Medial Pulvinar Nucleus as a Causal Hub for Heteromodal Naming

Abstract

Our ability to retrieve the names of objects in our environment is a fundamental aspect of everyday life. This process requires a complex, dynamic network of cortical and subcortical interactions. While the cortical constituents of this network have been extensively studied with intracranial recordings, the subcortical nodes of the naming network are unclear. We probed the role of the left medial pulvinar nucleus in naming with direct intracranial recordings and stimulation in eight humans (three male, five female) as they named objects using pictures and auditory and written descriptions. We found a spectrotemporal signature of naming in the left medial pulvinar nucleus, characterized by a low frequency (8–20 Hz) suppression, consistent across sensory modalities during naming, and absent during other non-naming language tasks. Within this frequency band, Granger causal interactions showed that the pulvinar nucleus received strong inputs from early visual, ventral temporal, and parahippocampal cortices. Direct thalamic stimulation reliably induced anomia, confirming that the left medial pulvinar nucleus is a critical node in the distributed naming network.