Browsing by Author "Hirvonen, Jussi"

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  • Alterations in Microstructure and Local Fiber Orientation of White Matter Are Associated with Outcome after Mild Traumatic Brain Injury
    (2020-12-15) Mohammadian, Mehrbod; Roine, Timo; Hirvonen, Jussi; Kurki, Timo; Posti, Jussi P.; Katila, Ari J.; Takala, Riikka S. K.; Tallus, Jussi; Maanpää, Henna-Riikka; Frantzen, Janek; Hutchinson, Peter J.; Newcombe, Virginia F.; Menon, David K.; Tenovuo, Olli
     A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
    Mild traumatic brain injury (mTBI) can have long-lasting consequences. We investigated white matter (WM) alterations at 6-12 months following mTBI using diffusion tensor imaging (DTI) and assessed if the alterations associate with outcome. Eighty-five patients with mTBI underwent diffusion-weighted magnetic resonance imaging (MRI) on average 8 months post-injury and patients' outcome was assessed at the time of imaging using the Glasgow Outcome Scale-Extended (GOS-E). Additionally, 30 age-matched patients with extracranial orthopedic injuries were used as control subjects. Voxel-wise analysis of the data was performed using a tract-based spatial statistics (TBSS) approach and differences in microstructural metrics between groups were investigated. Further, the susceptibility of the abnormalities to specific fiber orientations was investigated by analyzing the first eigenvector of the diffusion tensor in the voxels with significant differences. We found significantly lower fractional anisotropy (FA) and higher mean diffusivity (MD) and radial diffusivity (RD) in patients with mTBI compared with control subjects, whereas no significant differences were observed in axial diffusivity (AD) between the groups. The differences were present bilaterally in several WM regions and correlated with outcome. Moreover, multiple clusters were found in the principal fiber orientations of the significant voxels in anisotropy, and similar orientation patterns were found for the diffusivity metrics. These directional clusters correlated with patients' functional outcome. Our study showed that mTBI is associated with WM changes at the chronic stage and these alterations occur in several WM regions. In addition, several significant clusters of WM alterations in specific fiber orientations were found and these clusters were associated with outcome.
  • Brain structural alterations in autism and criminal psychopathy
    (2022) Noppari, Tuomo; Sun, Lihua; Lukkarinen, Lasse; Putkinen, Vesa; Tani, Pekka; Lindberg, Nina; Saure, Emma; Lauerma, Hannu; Tiihonen, Jari; Venetjoki, Niina; Salomaa, Marja; Rautio, Päivi; Hirvonen, Jussi; Salmi, Juha; Nummenmaa, Lauri
     A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
    The goal of this study was to elucidate the anatomical brain basis of social cognition through two disorders with distinctively different phenotypes of social interaction. We compared structural MR images of 20 individuals with autism spectrum disorder (ASD), 19 violent offenders with high psychopathic traits, and 19 control participants using voxel-based morphometry (VBM). Our earlier study showed lower grey matter volume (GMV) values in the insula, frontal cortex, and sensorimotor cortex of the offender group compared to controls. In the present study, the images of the ASD group revealed lower GMV in the left precuneus, right cerebellum, and right precentral gyrus in comparison with controls. The comparison between the offender and ASD groups showed lower GMV values for the right temporal pole and left inferior frontal gyrus in the offender group. There was also an overlap of both disorders in the right pre-central cortex, showing lower GMV compared to controls. Our findings suggest structural differences between violent offenders with high psychopathy traits and ASD individuals in the frontotemporal social brain network areas, previously associated with empathy. We also provide evidence of similar abnormal structures in the motor cortex for both of these disorders, possibly related to uniting issues of social cognition.
