Regulating habits

• Applicants: Professor Dr. Björn Brembs; Radostina Lyutova, Ph.D.
• Subject Area: Cognitive, Systems and Behavioural Neurobiology
• Term: since 2025
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 556082664

Humans and other animals can either react quickly and efficiently, but lose flexibility in the process, or they can act flexibly and deliberately, albeit with higher cognitive load and slower speed. This dichotomy is not innate but is continually regulated and adjusted by the nervous system. Initially slow and laborious actions such as writing, tying shoelaces, or riding a bicycle can become semi-automatic habits. Genetic analyses suggest that the process by which this regulation is accomplished evolved over 550 million years ago and has been conserved in evolution ever since. This implies that the regulatory process can be studied in all bilaterians, including the fruit fly Drosophila. In this organism, we have discovered that two distinct learning processes interact during this regulation, allowing the automation of behaviors to occur at different speeds. We now know of two populations of neurons essential for this regulation. Subpopulations of mushroom body neurons send inhibitory signals to the ventral nerve cord to influence the plasticity of motoneurons. The experiments proposed here investigate how mushroom body neurons shape these inhibitory signals and the path these signals take to reach the ventral nerve cord. In the long term, this research allows us to understand the neurobiological mechanism that allows habits to form at the adaptively correct time—neither too soon nor too late. In addition to enhancing our understanding of fundamental brain function, this research is also helpful in understanding the dysregulation of stereotypies, such as those that can occur in substance abuse disorders, Tourette syndrome, or obsessive-compulsive disorder.

• DFG Programme: Research Grants