Image processing software for Near Earth Objects (NEOs) detection

Treballs Finals de Grau de Física, Facultat de Física, Universitat de Barcelona, Any: 2014, Tutor: Jorge NúñezThe development of image processing software has been one of the most relevant achievements in astronomy of the last decade. After succeeding to get technical improvement on telescopes and detection systems it was needed to perfect the image processing software in order to make good use of the equipment provided. Matched lter algorithms were implemented within a exible test oriented software which allows the exploration of various scenarios that could arise during the research. These matched lter techniques have proved to be more precise when processing stellar imagery for asteroid detection and tracking. The main purpose of this report is to put into operation the image processing code SALTAD, which stands for SAIC Algorithm Test bed for Asteroid Detection, and compare its results with another image processing software, Visual PinPoint

Dynamic and functional alterations of neuronal networks in vitro upon physical damage: a proof of concept

There is a growing technological interest in combining biological neuronal networks with electronic ones, specifically for biological computation, human-machine interfacing and robotic implants. A major challenge for the development of these technologies is the resilience of the biological networks to physical damage, for instance, when used in harsh environments. To tackle this question, here, we investigated the dynamic and functional alterations of rodent cortical networks grown in vitro that were physically damaged, either by sequentially removing groups of neurons that were central for information flow or by applying an incision that cut the network in half. In both cases, we observed a remarkable capacity of the neuronal cultures to cope with damage, maintaining their activity and even reestablishing lost communication pathways. We also observed¿particularly for the cultures cut in half¿that a reservoir of healthy neurons surrounding the damaged region could boost resilience by providing stimulation and a communication bridge across disconnected areas. Our results show the remarkable capacity of neuronal cultures to sustain and recover from damage, and may be inspirational for the development of future hybrid biological-electronic systems

Spontaneous brain activity in healthy aging: an overview through fluctuations and regional homogeneity

Introduction: This study aims to explore whole-brain resting-state spontaneous brain activity using fractional amplitude of low-frequency fluctuation (fALFF) and regional homogeneity (ReHo) strategies to find differences among age groups within a population ranging from middle age to older adults. Methods: The sample comprised 112 healthy persons (M = 68.80, SD = 7.99) aged 48-89 who were split into six age groups (< 60, 60-64, 65-69, 70-74, 75-79, and ≥ 80). Fractional amplitude of low-frequency fluctuation and ReHo analyses were performed and were compared among the six age groups, and the significant results commonly found across groups were correlated with the gray matter volume of the areas and the age variable. Results: Increased activity was found using fALFF in the superior temporal gyrus and inferior frontal gyrus when comparing the first group and the fifth. Regarding ReHo analysis, Group 6 showed increased ReHo in the temporal lobe (hippocampus), right and left precuneus, right caudate, and right and left thalamus depending on the age group. Moreover, significant correlations between age and fALFF and ReHo clusters, as well as with their gray matter volume were found, meaning that the higher the age, the higher the regional synchronization, the lower the fALFF activation, and the lower gray matter of the right thalamus. Conclusion: Both techniques have been shown to be valuable and usable tools for disentangling brain changes in activation in a very low interval of years in healthy aging

Functional interactions in patients with hemianopia: A graph theory-based connectivity study of resting fMRI signal

Podeu consultar les dades primàries associades a l'article a: http://hdl.handle.net/2445/136617The assessment of task-independent functional connectivity (FC) after a lesion causing hemianopia remains an uncovered topic and represents a crucial point to better understand the neural basis of blindsight (i.e. unconscious visually triggered behavior) and visual awareness. In this light, we evaluated functional connectivity (FC) in 10 hemianopic patients and 10 healthy controls in a resting state paradigm. The main aim of this study is twofold: first of all we focused on the description and assessment of density and intensity of functional connectivity and network topology with and without a lesion affecting the visual pathway, and then we extracted and statistically compared network metrics, focusing on functional segregation, integration and specialization. Moreover, a study of 3-cycle triangles with prominent connectivity was conducted to analyze functional segregation calculated as the area of each triangle created connecting three neighboring nodes. To achieve these purposes we applied a graph theory-based approach, starting from Pearson correlation coefficients extracted from pairs of regions of interest. In these analyses we focused on the FC extracted by the whole brain as well as by four resting state networks: The Visual (VN), Salience (SN), Attention (AN) and Default Mode Network (DMN), to assess brain functional reorganization following the injury. The results showed a general decrease in density and intensity of functional connections, that leads to a less compact structure characterized by decrease in functional integration, segregation and in the number of interconnected hubs in both the Visual Network and the whole brain, despite an increase in long-range inter-modules connections (occipito-frontal connections). Indeed, the VN was the most affected network, characterized by a decrease in intra- and inter-network connections and by a less compact topology, with less interconnected nodes. Surprisingly, we observed a higher functional integration in the DMN and in the AN regardless of the lesion extent, that may indicate a functional reorganization of the brain following the injury, trying to compensate for the general reduced connectivity. Finally we observed an increase in functional specialization (lower between-network connectivity) and in inter-networks functional segregation, which is reflected in a less compact network topology, highly organized in functional clusters. These descriptive findings provide new insight on the spontaneous brain activity in hemianopic patients by showing an alteration in the intrinsic architecture of a large-scale brain system that goes beyond the impairment of a single RSN

