The Neuromelanin-related T2* Contrast in Postmortem Human Substantia Nigra with 7T MRI

High field magnetic resonance imaging (MRI)-based delineation of the substantia nigra (SN) and visualization of its inner cellular organization are promising methods for the evaluation of morphological changes associated with neurodegenerative diseases; however, corresponding MR contrasts must be matched and validated with quantitative histological information. Slices from two postmortem SN samples were imaged with a 7 Tesla (7T) MRI with T1 and T2* imaging protocols and then stained with Perl???s Prussian blue, Kluver-Barrera, tyrosine hydroxylase, and calbindin immunohistochemistry in a serial manner. The association between T2* values and quantitative histology was investigated with a co-registration method that accounts for histology slice preparation. The ventral T2* hypointense layers between the SNr and the crus cerebri extended anteriorly to the posterior part of the crus cerebri, which demonstrates the difficulty with an MRI-based delineation of the SN. We found that the paramagnetic hypointense areas within the dorsolateral SN corresponded to clusters of neuromelanin (NM). These NM-rich zones were distinct from the hypointense ventromedial regions with high iron pigments. Nigral T2* imaging at 7T can reflect the density of NM-containing neurons as the metal-bound NM macromolecules may decrease T2* values and cause hypointense signalling in T2* imaging at 7T.ope

The still under-investigated role of cognitive deficits in PML diagnosis

Background: Despite cognitive deficits frequently represent the first clinical manifestations of Progressive Multifocal Leukoencephalopathy (PML) in Natalizumab-treated MS patients, the importance of cognitive deficits in PML diagnosis is still under-investigated. The aim of the current study is to investigate the cognitive deficits at PML diagnosis in a group of Italian patients with PML. Methods: Thirty-four PML patients were included in the study. The demographic and clinical data, the lesion load and localization, and the longitudinal clinical course was compared between patients with (n = 13) and without (n = 15) cognitive deficit upon PML suspicion (the remaining six patients were asymptomatic). Clinical presentation of cognitive symptoms was described in detail. Result: After symptoms detection, the time to diagnosis resulted to be shorter for patients presenting with cognitive than for patients with non cognitive onset (p = 0.03). Within patients with cognitive onset, six patients were presenting with language and/or reading difficulties (46.15%); five patients with memory difficulties (38.4%); three patients with apraxia (23.1%); two patients with disorientation (15.3%); two patients with neglect (15.3%); one patients with object agnosia (7.7%), one patient with perseveration (7.7%) and one patient with dementia (7.7%). Frontal lesions were less frequent (p = 0.03), whereas temporal lesions were slightly more frequent (p = 0.06) in patients with cognitive deficits. The longitudinal PML course seemed to be more severe in cognitive than in non cognitive patients (F = 2.73, p = 0.03), but differences disappeared (F = 1.24, p = 0.29) when balancing for the incidence of immune reconstitution syndrome and for other treatments for PML (steroids, plasma exchange (PLEX) and other therapies (Mefloquine, Mirtazapine, Maraviroc). Conclusion: Cognitive deficits at PML onset manifest with symptoms which are absolutely rare in MS. Their appearance in MS patients should strongly suggest PML. Clinicians should be sensitive to the importance of formal neuropsychological evaluation, with particular focus on executive function, which are not easily detected without a formal assessment

Diffusion tensor MRI of the corpus callosum in amyotrophic lateral sclerosis

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/106143/1/jmri24218.pd

Fenomenologia dell'improvvisazione musicale. La prospettiva del performer.

L\u2019improvvisazione musicale \ue8 una pratica che ha visto negli ultimi anni il fiorire di numerosi studi che tentano di indagarne le caratteristiche pi\uf9 importanti. L\u2019obiettivo di questo lavoro \ue8 descrivere le caratteristiche fenomenologiche dell\u2019atto improvvisativo dal punto di vista dell\u2019esecutore. In particolare, quali sono le caratteristiche strutturali del processo improvvisativo? Cosa s\u2019intende per nonlinearit\ue0 dell\u2019agire improvvisativo? E in che senso l\u2019atto improvvisativo \ue8 emergenziale? Per rispondere a queste domande si \ue8 adottato un punto di vista fenomenologico incentrato sulla figura del performer. Si \ue8 analizzato il processo improvvisativo comparando esperienze e pratiche musicali eterogenee, descrivendo e analizzando tali esperienze e pratiche. E' per questa ragione che lo svolgimento del percorso di ricerca comporta che la tematica della non-linearit\ue0 (di stampo musicologico) incontri proficuamente il concetto di invarianza (dalla provenienza ancor pi\uf9 ramificata: scientifica, matematica, psicologica e filosofica), e infine quello di emergenza. La visione fenomenologica che caratterizza il percorso argomentativo ha messo in risalto la forza descrittiva di tali categorie e le loro analogie verso una comprensione dell'atto improvvisativo dal punto di vista dell'esecutore. La prima parte della tesi indaga gli strumenti filosofici offerti dalla fenomenologia husserliana, utili per comprendere la nozione di suono in rapporto alla temporalit\ue0 della coscienza. La nozione di invarianza \ue8 utile per comprendere i problemi dell'identit\ue0 sonora e come questa assume importanza dal punto di vista fenomenologico per descrivere i processi improvvisativi. Nella seconda parte della tesi il concetto di invarianza \ue8 alla base della descrizione dell'atto improvvisativo e del rapporto fra linearit\ue0 e nonlinearit\ue0 dell'improvvisazione. Viene analizzato il concetto di \u201cinizio dell'improvvisazione\u201d e \u201cfine dell'improvvisazione\u201d. In ultima analisi, l'atto improvvisativo si mostra come un processo emergenziale di cui l'invarianza e la nonlinearit\ue0 ne sono gli ingredienti costitutivi. In ultima analisi l\u2019atto improvvisativo si viene a delineare come un atto della coscienza che ha una struttura emergenziale, ovvero invariante rispetto a trasformazioni improvvise, in altre parole il fluire in un presente continuamente emergente, rispetto a un\u2019attesa improvvisa e a una ritenzione sfuggente

