Myelination in the neocortex is a lifelong process in which new myelin membranes and patterns shape spike arrival times and cognitive processing. By studying the myelin sheath of layer 5 pyramidal neuron axons, we identified key ultrastructural and electrophysiological properties responsible for the rapid saltatory propagation of action potentials. In recent work, we investigated the long-range cortico-thalamic transmission from layer 5 to the posteromedial nucleus (POm) of the thalamus using retrograde AAV tracing, in vivo juxtacellular patch-clamp recordings, and silicon Neuropixels probes. We found that myelination of neocortical internodes is required to reliably conduct high-frequency spikes within bursts and across white matter tracts. Pairing optically evoked spikes with whisker stimulation demonstrated that myelination is critical for accurate coincidence detection in the thalamus, suggesting functions beyond speed.
Organizer
Chris de Zeeuw
c.dezeeuw@erasmusmc.nl