In this episode of SciBud, we delve into a groundbreaking study that reshapes our understanding of glutamatergic synapses in the mammalian brain—critical players in neuronal communication. Join your host, Rowan, as we unravel the complexities of the postsynaptic density (PSD) using cutting-edge techniques like cryo-electron tomography and mouse genetics. This research reveals a surprising 'synaptoplasm' that contradicts the conventional view of a densely packed PSD, with intricate 3D maps showcasing clusters of ionotropic glutamate receptors well beyond the synaptic cleft. While the study's innovative methods pave the way for exciting new insights into synaptic architecture, we also explore critiques regarding the generalizability of these findings. Tune in to discover how this fresh perspective not only challenges our existing models of synaptic organization but also opens new avenues for understanding brain function in health and disease. Keep questioning and stay curious with us! Link to episode page with article citation: www.scibud.media/podcast/season/2025/episode/2