Learning Centre

Dynamic similarity of brain activity in humans: from single areas to functional networks

 |  Login

Show simple item record

dc.contributor Aalto-yliopisto fi
dc.contributor Aalto University en
dc.contributor.author Glerean, Enrico
dc.date.accessioned 2015-11-25T10:02:20Z
dc.date.available 2015-11-25T10:02:20Z
dc.date.issued 2015
dc.identifier.isbn 978-952-60-6542-7 (electronic)
dc.identifier.isbn 978-952-60-6541-0 (printed)
dc.identifier.issn 1799-4942 (electronic)
dc.identifier.issn 1799-4934 (printed)
dc.identifier.issn 1799-4934 (ISSN-L)
dc.identifier.uri https://aaltodoc.aalto.fi/handle/123456789/18764
dc.description.abstract What makes us similar and different? The intriguing problem has been studied throughout the centuries by philosophers and scientists and affects the way we live our lives in relationship to the people around us. The brain can process the external world in a similar way across people and even across animal species, but the boundary between similar/different is a dynamic one that changes in space – "where" in the brain we are similar – and in time – "when" brain activity is similar between us. It has been possible to show how localized brain regions show varying levels of intersubject similarity during controlled and naturalistic experiments using functional magnetic resonance imaging. However, the temporal dimension – "when" brain activity is similar between two brains – has remained poorly explored. Furthermore, the brain is a network and the concept of network-level intersubject similarity poses novel challenges especially when considering inter-individual differences both between and within healthy and clinical populations. Here we studied how intersubject similarity of brain activity is modulated in time due to the content of the stimuli or to the psychological perspective that subjects take. These novel problems led to the development of new methods to quantify instantaneous similarity between brains. In addition, moving emphasis from local neuronal activity to distributed network activity, we addressed the challenge of defining the similarity between brain subnetworks to identify their intersubject similarity in relation to behavioural measures. In the first study we used videoclips to induce strong emotions during fMRI scanning and computed how time-varying intersubject correlation of brain activity was modulated by the emotional experience. Feeling similar emotions makes the brains tick in sync. In the second study we introduced novel measures for instantaneous brain similarity for local activity and for dynamic functional connectivity. In the third study we considered how taking different psychological perspectives is reflected in brain activity. Finally, in the fourth study we isolated functional brain networks of high functioning individuals with autism spectrum disorder and healthy controls while watching a feature film, and proposed a method to correlate the autism quotient and the configuration of brain subnetworks. The work presented here reflects recent developments in human non-invasive neuroscience, by stressing the importance of the temporal dimension from local activity dynamics to time-varying networks and the individuality of each brain in relationship to others. Mutual understanding and similarity of behaviour between individuals might be related to similarity of brain function and structure. Although the causality of such relationships might be difficult to disentangle, the current work proposes tools to quantify them. en
dc.format.extent 81 + app. 73
dc.format.mimetype application/pdf en
dc.language.iso en en
dc.publisher Aalto University en
dc.publisher Aalto-yliopisto fi
dc.relation.ispartofseries Aalto University publication series DOCTORAL DISSERTATIONS en
dc.relation.ispartofseries 199/2015
dc.relation.haspart [Publication 1]: Nummenmaa, L., Glerean, E., Viinikainen, M., Jääskeläinen, I. P., Hari, R., & Sams, M. (2012). Emotions promote social interaction by synchronizing brain activity across individuals. Proceedings of the National Academy of Sciences, 109(24), 9599–604. DOI:10.1073/pnas.1206095109
dc.relation.haspart [Publication 2]: Glerean, E., Salmi, J., Lahnakoski, J. M., Jääskeläinen, I. P., & Sams, M. (2012). Functional magnetic resonance imaging phase synchronization as a measure of dynamic functional connectivity. Brain Connectivity, 2(2), 91–101. DOI:10.1089/brain.2011.0068
dc.relation.haspart [Publication 3]: Lahnakoski, J. M., Glerean, E., Jääskeläinen, I. P., Hyönä, J., Hari, R., Sams, M., & Nummenmaa, L. (2014). Synchronous brain activity across individuals underlies shared psychological perspectives. NeuroImage, 100, 316–324. DOI:10.1016/j.neuroimage.2014.06.022
dc.relation.haspart [Publication 4]: Glerean, E., Pan, R. K., Salmi, J., Kujala, R., Lahnakoski, J., Roine, U., Nummenmaa, L., Leppämäki, S., Nieminen-von Wendt, T., Tani, P., Saramäki, J., Sams, M., & Jääskeläinen, I. P. (2015). Reorganization of functionally connected brain subnetworks in high-functioning autism. Neurons and Cognition. http://arxiv.org/abs/1503.04851, 35 pages. (Under revision in Human Brain Mapping)
dc.subject.other Medical sciences en
dc.title Dynamic similarity of brain activity in humans: from single areas to functional networks en
dc.type G5 Artikkeliväitöskirja fi
dc.contributor.school Perustieteiden korkeakoulu fi
dc.contributor.school School of Science en
dc.contributor.department Neurotieteen ja lääketieteellisen tekniikan laitos fi
dc.contributor.department Department of Neuroscience and Biomedical Engineering en
dc.subject.keyword brain en
dc.subject.keyword fMRI en
dc.subject.keyword intersubject similarity en
dc.subject.keyword phase synchronization en
dc.subject.keyword graph theory en
dc.subject.keyword functional connectivity en
dc.subject.keyword autism en
dc.identifier.urn URN:ISBN:978-952-60-6542-7
dc.type.dcmitype text en
dc.type.ontasot Doctoral dissertation (article-based) en
dc.type.ontasot Väitöskirja (artikkeli) fi
dc.contributor.supervisor Sams, Mikko, Prof., Aalto University, Department of Neuroscience and Biomedical Engineering, Finland
dc.opn Honey, Christopher J., Assistant Prof., University of Toronto, Canada
dc.contributor.lab Brain and Mind Laboratory en
dc.rev Hasson, Uri, Prof., Princeton University, USA
dc.rev Tohka, Jussi, Docent, Universidad Carlos III de Madrid, Spain
dc.date.defence 2015-12-18
local.aalto.digifolder Aalto_64672
local.aalto.formfolder 2015_11_25_klo_09_59
local.aalto.archive yes
local.aalto.digiauth ask

Files in this item

This item appears in the following Collection(s)

Show simple item record

Search archive

Advanced Search

article-iconSubmit a publication