Biology subjects

Harju, H.

Publications and source records attributed to Harju, H..

5 recordsLinked to original sources

bioRxiv2025

CEREBRAL GLUCOSE UTILISATION DURING MUSICAL EMOTIONS: A MULTIMODAL FUNCTIONAL PET/MRI STUDY.

Functional magnetic resonance imaging (fMRI) studies have demonstrated music-induced activation of the blood-oxygen-level-dependent (BOLD) signal across brain networks associated with auditory perception, motor control, and emotion. However, BOLD-fMRI reflects vascular responses that may not fully capture underlying neural activity. Here, we used simultaneous [18F]fluorodeoxyglucose (FDG) functional positron emission tomography (fPET) and fMRI to examine glucose metabolism closely linked to neural activity, alongside hemodynamic responses during pleasurable music listening. Thirty-five female participants listened to self-selected pleasurable music and control stimuli while undergoing 90-minute PET-MRI scans. fPET revealed music-evoked increase in glucose consumption in auditory and motor cortices, as well as reward-related regions, including the nucleus accumbens (NAcc), caudate, insula, and orbitofrontal cortex. The fPET and fMRI results showed substantial overlap though some discrepancies were also observed. Notably, the NAcc exhibited increased glucose consumption in fPET but showed no activation in fMRI. Conversely, deactivation of the default mode network during music processing was only observed with fMRI. These results highlight the complementary nature of neurometabolic and neurovascular processes and offer novel insights into their dynamics during the processing of aesthetic rewards.

neuroscience↗

bioRxiv2025

TURBO: Automated Total-body PET Image Processing and Kinetic Modeling Toolbox

Long axial field of view (LAFOV) PET imaging requires a high level of automation and standardization, as the large number of target tissues increases the manual workload significantly. We introduce an automated analysis pipeline (TurBO, Turku total-BOdy) for preprocessing and kinetic modelling of LAFOV [15O]H2O and [18F]FDG PET data, enabling efficient and reproducible analysis of tissue perfusion and metabolism at regional and voxel-levels. The approach employs automated processing including co-registration, motion correction, automated CT segmentation for region of interest (ROI) delineation, image-derived input determination, and region-specific kinetic modelling of PET data. MethodsWe validated the analysis pipeline using Biograph Vision Quadra (Siemens Healthineers) LAFOV PET/CT scans from 21 subjects scanned with [15O]H2O and 16 subjects scanned with [18F]FDG using six segmented CT-based ROIs (cortical brain gray matter, left iliopsoas muscle, right kidney cortex and medulla, pancreas, spleen and liver) representing different levels of blood flow and glucose metabolism. ResultsModel fits showed good quality with consistent parameter estimates at both regional and voxel-levels (R{superscript 2} > 0.83 for [15O]H2O, R{superscript 2} > 0.99 for [18F]FDG). Estimates from manual and automated input functions were in concordance (R{superscript 2} > 0.74 for [15O]H2O, and R{superscript 2} > 0.78 for [18F]FDG) with minimal bias (<4% for [15O]H2O and <10% for [18F]FDG). Manually and automatically (CT-based) extracted ROI level data showed strong agreement (R{superscript 2} > 0.82 for [15O]H2O and R{superscript 2} > 0.83 for [18F]FDG), while motion correction had little impact on parameter estimates (R{superscript 2} > 0.71 for [15O]H2O and R{superscript 2} > 0.78 for [18F]FDG) compared with uncorrected data. ConclusionOur automated analysis pipeline provides reliable and reproducible parameter estimates across different regions, with an approximate processing time of 1-1.5 h per subject. This pipeline completely automates LAFOV PET analysis, reducing manual effort and enabling reproducible studies of inter-organ blood flow and metabolism, including brain-body interactions.

neuroscience↗

bioRxiv2025

Shared brain basis of aggression in clinical, forensic, and healthy samples: A meta-analysis

