Auditory thalamus in exploration and decision-making
1 Deutsches Zentrum für Neurodegenerative Erkrankungen (DZNE)
Auditory thalamus (medial geniculate body, MGB) dynamically encodes sensory and task-related information. A subset of MGB neurons show ramping activity during reward-preceding delay periods in head-fixed Go/Nogo detection paradigms, which was suggested to predict reward outcome and maintain short-term memory to guide the next action. Nevertheless, it remains unknown if MGB plastically encodes different aspects of decision-making. We propose that MGB encodes several stages of self-paced, reward-driven decision-making such as the assessment of choices after presentation of sensory stimuli and the execution of decisions. To test this hypothesis, we use a two-choice automated T-maze paradigm with four possible outcomes. Here, mice with an 80 % performance rate showed an optimized trajectory during correct versus incorrect trials. Additionally, lick patterns varied between correct and incorrect trials. To track MGB and thalamostriatal activity, we are currently establishing a dual-color miniature microscope imaging approach to measure the activity of thalamostriatal projection neurons as well as the local MGB population activity. To precisely quantify neuronal activity during decision-making, we will identify decision variables and establish correlations of neuronal activity with behavioral variables during task performance. Ultimately, we want to elucidate whether the neuronal activity in MGB and its thalamostriatal projection neurons serves as a significant predictor of decision-outcome in self-paced behaviors.