Dendritic integration in neocortical pyramidal neurons as basis for multisensory learning

Research project

Neurons in the neocortex of the brain possess elaborate dendritic arbors that receive and integrate diverse input signals. In many cortical areas, information from different sensory modalities (visual, auditory, tactile) converges onto the superficial dendritic tufts of pyramidal neurons. Adaptations of how dendrites integrate these inputs – depending on their behavioral relevance – may be required for animals to learn appropriately.

In this project, we developed tools to identify changes in dendritic responses during learning. By performing chronic two-photon calcium imaging in mice during texture discrimination learning, we tracked activity in the same dendritic branches from naïve (first trials of behavioral task) to expert state. We applied sophisticated high-dimensional analysis across trials to extract learning-related changes. In addition, we applied a technic called optogenetic inhibition – which suppresses dendritic activity – and could show that the observed signals are relevant for learning.

We now use and further develop these tools with the goal to study how multisensory learning depends on integration in dendrites. For this, we develop a new behavioral paradigm for quantification of multisensory learning in mice in collaboration with the research groups of Christian Ruff and Silvia Brem, who apply similar tasks in human experiments.

Once the behavioral tasks are established, we aim to measure dendritic activity and its learning-related changes during stimulus presentation and during reward-based learning. In addition, by interfering with dendritic integration, we will verify its relevance for successful adaptation of behavior.

Research Groups

Principal Investigators: Fritjof Helmchen, Christian Ruff, Silvia Brem, Valerio Mante

PhD Students: Gwendolin Schönfeld (until 31.08.2022, now PostDoc part time), Johanna Nieweler

Collaborators: Shuting Han, Chris Lewis

Platforms: HDDA

Publications

Han S, Helmchen F (2024) Behaviour-relevant top-down cross-modal predictions in mouse neocortex Nature Neuroscience 27, 298–308

Schoenfeld G, Kollmorgen S, Lewis C, Bethge P, Reuss AM, Aguzzi A, Mante V, Helmchen F (2021) Dendritic integration of sensory and reward information facilitates learning. bioRxiv, doi.org/10.1101/2021.12.28.474360.

Underlined: AdaBD researchers