Group members and Alumni

Sleep Team Helsinki Group consists of a variable number of staff and students.

Thirteen PhD students from the group have defended.

Educational activities of the group include monthly "Sleep School" seminars that are open for all interested in sleep research. The group has arranged several training courses for both domestic and international students on differents aspects of sleep and methods used in sleep research.

The group also regularly hosts both international students (through ERASMUS, CIMO and Fullbright programs) as well as visiting researchers.

Tarja Stenberg (Porkka-Heiskanen); MD, PhD

Tarja Stenberg (née Porkka-Heiskanen) is the group leader. She is responsible for the planning of the scientific activities as well as attracting funds for the research.

Her main scientific interests are the cellular level mechanisms of sleep homeostasis. Her work has established adenosine as a key molecule in regulation of sleep homeostasis , as well as basal forebrain as one of the central regulatory areas of sleep homeostasis.

She is the former president of the Brain Research Society of Finland and coordinator of three EU funded Frame Work Program consortia.

She is active in developing new teaching methods and gives numerous lectures on different aspects of sleep for both professionals and laymen.

Recent Publications
Henna-Kaisa Wigren; PhD, junior group leader

She is interested in the role of microglia in regulation of sleep/sleep loss and developmental aspects of sleep, including the effect of sleep on neural plasticity.

She leads her own research project:  "Microglial activation in sleep loss"  -and is responsible for the scientific development of the zebra fish project.

In addition, she  supervises the practical scientific work in the laboratory and mentors one PhD student and two Master's students.

She defended year 2009 on the topic "Cellular Mechanisms of Sleep Homeostasis: Studies on Brain Energy Metabolism and Aging". After that she worked as a postdoctoral student in Professor Kai Kaila's laboratory studying the early development of brain activities in neonatal rodent models.

Sarah Steffens, MSc in Neurobiology, PhD candidate

She is a Masters student through the ERASMUS program, interested in learning the methods of sleep research. She is studying, mentored by Dr. Wigren, the changes in microglial shape and mobility during different periods and types of sleep restriction in rodents. She is preparing a masters thesis on the topic for the University of Freiburg.

Heidi Ikonen, student

She is conducting research on the zebra fish model of sleep regulation, using it in long-term light/nutrition experiments, combined with sleep restriction. These studies have been funded by an European Union Grant EURhythDia ("Chronotherapeutic lifestyle intervention for diabetes and obesity to reset the circadian rhythm and improve cardiometabolic risk in the European working population"), which investigates the relationship between circadian rhythm and sleep disturbances and diseases, particularly type2diabetes and cardiometabolic diseases, in connection with shift work.  

Aho V, Vainikka M, Puttonen H, Ikonen H, Panula P, Porkka-Heiskanen T. Wigren H-K, Sleep rebound in light after sleep deprivation by water flow in zebrafish larvae. J Sleep Res. 2017


Sleep Team Helsinki has educated many alumni. In addition to scientific education, we include introductions to Finnish way of life for our foreign students.

This is introduction to cross country skiing.

Olena Santangeli (née Ventskovska), PhD Student

Her scientific interest is the relationship between sleep regulation and depression. She is preparing a dissertation on this topic, and has published already four articles. She studied and developed an animal model of depression, which reflects the consequences of early life stress on behavior and metabolism in adolescence and adulthood.

Santangeli O, Lehtikuja H, Palomäki E, Wigren HK, Paunio T, Porkka-Heiskanen T. Sleep and Behavior in Cross-Fostering Rats: Developmental and Sex Aspects. Sleep. 2016 Dec 1;39(12):2211-2221. doi: 10.5665/sleep.6328.

Vilma Aho, PhD

She defended year 2016 on the topic “Kuolema kuittaa univelat? Effects of cumulative sleep loss on immune functions and lipid metabolism.

The theses combined experimental sleep restriction studies to epidemiological studies in a unique way. She was able to show that sleep restriction launches defense reactions, which include activation of cytokines, and induce a state of low-grade inflammation. Also lipid metabolism was affected by sleep restriction. These data formed a basis for the hypothesis, that the epidemiologically evidenced connection between short/bad quality sleep may be induced via activation of a low grade inflammation.

Wiebke Theilmann PhD, postdoctoral fellow

She is working as a visiting researcher from Dr. Tomi Rantamäki’s group at the University of Helsinki.


Paula Araujo, PhD

She was a post doctoral researcher.  Worked on project clarifying the immunological consequences of restricted sleep. Returned to University of Sao Paulo, Brazil, where she works as a postdoctoral fellow.  

Stanislav Rozov, PhD

He works as a visiting researcher and consultant. Defended year 2016 on the topic “Circadian and Histaminergic regulation of the sleep-wake cycle”. Continues to work on the aspects of circadian regulation of sleep homeostasis.

Lauri Alanko MD, PhD

He defended year 2005 on the topic  “Adenosine during prolonged wakefulness in the rat brain”. Presently he works as a specialist in sports medicine at Helsinki region.

Sonja Sulkava MD, PhD student

She is studying genetics of sleep, supervised by Professor Tiina Paunio, and Tarja Stenberg as a co-mentor. Her latest publication shows that melatonin receptor variants are associated with job-related exhaustion in shift workers.

Common Genetic Variation Near Melatonin Receptor 1A Gene Linked to Job-Related Exhaustion in Shift Workers

Natalia Gass, PhD
Anna Kalinhuck PhD, visiting researcher, CIMO fellow

She worked in the group as a visiting researcher.  She was the PI in the nitric oxide project and responsible for the many important findings in that project. She contributed significantly also to the adenosine and energy metabolism studies. She works presently as an instructor at Harvard medical School.

