High Bandwidth Synaptic Transmission in Human Neocortex

Human mental abilities far exceed those of other organisms. The reason for this remains enigmatic. We hypothesized that at a fundamental level, the dynamics of information encoding and transmission between neocortical principal cells in the brain may be better optimized for high processing capacity. Here, we find in unitary synaptic connections between human neocortical pyramidal neurons that the synaptic machinery rapidly recovers during repeated activation. This enables fast and sustainable information transfer between neurons at gamma band frequencies. Furthermore, we find that human principal cells can collectively track fine temporal features conveyed in their inputs at a much wider bandwidth than reported for rodents. This enables reliable information encoding into spike trains. Thereby, information processing and transfer can occur at high rates in human neocortical circuits.