Rich dynamics and functional organization on topographically designed neuronal networks in vitro

Neuronal cultures are a prominent experimental tool to understand complex functional organization in neuronal assemblies. However, neurons grown on flat surfaces exhibit a strongly coherent bursting behavior with limited functionality. To approach the functional richness of naturally formed neuronal circuits, here we studied neuronal networks grown on polydimethylsiloxane (PDMS) topographical patterns shaped as either parallel tracks or square valleys.We followed the evolution of spontaneous activity in these cultures along 20 days in vitro using fluorescence calcium imaging. The networks were characterized by rich spatiotemporal activity patterns that comprised from small regions of the culture to its whole extent. Effective connectivity analysis revealed the emergence of spatially compact functional modules that were associated with both the underpinned topographical features and predominant spatiotemporal activity fronts. Our results showthe capacity of spatial constraints tomold activity and functional organization, bringing new opportunities to comprehend the structure-function relationship in living neuronal circuits

Estimation of brain functional connectivity in patients with mild cognitive impairment.

Mild cognitive impairment is defined as greater cognitive decline than expected for a person at a particular age and is sometimes considered a stage between healthy aging and Alzheimer's disease or other dementia syndromes. It is known that functional connectivity patterns change in people with this diagnosis. We studied functional connectivity patterns and functional segregation in a resting-state fMRI paradigm comparing 10 MCI patients and 10 healthy controls matched by education level, age and sex. Ninety ROIs from the automated anatomical labeling (AAL) atlas were selected for functional connectivity analysis. A correlation matrix was created for each group, and a third matrix with the correlation coefficient differences between the two matrices was created. Functional segregation was analyzed with the 3-cycle method, which is novel in studies of this topic. Finally, cluster analyses were also performed. Our results showed that the two correlation matrices were visually similar but had many differences related to different cognitive functions. Differences were especially apparent in the anterior default mode network (DMN), while the visual resting-state network (RSN) showed no differences between groups. Differences in connectivity patterns in the anterior DMN should be studied more extensively to fully understand its role in the differentiation of healthy aging and an MCI diagnosis

Dynamic and Functional Alterations of Neuronal Networks In Vitro upon Physical Damage: A Proof of Concept

There is a growing technological interest in combining biological neuronal networks with electronic ones, specifically for biological computation, human–machine interfacing and robotic implants. A major challenge for the development of these technologies is the resilience of the biological networks to physical damage, for instance, when used in harsh environments. To tackle this question, here, we investigated the dynamic and functional alterations of rodent cortical networks grown in vitro that were physically damaged, either by sequentially removing groups of neurons that were central for information flow or by applying an incision that cut the network in half. In both cases, we observed a remarkable capacity of the neuronal cultures to cope with damage, maintaining their activity and even reestablishing lost communication pathways. We also observed—particularly for the cultures cut in half—that a reservoir of healthy neurons surrounding the damaged region could boost resilience by providing stimulation and a communication bridge across disconnected areas. Our results show the remarkable capacity of neuronal cultures to sustain and recover from damage, and may be inspirational for the development of future hybrid biological–electronic systems

Functional interactions in patients with hemianopia: a graph theory-based connectivity study of resting fMRI signal (Raw data)

