Neuronal implementation of cognitive maps for navigation

Projektbeschreibung

Kartierung der Konnektivität neuronaler Netze für Kognition

Intelligentes Verhalten stützt sich auf interne Modelle zur Simulation und Planung, wobei Orts- und Gitterzellen im hippocampalen-entorhinalen System kognitive Karten der Umgebung bilden. Dank der jüngsten Entdeckungen zahlreicher Ortszellen im Telencephalon des Zebrafisches konnten Fortschritte im Verständnis dieser Mechanismen verzeichnet werden. Im Rahmen des ERC-finanzierten Projekts COGNECTOMICS kommen Volumenelektronenmikroskopie und transkriptomische Profilerstellung zum Einsatz, um die neuronale Konnektivität auf synaptischer Ebene in kleinen Gehirnen abzubilden. Es wird untersucht, wie Interaktionen zwischen spezifischen Neuronenuntergruppen zu den funktionellen Eigenschaften von Ortszellen beitragen und wie Netzwerkstrukturen die Populationsaktivität beeinflussen. Das Projektteam wird außerdem die Entwicklung und Reifung neuronaler Schaltkreise sowie die Funktion kognitiver Karten bei Verhaltensweisen erforschen, die mit intern generierten Vorhersagen zusammenhängen.

Ziel

Intelligent behavior is based on internal models of the world that enable mental simulations and strategic planning. A leading model to study such “cognitive maps” are networks of place cells and grid cells in the mammalian hippocampal-entorhinal system. These neurons are active at defined locations and collectively represent a physical environment as a low-dimensional topographic map in neural activity space. However, a mechanistic understanding of the underlying computations and their biological implementation remains elusive. Using new methods for brain-wide activity imaging during behavior, members of our team discovered an abundance of place cells in the telencephalon of zebrafish. We will combine this approach with volume electron microscopy to reconstruct large-scale connectivity in the same brains at synaptic resolution and with transcriptomic profiling to identify molecular cell types, taking advantage of small brain size. The joint analysis of network connectivity and population dynamics will allow us to determine how functional properties of place cells are established by interactions between specific subsets of neurons across brain areas, and how network structure constrains population activity to topographically organized attractor manifolds. The results will disambiguate computational models that make conflicting assumptions about network connectivity. We will further explore the emergence of cell types during development and the concomitant structural and functional maturation of neuronal circuits. The relevance of cognitive maps for neuronal computations and behaviors involving internally generated predictions will be explored by activity measurements in a virtual reality and by functional manipulations of genetically targeted neurons. Capitalizing on the unique combination of expertise among team members, this project is expected to fundamentally advance our mechanistic understanding of biological and potentially artificial intelligence.