Author
University of TurkuORCID 0000-0002-9405-7301Unclaimed ORCID profile · follow to get notified of new preprints
9 papers
Recent·Most cited
Lihua Sun, Heidi Liljenbäck, Jenni Virta, Johan Rajander, Semi Helin, Emrah Yatkin, Jing Tang, Anne Roivainen
This study shows that seasonal photoperiod cycling reduces inter-individual variability in mu-opioid receptor density in rats compared to constant photoperiod conditions.
bioRxiv · Aug 5, 2026 · PreprintNeuroscience
Kerttu Seppälä, Vesa Putkinen, Harri Harju, Eleni Rebelos, Jussi Hirvonen, Semi Helin, Johan Rajander, Henry K. Karlsson, Jani P. Saunavaara, Jukka Hyönä, Lauri Nummenmaa
This study investigates how the endogenous opioid system modulates brain responses to threat and safety signals in humans using fMRI and PET.
Molecular Psychiatry · Dec 24, 2025Peer-reviewedNeuroscience
Tuomo Noppari, Jouni Tuisku, Lasse Lukkarinen, Pekka Tani, Nina Lindberg, Emma Saure, Hannu Lauerma, Jari Tiihonen, Jussi Hirvonen, Semi Helin, Johan Rajander, Juha Salmi, Lauri Nummenmaa
This study investigates dopamine D2R and opioid MOR receptor availabilities in ASD using PET imaging and finds reduced D2R availability in striatum and nucleus accumbens, and MOR changes in hippocampi and precuneus.
bioRxiv · Apr 9, 2024 · PreprintNeuroscience
Lasse Lukkarinen, Jouni Tuisku, Lihua Sun, Semi Helin, Henry K. Karlsson, Niina Venetjoki, Marja Salomaa, Päivi Rautio, Jussi Hirvonen, Hannu Lauerma, Jari Tiihonen, Lauri Nummenmaa
This study finds reduced D2R availability in psychopathic offenders compared to controls, suggesting a potential neuromolecular pathway for psychopathy.
bioRxiv · Jun 21, 2023 · PreprintNeuroscience
Patrick Jern, Jinglu Chen, Jouni Tuisku, Tiina Saanijoki, Jussi Hirvonen, Lasse Lukkarinen, Sandra Manninen, Semi Helin, Vesa Putkinen, Lauri Nummenmaa
This study uses PET and fMRI to show endogenous opioid release in the hippocampus and increased hemodynamic activity in brain regions associated with sexual arousal following orgasm.
bioRxiv · Dec 21, 2022 · PreprintNeuroscience
Anniina Snellman, Laura L. Ekblad, Jouni Tuisku, Mikko Koivumäki, Nicholas James Ashton, Juan Lantero‐Rodriguez, Thomas K. Karikari, Semi Helin, Marco Bucci, Eliisa Löyttyniemi, Riitta K Parkkola, Mira Karrasch, Michael Schöll, Henrik Zetterberg, Kaj Blennow, Juha O. Rinne
The paper examines the effect of APOE ε4 gene dose on glial reactivity and β-amyloid pathology in cognitively unimpaired individuals using PET, MRI, and plasma biomarkers.
bioRxiv · Sep 19, 2022 · PreprintNeuroscience
Lihua Sun, Richard Aarnio, Erika Atencio Herre, Salli Kärnä, Senthil Palani, Helena Virtanen, Heidi Liljenbäck, Jenni Virta, Aake Honkaniemi, Vesa Oikonen, Chunlei Han, Sanna Laurila, Marco Bucci, Semi Helin, Emrah Yatkin, , Anne Roivainen
This study investigates how photoperiod affects mu-opioid receptor availability in brown adipose tissue using PET imaging and immunofluorescence in rats.
bioRxiv · Apr 8, 2022 · PreprintMolecular Biology
Henry K. Karlsson, Lauri J. Tuominen, Semi Helin, Paulina T. P. Salminen, Pirjo Nuutila, Lauri Nummenmaa
This study shows that bariatric surgery restores disrupted opioid-dopamine interaction in the ventral striatum of obese individuals.
Translational Psychiatry · May 1, 2021Peer-reviewedNeuroscience
Lihua Sun, Jing Ping Tang, Heidi Liljenbäck, Aake Honkaniemi, Jenni Virta, Janne Isojärvi, Tomi Karjalainen, Tatu Kantonen, Pirjo Nuutila, Jarmo A. Hietala, Valtteri Kaasinen, Kari K. Kalliokoski, Jussi Hirvonen, Harry Scheinin, Semi Helin, , Lauri Nummenmaa
This study finds seasonal variation in brain mu-opioid receptor availability in humans, showing an inverted U-shaped relationship with daylength.
Journal of Neuroscience · Dec 23, 2020Peer-reviewedNeuroscience