Fig. 2.

Human local pyramidal-to-pyramidal connections are reliable. a) Example connections show average presynaptic AP and postsynaptic EPSP traces for human (orange) and mouse (green). b) Traces correspond to example individual traces from those same connections. c) Median failure rates (P < 0.0001, Mann–Whitney test). d) Cumulative distribution of failure rates for human and mouse. e) Example average traces for all traces, including failed events (left) and only counting success sweeps (right) show that EPSP amplitude of “success-only” traces (i.e. EPSP potency) was still larger in human. f) Median EPSP potency (P < 0.01, Mann–Whitney test). g) Mean c.v. was significantly larger in mouse connections (P < 0.0001, unpaired t-test). h) Example traces for human (top, presynaptic trace in black, postsynaptic trace in orange) and mouse (bottom, presynaptic trace in black, postsynaptic trace in green) of postsynaptic responses to a 5 Hz train and recovery pulse of presynaptic action potentials. i) Median utilization of synaptic efficacy, U (P < 0.05, Mann–Whitney test), blue datapoints correspond to the example connections shown in h).