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Title:Connectivity of functional brain networks during ostracism : doctoral dissertation
Authors:ID Lesar, Mateja (Author)
ID Levnajić, Zoran (Mentor) More about this mentor... New window
ID Drevenšek, Gorazd (Comentor)
ID Rogelj, Peter (Comentor)
Files:.pdf DR_Lesar_Mateja_2026.pdf (7,34 MB)
MD5: 59D224D9856151B7797C56D7F77CDA19
 
Language:English
Work type:Doctoral dissertation
Typology:2.08 - Doctoral Dissertation
Organization:FIŠ - Faculty of Information Studies in Novo mesto
Abstract:This dissertation investigates two distinct yet interconnected aspects of human cognition: the influence of caffeine on cognitive performance and the neural dynamics of social exclusion. Using electroencephalography (EEG) as the primary methodological tool, this research builds on two neuroscience experiments to explore the brain activity underpinning these processes. The first experiment examines caffeine's impact on attention and cognitive performance through an auditory oddball paradigm and a mental arithmetic task. Results reveal that caffeine enhances cognitive performance by improving reaction times, accompanied by distinct changes in event-related potentials (ERPs), particularly the P3 component, and the resting-state EEG dynamics. The study demonstrates the ‘ritual dimension’ of coffee: while behavioural effects appeared after consumption of both caffeine and placebo, specific neural changes (P3 modulation, reduced alpha/beta power) occurred only after caffeine ingestion. Cardiovascular responses further show caffeine's physiological impacts. The second experiment addresses the mental state of social exclusion through the Cyberball paradigm, focusing on its neural correlates. EEG findings reveal important differences in the brain activity between inclusion and exclusion conditions. Statistical analyses reveal theta oscillations at CP2 and increased activity at ROI dACC during exclusion. Functional connectivity analyses show network-level reconfiguration across multiple frequency bands. Machine learning classification achieved ~99% accuracy (subject-variant) and ~58% (subject-invariant), revealing high inter-individual variability while identifying distributed network patterns. Together, these experiments underscore the utility of EEG, combined with advanced data science methods, in enhancing our understanding of human brain mechanisms behind cognitive processes and social conditions. The overall findings contribute to both the theoretical framework and the practical applications of cognitive neuroscience.
Keywords:electroencephalography, cognitive performance, social cognition, auditory oddball, Cyberball, functional brain connectivity, statistical analysis, machine learning
Publication status:Published
Publication version:Version of Record
Place of publishing:Novo mesto
Place of performance:Novo mesto
Publisher:M. Lesar
Year of publishing:2026
Year of performance:2026
Number of pages:XXIII, 240 str.
PID:20.500.12556/ReVIS-13459 New window
COBISS.SI-ID:273363715 New window
UDC:616.8
Note:Na ov.: Doctoral dissertation;
Publication date in ReVIS:31.03.2026
Views:31
Downloads:0
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Licences

License:CC BY-NC-ND 4.0, Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International
Link:http://creativecommons.org/licenses/by-nc-nd/4.0/
Description:The most restrictive Creative Commons license. This only allows people to download and share the work for no commercial gain and for no other purposes.

Secondary language

Language:Slovenian
Title:Povezljivost funkcionalnih možganskih omrežij ob socialni izključenosti : doktorska disertacija
Abstract:Disertacija raziskuje dva različna, a medsebojno povezana vidika človeške kognicije: vpliv kofeina na kognitivno zmogljivost in funkcionalno povezljivost socialne izključenosti. Kot glavno metodološko orodje je uporabljena elektroencefalografija (EEG), ki omogoča raziskovanje korelacij kognitivnih procesov z možgansko aktivnostjo. Prvi eksperiment proučuje vpliv kofeina na pozornost in kognitivno zmogljivost z uporabo naloge slušne pozornosti (ang. auditory oddball task) in naloge mentalne aritmetike. Rezultati kažejo, da kofein izboljšuje kognitivno zmogljivost s krajšanjem reakcijskega časa. To spremljajo specifične spremembe z dogodkom povezanih potencialov (ERP), predvsem komponente P3, ter dinamike EEG v stanju mirovanja. Študija razkriva `ritualno dimenzijo`pitja kave: medtem ko so se vedenjski učinki pojavili pri obeh skupinah, so se specifične nevralne spremembe (modulacija P3, znižana alfa/beta moč) pojavile le po zaužitju kofeina. Kardiovaskularni odzivi dodatno potrjujejo fiziološke učinke kofeina. Drugi eksperiment obravnava socialno izključenost prek Cyberball paradigme in se osredotoča na njene nevronske korelate. Ugotovitve EEG kažejo pomembne razlike v možganski aktivnosti med pogoji vključenosti in izključenosti. Statistične analize so razkrile theta oscilacije na elektrodi CP2 in povečano aktivnost ROI dACC med izključenostjo. Analize funkcionalne povezljivosti so pokazale razlikovaanje omrežij med socialno izključenostjo in vključenostjo v več frekvenčnih pasovih. Strojno učenje je doseglo natančnost klasifikacije ~99 % (subject-variant pristop) in ~58 % (subject-invariant pristop), kar razkriva visoko intersubjektno variabilnost ter različne mrežne vzorce. Skupaj eksperimenta poudarjata uporabnost EEG v kombinaciji z naprednimi analitičnimi metodami pri poglabljanju razumevanja kognitivnih in socialnih procesov. Ugotovitve prispevajo k teoretičnim okvirjem in praktičnim aplikacijam v kognitivni znanosti.
Keywords:elektroencefalografija, kognitivna zmogljivost, socialna kognicija, socialna izključenost, naloga slušne pozornosti, funkcionalna možganska povezljivost, Cyberball, statistična analiza, strojno učenje


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