Browsing by Subject "functional connectivity"
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Activity and functional connectivity of key nodes in depression network : A resting state EEG study (2024)Major Depressive Disorder (MDD) is a prevalent health issue worldwide, yet one third of patients are unresponsive to first-line treatment. Repetitive Transcranial Magnetic Stimulation (rTMS) is a promising alternative treatment and better understanding of the neural network impairments associated with MDD could significantly improve its efficacy. Recent research has identified a ‘depression network’ involving key brain regions, suggesting that MDD symptoms arise from functional connectivity impairments within this network. This thesis aims to map the activity and functional connectivity of six bilateral regions of interest (ROIs) implicated in MDD: dorsolateral prefrontal cortex (dlPFC), dorsomedial prefrontal cortex (dmPFC), ventromedial prefrontal cortex (vmPFC), inferior frontal gyrus (IFG), intraparietal sulci (IPS) and pre-supplementary motor area (pre-SMA). The intention is to describe biomarkers of depression and map the depression network to identify connectivity impairments between these cortical sites. Literature on these ROIs was reviewed and rsEEG data from 24 MDD patients and 9 healthy controls was collected to analyze the activity and functional connectivity of selected ROIs. Our results suggest that MDD involves widespread connectivity impairment including in regions that have not previously been included in the research on depression, such as IFG and IPS. Most ROIs showed trends of reduced activity in delta, theta, alpha and beta bands. The effects were most noticeable in the theta band, especially in the IFG, dmPFC, and dlPFC. However, the functional connectivity impairments were more prominent and significant, particularly in the beta and alpha bands. Notably, the IPS and vmPFC stood out as key nodes with the most dysfunctional connections in MDD. These findings support the idea of a depression network characterized by connectivity abnormalities rather than localized activity impairments. This study emphasizes the importance of a network-based approach in understanding MDD. The search for biomarkers as well as novel stimulation targets should consider regions beyond the traditional dlPFC or the frontal cortex, to include regions such as IPS, IFG and vmPFC.
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(2013)We have not succeeded to halt biodiversity loss despite international agreements. Conserving ecological connectivity is crucial when conserving biodiversity in the long run. This thesis studies policy instruments that promote ecological connectivity and conserve ecological processes. The aim of this study is to find out how Finnish environmental policy should be developed in order to promote ecological connectivity and biodiversity conservation. The research questions are: 1) How current nature conservation policy instruments promote ecological connectivity? 2) How policy instruments could promote ecological connectivity better? 3) Could green infrastructure approach help to conserve biodiversity? Ecological connectivity affects the biodiversity especially trough species dispersal. The environment is governed by different policy instruments, which have various effects on ecological connectivity. The green infrastructure is a new policy approach that underlines holistic planning. The green infrastructure is ecologically connected network of green and blue spaces that produces ecosystem services. The data comes from a SCALES project survey on Securing the Conservation of Biodiversity Across Administrative Levels and Spatial, Ecological and Temporal Scales. A link to the web-based questionnaire was sent to 214 Finnish experts of ecological connectivity and 47 persons answered to the questions. The data was analysed quantitatively and qualitatively. The main analysis methods were repeated measures ANOVA and cluster analysis. Content analysis was done from qualitative data. The experts thought that ecological connectivity is more important than the current consideration shows. The policy instruments that promote ecological connectivity in the best way are the instruments, which have a wide spatial cover and urban and small-scale instruments are considered worse. The potential of policy instruments to promote ecological connectivity is higher than the current implementation demonstrates. The integration of biodiversity conservation to the other sector policies is considered important. Nature conservation was thought to be more important aspect than ecosystem services in implementation of green infrastructure. The respondent believed that green infrastructure has could have potential of enhancing nature conservation.
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