Search results for " morphometry"
showing 10 items of 80 documents
Examining stability of independent component analysis based on coefficient and component matrices for voxel-based morphometry of structural magnetic …
2018
Independent component analysis (ICA) on group-level voxel-based morphometry (VBM) produces the coefficient matrix and the component matrix. The former contains variability among multiple subjects for further statistical analysis, and the latter reveals spatial maps common for all subjects. ICA algorithms converge to local optimization points in practice and the mostly applied stability investigation approach examines the stability of the extracted components. We found that the practically stable components do not guarantee to produce the practically stable coefficients of ICA decomposition for the further statistical analysis. Consequently, we proposed a novel approach including two steps: …
An integrated approach to the study of Hypericum occurring in Sicily
2020
An integrated approach to the study of taxa of the genus Hypericum occurring in Sicily is proposed. The results of morphological, biochemical, and molecular analyses are combined to better assess the relationships between the species investigated and test the suitability of DNA barcoding technique in the discrimination of these taxa. For the name Hypericum aegypticum subsp. webbii (Spach) N. Robson a lectotype is designated. For Hypericum triquetrifolium Turra a lectotype and a supporting epitype are designated. The presence of Hypericum perforatum L. subsp. perforatum is excluded from Sicily and the previous reports have to be referred to H. perforatum subsp. veronense (Schrank) Ces. Hyper…
Brain Structure MR Imaging Methods: Morphometry and Tractography
2013
Brain morphology is in constant change from the very beginning of the neurodevelopment in human beings. The characterization of the brain morphology and its biological implications on a specific subject is a complex task which requires efficient computational approaches. Radiology has traditionally assessed the main brain changes in different alterations from a macroscopic point of view, thus, not considering subtle changes as a results of neuronal plasticity. In conjunction with functional information, the structural neuroimaging methods have established as the key in the diagnosis of several central nervous system disorders, including tumours, neurodegenerative disorders and psychiatric d…
2020
Regular physical activity (PA) offers positive effects on the human body. However, the effects of PA on cognition and in the brain are less clear. In this paper, we narratively review the relationship of PA with cognition and dementia, first from general perspective and then through genetically informed studies on the topic. Then we move on to imaging studies on exercise and brain anatomy first by presenting an overall picture of the topic and then discussing brain imaging studies addressing PA and brain structure in twins in more detailed way. Regarding PA and cognition or dementia, genetically informed studies are uncommon, even though the relationship between PA and cognitive ageing has …
Neuroanatomical changes in early Parkinson’s disease with mild cognitive impairment: a VBM study; the Parkinson’s Disease Cognitive Impairment Study …
2021
Introduction: Mild cognitive impairment (MCI) is common in Parkinson’s disease (PD), but the underlying pathological mechanism has not been fully understood. Voxel-based morphometry could be used to evaluate regional atrophy and its relationship with cognitive performances in early PD-MCI. Patients and Methods: One hundred and six patients with PD were recruited from a larger cohort of patients, the Parkinson’s Disease Cognitive Impairment Study (PaCoS). Subject underwent a T1-3D MRI and a complete clinical and neuropsychological evaluation. Patients were divided into PD with normal cognition (PD-NC) and PD-MCI according to the MDS level II criteria–modified for PD-MCI. A subgroup of early …
Brain Morphometry and Psychobehavioural Measures in Autistic Low-Functioning Subjects
1997
In the last two decades neurological research has significantly increased knowledge on the neuroanatomic bases of autism. Several autopsy and quantitative magnetic resonance imaging (MRI) studies have reported central nervous system (CNS) abnormalities which may underlie the social, language and cognitive dysfunction typical of the autistic disorder.Despite the wealth of evidence that the “autistic brain” is different from normal in a number of structures, the relationship between the severity of the developmental impairment in autism and the degree of the brain abnormality remains unknown.The aim of the present study is to correlate the areas of some brain regions, as calculated on the bas…
Gray Matter Changes in Adolescents Participating in a Meditation Training
2020
Meditation has shown to benefit a wide range of conditions and symptoms, but the neural mechanisms underlying the practice remain unclear. Magnetic resonance imaging (MRI) studies have investigated the structural brain changes due to the practice by examining volume, density, or cortical thickness changes. However, these studies have focused on adults; meditation’s structural effects on the adolescent brain remain understudied. In this study, we investigated how meditation training affects the structure of the adolescent brain by scanning a group of 38 adolescents (16.48 ± 1.29 years) before and after participating in a 12-week meditation training. Subjects underwent Training for Awareness,…
Chronic Background Radiation Correlates With Sperm Swimming Endurance in Bank Voles From Chernobyl
2022
Sperm quantity and quality are key features explaining intra- and interspecific variation in male reproductive success. Spermatogenesis is sensitive to ionizing radiation and laboratory studies investigating acute effects of ionizing radiation have indeed found negative effects of radiation on sperm quantity and quality. In nature, levels of natural background radiation vary dramatically, and chronic effects of low-level background radiation exposure on spermatogenesis are poorly understood. The Chernobyl region offers a unique research opportunity for investigating effects of chronic low-level ionizing radiation on reproductive properties of wild organisms. We captured male bank voles (Myo…
Lake size and fish diversity determine resource use and trophic position of a top predator in high-latitude lakes
2015
Prey preference of top predators and energy flow across habitat boundaries are of fundamental importance for structure and function of aquatic and terrestrial ecosystems, as they may have strong effects on production, species diversity, and food-web stability. In lakes, littoral and pelagic food-web compartments are typically coupled and controlled by generalist fish top predators. However, the extent and determinants of such coupling remains a topical area of ecological research and is largely unknown in oligotrophic high-latitude lakes. We analyzed food-web structure and resource use by a generalist top predator, the Arctic charr Salvelinus alpinus (L.), in 17 oligotrophic subarctic lakes…