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1.
Oncologist ; 28(9): 825-e817, 2023 09 07.
Artículo en Inglés | MEDLINE | ID: mdl-37196069

RESUMEN

BACKGROUND: Hypofractionated stereotactic radiotherapy (hFSRT) is a salvage option for recurrent glioblastoma (GB) which may synergize anti-PDL1 treatment. This phase I study evaluated the safety and the recommended phase II dose of anti-PDL1 durvalumab combined with hFSRT in patients with recurrent GB. METHODS: Patients were treated with 24 Gy, 8 Gy per fraction on days 1, 3, and 5 combined with the first 1500 mg Durvalumab dose on day 5, followed by infusions q4weeks until progression or for a maximum of 12 months. A standard 3 + 3 Durvalumab dose de-escalation design was used. Longitudinal lymphocytes count, cytokines analyses on plasma samples, and magnetic resonance imaging (MRI) were collected. RESULTS: Six patients were included. One dose limiting toxicity, an immune-related grade 3 vestibular neuritis related to Durvalumab, was reported. Median progression-free interval (PFI) and overall survival (OS) were 2.3 and 16.7 months, respectively. Multi-modal deep learning-based analysis including MRI, cytokines, and lymphocytes/neutrophil ratio isolated the patients presenting pseudoprogression, the longest PFI and those with the longest OS, but statistical significance cannot be established considering phase I data only. CONCLUSION: Combination of hFSRT and Durvalumab in recurrent GB was well tolerated in this phase I study. These encouraging results led to an ongoing randomized phase II. (ClinicalTrials.gov Identifier: NCT02866747).


Asunto(s)
Neoplasias Encefálicas , Glioblastoma , Radiocirugia , Reirradiación , Humanos , Glioblastoma/tratamiento farmacológico , Glioblastoma/radioterapia , Resultado del Tratamiento , Neoplasias Encefálicas/tratamiento farmacológico , Neoplasias Encefálicas/radioterapia , Recurrencia Local de Neoplasia/tratamiento farmacológico , Recurrencia Local de Neoplasia/radioterapia , Radiocirugia/efectos adversos , Citocinas
2.
J Ultrasound Med ; 41(9): 2203-2215, 2022 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-34859905

RESUMEN

OBJECTIVES: Worldwide, lung ultrasound (LUS) was utilized to assess coronavirus disease 2019 (COVID-19) patients. Often, imaging protocols were however defined arbitrarily and not following an evidence-based approach. Moreover, extensive studies on LUS in post-COVID-19 patients are currently lacking. This study analyses the impact of different LUS imaging protocols on the evaluation of COVID-19 and post-COVID-19 LUS data. METHODS: LUS data from 220 patients were collected, 100 COVID-19 positive and 120 post-COVID-19. A validated and standardized imaging protocol based on 14 scanning areas and a 4-level scoring system was implemented. We utilized this dataset to compare the capability of 5 imaging protocols, respectively based on 4, 8, 10, 12, and 14 scanning areas, to intercept the most important LUS findings. This to evaluate the optimal trade-off between a time-efficient imaging protocol and an accurate LUS examination. We also performed a longitudinal study, aimed at investigating how to eventually simplify the protocol during follow-up. Additionally, we present results on the agreement between AI models and LUS experts with respect to LUS data evaluation. RESULTS: A 12-areas protocol emerges as the optimal trade-off, for both COVID-19 and post-COVID-19 patients. For what concerns follow-up studies, it appears not to be possible to reduce the number of scanning areas. Finally, COVID-19 and post-COVID-19 LUS data seem to show differences capable to confuse AI models that were not trained on post-COVID-19 data, supporting the hypothesis of the existence of LUS patterns specific to post-COVID-19 patients. CONCLUSIONS: A 12-areas acquisition protocol is recommended for both COVID-19 and post-COVID-19 patients, also during follow-up.