  • Decoding brain basis of laughter and crying in natural scenes
    (2023-06) Nummenmaa, Lauri; Malèn, Tuulia; Nazari-Farsani, Sanaz; Seppälä, Kerttu; Sun, Lihua; Santavirta, Severi; Karlsson, Henry K.; Hudson, Matthew; Hirvonen, Jussi; Sams, Mikko; Scott, Sophie; Putkinen, Vesa
     A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
    Laughter and crying are universal signals of prosociality and distress, respectively. Here we investigated the functional brain basis of perceiving laughter and crying using naturalistic functional magnetic resonance imaging (fMRI) approach. We measured haemodynamic brain activity evoked by laughter and crying in three experiments with 100 subjects in each. The subjects i) viewed a 20-minute medley of short video clips, and ii) 30 min of a full-length feature film, and iii) listened to 13.5 min of a radio play that all contained bursts of laughter and crying. Intensity of laughing and crying in the videos and radio play was annotated by independent observes, and the resulting time series were used to predict hemodynamic activity to laughter and crying episodes. Multivariate pattern analysis (MVPA) was used to test for regional selectivity in laughter and crying evoked activations. Laughter induced widespread activity in ventral visual cortex and superior and middle temporal and motor cortices. Crying activated thalamus, cingulate cortex along the anterior-posterior axis, insula and orbitofrontal cortex. Both laughter and crying could be decoded accurately (66–77% depending on the experiment) from the BOLD signal, and the voxels contributing most significantly to classification were in superior temporal cortex. These results suggest that perceiving laughter and crying engage distinct neural networks, whose activity suppresses each other to manage appropriate behavioral responses to others’ bonding and distress signals.
  • Dissociable neural systems for unconditioned acute and sustained fear
    (2020-08-01) Hudson, Matthew; Seppälä, Kerttu; Putkinen, Vesa; Sun, Lihua; Glerean, Enrico; Karjalainen, Tomi; Karlsson, Henry K.; Hirvonen, Jussi; Nummenmaa, Lauri
     A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
    Fear protects organisms by increasing vigilance and preparedness, and by coordinating survival responses during life-threatening encounters. The fear circuit must thus operate on multiple timescales ranging from preparatory sustained alertness to acute fight-or-flight responses. Here we studied the brain basis of sustained and acute fear using naturalistic functional magnetic resonance imaging (fMRI) enabling analysis of different time-scales of fear responses. Subjects (N ​= ​37) watched feature-length horror movies while their hemodynamic brain activity was measured with fMRI. Time-variable intersubject correlation (ISC) was used to quantify the reliability of brain activity across participants, and seed-based phase synchronization was used for characterizing dynamic connectivity. Subjective ratings of fear were used to assess how synchronization and functional connectivity varied with emotional intensity. These data suggest that acute and sustained fear are supported by distinct neural pathways, with sustained fear amplifying mainly sensory responses, and acute fear increasing activity in brainstem, thalamus, amygdala and cingulate cortices. Sustained fear increased ISC in regions associated with acute fear, and also amplified functional connectivity within this network. The results were replicated in an independent experiment with a different subject sample and stimulus movie. The functional interplay between cortical networks involved in sustained anticipation of, and acute response to, threat involves a complex and dynamic interaction that depends on the proximity of threat, and the need to employ threat appraisals and vigilance for decision making and response selection.
  • Dorsal striatum and its limbic connectivity mediate abnormal anticipatory reward processing in obesity
    (2012) Nummenmaa, Lauri; Hirvonen, Jussi; Hannukainen, Jarna C.; Immonen, Heidi; Lindroos, Markus M.; Salminen, Paulina; Nuutila, Pirjo
     A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
    Obesity is characterized by an imbalance in the brain circuits promoting reward seeking and those governing cognitive control. Here we show that the dorsal caudate nucleus and its connections with amygdala, insula and prefrontal cortex contribute to abnormal reward processing in obesity. We measured regional brain glucose uptake in morbidly obese (n = 19) and normal weighted (n = 16) subjects with 2-[18F]fluoro-2-deoxyglucose ([18F]FDG) positron emission tomography (PET) during euglycemic hyperinsulinemia and with functional magnetic resonance imaging (fMRI) while anticipatory food reward was induced by repeated presentations of appetizing and bland food pictures. First, we found that glucose uptake rate in the dorsal caudate nucleus was higher in obese than in normal-weight subjects. Second, obese subjects showed increased hemodynamic responses in the caudate nucleus while viewing appetizing versus bland foods in fMRI. The caudate also showed elevated task-related functional connectivity with amygdala and insula in the obese versus normal-weight subjects. Finally, obese subjects had smaller responses to appetizing versus bland foods in the dorsolateral and orbitofrontal cortices than did normal-weight subjects, and failure to activate the dorsolateral prefrontal cortex was correlated with high glucose metabolism in the dorsal caudate nucleus. These findings suggest that enhanced sensitivity to external food cues in obesity may involve abnormal stimulus-response learning and incentive motivation subserved by the dorsal caudate nucleus, which in turn may be due to abnormally high input from the amygdala and insula and dysfunctional inhibitory control by the frontal cortical regions. These functional changes in the responsiveness and interconnectivity of the reward circuit could be a critical mechanism to explain overeating in obesity.
