Figure 7.

Altered transmission at IB2−/− cerebellar climbing fiber–Purkinje cell synapses. Purkinje cells were whole-cell patched using pipettes filled with CsCl-based solution containing 2 mm QX-314. All-or-nothing EPSCs were recorded following climbing fiber stimulation while voltage clamping cells at +40 mV; under these conditions, AMPA/kainate-evoked currents were outward, NMDA currents (if any) were suppressed, and voltage-gated calcium currents were also suppressed by inactivation. A, Wild-type Purkinje cell climbing fiber-evoked EPSC has large amplitude and rapid onset and decay, and current is fully blocked by bath perfusion with NBQX. B, An IB2−/− Purkinje cell EPSC representative of 53% (9 of 17) recorded cells shows normal amplitude and kinetics. C, IB2−/− Purkinje cell EPSC representative of 47% (8 of 17) recorded cells is anomalously small and delayed (note different current scale). D, In a plot of EPSC density versus time-to-peak for all recorded Purkinje cells, IB2−/− cells fall into either normal or anomalous response classes. See accompanying data summaries in supplemental Table 3 (available at www.jneurosci.org as supplemental material).