Asunto(s)
COVID-19 , Humanos , Estudios Longitudinales , Pulmón/diagnóstico por imagen , SARS-CoV-2 , Ultrasonografía/métodos
3.
J Ultrasound Med ; 40(8): 1627-1635, 2021 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-33155689

RESUMEN

OBJECTIVES: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection can generate severe pneumonia associated with high mortality. A bedside lung ultrasound (LUS) examination has been shown to have a potential role in this setting. The purpose of this study was to evaluate the potential prognostic value of a new LUS protocol (evaluation of 14 anatomic landmarks, with graded scores of 0-3) in patients with SARS-CoV-2 pneumonia and the association of LUS patterns with clinical or laboratory findings. METHODS: A cohort of 52 consecutive patients with laboratory-confirmed SARS-CoV-2 underwent LUS examinations on admission in an internal medicine ward and before their discharge. A total LUS score as the sum of the scores at each explored area was computed. We investigated the association between the LUS score and clinical worsening, defined as a combination of high-flow oxygen support, intensive care unit admission, or 30-day mortality as the primary end point. RESULTS: Twenty (39%) patients showed a worse outcome during the observation period; the mean LUS scores ± SDs were 20.4 ± 8.5 and 29.2 ± 7.3 in patients without and with worsening, respectively (P < .001). In a multivariable analysis, adjusted for comorbidities (>2), age (>65 years), sex (male), and body mass index (≥25 kg/m2 ), the association between the LUS score and worsening (odds ratio, 1.17; 95% confidence interval, 1.05 to 1.29; P = .003) was confirmed, with good discrimination of the model (area under the receiver operating characteristic curve, 0.82). A median LUS score higher than 24 was associated with an almost 6-fold increase in the odds of worsening (odds ratio, 5.67; 95% confidence interval, 1.29 to 24.8; P = .021). CONCLUSIONS: Lung ultrasound can represent an effective tool for monitoring and stratifying the prognosis of patients with SARS-CoV-2 pulmonary involvement.


Asunto(s)
COVID-19 , Neumonía , Anciano , Humanos , Pulmón/diagnóstico por imagen , Masculino , SARS-CoV-2 , Ultrasonografía
4.
Genet Med ; 22(11): 1903-1908, 2020 11.
Artículo en Inglés | MEDLINE | ID: mdl-32661355

RESUMEN

PURPOSE: We aimed to determine the origin and genetic characteristics of Huntington disease (HD) in the Middle East. METHODS: We performed genetic and genealogical analyses to establish the ancestral origin of the HTT pathgenic variant from a large kindred from Oman (hereafter called the OM-HD-01 pedigree) by single-nucleotide polymorphism and dense haplotype analysis genotyping. RESULTS: We traced the oldest ancestry of the largest, eight-generation, OM-HD-01 pedigree (n = 302 subjects, with 54 showing manifest HD) back to sub-Saharan Africa and identified a unique HD haplotype carried by all pedigree members, which consisted of portions of the C6 and C9 haplotypes and was carried by all affected members. Such a unique HD haplotype was of African origin and appeared to be associated with large CAG repeat expansions on average and high frequency of juvenile-onset HD. Three other families from the same area were also identified and found carrying a Caucasian HD haplotype A, also shared by most families of Arab ancestry. CONCLUSION: Mutated HTT spread into Middle East with a unique haplotype of African origin, appeared to be associated with juvenile-onset, a HD condition frequently occurring in Black Africans, and may have a significant impact on further development of novel targeted genetic therapies.


