Randy Bruno

Title:

High-Order Thalamus in Behavior

Abstract:

Each sensory modality has its own primary and secondary thalamic nuclei. While the primary thalamic nuclei are well understood to relay sensory information from the periphery to the cortex, the role of secondary sensory nuclei is elusive. One hypothesis has been that secondary nuclei may support feature-based attention. If this is true, one would also expect the activity in different nuclei to reflect the degree to which modalities are or are not behaviorally relevant in a task. We trained head-fixed mice to attend to one sensory modality while ignoring a second modality and simultaneously recorded from secondary somatosensory and visual thalamus. Training could switch the modality that maximally activated a secondary thalamic nucleus. Movements do not account for this dramatic switch. Secondary nuclei appear to encode behaviorally relevant, reward-predicting stimuli regardless of stimulus modality. This may facilitate cortical plasticity during learning by activating apical dendrites in layer 1.