Kalinchuk,A., Lu,Y., Stenberg,D., Rosenberg,P.A., Porkka-Heiskanen,T., Nitric oxide production in the basal forebrain is required for recovery sleep. J Neurochem. 99:483-498, 2006

Kalinchuk, A., Stenberg,D., Rosenberg, P., Porkka-Heiskanen,T., Inducible and neuronal nitric oxide synthases (NOS) have complementary roles in recovery sleep induction. Eur J Neurosci 24:1443-1456, 2006

Wessel van Leeuwen, PhD student

He prepares his dissertation while working at the Stress Research Institute in Stockholm, Sweden as research assistant. He has studied the effects of partial sleep restriction on human health and published several articles on the topic.

van Leeuwen WM, Hublin C, Sallinen M, Härmä M, Hirvonen A, Porkka-Heiskanen T. Prolonged sleep restriction affects glucose metabolism in healthy young men. Int J Endocrinol. 2010;2010:108641. doi: 10.1155/2010/108641.

van Leeuwen WM, Lehto M, Karisola P, Lindholm H, Luukkonen R, Sallinen M, Härmä M, Porkka-Heiskanen T, Alenius H. Sleep restriction increases the risk of developing cardiovascular diseases by augmenting proinflammatory responses through IL-17 and CRP.PLoS One. 2009;4(2):e4589. doi: 10.1371/journal.pone.0004589.

Andrey Kostin PhD, CIMO fellow

He worked in the group as a Marie Curie fellow, visiting researcher. He was responsible for the studies on nitric oxide electrophysiology. He works presently as senior researcher at UCLA.

Kostin A, Stenberg D, Porkka-Heiskanen T. Nitric oxide modulates the discharge rate of basal forebrain neurones: a study in freely moving rats. J Sleep Res. 2009 Dec;18(4):447-53. doi: 10.1111/j.1365-2869.2009.00761.x.

Kostin A, Stenberg D, Kalinchuk AV, Porkka-Heiskanen T. Nitric oxide modulates the discharge rate of basal forebrain neurons. Psychopharmacology (Berl). 2008 Nov;201(1):147-60. doi: 10.1007/s00213-008-1257-x.

Zoltan Lelkes MD, PhD

He is a regularly visiting senior researcher, located permanently at Szeged University, Hungary.

Lelkes Z, Porkka-Heiskanen T, Stenberg D.Cholinergic basal forebrain structures are involved in the mediation of the arousal effect of noradrenaline. J Sleep Res. 2013 Dec;22(6):721-6. doi: 10.1111/jsr.12061

Markus Lagus, PhD

He defended year 2013 on the project “Molecular mechanisms of sleep and mood” Professor Tiina Paunio as his principal mentor.

Leena Laine, B.Sc.

She worked as economist and was responsible for administration of two EU-funded consortia coordinated by Dr. Stenberg. Retired.

Nina Lindberg, MD, PhD

She defended year 2003 on the topic “Sleep in mental and behavioural disorders”. She works presently as acting Professor of Forensic Psychiatry at University of Helsinki.


Ernst Mecke, B.Sc.

He worked as laboratory technician and specialist in animal care. He also acted as language reviser for the group, as well as took care of briefing of the new laboratory members and students. Retired.

Hanna Ollila, PhD

She defended year 2012 on the topic “Genetics of Sleep - Sleep and Comorbidities - Connection at the Genetic Level”, professor Tiina Paunio as her principal mentor.  She works presently as postdoctoral fellow at Stanford.

Amy Sanders, ERASMUS student
Sergey Saveljev, CIMO fellow

He worked with the pharmacological depression model, clomipramine treatment, and showed that behavioral depression in clomipramine treated rats is associated with changes in sleep, particularly REM sleep, as well as adenosine, BDNF and nitric oxide levels.

Savelyev SA, Rantamäki T, Rytkönen KM, Castren E, Porkka-Heiskanen T. Sleep homeostasis and depression: studies with the rat clomipramine model of depression. Neuroscience. 2012 Jun 14;212:149-58. doi: 10.1016/j.neuroscience.2012.03.029

Silja Soini, M.Sc.

She prepared here Master's theses "Solunulkoisen adenosiinin lähde etuaivojen pohjaosassa univajeen aikana" mentored by Dr. Wigren and gained her degree year 2017.

Pekka Tani, MD, PhD

He defended year 2004 “Sleep in adults with asperger syndrome” and continues studies on Asperger syndorme at the clinick for neuropsychiatric disorders, Helsinki University Hospital.

Jussi Toppila, MD, PhD
Anna-Sofia Urrila, MD, PhD
Siddeshwar Utge, PhD

He defended year 2013 on the topic “A study of candidate genes in depression and disturbed sleep” Professor Tiina Paunio as his principal mentor.

Maija Vainikka

She was instrumental in setting up the early version of the zebra fish recording system and developing methods for sleep restriction in this species.

Aho V, Vainikka M, Puttonen H, Ikonen H, Panula P, Porkka-Heiskanen T. Wigren H-K, Sleep rebound in light after sleep deprivation by water flow in zebrafish larvae. J Sleep Res. 2017

Janneke Cornelia Zant, PhD

She defended year 2012 on the topic “What keeps us awake? The role of the ascending arousal system in the regulation of sleep and wakefulness mediated by the basal forebrain”. After completing a postdoctoral period at Harvard Medical School she  returned to Holland.

Kirsi-Marja Zitting (née Rytkönen), PhD