRNFL and GCIPL thickness were significantly lower in patients with P-MS than in HCs (p = 0.003 and p < 0.0001, respectively). INL was significantly thicker in patients aged < 51 years compared to the older ones and HCs (38.2 vs 36.5 and 36.7 m; p = 0.038 and p = 0.04, respectively) and in those who presented MRI activity (new T2/gadolinium-enhancing lesions) in the previous 12 months compared to the ones who did not and HCs (39.5 vs 36.4 and 36.7 m; p = 0.003 and p = 0.008, respectively). Recent MRI activity was significantly predicted by greater INL thickness (Nagelkerke R2 0.36, p = 0.001).ConclusionsINL thickness was higher in younger patients with P-MS with recent MRI activity, a criterion used in previous studies to identify a specific subset of patients with P-MS who best responded to disease-modifying treatment. If this finding is confirmed, we suggest that INL thickness might be a useful tool in stratification of patients with P-MS for current and experimental treatment choic

Evidence for heavy fuel oil combustion aerosols from chemical analyses at the island of Lampedusa: a possible large role of ships emissions in the Mediterranean

Measurements of aerosol chemical composition made on the island of Lampedusa, south of the Sicily channel, during years 2004–2008, are used to identify the influence of heavy fuel oil (HFO) combustion emissions on aerosol particles in the Central Mediterranean. Aerosol samples influenced by HFO are characterized by elevated Ni and V soluble fraction (about 80% for aerosol from HFO combustion, versus about 40% for crustal particles), high V and Ni to Si ratios, and values of V<sub>sol</sub>>6 ng m<sup>−3</sup>. Evidence of HFO combustion influence is found in 17% of the daily samples. Back trajectories analysis on the selected events show that air masses prevalently come from the Sicily channel region, where an intense ship traffic occurs. This behavior suggests that single fixed sources like refineries are not the main responsible for the elevated V and Ni events, which are probably mainly due to ships emissions. <br><br> V<sub>sol</sub>, Ni<sub>sol</sub>, and non-sea salt SO<sub>4</sub><sup>2−</sup> (nssSO<sub>4</sub><sup>2−</sup>) show a marked seasonal behaviour, with an evident summer maximum. Such a pattern can be explained by several processes: (i) increased photochemical activity in summer, leading to a faster production of secondary aerosols, mainly nssSO<sub>4</sub><sup>2−</sup>, from the oxidation of SO<sub>2</sub> (ii) stronger marine boundary layer (MBL) stability in summer, leading to higher concentration of emitted compounds in the lowest atmospheric layers. A very intense event in spring 2008 was studied in detail, also using size segregated chemical measurements. These data show that elements arising from heavy oil combustion (V, Ni, Al, Fe) are distributed in the sub-micrometric fraction of the aerosol, and the metals are present as free metals, carbonates, oxides hydrates or labile complex with organic ligands, so that they are dissolved in mild condition (HNO<sub>3</sub>, pH1.5). <br><br> Data suggest a characteristic nssSO<sub>4</sub><sup>2−</sup>/V ratio in the range 200–400 for HFO combustion aerosols in summer at Lampedusa. By using the value of 200 a lower limit for the HFO contribution to total sulphates is estimated. HFO combustion emissions account, as a summer average, at least for 1.2 μg m<sup>−3</sup>, representing about 30% of the total nssSO<sub>4</sub><sup>2−</sup>, 3.9% of PM<sub>10</sub>, 8% of PM<sub>2.5</sub>, and 11% of PM<sub>1</sub>. Within the used dataset, sulphate from HFO combustion emissions reached the peak value of 6.1 μg m<sup>−3</sup> on 26 June 2008, when it contributed by 47% to nssSO<sub>4</sub><sup>2−</sup>, and by 15% to PM<sub>10</sub>