Five Improvisations: aspetti nonlineari di un’improvvisazione

This article aims to show how it is possible to enrich our knowledge of music through a linear and nonlinear analysis of sound. For this purpose, 1. I conduct a nonlinear analysis of a specific improvised music for winds and percussion, 2. I describe the sound characteristics of the invariants present in the improvisation, and 3. I finally show the relationship between linear and nonlinear properties of music

La Nonlinearità nella musica di Schumann: Un esempio dal Nachtstücke op.23

In questo scritto, rifletto sulla nonlinearità in alcune composizioni e improvvisazioni musicali. Le analisi nonlineari scritte da Jonathan Kramer sono ben conosciute. Intendo estendere un approccio analogo alle composizioni, alle improvvisazioni e alle esecuzioni musicali, adottando la prospettiva del musicista che restituisce il rapporto fra linearità e nonlinearità nell’atto concreto dell’esecuzione musicale.In this paper, I reflect on nonlinearity in some musical compositions and improvisations. The nonlinear analyses written by Jonathan Kramer are well known. I intend to extend a similar approach to musical compositions, improvisations and performances by adopting the perspective of the musician who restores the relationship between linearity and nonlinearity in the concrete act of musical performance

Invarianza, tempo e improvvisazione musicale.

The notion of invariance permeates different research areas and often takes on different meanings. In different fields (psychology, phenomenology, physics, and ethics) the invariance concept attempts to explain the mechanisms of perceptual grouping. In this article invariance is considered a structural condition of our way of perceiving music and especially musical improvisation. It helps to understand the relationship between musical improvisation and nonlinearity, i.e. between what is transformed and what remains unchanged in the process of improvisation. I argue that every musical improvisation whose characteristics are nonlinear implies perceptual invariance with respect to time

Improvvisazione e non linearità. Riflessioni su “Oscillazioni”

Il rapporto fra nonlinearità e improvvisazione musicale grazie all'analisi e allo studio della partitura di un brano musicale che contiene segni musicali in notazione standard e grafica. Se l'uso della notazione musicale tradizionale veicola contenuti musicali fondamentalmente lineari, il segno grafico consente di aprire il campo all'improvvisazione e all'esecuzione di contenuti musicali nonlineari

Studying Alzheimer disease, Parkinson disease, and amyotrophic lateral sclerosis with 7-T magnetic resonance

Ultra-high-field (UHF) magnetic resonance (MR) scanners, that is, equipment operating at static magnetic field of 7 tesla (7 T) and above, enable the acquisition of data with greatly improved signal-to-noise ratio with respect to conventional MR systems (e.g., scanners operating at 1.5 T and 3 T). The change in tissue relaxation times at UHF offers the opportunity to improve tissue contrast and depict features that were previously inaccessible. These potential advantages come, however, at a cost: in the majority of UHF-MR clinical protocols, potential drawbacks may include signal inhomogeneity, geometrical distortions, artifacts introduced by patient respiration, cardiac cycle, and motion. This article reviews the 7 T MR literature reporting the recent studies on the most widespread neurodegenerative diseases: Alzheimer’s disease, Parkinson’s disease, and amyotrophic lateral sclerosis

Epilepsy and phenylketonuria: a case description and EEG-fMRI findings.

Phenylketonuria (PKU) is characterized by phenylalanine accumulation due to phenylalanine hydroxylase deficiency. Up to 50% of PKU patients experience seizures. We evaluated an adult PKU patient who suffered from absences and primarily generalized tonicclonic seizures, associated with generalized spikeand-wave discharges (GSWs) on EEG. An analysis of blood oxygenation level-dependent (BOLD) signal changes during interictal epileptiform discharges showed early activation of the left perirolandic cortex followed by a BOLD signal decrease within cortical regions belonging to the default mode network and left frontoparietal cortex. Moreover, deactivation of the head of the right caudate nucleus and the left thalamus was observed. The fMRI pattern observed in our patient during GSWs is similar but not identical to that observed in idiopathic generalized epilepsy, suggesting different neurophysiological mechanisms. This is the first description of BOLD-fMRI patterns in a PKU patient with epilepsy. Similar studies in more patients might help to uncover the pathophysiology of seizures in this disease