Nikolas Karalis: exploring the brain dynamics of our internal states

Portrait Published February 15 2024
Open / close summary

Nikolas Karalis joined the Brain Institute in January 2024. His work will focus on the fundamental link between brain activity and neurotransmitter balance.

What is your background?

My academic journey began in Greece, where I completed a Bachelor’s and Master’s degree in mathematics and physics. Alongside my studies, my interest in neurobiology began to take shape, particularly in understanding the neural mechanisms underlying consciousness and brain dysfunction.

During an Erasmus exchange in Toulouse, I worked on the analysis of human data focusing on the neural correlates of meditation among expert meditators and yoga practitioners. This experience provided valuable insights into interdisciplinary research methodologies and helped me realize the need and importance of my technical training for the study of the brain.

Subsequently, I pursued a Master’s degree in neuroscience, split between Berlin and Bordeaux, where my research concentrated on investigating interactions among specific brain regions during fear-induced behaviors in mice, laying the groundwork for my doctoral studies.

For my Ph.D., I moved to Tübingen and later Munich in Germany, where I continued exploring the oscillatory architecture of neuronal circuits. It was during this phase that we discovered a fundamental phenomenon: the influence of breathing patterns on organizing and coordinating the neuronal activity and dynamics across various brain regions, leading to a deeper investigation into this phenomenon. Indeed, we found that the breathing rhythm generators provide an “internal copy” of this rhythm to the rest of the brain, which is used to synchronize the activity of different regions.

Transitioning to Basel for my postdoctoral work, I expanded my research interests while maintaining a focus on understanding the mechanisms organizing brain activity and their role in implementing internal states. This period of exploration served as a crucial stepping stone in my academic journey, ultimately guiding me to my current position, starting a new team at the Paris Brain Institute.

Why did you apply to Paris Brain Institute?

The primary motivation behind my application to the Paris Brain Institute stems from the institution’s unique profile. What particularly appealed to me was the Institute’s emphasis on multidisciplinary collaboration, offering the opportunity to engage with researchers investigating various aspects of brain function using diverse methodologies.

Unlike institutes focusing solely on specific disorders, the Paris Brain Institute provides a platform for interaction across a spectrum of research domains. This includes but is not limited to, studies ranging from disease pathology to cognitive processes, computational approaches, and fundamental neurobiological investigations. The breadth of research interests and methodologies, spanning from genetics to network dynamics, from cellular mechanisms to whole-brain studies, is truly compelling.

Moreover, the Institute offers access to cutting-edge facilities, essential for conducting state-of-the-art research. Recognizing that groundbreaking discoveries often emerge from environments that foster innovation, the opportunity to work within such a dynamic and well-equipped setting greatly influenced my decision to apply.

What will you be working on?

In my upcoming work, I aim to build upon the research trajectory established during my postdoctoral tenure. Specifically, my focus will be on elucidating the influence of various neuromodulators on different brain regions across diverse behavioral states. By investigating this phenomenon, I intend to delve deeper into understanding how these neuromodulatory mechanisms contribute to the fundamental organization of neural circuits within the brain. This line of inquiry holds promise for uncovering insights into the intricate dynamics of brain function and its implications for cognition and behavior.

Concurrently, our research endeavors will persist in investigating the phenomenon of oscillatory synchronization within the brain, alongside the intricate processes of brain-body interaction and interoception. This next phase of our work will involve a more comprehensive exploration of the underlying mechanisms governing these processes, with a particular emphasis on elucidating the bidirectional causal influence of the body on the brain and vice versa. By elucidating the role and function of these processes in both healthy brain function and pathological states, we aim to advance our understanding of their significance for cognition and overall brain health.

Scientific teams

Team "Neuronal Circuits & Brain Dynamics"
Team leader
Nikolas KARALIS Team leader Contact by email

We are interested in how neuronal circuits are organized and how the collective action of neurons gives rise to the emergent complex brain dynamics and behavior.
We focus on how neurochemicals and bodily signals influence the brain.
  • We study how the simultaneous release of neuromodulators, such as dopamine and serotonin, influences the activity of neurons and the coordination of brain regions
  • We also study how bodily signals, such as breathing, serve as fundamental elements of the oscillatory circuit architecture
  • We employ our approach to study the brain dynamics during behavior and sleep and their involvement in the transformation of fleeting experiences into long-term memories

To answer these fundamental questions about the nature and function of the brain, we combine a range of cutting-edge neurotechnologies that enable us to observe and control the activity of the brain.


Using these approaches, we aim to identify and explore the fundamental principles of neural circuit organization and apply our understanding for the improvement of the human condition.

Read more