M De Luca

Bio: M De Luca is an academic researcher from University of Siena. The author has contributed to research in topics: Resting state fMRI & Magnetic resonance imaging. The author has an hindex of 4, co-authored 8 publications receiving 12228 citations. Previous affiliations of M De Luca include University of Oxford & John Radcliffe Hospital.

Evidence of early cortical atrophy in MS Relevance to white matter changes and disability

Abstract: Objective: To assess cortical gray matter (GM) changes in MS and establish their relevance to clinical disability and to inflammatory changes of white matter (WM) in patients with the relapsing–remitting (RR) and primary progressive (PP) forms of the disease. Methods: Conventional MRI examinations were obtained in patients with definite MS who had either the RR or the PP form of the disease. An automated analysis tool was used with conventional T1-weighted MR images to obtain total and cortical brain volumes normalized for head size. Total brain lesion load was estimated on conventional proton density and T2-weighted MR images. The relationship between volumetric MR measures and scores of clinical disability was assessed. Results: Normalized cortical volumes (NCV) were lower for both RR and PP MS patients than for normal control subjects ( p p > 0.5). NCV decreases in both patients groups were detected even in those patients with short disease duration ( p p p p r = −0.47, p r = −0.25, p p r = −0.64, p r = −0.27, p = 0.04) MS patients. Conclusions: These data confirm substantial neocortical volume loss in MS patients and suggest that neocortical GM pathology may occur early in the course of the disease in both RR and PP MS patients and contribute significantly to neurologic impairment. Although a proportion of this neocortical pathology may be secondary to WM inflammation, the extent of the changes suggests that, especially in patients with PP MS, an independent neurodegenerative process also is active.

Prominent brain axonal damage and functional reorganization in “pure” adrenomyeloneuropathy

Abstract: Background: Cerebral involvement is usually absent in pure adrenomyeloneuropathy (AMN). Recently, nonconventional MR studies have reported brain abnormalities in patients with pure AMN, providing evidence that occult cerebral involvement may occur in this disease. It remains unclear, however, whether these brain abnormalities reflect centripetal extension of spinal cord long-tract axonopathy or can be the expression of a pathologic process largely involving the brain. Methods: Conventional MRI and proton MR spectroscopic imaging ( 1 H-MRSI) data of four patients with pure AMN were compared to those of four men with spinal cord injury (SCI) and 10 age-matched healthy men (HM). Resonance intensity areas of N -acetylaspartate (NAA) and choline were calculated as ratios to creatine (Cr) in voxels located in white matter (WM) regions. Functional MRI (fMRI) data during simple motor task were obtained in a separate session in three patients with AMN and three age-matched HM. Results: Conventional MRI examinations were normal in all patients. On 1 H-MRSI, NAA/Cr values were lower in all WM regions of patients with AMN than in those of patients with SCI ( p p p = 0.04). At fMRI, patients with AMN showed a more pronounced activation than HM in all movement-associated cortical regions contralateral to the hand moved and an exclusive voxel activation of the primary motor, somatosensory, and posterior parietal cortices ipsilateral to the hand moved. Conclusions: CNS damage in pure adrenomyeloneuropathy is not confined exclusively to spinal cord and seems to primarily involve the brain. GLOSSARY: 1 H-MRSI = proton MR spectroscopic imaging; AC = anterior commissure; AMN = adrenomyeloneuropathy; BOLD = blood oxygenation level dependent; BR = brisk reflexes; Cho/Cr = choline to creatine ratio; Cr = creatine; DTI = diffusion tensor imaging; EA = endocrine abnormalities; FLAIR = fluid-attenuated inversion recovery; fMRI = functional MRI; FMRIB = Functional Magnetic Resonance Imaging of the Brain; FILM = FMRIB’s improved linear model; Fr-WM = frontal WM; HM = healthy men; Lac = lactate; MD = motor deficits; NAA = N -acetylaspartate; Naa/Cr = N -acetylaspartate to creatine ratio; PC = posterior commissure; PD = proton density; Post-WM = deep posterior WM; Pv-WM = periventricular WM; SA = sensory abnormalities; SCI = spinal cord injury; SP = spastic paraparesis; Sph Dis = sphincteric disturbances; VLCFA = very-long-chain fatty acids; VOI = volume of interest; WM = white matter.

Synchronous malignant transformation of bilateral symmetrical retinocytoma

Abstract: Purpose To report the outcome of a 4-year-old girl who was found to have bilateral malignant transformed retinocytoma. Methods The patient was treated with systemic chemotherapy and photocoagulation followed by intraarterial chemotherapy. Results Complete remission was achieved. Conclusion Chemotherapy destroyed malignant retinoblastoma and the “retinoma” component remained unchanged.