Asunto(s)
Enfermedad de Huntington , Alelos , Haplotipos , Humanos , Proteína Huntingtina/genética , Enfermedad de Huntington/epidemiología , Enfermedad de Huntington/genética , Medio Oriente/epidemiología , Población Blanca
5.
Mov Disord ; 35(11): 1957-1965, 2020 11.
Artículo en Inglés | MEDLINE | ID: mdl-32882100

RESUMEN

Multiple system atrophy (MSA) is a rare and fatal neurodegenerative disease with limited symptomatic treatment options. Aggregation of α-synuclein in oligodendrocytes is believed to be a central mechanism of the neurodegenerative process. PD01A and PD03A are 2 novel therapeutic vaccine candidates containing short peptides as antigenic moieties that are designed to induce a sustained antibody response, specifically targeting pathogenic assemblies of α-synuclein. The objectives of the current study were to evaluate primarily the safety and tolerability of PD01A and PD03A in patients with early MSA. Thirty patients (11 women) were randomized to receive 5 subcutaneous injections of either PD01A (n = 12), PD03A (n = 12), or placebo (n = 6) in this patient- and examiner-blinded, placebo-controlled, 52-week phase 1 clinical trial (ClinicalTrial.gov identifier: NCT02270489). Immunogenicity and clinical scores were assessed as secondary objectives. Twenty-nine patients reported a total of 595 treatment-emergent adverse events (mild or moderate, n = 555; severe, n = 40). Treatment-related adverse events included 190 injection-site reactions typically observed in vaccination trials with similar per-subject incidence in the treatment groups over time. Sustained IgG titers were observed in the PD01A-treated group, and 89% of treated patients developed a PD01-specific antibody response after receiving all injections. Induced antibodies displayed clear reactivity to the α-synuclein target epitope. Titers and antibody responder rate (58%) were lower in the PD03A-treated group. In conclusion, both PD01A and PD03A were safe and well tolerated. PD01A triggered a rapid and long-lasting antibody response that specifically targeted the α-synuclein epitope. © 2020 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.


Asunto(s)
Atrofia de Múltiples Sistemas , Enfermedad de Parkinson , Femenino , Humanos , Masculino , Atrofia de Múltiples Sistemas/tratamiento farmacológico , Enfermedad de Parkinson/tratamiento farmacológico , Péptidos , Vacunación , alfa-Sinucleína
6.
BMC Cancer ; 19(1): 1197, 2019 Dec 06.
Artículo en Inglés | MEDLINE | ID: mdl-31810452

RESUMEN

BACKGROUND: Glioblastoma multiform (GBM), a malignant brain tumour, has a very often poor prognosis. The therapeutic approach is represented by surgery followed by radiotherapy and chemotherapy. Hypoxia is a factor that causes a reduction of both radiotherapy and chemotherapy effectiveness in GBM and other cancers. Through the use of [64Cu][Cu(ATSM)], a hypoxia-targeting positron emission tomography (PET) radiotracer, is possible to identify the presence of hypoxic areas within a lesion and therefore modulate the therapeutic approach according to the findings. CASE PRESENTATION: In this case report, we observed an increase of radiotracer uptake from early acquisition to late acquisition in hypoxia sites and high correlation between [64Cu][Cu(ATSM) PET/CT results and expression of the hypoxia marker HIF-1α. CONCLUSIONS: [64Cu][Cu(ATSM) PET/CT represents a valid opportunity to reveal in vivo hypoxic areas in GBM lesion which can guide clinicians on selecting GMB patient's therapeutic scheme.


Asunto(s)
Neoplasias Encefálicas/diagnóstico por imagen , Glioblastoma/diagnóstico por imagen , Compuestos Organometálicos/farmacocinética , Tiosemicarbazonas/farmacocinética , Anciano , Neoplasias Encefálicas/metabolismo , Neoplasias Encefálicas/patología , Neoplasias Encefálicas/radioterapia , Hipoxia de la Célula , Complejos de Coordinación , Relación Dosis-Respuesta en la Radiación , Glioblastoma/metabolismo , Glioblastoma/patología , Glioblastoma/radioterapia , Humanos , Subunidad alfa del Factor 1 Inducible por Hipoxia/metabolismo , Masculino , Tomografía Computarizada por Tomografía de Emisión de Positrones , Trazadores Radiactivos , Radioterapia de Intensidad Modulada , Resultado del Tratamiento
7.
Mov Disord ; 34(4): 487-495, 2019 04.
Artículo en Inglés | MEDLINE | ID: mdl-30759325

