Arvo building, Jarmo Visakorpi auditorium, address: Arvo Ylpön katu 34.
Doctoral defence of M.Sc. Meeri Mäkinen
The field of science of the dissertation is Cell and Tissue Technology.
The opponent is professor Ulrich Egert (University of Freiburg, Germany). Docent Susanna Narkilahti acts as the custos.
The language of the dissertation defence is English.
Electrically functional stem cell models aid in understanding the origins of brain activity
Brains are the center of our cognitive functions, required for learning and behaving, for thinking and feeling. The cognitive functions are carried out by electrically active neural networks. These neural networks are constructed during development as neurons become connected. Diseases and traumas disrupt the function of neurons and neural networks. These disruptions are reflected in our cognitive functions, for example as memory problems and blindness. The formation of brain activity and functionality, in heath and sickness, from individual neurons and neural networks remains poorly understood.
Master of Science, Meeri Mäkinen, sheds light on the topic in her Thesis, where she studied the formation of electrical network activity patterns in human stem cell derived neurons and neural networks. During development, the structure and the electrical activity of the brain are in constant change. This has been studied with animal models, especially in rodents. However, the structural development of human and rodent brain differs. This difference makes drawing conclusions about the human brain difficult.
- Human stem cell derived neurons resemble the neurons generated during the brain development. These neurons have the ability to produce electrical activity and they are able to organize into neural networks with patterned electrical activity. This in vitro model provides a unique opportunity to observe how the first connections are formed within the early neural networks and how the activity of the neural network is generated from its individual components, describes Meeri Mäkinen.
To understand the physiological properties of single neurons in the context the emerging network activity patterns, Mäkinen developed new tools for measurement and analysis in her Thesis.
- Newly born neurons differ from mature neurons in their physiology. They, for example, produce weaker electrical activity. Weak activity provides challenges for efficiently measuring the electrical network activity patterns. Furthermore, it is important to be able to reach a resolution that allows for the measurement of hundreds of individual neurons while measuring the activity produced by the network, claims Mäkinen.
The network activity pattern in human stem cell -derived neural networks arises from a mixed but cooperating population of neurons of different functional maturity. The mechanisms orchestrating the organization of network activity patterns in neural networks of human origin are the same as during rodent brain development. However, these mechanisms are utilized differently in the human neural networks. This is a promising start for understanding the detailed mechanism of brain activity generation in human neural networks.
The dissertation is published in the publication series of Acta Universitatis Tamperensis; 2391, Tampere University Press, Tampere 2018. The dissertation is also published in the e-series Acta Electronica Universitatis Tamperensis; 1900, Tampere University Press 2018.