Figure 4.

Stimulus intensity–response profile for ST-evoked mixed monosynaptic and polysynaptic inputs. Input 1 was monosynaptic (latency, 2.2; jitter, 118 μs), and input 2 was polysynaptic (latency, 3.4; jitter, 387 μs). The top part displays traces of EPSCs elicited by stimulus shocks that were suprathreshold for both inputs. The ovals mark the two time windows for analysis of the onset of the responses. Event amplitudes did not change with ST shock intensities severalfold above threshold (bottom plot). Note that failures of the polysynaptic input pathway produced lower amplitude EPSCs to input 1 despite stimulus shock intensities severalfold above threshold for either input. Error bars indicate SEM.