Neural Representation of Associative Threat Learning in Pulvinar Divisions, Lateral Geniculate Nucleus, and Mediodorsal Thalamus in Humans.

Understanding the neural mechanisms underlying associative threat learning is essential for advancing behavioral models of threat and adaptation. We investigated distinct activation patterns across thalamic pulvinar divisions, lateral geniculate nucleus (LGN), and mediodorsal thalamus (MD) during the acquisition of associative threat learning in the MRI. We revealed parallel thalamic learning systems within the anterior pulvinar and MD, supporting distinct mechanisms of automatic survival vs. more deliberate learning. Additionally, our findings support a novel hierarchical pulvinar model during fear conditioning: the medial pulvinar mediates basic threat information from the inferior and lateral divisions to the anterior pulvinar for integrative learning. Pulvinar divisions and MD support extinction learning. These regions also process salience and modulate safe/threat memory expression during extinction recall and threat renewal. The LGN sustains feedforward processing of anticipated visual input throughout all threat phases. This study extends dominant brain models of threat learning and memory, reframing our understanding of distinct thalamic roles in these psychological processes.