Project Details
Projekt
The mediodorsal thalamus as a central hub in olfactory learning
Subject Area
Cognitive, Systems and Behavioural Neurobiology
Term
since 2023
Project identifier
Deutsche Forschungsgemeinschaft (DFG) - Project number 520223756
Social transmission of food preference learning (STFP) is a model of food choice learning in a social context. STFP is an ethologically relevant rodent one-shot learning behavior based on the social transmission of a food safety signal. We want to study encoding and retrieval of STFP learning in an olfactory cortico-thalamic-neocortical loop involving the primary olfactory or piriform cortex (PC), the mediodorsal thalamus (MDT), and the orbitofrontal cortex (OFC). All three components of this PC-MDT-OFC (PMO)-loop have a critical role in olfactory-guided behavior related to learning and evaluation. The MDT receives direct inputs from the ventral pallidum, a canonic hedonic hotspot related to feeding. This puts the MDT at a central position when it comes to attributing reward value to olfactory stimuli processed in the PC and OFC. The stable representation of context in learning requires the synchronous activity of neuronal engram ensembles. Brain-wide mapping recently identified an engram complex consisting of interdependent regional engram ensembles. Our central hypothesis is that the MDT serves as a synchronizing hub for processing reward value and directing attention to salient stimuli in the PMO-loop during STFP learning, thereby facilitating engram complex formation. With this proposal, our two laboratories will perform longitudinal analysis and manipulation of neuronal engram ensembles mediating encoding and retrieval of STFP learning in the PC, OFC, and MDT in awake mice. We will use state-of-the-art imaging (miniscope and two-photon) and electrophysiological (multi-site electrophysiological unit recordings with neuropixel probes) techniques for the dynamic real-time analysis of neuronal activity. Interregional opto- and pharmacogenetic manipulations will utilize transgenic and viral tools for circuit-specific expression to tackle questions of causality. We will direct our joint effort at three different objectives: First, we will investigate the effect of manipulating the activity of MDT outputs in the PMO-loop during encoding and retrieval on behavioral outcome. Second, we will use imaging to longitudinally analyze the emergence of stable behavior- and stimulus-associated neuronal activity patterns of specified projection neuron populations in the PMO-loop during encoding and retrieval of STFP learning at the mesoscale. Here, we expect to longitudinally observe the same neurons over the different phases of STFP learning. Third, we will perform multi-site electrophysiological unit recordings of behavior- and stimulus-associated neuronal activity patterns in the PMO-loop during encoding and retrieval of STFP learning at high temporal resolution. Here, we expect to characterize the interdependent and synchronous activation of functionally connected neuronal ensembles in different regions of the PMO-loop to mediate encoding and retrieval of STFP learning.
DFG Programme
Priority Programmes
International Connection
Israel