RESUMEN

BACKGROUND: No prospective study of patients with Parkinson's disease (PD) has investigated the appearance of vertical gaze abnormalities, a feature suggestive of progressive supranuclear palsy (PSP). OBJECTIVE: To identify, within a cohort of patients with an initial diagnosis of PD, those who developed vertical gaze abnormalities during a 4-year follow-up, and to investigate the performance of new imaging biomarkers in predicting vertical gaze abnormalities. METHODS: A total of 110 patients initially classified as PD and 74 controls were enrolled. All patients underwent clinical assessment at baseline and every year up to the end of the follow-up. The pons/midbrain area ratio 2.0 and the Magnetic Resonance Parkinsonism Index 2.0 were calculated. RESULTS: After 4-year follow-up, 100 of 110 patients maintained the diagnosis of PD, whereas 10 PD patients (9.1%) developed vertical gaze abnormalities, suggesting an alternative diagnosis of PSP-parkinsonism. At baseline, the Magnetic Resonance Parkinsonism Index 2.0 was the most accurate biomarker in differentiating PD patients who developed vertical gaze abnormalities from those who maintained an initial diagnosis of PD. At the end of follow-up, both of these biomarkers accurately distinguished PSP-parkinsonism from PD. CONCLUSIONS: Our results demonstrate that a number of patients with an initial diagnosis of PD developed vertical gaze abnormalities during a 4-year follow-up, and the diagnosis was changed from PD to PSP-parkinsonism. In PD patients, baseline Magnetic Resonance Parkinsonism Index 2.0 showed the best performance in predicting the clinical evolution toward a PSP-parkinsonism phenotype, enabling PSP-parkinsonism patients to be identified at the earliest stage of the disease for promising disease-modifying therapies. © 2019 The Authors. Movement Disorders published by Wiley Periodicals, Inc. on behalf of International Parkinson and Movement Disorder Society.


Asunto(s)
Encéfalo/diagnóstico por imagen , Enfermedad de Parkinson/diagnóstico , Parálisis Supranuclear Progresiva/diagnóstico , Adulto , Anciano , Anciano de 80 o más Años , Diagnóstico Diferencial , Errores Diagnósticos , Femenino , Humanos , Procesamiento de Imagen Asistido por Computador , Imagen por Resonancia Magnética , Masculino , Persona de Mediana Edad , Enfermedad de Parkinson/diagnóstico por imagen
10.
Hum Brain Mapp ; 38(10): 5141-5160, 2017 10.
Artículo en Inglés | MEDLINE | ID: mdl-28681960

RESUMEN

Cortical hubs play a fundamental role in the functional architecture of brain connectivity at rest. However, the anatomical scaffold underlying their centrality is still under debate. Certainly, the brain function and anatomy are significantly entwined through synaptogenesis and pruning mechanisms that continuously reshape structural and functional connections. Thus, if hubs are expected to exhibit a large number of direct anatomical connections with the rest of the brain, such a dense wiring is extremely inefficient in energetic terms. In this work, we investigate these aspects on fMRI and DTI data from a set of know resting-state networks, starting from the hypothesis that to promote integration, functional, and anatomical connections link different areas at different scales or hierarchies. Thus, we focused on the role of functional hubs in this hierarchical organization of functional and anatomical architectures. We found that these regions, from a structural point of view, are first linked to each other and successively to the rest of the brain. Thus, functionally central nodes seem to show few strong anatomical connections. These findings suggest an efficient strategy of the investigated cortical hubs in exploiting few direct anatomical connections to link functional hubs among each other that eventually reach the rest of the considered nodes through local indirect tracts. Hum Brain Mapp 38:5141-5160, 2017. © 2017 Wiley Periodicals, Inc.