The Brain's Default Network Anatomy, Function, and Relevance to Disease

Abstract: Thirty years of brain imaging research has converged to define the brain’s default network—a novel and only recently appreciated brain system that participates in internal modes of cognition Here we synthesize past observations to provide strong evidence that the default network is a specific, anatomically defined brain system preferentially active when individuals are not focused on the external environment Analysis of connectional anatomy in the monkey supports the presence of an interconnected brain system Providing insight into function, the default network is active when individuals are engaged in internally focused tasks including autobiographical memory retrieval, envisioning the future, and conceiving the perspectives of others Probing the functional anatomy of the network in detail reveals that it is best understood as multiple interacting subsystems The medial temporal lobe subsystem provides information from prior experiences in the form of memories and associations that are the building blocks of mental simulation The medial prefrontal subsystem facilitates the flexible use of this information during the construction of self-relevant mental simulations These two subsystems converge on important nodes of integration including the posterior cingulate cortex The implications of these functional and anatomical observations are discussed in relation to possible adaptive roles of the default network for using past experiences to plan for the future, navigate social interactions, and maximize the utility of moments when we are not otherwise engaged by the external world We conclude by discussing the relevance of the default network for understanding mental disorders including autism, schizophrenia, and Alzheimer’s disease

The organization of the human cerebral cortex estimated by intrinsic functional connectivity

Abstract: Information processing in the cerebral cortex involves interactions among distributed areas. Anatomical connectivity suggests that certain areas form local hierarchical relations such as within the visual system. Other connectivity patterns, particularly among association areas, suggest the presence of large-scale circuits without clear hierarchical relations. In this study the organization of networks in the human cerebrum was explored using resting-state functional connectivity MRI. Data from 1,000 subjects were registered using surface-based alignment. A clustering approach was employed to identify and replicate networks of functionally coupled regions across the cerebral cortex. The results revealed local networks confined to sensory and motor cortices as well as distributed networks of association regions. Within the sensory and motor cortices, functional connectivity followed topographic representations across adjacent areas. In association cortex, the connectivity patterns often showed abrupt transitions between network boundaries. Focused analyses were performed to better understand properties of network connectivity. A canonical sensory-motor pathway involving primary visual area, putative middle temporal area complex (MT+), lateral intraparietal area, and frontal eye field was analyzed to explore how interactions might arise within and between networks. Results showed that adjacent regions of the MT+ complex demonstrate differential connectivity consistent with a hierarchical pathway that spans networks. The functional connectivity of parietal and prefrontal association cortices was next explored. Distinct connectivity profiles of neighboring regions suggest they participate in distributed networks that, while showing evidence for interactions, are embedded within largely parallel, interdigitated circuits. We conclude by discussing the organization of these large-scale cerebral networks in relation to monkey anatomy and their potential evolutionary expansion in humans to support cognition.

Spontaneous fluctuations in brain activity observed with functional magnetic resonance imaging.

Abstract: The majority of functional neuroscience studies have focused on the brain's response to a task or stimulus. However, the brain is very active even in the absence of explicit input or output. In this Article we review recent studies examining spontaneous fluctuations in the blood oxygen level dependent (BOLD) signal of functional magnetic resonance imaging as a potentially important and revealing manifestation of spontaneous neuronal activity. Although several challenges remain, these studies have provided insight into the intrinsic functional architecture of the brain, variability in behaviour and potential physiological correlates of neurological and psychiatric disease.

Dissociable Intrinsic Connectivity Networks for Salience Processing and Executive Control

Abstract: Variations in neural circuitry, inherited or acquired, may underlie important individual differences in thought, feeling, and action patterns. Here, we used task-free connectivity analyses to isolate and characterize two distinct networks typically coactivated during functional MRI tasks. We identified a "salience network," anchored by dorsal anterior cingulate (dACC) and orbital frontoinsular cortices with robust connectivity to subcortical and limbic structures, and an "executive-control network" that links dorsolateral frontal and parietal neocortices. These intrinsic connectivity networks showed dissociable correlations with functions measured outside the scanner. Prescan anxiety ratings correlated with intrinsic functional connectivity of the dACC node of the salience network, but with no region in the executive-control network, whereas executive task performance correlated with lateral parietal nodes of the executive-control network, but with no region in the salience network. Our findings suggest that task-free analysis of intrinsic connectivity networks may help elucidate the neural architectures that support fundamental aspects of human behavior.