There are twenty zip files each one corresponding to a participant. The acronym PT stands for patients (from 01 to 10) and HC stands for healthy controls (from 01 to 10). Once unzipped, structural and functional data of each patient and healthy control are located in the folder indicated by the specific acronym and number of the participant (i.e. PT01). Thus, each folder contains the original functional data of the resting state sequence (fmri.nii.gz), the preprocessed functional data (fmri_res.nii.gz), the original structural T1-weighted image (T1.nii.gz) and the structural T1-weighted image after applying the brain extraction with the Brain Extraction Tool of fsl (T1_brain.nii.gz) and used to perform the co-registration with the functional data. All images are in NIfTI (Neuroimaging Computer Technology Initiative) format, as a gzip compressed file, normally used by different software as the software library FMRIB (FSL). We also provide the NIfTI file of the AAL Atlas used to parcellate the brain during the analysis (AAL_Contract_90_3MM.nii) and the corresponding text file indicating the list of regions composing the atlas (AAL_LabelID_90.txt).Podeu consultar el document publicat a: http://hdl.handle.net/2445/161359Dades primàries associades a un article publicat a la revista PLoS One, 2020, vol. 15, num. 1, p. e0226816 [https://doi.org/10.1371/journal.pone.0226816]We tested 10 hemianopic patients and 10 healthy participants. They were scanned in a 1.5 Tesla Philips scanner at the Borgo Roma Hospital in Verona (Italy). We collected a whole brain high-resolution (1x1x1 mm3) 3D T1-weighted image with magnetization-prepared rapid acquisition gradient echo (MPRAGE) and one hundred sixty resting state volumes with TR=2500ms, Echo Time=50ms; 30 slices with slice thickness of 4mm, Field of View = 224x224mm, time duration = 6.47m and echo train length = 39. The entire sample was were scanned during the period of time going from February 2017 until July 2018

Psicothema

Resumen tomado de la publicaciónConectividad dinámica funcional en situación de reposo y envejecimiento sano: análisis de redes mediante ventanas móviles. Antecedentes: la Teoría de Grafos se ha utilizado para estudiar los cambios de la conectividad cerebral en el envejecimiento sano. Trabajos recientes han centrado su interés en los cambios dinámicos en registro fMRI en estado de reposo para identificar patrones no estacionarios en el proceso de envejecimiento. Este artículo tiene como objetivo caracterizar la dinámica de la red fMRI para estudiar envejecimiento saludable. Método: se registraron 114 adultos sanos mayores de 65 años en un paradigma de estado de reposo mediante señal fMRI. Se usó Teoría de Grafos para medir el grado medio de conectividad, la longitud promedio de las conexiones, el coeficiente de agrupamiento y el small-world de cada subred. Se evaluó el impacto de la edad y el tiempo en cada medida de grafo. Resultados: se detectó un efecto combinado de la edad y el tiempo en diversas medidas, los participantes de 75 a 79 años mostraron una tendencia curvilínea de la densidad y agrupación de red reducidas, pero un coeficiente small-world mayor en las ventanas centrales. Conclusión: se observó un efecto de la edad en la longitud promedio y los participantes más jóvenes mostraron puntuaciones más bajas en los indicadores de red.Universidad de Oviedo. Biblioteca de Psicología; Plaza Feijoo, s/n.; 33003 Oviedo; Tel. +34985104146; Fax +34985104126; [email protected]

Age-related changes in resting-state functional connectivity in older adults

Age-related changes in the brain connectivity of healthy older adults have been widely studied in recent years, with some differences in the obtained results. Most of these studies showed decreases in general functional connectivity, but they also found increases in some particular regions and areas. Frequently, these studies compared young individuals with older subjects, but few studies compared different age groups only in older populations. The purpose of this study is to analyze whole-brain functional connectivity in healthy older adult groups and its network characteristics through functional segregation. A total of 114 individuals, 48 to 89 years old, were scanned using resting-state functional magnetic resonance imaging in a resting state paradigm and were divided into six different age groups (< 60, 60–64, 65–69, 70–74, 75–79, ≥ 80 years old). A partial correlation analysis, a pooled correlation analysis and a study of 3-cycle regions with prominent connectivity were conducted. Our results showed progressive diminution in the functional connectivity among different age groups and this was particularly pronounced between 75 and 79 years old. The oldest group (≥ 80 years old) showed a slight increase in functional connectivity compared to the other groups. This occurred possibly because of compensatory mechanism in brain functioning. This study provides information on the brain functional characteristics of every age group, with more specific information on the functional progressive decline, and supplies methodological tools to study functional connectivity characteristics. Approval for the study was obtained from the ethics committee of the Comisión de Bioética de la Universidad de Barcelona (approval No. PSI2012-38257) on June 5, 2012, and from the ethics committee of the Barcelona’s Hospital Clínic (approval No. 2009-5306 and 2011-6604) on October 22, 2009 and April 7, 2011 respectively