Asunto(s)
Corteza Cerebral/anatomía & histología , Corteza Cerebral/fisiología , Adulto , Corteza Cerebral/diagnóstico por imagen , Imagen de Difusión Tensora , Femenino , Humanos , Imagen por Resonancia Magnética , Masculino , Vías Nerviosas/anatomía & histología , Vías Nerviosas/diagnóstico por imagen , Vías Nerviosas/fisiología , Descanso
11.
J Cogn Neurosci ; 28(5): 724-38, 2016 May.
Artículo en Inglés | MEDLINE | ID: mdl-26807842

RESUMEN

Several studies have already shown that transcranial direct current stimulation (tDCS) is a useful tool for enhancing recovery in aphasia. However, no reports to date have investigated functional connectivity changes on cortical activity because of tDCS language treatment. Here, nine aphasic persons with articulatory disorders underwent an intensive language therapy in two different conditions: bilateral anodic stimulation over the left Broca's area and cathodic contralesional stimulation over the right homologue of Broca's area and a sham condition. The language treatment lasted 3 weeks (Monday to Friday, 15 sessions). In all patients, language measures were collected before (T0) and at the end of treatment (T15). Before and after each treatment condition (real vs. sham), each participant underwent a resting-state fMRI study. Results showed that, after real stimulation, patients exhibited the greatest recovery not only in terms of better accuracy in articulating the treated stimuli but also for untreated items on different tasks of the language test. Moreover, although after the sham condition connectivity changes were confined to the right brain hemisphere, real stimulation yielded to stronger functional connectivity increase in the left hemisphere. In conclusion, our data provide converging evidence from behavioral and functional imaging data that bilateral tDCS determines functional connectivity changes within the lesioned hemisphere, enhancing the language recovery process in stroke patients.


Asunto(s)
Afasia/etiología , Afasia/terapia , Lesiones Encefálicas/complicaciones , Área de Broca/fisiología , Lateralidad Funcional/fisiología , Estimulación Transcraneal de Corriente Directa/métodos , Anciano , Afasia/diagnóstico por imagen , Mapeo Encefálico , Femenino , Humanos , Procesamiento de Imagen Asistido por Computador , Pruebas del Lenguaje , Imagen por Resonancia Magnética , Masculino , Persona de Mediana Edad , Vías Nerviosas/fisiología , Oxígeno/sangre , Índice de Severidad de la Enfermedad , Vocabulario
12.
Hum Brain Mapp ; 36(1): 50-66, 2015 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-25145324

RESUMEN

In Huntington's disease, iron accumulation in basal ganglia accompanies neuronal loss. However, if iron content changes with disease progression and how it relates to gray matter atrophy is not clear yet. We explored iron content in basal ganglia and cortex and its relationship with gray matter volume in 77 mutation carriers [19 presymptomatic, 8 with soft symptoms (SS), and 50 early-stage patients) and 73 matched-controls by T2*relaxometry and T1-weighted imaging on a 3T scanner. The ANCOVA model showed that iron accumulates in the caudate in presymptomatic subjects (P = 0.004) and remains relatively stable along disease stages in this nucleus; while increases in putamen and globus pallidus (P < 0.05). Volume instead decreases in basal ganglia, starting from the caudate (P < 0.0001) and extending to the putamen and globus pallidus (P ≤ 0.001). The longer the disease duration and the higher the CAG repeats, the higher the iron accumulation and the smaller the volume. In the cortex, iron decreases in parieto-occipital areas in SS (P < 0.027); extending to premotor and parieto-temporo-occipital areas in patients (P < 0.003); while volume declines in frontoparietal and temporal areas in presymptomatic (P < 0.023) and SS (P < 0.045), and extends throughout the cortex, with the exception of anterior frontal regions, in patients (P < 0.023). There is an inverse correlation between volume and iron levels in putamen, globus pallidus and the anterior cingulate; and a direct correlation in cortical structures (SMA-sensoriomotor and temporo-occipital). Iron homeostasis is affected in the disease; however, there appear to be differences in the role played by iron in basal ganglia and in cortex.


