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14 results on '"Vallinoja, Jaakko"'

8. Gating Patterns to Proprioceptive Stimulation in Various Cortical Areas : An MEG Study in Children and Adults using Spatial ICA

Author

Vallinoja, Jaakko, Jaatela, Julia, Nurmi, Timo, Piitulainen, Harri, Department of Neuroscience and Biomedical Engineering, Aalto-yliopisto, and Aalto University

Subjects
magnetoencephalography, MEG, liikeaisti, independent component analysis, proprioception, signaalianalyysi, ärsykkeet, paired stimulus, somatosensory
Abstract

Proprioceptive paired-stimulus paradigm was used for 30 children (10–17 years) and 21 adult (25–45 years) volunteers in magnetoencephalography (MEG). Their right index finger was moved twice with 500-ms interval every 4 ± 25 s (repeated 100 times) using a pneumatic-movement actuator. Spatial-independent component analysis (ICA) was applied to identify stimulus-related components from MEG cortical responses. Clustering was used to identify spatiotemporally consistent components across subjects. We found a consistent primary response in the primary somatosensory (SI) cortex with similar gating ratios of 0.72 and 0.69 for the children and adults, respectively. Secondary responses with similar transient gating behavior were centered bilaterally in proximity of the lateral sulcus. Delayed and prolonged responses with strong gating were found in the frontal and parietal cortices possibly corresponding to larger processing network of somatosensory afference. No significant correlation between age and gating ratio was found. We confirmed that cortical gating to proprioceptive stimuli is comparable to other somatosensory and auditory domains, and between children and adults. Gating occurred broadly beyond SI cortex. Spatial ICA revealed several consistent response patterns in various cortical regions which would have been challenging to detect with more commonly applied equivalent current dipole or distributed source estimates.

Published
2021

9. Stronger proprioceptive BOLD-responses in the somatosensory cortices reflect worse sensorimotor function in adolescents with and without cerebral palsy

Author

Nurmi, Timo, Jaatela, Julia, Vallinoja, Jaakko, Mäenpää, Helena, Piitulainen, Harri, Department of Neuroscience and Biomedical Engineering, University of Helsinki, Aalto-yliopisto, Aalto University, HUS Children and Adolescents, and Lastenneurologian yksikkö

Subjects
CP-oireyhtymä, CHILDREN, SM1, PASSIVE FINGER, DP, diplegic, 3124 Neurology and psychiatry, EVOKED-POTENTIALS, BRAIN, Child, MOTOR CORTEX, Passive movement, TE, echo time, EM, expectation maximization, liikeaisti, BOLD, Blood-Oxygen-Level-Dependent signal, Regular Article, Magnetic Resonance Imaging, TD, typically-developed, TR, repetition time, SII, GMFCS, Gross Motor Function Classification System, MANCOVA, Multivariate analysis of covariance, EPI, echo planar imaging, HP, hemiplegic, fMRI, functional magnetic resonance imaging, Female, TACTILE STIMULATION, halvaus, AGE-RELATED DIFFERENCES, Adolescent, Computer applications to medicine. Medical informatics, R858-859.7, Hemiplegia, ORGANIZATION, Diplegia, tuntoaisti, MOVEMENT, SIPT, Sensory Integration and Praxis Tests, ROI, regions of interest, Humans, SI, SII cortex, secondary somatosensory cortex, CP, cerebral palsy, RC346-429, ComputingMethodologies_COMPUTERGRAPHICS, GLM, General Linear Model, Cerebral Palsy, 3112 Neurosciences, SPM, Statistical Parametric Mapping, Somatosensory Cortex, Hand, Proprioception, SI cortex, primary somatosensory cortex, GABA CONCENTRATION, Kinesthesia, Neurology. Diseases of the nervous system, PSC, percent signal change
Abstract

Graphical abstract, Highlights • Cerebral palsy adolescents had stronger proprioceptive BOLD-responses. • Cerebral palsy adolescents had worse sensorimotor performance. • Stronger BOLD-responses were associated with worse sensorimotor performance., Cerebral palsy (CP) is a motor disorder where the motor defects are partly due to impaired proprioception. We studied cortical proprioceptive responses and sensorimotor performance in adolescents with CP and their typically-developed (TD) peers. Passive joint movements were used to stimulate proprioceptors during functional magnetic resonance imaging (fMRI) session to quantify the proprioceptive responses whose associations to behavioral sensorimotor performance were also examined. Twenty-three TD (15 females, age: mean ± standard deviation 14.2 ± 2.4 years) and 18 CP (12 females, age: mean ± standard deviation, 13.8 ± 2.3 years; 12 hemiplegic, 6 diplegic) participants were included in this study. Participants’ index fingers and ankles were separately stimulated at 3 Hz and 1 Hz respectively with pneumatic movement actuators. Regions-of-interest were used to quantify BOLD-responses from the primary sensorimotor (SM1) and secondary (SII) somatosensory cortices and were compared across the groups. Associations between responses strengths and sensorimotor performance measures were also examined. Proprioceptive responses were stronger for the individuals with CP compared to their TD peers in SM1 (p