  • Functional organization of social perception networks in the human brain
    (2023-05-15) Santavirta, Severi; Karjalainen, Tomi; Nazari-Farsani, Sanaz; Hudson, Matthew; Putkinen, Vesa; Seppälä, Kerttu; Sun, Lihua; Glerean, Enrico; Hirvonen, Jussi; Karlsson, Henry K.; Nummenmaa, Lauri
     A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
    Humans rapidly extract diverse and complex information from ongoing social interactions, but the perceptual and neural organization of the different aspects of social perception remains unresolved. We showed short movie clips with rich social content to 97 healthy participants while their haemodynamic brain activity was measured with fMRI. The clips were annotated moment-to-moment for a large set of social features and 45 of the features were evaluated reliably between annotators. Cluster analysis of the social features revealed that 13 dimensions were sufficient for describing the social perceptual space. Three different analysis methods were used to map the social perceptual processes in the human brain. Regression analysis mapped regional neural response profiles for different social dimensions. Multivariate pattern analysis then established the spatial specificity of the responses and intersubject correlation analysis connected social perceptual processing with neural synchronization. The results revealed a gradient in the processing of social information in the brain. Posterior temporal and occipital regions were broadly tuned to most social dimensions and the classifier revealed that these responses showed spatial specificity for social dimensions; in contrast Heschl gyri and parietal areas were also broadly associated with different social signals, yet the spatial patterns of responses did not differentiate social dimensions. Frontal and subcortical regions responded only to a limited number of social dimensions and the spatial response patterns did not differentiate social dimension. Altogether these results highlight the distributed nature of social processing in the brain.
  • Heat pumps in energy and cost efficient nearly zero energy buildings in Finland
    (2015) Hirvonen, Jussi; Jokisalo, Juha; Knuuti, Antti; Kosonen, Risto; Niemelä, Tuomo; Paiho, Satu; Pulakka, Sakari
     Commissioned report
  • Interindividual variability and lateralization of μ-opioid receptors in the human brain: Individual differences in the μ-opioid receptor system
    (2020-08-15) Kantonen, Tatu; Karjalainen, Tomi; Isojärvi, Janne; Nuutila, Pirjo; Tuisku, Jouni; Rinne, Juha; Hietala, Jarmo; Kaasinen, Valtteri; Kalliokoski, Kari; Scheinin, Harry; Hirvonen, Jussi; Vehtari, Aki; Nummenmaa, Lauri
     A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
    Alterations in the brain's μ-opioid receptor (MOR) system have been associated with several neuropsychiatric disorders. Central MOR availability also varies considerably in healthy individuals. Multiple epidemiological factors have been proposed to influence the MOR system, but due to small sample sizes the magnitude of their influence remains inconclusive. We compiled [11C]carfentanil positron emission tomography scans from 204 individuals with no neurologic or psychiatric disorders, and estimated the effects of sex, age, body mass index (BMI) and smoking on [11C]carfentanil binding potential using between-subject regression analysis. We also examined hemispheric differences in MOR availability. Older age was associated with increase in MOR availability in frontotemporal areas but decrease in amygdala, thalamus, and nucleus accumbens. The age-dependent increase was stronger in males. MOR availability was globally lowered in smokers but independent of BMI. Finally, MOR availability was higher in the right versus the left hemisphere. The presently observed variation in MOR availability may explain why some individuals are prone to develop MOR-linked pathological states, such as chronic pain or psychiatric disorders. Lateralized MOR system may reflect hemispheric work specialization in central emotion and pain processes.
