Photo of Michal Pietrzak

Michal Pietrzak

Resident Physician at the University Hospital in Linköping and PhD student at CSAN.

Ongoing research projects

  • ”Behavioral, affective and cognitive consequences of bariatric surgery”
  • ”Effects of the appetite-inducing hormone ghrelin on decision making in healthy volunteers”

Ghrelin, a hormone produced in the stomach, is the endogenous ligand for the growth hormone secretagogue receptor (GHSR), and promotes appetite through hypothalamic actions. GHS-R is also expressed in brain areas involved in motivation and decision-making, such as the mesolimbic dopamine (DA) pathway. Reduction of ghrelin levels is thought to be an important mechanism contributing to the weight loss following bariatric surgery. Findings also have shown that ghrelin influences drug- and food reward as well as novelty seeking. Finally, ghrelin also plays a role in integrating central circuitry involved in anxiety and responses to stress.

Decision making processes that involve reward and risk assessment subserve the solution of the tradeoff between exploiting available resources vs exploring the environment for novel resources. We hypothesize that these processes are modulated by signals that communicate the availability of food.

Publications

2024

Reinoud Kaldewaij, Paula Salamone, Adam Enmalm, Lars Östman Vasko, Michal Pietrzak, Hanna Karlsson, Andreas Löfberg, Emelie Gauffin, Martin Samuelsson, Sarah Gustavson, Andrea Johansson Capusan, Håkan Olausson, Markus Heilig, Rebecca Böhme (2024) Ketamine reduces the neural distinction between self- and other-produced affective touch: a randomized double-blind placebo-controlled study Neuropsychopharmacology (Article in journal) Continue to DOI
Michal Pietrzak, Adam Yngve, Paul J. Hamilton, Anna Asratian, Emelie Gauffin, Andreas Löfberg, Sarah Gustavson, Emil Persson, Andrea Johansson Capusan, Lorenzo Leggio, Irene Perini, Gustav Tinghög, Markus Heilig, Rebecca Böhme (2024) Ghrelin decreases sensitivity to negative feedback and increases prediction-error related caudate activity in humans, a randomized controlled trial Neuropsychopharmacology, Vol. 49, p. 1042-1049 (Article in journal) Continue to DOI

2023

Michal Pietrzak, Adam Yngve, Paul Hamilton, Robin Kämpe, Rebecca Böhme, Anna Asratian, Emelie Gauffin, Andreas Löfberg, Sarah Gustavsson, Emil Persson, Andrea Johansson Capusan, Lorenzo Leggio, Irene Perini, Gustav Tinghög, Markus Heilig (2023) A randomized controlled experimental medicine study of ghrelin in value-based decision making Journal of Clinical Investigation, Vol. 133, Article e168260 (Article in journal) Continue to DOI

2020

Irene Perini, Robin Kämpe, Theodor Arlestig, Hanna Karlsson, Andreas Löfberg, Michal Pietrzak, Abraham Zangen, Markus Heilig (2020) Repetitive transcranial magnetic stimulation targeting the insular cortex for reduction of heavy drinking in treatment-seeking alcohol-dependent subjects: a randomized controlled trial Neuropsychopharmacology, Vol. 45, p. 842-850 (Article in journal) Continue to DOI

Research

Organisation