Characterization of PM10 sources in the central Mediterranean

The Mediterranean Basin atmosphere is influenced by both strong natural and anthropogenic aerosol emissions and is also subject to important climatic forcings. Several programs have addressed the study of the Mediterranean basin; nevertheless important pieces of information are still missing. In this framework, PM10 samples were collected on a daily basis on the island of Lampedusa (35.5° N, 12.6° E; 45 m a.s.l.), which is far from continental pollution sources (the nearest coast, in Tunisia, is more than 100 km away). After mass gravimetric measurements, different portions of the samples were analyzed to determine the ionic content by ion chromatography (IC), the soluble metals by inductively coupled plasma atomic emission spectrometry (ICP-AES), and the total (soluble + insoluble) elemental composition by particle-induced x-ray emission (PIXE). Data from 2007 and 2008 are used in this study. The Positive Matrix Factorization (PMF) model was applied to the 2-year long data set of PM10 mass concentration and chemical composition to assess the aerosol sources affecting the central Mediterranean basin. Seven sources were resolved: sea salt, mineral dust, biogenic emissions, primary particulate ship emissions, secondary sulfate, secondary nitrate, and combustion emissions. Source contributions to the total PM10 mass were estimated to be about 40 % for sea salt, around 25 % for mineral dust, 10 % each for secondary nitrate and secondary sulfate, and 5 % each for primary particulate ship emissions, biogenic emissions, and combustion emissions. Large variations in absolute and relative contributions are found and appear to depend on the season and on transport episodes. In addition, the secondary sulfate due to ship emissions was estimated and found to contribute by about one-third to the total sulfate mass. Results for the sea-salt and mineral dust sources were compared with estimates of the same contributions obtained from independent approaches, leading to an estimate of the water content bound to the sea salt in the marine source

Constraining the ship contribution to the aerosol of the Central Mediterranean

Abstract. Particulate matter with aerodynamic diameters lower than 10 µm, (PM10) aerosol samples were collected during summer 2013 within the framework of the Chemistry and Aerosol Mediterranean Experiment (ChArMEx) at two sites located north (Capo Granitola) and south (Lampedusa Island), respectively, of the main Mediterranean shipping route in the Straight of Sicily. The PM10 samples were collected with 12 h time resolutions at both sites. Selected metals, main anions, cations and elemental and organic carbon were determined. The evolution of soluble V and Ni concentrations (typical markers of heavy fuel oil combustion) was related to meteorology and ship traffic intensity in the Straight of Sicily, using a high-resolution regional model for calculation of back trajectories. Elevated concentration of V and Ni at Capo Granitola and Lampedusa are found to correspond with air masses from the Straight of Sicily and coincidences between trajectories and positions of large ships; the vertical structure of the planetary boundary layer also appears to play a role, with high V values associated with strong inversions and a stable boundary layer. The V concentration was generally lower at Lampedusa than at Capo Granitola V, where it reached a peak value of 40 ng m−3. Concentrations of rare earth elements (REEs), La and Ce in particular, were used to identify possible contributions from refineries, whose emissions are also characterized by elevated V and Ni amounts; refinery emissions are expected to display high La ∕ Ce and La ∕ V ratios due to the use of La in the fluid catalytic converter systems. In general, low La ∕ Ce and La ∕ V ratios were observed in the PM samples. The combination of the analyses based on chemical markers, air mass trajectories and ship routes allows us to unambiguously identify the large role of the ship source in the Straight of Sicily. Based on the sampled aerosols, ratios of the main aerosol species arising from ship emission with respect to V were estimated with the aim of deriving a lower limit for the total ship contribution to PM10. The estimated minimum ship emission contributions to PM10 were 2.0 µg m−3 at Lampedusa and 3.0 µg m−3 at Capo Granitola, corresponding with 11 and 8.6 % of PM10, respectively

roots§routes - research on visual culture

Ogni numero di roots§routes ha un filo conduttore in base al quale vengono chiesti dei contributi a diversi ricercatori, teorici e artisti. Come redattore mi sono occupata insieme al resto del team della selezione dei contributi e del loro editing seguendone tutto il processo fino alla pubblicazione. Ho curato la strategia di social media management per la promozione della rivista tramite i canali facebook e twitter sia dal punto di vista progettuale che esecutivo producendo e selezionando i contenuti audiovisivi a corredo degli articoli