  • Lisäinformaation arvo monikriteerisessä projektiportfoliovalinnassa
    (2015-07-29) Hirvonen, Jussi
     Perustieteiden korkeakoulu | Bachelor's thesis
  • Neural Circuits for Cognitive Appetite Control in Healthy and Obese Individuals: An fMRI Study
    (2015) Tuulari, Jetro J.; Karlsson, Henry K.; Hirvonen, Jussi; Salminen, Paulina; Nuutila, Pirjo; Nummenmaa, Lauri
     A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
    The mere sight of foods may activate the brain’s reward circuitry, and humans often experience difficulties in inhibiting urges to eat upon encountering visual food signals. Imbalance between the reward circuit and those supporting inhibitory control may underlie obesity, yet brain circuits supporting volitional control of appetite and their possible dysfunction that can lead to obesity remain poorly specified. Here we delineated the brain basis of volitional appetite control in healthy and obese individuals with functional magnetic resonance imaging (fMRI). Twenty-seven morbidly obese women (mean BMI = 41.4) and fourteen age-matched normal-weight women (mean BMI = 22.6) were scanned with 1.5 Tesla fMRI while viewing food pictures. They were instructed to inhibit their urge to eat the foods, view the stimuli passively or imagine eating the foods. Across all subjects, a frontal cortical control circuit was activated during appetite inhibition versus passive viewing of the foods. Inhibition minus imagined eating (appetite control) activated bilateral precunei and parietal cortices and frontal regions spanning anterior cingulate and superior medial frontal cortices. During appetite control, obese subjects had lower responses in the medial frontal, middle cingulate and dorsal caudate nuclei. Functional connectivity of the control circuit was increased in morbidly obese versus control subjects during appetite control, which might reflect impaired integrative and executive function in obesity.
  • Obesity Is Associated with Decreased µ-Opioid But Unaltered Dopamine D2 Receptor Availability in the Brain
    (2015) Karlsson, Henry K.; Tuominen, Lauri; Tuulari, Jetro J.; Hirvonen, Jussi; Parkkola, Riitta; Helin, Semi; Salminen, Paulina; Nuutila, Pirjo; Nummenmaa, Lauri
     A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
  • Plasma neurofilament light admission levels and development of axonal pathology in mild traumatic brain injury
    (2023-08-15) Hossain, Iftakher; Mohammadian, Mehrbod; Maanpää, Henna Riikka; Takala, Riikka S.K.; Tenovuo, Olli; van Gils, Mark; Hutchinson, Peter; Menon, David K.; Newcombe, Virginia F.; Tallus, Jussi; Hirvonen, Jussi; Roine, Timo; Kurki, Timo; Blennow, Kaj; Zetterberg, Henrik; Posti, Jussi P.
     A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
    BACKGROUND: It is known that blood levels of neurofilament light (NF-L) and diffusion-weighted magnetic resonance imaging (DW-MRI) are both associated with outcome of patients with mild traumatic brain injury (mTBI). Here, we sought to examine the association between admission levels of plasma NF-L and white matter (WM) integrity in post-acute stage DW-MRI in patients with mTBI. METHODS: Ninety-three patients with mTBI (GCS ≥ 13), blood sample for NF-L within 24 h of admission, and DW-MRI ≥ 90 days post-injury (median = 229) were included. Mean fractional anisotropy (FA), mean diffusivity (MD), axial diffusivity (AD), and radial diffusivity (RD) were calculated from the skeletonized WM tracts of the whole brain. Outcome was assessed using the Extended Glasgow Outcome Scale (GOSE) at the time of imaging. Patients were divided into CT-positive and -negative, and complete (GOSE = 8) and incomplete recovery (GOSE < 8) groups. RESULTS: The levels of NF-L and FA correlated negatively in the whole cohort (p = 0.002), in CT-positive patients (p = 0.016), and in those with incomplete recovery (p = 0.005). The same groups showed a positive correlation with mean MD, AD, and RD (p < 0.001-p = 0.011). In CT-negative patients or in patients with full recovery, significant correlations were not found. CONCLUSION: In patients with mTBI, the significant correlation between NF-L levels at admission and diffusion tensor imaging (DTI) measurements of diffuse axonal injury (DAI) over more than 3 months suggests that the early levels of plasma NF-L may associate with the presence of DAI at a later phase of TBI.