Asunto(s)
Encéfalo/patología , Sustancia Gris/metabolismo , Enfermedad de Huntington/complicaciones , Hierro/metabolismo , Enfermedades Neurodegenerativas/etiología , Enfermedades Neurodegenerativas/patología , Adulto , Anciano , Análisis de Varianza , Estudios de Casos y Controles , Progresión de la Enfermedad , Femenino , Sustancia Gris/patología , Humanos , Proteína Huntingtina , Enfermedad de Huntington/genética , Imagenología Tridimensional , Imagen por Resonancia Magnética , Masculino , Persona de Mediana Edad , Proteínas del Tejido Nervioso/genética , Índice de Severidad de la Enfermedad , Repeticiones de Trinucleótidos/genética
13.
Neurocase ; 21(5): 573-83, 2015.
Artículo en Inglés | MEDLINE | ID: mdl-25279725

RESUMEN

Developmental topographical disorientation (DTD) causes impaired spatial orientation and navigation from early childhood with no evidence of cerebral damage. Using fMRI and a landmark sequencing task, we investigated the hypothesis that Dr Wai's abnormal cerebral activation pattern was related to his peculiar behavioral profile. Although Dr Wai was able to correctly perform landmark sequencing, he showed a lack of activity in regions activated in all control subjects and activity in areas that were not activated in any control subject. These results are discussed in light of cognitive and functional model of navigation, with relevant implications for DTD physiology.


Asunto(s)
Corteza Cerebral/fisiopatología , Orientación/fisiología , Navegación Espacial/fisiología , Procesamiento Espacial/fisiología , Adulto , Mapeo Encefálico , Humanos , Imagen por Resonancia Magnética , Masculino , Pruebas Neuropsicológicas , Adulto Joven
15.
Neuroimmunomodulation ; 21(1): 8-12, 2014.
Artículo en Inglés | MEDLINE | ID: mdl-24080899

RESUMEN

OBJECTIVE: A long-lasting neuroinflammatory cascade may lead to the progression of brain damage, favoring neurodegeneration and cognitive impairment in patients with traumatic brain injury (TBI), but the potential mechanisms underlying this sequence of events remain elusive. Here we aimed to evaluate the impact of interleukin (IL)-18, a proinflammatory cytokine elevated in post-acute head injury and associated with neurodegeneration, on the long-term outcome of patients with chronic TBI. METHODS: The serum content of IL-18 was evaluated in 16 patients with severe TBI, during their rehabilitation phase, and in a matched group of 16 healthy controls. The disability of the enrolled patients was evaluated by means of the Glasgow Outcome Scale, Levels of Cognitive Functioning, and the Disability Rating Scale. RESULTS: The circulating levels of IL-18 were significantly increased in chronic TBI patients, as compared to healthy subjects, and correlated with the patients' cognitive impairment and disability severity. CONCLUSIONS: IL-18 may contribute to the long-term outcome and neurodegeneration in TBI patients. Even though further studies are needed to understand the molecular mechanisms underlying the effects of IL-18 on TBI progression and its associated drop in cognitive function, a possible role of this cytokine as a therapeutic target in TBI can be envisaged.


Asunto(s)
Lesiones Encefálicas/sangre , Lesiones Encefálicas/diagnóstico , Interleucina-18/sangre , Adulto , Femenino , Escala de Consecuencias de Glasgow , Humanos , Estudios Longitudinales , Masculino , Adulto Joven
16.
Artículo en Inglés | MEDLINE | ID: mdl-39367695

