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. 2010 Jul 5;588(Pt 16):3045–3062. doi: 10.1113/jphysiol.2010.188466

Figure 1. Corticostriatal t-LTP and t-LTD.

Figure 1

A, characteristic membrane properties and spiking pattern of a MSN: a hyperpolarized RMP, an inward rectification and a long depolarizing ramp to the AP threshold leading to a delayed spike discharge. Raw traces show individual voltage responses to series of 500 ms current pulses from −140 pA to +200 pA with 40 pA steps (black traces) and to +50 pA above AP threshold (red trace). The MSN steady-state I–V relationship illustrates the inward rectification. B, cortically evoked MSN EPSCs (averages of 10 traces) in control and with CNQX (10 μm) and d-AP5 (40 μm). C, schematic representation of STDP protocol and the corresponding raw traces of the postsynaptic MSN. An AP was evoked in the MSN a few milliseconds before (post–pre sequence) (left side) or after (pre–post sequence) (right side) a cortical stimulation (100 paired stimulations at 1 Hz). Post–pre pairings induced t-LTP and pre–post pairings induced t-LTD, as illustrated by EPSCs (averages of 10 raw traces) evoked before (black traces) or 60 min after (grey traces) the cellular conditioning protocol. D, spike timing-dependent changes in synaptic efficacy estimated 60 min after STDP induction. After post–pre pairings (−30 < Δt < 0 ms), a significant (P < 0.001) t-LTP (161.2 ± 14.1%, n = 21) occurred. Conversely, pre–post pairings (0 < Δt < +40 ms) induced a significant (P < 0.01) t-LTD (72.3 ± 6.9%, n = 14). No more LTP and LTD was observed for Δt > −30 ms (87.7±1%, n = 2) and Δt > +40 ms (110.2 ± 6.6%, n = 2), respectively. E, representative experiments illustrating the time courses of synaptic efficacy changes induced by post–pre (upper panel) and pre–post pairings (lower panel), respectively, in the absence (black circles and triangles) and presence of bicuculline (20 um) (open circles and triangles). The black arrow indicates the STDP protocol induction and the grey arrow the measurement of the induced plasticity. Evolution of input resistance and holding current illustrates the stability of the recordings with time. F, the inhibition of GABAergic transmission by bicuculline affects the spike-timing dependence. Post–pre pairings induced t-LTP in control condition but a t-LTD was observed in the presence of bicuculline, in the presence of bicuculline. Conversely, pre-post pairings induced t-LTD in control conditions but a t-LTP with bicuculline. *P < 0.05, **P < 0.01, ***P < 0.001.