  • Procedural Generation of Infinite Formations
    (2021-10-18) Hirvonen, Jussi
     Perustieteiden korkeakoulu | Master's thesis
    In this master's thesis, we explore how an infinite formation can be achieved in a computer program. We call an infinite formation a data structure that, when expressed in a coordinate system, extends indefinitely in at least one direction. An infinite formation, as the name suggests, comprises an infinite amount of data. Because we do not have infinite storage space, infinite formations have to be procedurally generated. They cannot be fully generated, however, as it is not possible to finish generating a structure that has no end. By dividing an infinite formation into parts that are finite in size, the parts can be generated and utilized. Therefore, in order to use an infinite formation, it has to be represented by an algorithm that can procedurally generate the formation in parts. We examine three ways of procedurally representing infinite formations: fractals, hash functions and noise functions. To evaluate the suitability of these methods, we compare their products with a theoretical, perfect infinite formation. An ideal infinite formation is deterministic, consists of unique parts, and all its parts are accessible in constant time. Our conclusion is that of the methods considered, noise functions produce infinite formations with the best qualities.
  • Sähkö energiamuotona elintarviketeollisuudessa
    (1986) Arhela, Risto
     Helsinki University of Technology | Master's thesis
  • Sisällönluonti videopeleissä
    (2018-01-10) Hirvonen, Jussi
     Perustieteiden korkeakoulu | Bachelor's thesis
  • Social laughter triggers endogenous opioid release in humans
    (2017-06-21) Manninen, Sandra; Tuominen, Lauri; Dunbar, Robin I.; Karjalainen, Tomi; Hirvonen, Jussi; Arponen, Eveliina; Hari, Riitta; Jääskeläinen, Iiro P.; Sams, Mikko; Nummenmaa, Lauri
     A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
    The size of human social networks significantly exceeds the network that can be maintained by social grooming or touching in other primates. It has been proposed that endogenous opioid release after social laughter would provide a neurochemical pathway supporting long-term relationships in humans (Dunbar, 2012), yet this hypothesis currently lacks direct neurophysiological support. We used PET and the μ-opioid-receptor (MOR)-specific ligand [11C]carfentanil to quantify laughter-induced endogenous opioid release in 12 healthy males. Before the social laughter scan, the subjects watched laughter-inducing comedy clips with their close friends for 30 min. Before the baseline scan, subjects spent 30 min alone in the testing room. Social laughter increased pleasurable sensations and triggered endogenous opioid release in thalamus, caudate nucleus, and anterior insula. In addition, baseline MOR availability in the cingulate and orbitofrontal cortices was associated with the rate of social laughter. In a behavioral control experiment, pain threshold—a proxy of endogenous opioidergic activation—was elevated significantly more in both male and female volunteers after watching laughter-inducing comedy versus non-laughter-inducing drama in groups. Modulation of the opioidergic activity by social laughter may be an important neurochemical pathway that supports the formation, reinforcement, and maintenance of human social bonds.