Published
2021

13. Feasibility of Collaborative Indoor Positioning Using Smartphones

Author

Särkkä, Simo, Solin, Arno, Perustieteiden korkeakoulu, Saramäki, Jari, Vallinoja, Jaakko, Särkkä, Simo, Solin, Arno, Perustieteiden korkeakoulu, Saramäki, Jari, and Vallinoja, Jaakko

Abstract

A reliable indoor positioning service for smartphones is a service that is often requested. There are several competing technologies already available but a lot of basic research is still done on the subject. This thesis studies the applicability and technological possibilities of improving the performance of a positioning service using peer to peer collaboration. The Bluetooth low energy technology (BLE) offers a possibility to use peer to peer radio signal measurements with smartphones. This could be used to improve the performance of existing positioning algorithms if enough service users are in close proximity to each other. In this thesis a pedestrian simulation system was implemented to study the probability that two positioning service users are in close enough proximity to each other for BLE usage. The suitability of BLE as the collaboration technology was studied by implementing a particle filter based positioning system that uses BLE measurements to track a smartphone. Finally the collaborative BLE system was integrated on top of an existing geomagnetic tracking algorithm and the effect on the positioning performance was studied. It was concluded that the BLE as a technology is suitable for positioning use despite the large measurement uncertainty. BLE based collaboration is feasible in improving the positioning results provided that the basic positioning technology is reliable enough. The pedestrian simulations concluded that with realistic expected number of users in one building most sessions would not benefit from collaboration but it would still likely happen frequently., Luotettava sisätilapaikannuspalvelu on haluttu ominaisuus mobiilipalveluiden kehityksessä. Useita kilpailevia ratkaisuja on jo markkinoilla, mutta ongelman parissa tehdään vielä huomattavan paljon perustutkimusta. Tässä diplomityössä tutkitaan mahdollisuutta parantaa paikannusjärjestelmän toimintaa käyttäen vertaisyhteistyötä. Bluetooth low energy -teknologia (BLE) tarjoaa mahdollisuuden käyttää laitteiden välisiä radiosignaalimittauksia älypuhelimilla. Tätä voidaan mahdollisesti hyödyntää parantamaan olemassa olevien paikannusalgoritmien toimintaa, jos riittävästi käyttäjiä on riittävän lähellä toisiaan. Tässä diplomityössä toteutettiin ihmisjoukkojen liikettä sisätiloissa mallintava järjestelmä, jolla tutkittiin todennäköisyyttä, että kaksi paikannusjärjestelmän käyttäjää olisi riittävän lähellä toisiaan käyttääkseen BLE-radiomittauksia. BLE:n soveltuvuutta paikannusteknologiana tutkittiin toteuttamalla partikkelisuotimeen perustuva paikannusjärjestelmä, joka käyttää BLE-mittauksia älypuhelimen seuraamiseen. Lopuksi BLE mittausjärjestelmä integroitiin olemassa olevaan magneettikenttään perustuvaan paikannusalgoritmiin ja BLE-yhteistyön vaikutusta algoritmin toimintaan tutkittiin. Työ osoitti, että BLE on paikannuskäyttöön soveltuva teknologia suuresta mittausepävarmuudesta huolimatta. BLE-perusteinen yhteistyö paikannustuloksen parantamisessa on toimiva ratkaisu, mikäli varsinainen paikannusteknologia on riittävän luotettava. Realistisesti odotettavissa olevilla paikannuspalvelun käyttäjämäärillä BLE-yhteistyötä todennäköisesti tapahtuisi suhteellisen usein, vaikka suurin osa paikannussessioista ei pääsisikään hyötymään siitä.

Published
2016

14. Gating Patterns to Proprioceptive Stimulation in Various Cortical Areas: An MEG Study in Children and Adults using Spatial ICA.

Author

Vallinoja J, Jaatela J, Nurmi T, and Piitulainen H

Subjects
Adolescent, Adult, Child, Evoked Potentials, Somatosensory physiology, Female, Humans, Magnetoencephalography, Male, Middle Aged, Cerebral Cortex physiology, Proprioception physiology
Abstract

Proprioceptive paired-stimulus paradigm was used for 30 children (10-17 years) and 21 adult (25-45 years) volunteers in magnetoencephalography (MEG). Their right index finger was moved twice with 500-ms interval every 4 ± 25 s (repeated 100 times) using a pneumatic-movement actuator. Spatial-independent component analysis (ICA) was applied to identify stimulus-related components from MEG cortical responses. Clustering was used to identify spatiotemporally consistent components across subjects. We found a consistent primary response in the primary somatosensory (SI) cortex with similar gating ratios of 0.72 and 0.69 for the children and adults, respectively. Secondary responses with similar transient gating behavior were centered bilaterally in proximity of the lateral sulcus. Delayed and prolonged responses with strong gating were found in the frontal and parietal cortices possibly corresponding to larger processing network of somatosensory afference. No significant correlation between age and gating ratio was found. We confirmed that cortical gating to proprioceptive stimuli is comparable to other somatosensory and auditory domains, and between children and adults. Gating occurred broadly beyond SI cortex. Spatial ICA revealed several consistent response patterns in various cortical regions which would have been challenging to detect with more commonly applied equivalent current dipole or distributed source estimates., (© The Author(s) 2020. Published by Oxford University Press.)

Published
2021
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