RESUMEN

BACKGROUND: Pediatric-onset Huntington's disease (POHD) exhibits a phenotype different from adult-onset HD (AOHD), with hypokinetic movement disorders (eg, rigidity, bradykinesia, and dystonia) rather than chorea typical of AOHD. OBJECTIVES: The aim was to identify pathophysiology-based biomarkers specific to POHD (≥60 CAG repeats). METHODS: Simultaneous hybrid imaging using [18F]fluoro-2-deoxy-d-glucose (FDG) positron emission tomography plus magnetic resonance imaging (FDG-PET/MRI) and clinical assessment using standardized Huntington's disease (HD) scales were employed. Exploratory longitudinal analyses were also performed. RESULTS: Striatal volume loss was remarkable and more severe in POHD (n = 5) than in AOHD (n = 14). Widespread, significantly altered glucose metabolism occurred in several different POHD cortical areas and thalamus, but not AOHD cortex, consistent with differences in clinical progression. CONCLUSIONS: POHD patients' brains exhibited distinct morphologic and metabolic traits compared to AOHD patients' brains, with longitudinal changes mirroring clinical progression. Hybrid FDG-PET/MRI highlighted a variable regional brain dysfunction in vivo, as a biological consequence of highly expanded CAG repeats. Findings provide further evidence that POHD is a distinct disease from AOHD.

17.
Neuroimage ; 69: 51-61, 2013 Apr 01.
Artículo en Inglés | MEDLINE | ID: mdl-23220493

RESUMEN

The principles of functional specialization and integration in the resting brain are implemented in a complex system of specialized networks that share some degree of interaction. Recent studies have identified wider functional modules compared to previously defined networks and reported a small-world architecture of brain activity in which central nodes balance the pressure to evolve segregated pathways with the integration of local systems. The accurate identification of such central nodes is crucial but might be challenging for several reasons, e.g. inter-subject variability and physiological/pathological network plasticity, and recent works reported partially inconsistent results concerning the properties of these cortical hubs. Here, we applied a whole-brain data-driven approach to extract cortical functional cores and examined their connectivity from a resting state fMRI experiment on healthy subjects. Two main statistically significant cores, centered on the posterior cingulate cortex and the supplementary motor area, were extracted and their functional connectivity maps, thresholded at three statistical levels, revealed the presence of two complex systems. One system is consistent with the default mode network (DMN) and gradually connects to visual regions, the other centered on motor regions and gradually connects to more sensory-specific portions of cortex. These two large scale networks eventually converged to regions belonging to the medial aspect of the DMN, potentially allowing inter-network interactions.


Asunto(s)
Mapeo Encefálico , Encéfalo/fisiología , Vías Nerviosas/fisiología , Descanso/fisiología , Adulto , Femenino , Humanos , Interpretación de Imagen Asistida por Computador , Imagen por Resonancia Magnética , Masculino
18.
Neuroimage ; 71: 19-29, 2013 May 01.
Artículo en Inglés | MEDLINE | ID: mdl-23313780

RESUMEN

In aeronautics, plan continuation error (PCE) represents failure to revise a flight plan despite emerging evidence suggesting that it is no longer safe. Assuming that PCE may be associated with a shift from cold to hot reasoning, we hypothesized that this transition may result from a large range of strong negative emotional influences linked with the decision to abort a landing and circle for a repeat attempt, referred to as a "go-around". We investigated this hypothesis by combining functional neuroimaging with an ecologically valid aviation task performed under contextual variation in incentive and situational uncertainty. Our goal was to identify regional brain activity related to the sorts of conservative or liberal decision-making strategies engaged when participants were both exposed to a financial payoff matrix constructed to bias responses in favor of landing acceptance, while they were simultaneously experiencing maximum levels of uncertainty related to high levels of stimulus ambiguity. Combined with the observed behavioral outcomes, our neuroimaging results revealed a shift from cold to hot decision making in response to high uncertainty when participants were exposed to the financial incentive. Most notably, while we observed activity increases in response to uncertainty in many frontal regions such as dorsolateral prefrontal cortex (DLPFC) and anterior cingulate cortex (ACC), less overall activity was observed when the reward was combined with uncertainty. Moreover, participants with poor decision making, quantified as a lower discriminability index d', exhibited riskier behavior coupled with lower activity in the right DLPFC. These outcomes suggest a disruptive effect of biased financial incentive and high uncertainty on the rational decision-making neural network, and consequently, on decision relevance.