BackgroundAggression, violence, and antisocial behaviour constitute a large-scale societal problem. Aggression is common in incarcerated offenders and psychiatric conditions, but also healthy and noninstitutionalized populations vary in violent and aggressive behaviour. The brain basis of aggression has been studied extensively in the past, but the similarities between criminal, pathological and everyday aggression in the brain remain elusive. MethodsWe conducted an activation likelihood estimation (ALE) meta-analysis of 406 neuroimaging studies with 28 968 subjects using structural magnetic resonance imaging (MRI), functional magnetic resonance imaging (fMRI), positron emission tomography (PET) and single photon emission tomography (SPECT). The included studies had either i) measured haemodynamic responses during aggression-related functional tasks, ii) compared the brain structure, molecular organization, or function between aggressive forensic and psychiatric populations and control groups, or iii) addressed the effects of trait aggression on brain structure or function. ResultsAggression was consistently associated with altered function and structure in the amygdala, hippocampus, basal ganglia, anterior cingulate cortex, and the dorsolateral and orbitofrontal cortices. Functional coactivation analysis suggested that these regions are most consistently associated with emotional and reward function as well as their regulation. The results were comparable in healthy subjects as well as forensic and psychiatric populations. ConclusionsAggression is linked with alterations in multiple neurocognitive systems forming a common network for aggressiveness. Particularly the neural systems implicated in reward, emotions and regulation were commonly associated with aggression. The established network is involved in the whole continuum of aggression from benign variations in healthy volunteers to forensic subjects and violent clinical populations, suggesting a common aggression network whose severe perturbations may be linked with criminal behaviour or pathological aggression.

neuroscience↗

bioRxiv2024

Endogenous opioid system modulates proximal and distal threat signals in the human brain

BACKGROUNDFear promotes rapid detection of threats and appropriate fight-or-flight responses. The endogenous opioid system modulates responses to pain and psychological stressors. Opioid agonists also have also anxiolytic effects. Fear and anxiety constitute major psychological stressors for humans, yet the contribution of the opioid system to acute human fear remains poorly characterized. METHODSWe induced intense unconditioned fear in the subjects by gradually exposing them to a living constrictor snake (threat trials) versus an indoor plant (safety trials). Brain haemodynamic responses were recorded from 33 subjects during functional magnetic resonance imaging (fMRI). In addition, 15 subjects underwent brain positron emission tomography (PET) imaging using [11C]carfentanil, a high affinity agonist radioligand for -opioid receptors (MORs). PET studies under threat or safety exposure were performed on separate days. Pupillary arousal responses to snake and plant exposure were recorded in 36 subjects. Subjective fear ratings were measured throughout the experiments. RESULTSSelf-reports and pupillometric responses confirmed significant experience of fear and autonomic activation during the threat trials. fMRI data revealed that proximity with the snake robustly engaged brainstem defense circuits as well as thalamus, dorsal attention network, and motor and premotor cortices. These effects were diminished during repeated exposures. PET data revealed that [11C]carfentanil binding to MORs was significantly higher during the fear versus safety condition, and the acute haemodynamic responses to threat were dependent on baseline MOR binding in the cingulate gyrus and thalamus. Finally, baseline MOR tone predicted dampening of the haemodynamic threat responses during the experiment. CONCLUSIONSPreparatory response during acute fear episodes involves a strong motor component in addition to the brainstem responses. These haemodynamic changes are coupled with a deactivation of the opioidergic circuit, highlighting the role of MORs in modulating the human fear response.

neuroscience↗

bioRxiv2024

Pleasurable music activates cerebral μ-opioid receptors: A combined PET-fMRI study

The -opioid receptor (MOR) system mediates incentive motivation and the hedonic component of primary rewards such as food and sex. However, there is no direct in vivo evidence for the involvement of the MOR system in pleasure derived from aesthetic rewards such as music. We measured MOR activation with positron emission tomography (PET) and the agonist radioligand [11C] carfentanil with high affinity for MORs during the listening of pleasurable music and neutral baseline condition. Haemodynamic responses to pleasurable music were measured using functional magnetic resonance imaging (fMRI). The PET results revealed that pleasurable music increased [11C]carfentanil binding in several cortical and subcortical regions, including ventral striatum and orbitofrontal cortex, known to contain "hedonic hotspots". Individual variation in baseline MOR tone influenced pleasure-dependent haemodynamic responses during music listening in regions associated with interoceptive, sensorimotor, and reward processing. Our results provide the first-ever neuroimaging evidence that listening to pleasurable music modulates MOR system activation and indicate that the -opioid system governs complex aesthetic rewards in addition to biologically salient primary rewards.

neuroscience↗