  • Stochastic approach to mid- and long-term forecasting of ERCOT real-time electricity price
    (2016-05-10) Hirvonen, Jussi
     Perustieteiden korkeakoulu | Master's thesis
    Tämän työn tavoitteena on mallintaa päivän sisäistä sähkönhintaa Teksasissa sijaitsevalla ERCOT-markkinalla. Lisäksi kehitetään simulointimenetelmä, jolla voidaan luoda hinta-aikasarjoja useaksi vuodeksi tulevaisuuteen. Selittäjämuuttujien vaikutus huomioidaan mallinnuksessa. Sähkönhinnan ennustaminen on tärkeää esimerkiksi voimalaitosinvestointien kannattavuutta laskettaessa. ERCOT:ssa voimalaitokset myyvät sähköä kolmella markkinalla: seuraavan päivän (DA), päivän sisäisellä (RT) sekä reservituotemarkkinalla (AS). Tavallisesti vain DA-markkinan hinta huomioidaan investointilaskelmissa. Nopeat voimalaitokset voivat kuitenkin hyötyä merkittävästi RT-markkinahinnan liikkeistä ja erityisesti sen ja DA-markkinahinnan erosta. Sähkönhinnan ennustamiseksi on olemassa kahdenlaisia menetelmiä - fundamentaalisia ja stokastisia. DA-markkinahinnan ennustamiseen käytetään yleisesti tietokoneohjelmia, joiden antamat tulokset ovat varsin tarkkoja niin lyhyellä kuin pitkälläkin ennustehorisontilla. RT-markkinahinnalle ei kuitenkaan ole olemassa vastaavia pitkän aikavälin ratkaisuja. Tässä työssä tutkitaan tilastollisesti RT-markkinahinnan muodostumista. Löydettyihin selittäjämuuttujiin perustuen rakennetaan bootstrap-menetelmää käyttäen stokastinen ennustemalli. Korkeiden hintapiikkien nähdään useimmiten tapahtuvan korkean DA-markkinahinnan ja alhaisen vapaan sähköntuotantokapasiteetin aikoina. Tavallisimmalla hintatasolla selittäjämuuttujiksi valitaan DA-markkinahinta, vapaan sähköntuotantokapasiteetin ennustevirhe, tuulituotannon ylittävän kulutuksen muutosnopeus sekä edellinen RT-markkinahinta. Selittäjämuuttujien arvot simuloidaan sähkömarkkinamallinnukseen tarkoitetulla tietokoneohjelmalla ja Markovin ketjuihin perustuvalla stokastisella menetelmällä. Simulointimenetelmän toimivuus varmistetaan ennustamalla menneisyyden hintoja ja havaitsemalla ennusteet tarpeeksi samanlaisiksi toteutuneiden kanssa. RT-markkinahintaa simuloidaan kahdessa tulevaisuuden skenaariossa. Tuulituotannon määrän kasvun nähdään kasvattavan hintavaihteluita RT-markkinalla.
  • Structural Brain Connectivity Correlates with Outcome in Mild Traumatic Brain Injury
    (2022-03) Roine, Timo; Mohammadian, Mehrbod; Hirvonen, Jussi; Kurki, Timo; Posti, Jussi P.; Takala, Riikka S.K.; Newcombe, Virginia F.; Tallus, Jussi; Katila, Ari J.; Maanpää, Henna-Riikka; Frantzen, Janek; Menon, David; Tenovuo, Olli
     A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
    We investigated the topology of structural brain connectivity networks and its association with outcome after mild traumatic brain injury, a major cause of permanent disability. Eighty-five patients with mild traumatic brain injury underwent magnetic resonance imaging (MRI) twice, about three weeks and eight months after injury, and 30 age-matched orthopedic trauma control subjects were scanned. Outcome was assessed with Extended Glasgow Outcome Scale on average eight months after injury. We performed constrained spherical deconvolution-based probabilistic streamlines tractography on diffusion MRI data and parcellated cortical and subcortical gray matter into 84 regions based on T1-weighted data to reconstruct structural brain connectivity networks weighted by the number of streamlines. Graph theoretical methods were employed to measure network properties in both patients and controls, and correlations between these properties and outcome were calculated. We found no global differences in the network properties between patients with mild traumatic brain injury and orthopedic control subjects at either stage. We found significantly increased betweenness centrality of the right pars opercularis in the chronic stage compared with control subjects, however. Further, both global and local network properties correlated significantly with outcome. Higher normalized global efficiency, degree, and strength as well as lower small-worldness were associated with better outcome. Correlations between the outcome and the local network properties were the most prominent in the left putamen and the left postcentral gyrus. Our results indicate that both global and local network properties provide valuable information about the outcome already in the acute/subacute stage and, therefore, are promising biomarkers for prognostic purposes in mild traumatic brain injury.