Asunto(s)
Aviación , Encéfalo/fisiología , Toma de Decisiones/fisiología , Incertidumbre , Adulto , Femenino , Humanos , Imagen por Resonancia Magnética , Masculino , Desempeño Psicomotor/fisiología
19.
Hum Brain Mapp ; 34(7): 1625-35, 2013 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-22359398

RESUMEN

Neurodegeneration of the striatum in Huntington disease (HD) is characterized by loss of medium-spiny neurons, huntingtin nuclear inclusions, reactive gliosis, and iron accumulation. Neuroimaging allows in vivo detection of the macro- and micro-structural changes that occur from presymptomatic stages of the disease (preHD). The aim of our study was to evaluate the reliability of multimodal imaging as an in vivo biomarker of vulnerability and development of the disease and to characterize macro- and micro-structural changes in subcortical nuclei in HD. Macrostructure (T1-weighted images), microstructure (diffusion tensor imaging), and iron content (R 2* relaxometry) of subcortical nuclei and medial temporal lobe structures were evaluated by a 3 T scanner in 17 preHD carriers, 12 early-stage patients and 29 matched controls. We observed a volume reduction and microstructural changes in the basal ganglia (caudate, putamen, and globus pallidus) and iron accumulation in the globus pallidus in both preHD and symptomatic subjects; all these features were significantly more pronounced in patients, in whom degeneration extended to the other subcortical nuclei (i.e., thalamus and accumbens). Mean diffusivity (MD) was the most powerful predictor in models explaining more than 50% of the variability in HD development in the caudate, putamen, and thalamus. These findings suggest that the measurement of MD may further enhance the well-known predictive value of striatal volume to assess disease progression as it is highly sensitive to tissue microimpairment. Multimodal imaging may detect brain changes even in preHD stages.


Asunto(s)
Ganglios Basales/patología , Mapeo Encefálico , Enfermedad de Huntington/diagnóstico , Imagen Multimodal , Adulto , Análisis de Varianza , Anisotropía , Ganglios Basales/metabolismo , Biomarcadores , Estudios Transversales , Imagen de Difusión Tensora , Progresión de la Enfermedad , Femenino , Ferritinas/metabolismo , Humanos , Imagenología Tridimensional , Hierro/metabolismo , Imagen por Resonancia Magnética , Masculino , Persona de Mediana Edad , Reproducibilidad de los Resultados
20.
J Magn Reson Imaging ; 37(1): 85-91, 2013 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-22987315

RESUMEN

PURPOSE: To investigate white matter heterogeneity using a multichannel segmentation of a large sample of structural and diffusion magnetic resonance imaging (MRI) data. MATERIALS AND METHODS: A sample of 50 subjects was segmented using channels comprising exclusively structural (longitudinal and transverse relaxation times T1 and T2 and transverse relaxation rate R2*) and diffusion-based MRI indices (mean diffusivity and fractional anisotropy). These data were analyzed using a data driven approach in which no prior information was used. RESULTS: The analysis revealed the splitting of white matter into two subclasses in which the longitudinal fasciculi were distinguished from inferior/superior ones. The distribution of the adopted indices in the obtained clusters showed that R2* was mainly responsible for this splitting. CONCLUSION: This result supports the observation, previously hypothesized in the literature, that R2* is influenced by the fiber orientation.


Asunto(s)
Mapeo Encefálico/métodos , Encéfalo/patología , Imagen de Difusión por Resonancia Magnética/métodos , Fibras Nerviosas Mielínicas/patología , Adulto , Anciano , Anisotropía , Análisis por Conglomerados , Diagnóstico por Imagen/métodos , Femenino , Humanos , Procesamiento de Imagen Asistido por Computador/métodos , Masculino , Persona de Mediana Edad , Modelos Estadísticos , Análisis Multivariante
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