Figure 6: rMS does not affect somatic inhibition.

(a,b) Slice cultures stained for gephyrin (green) and parvalbumin (red). Note the parvalbumin-positive interneuron (asterisk in a) in pyr. The axons of these neurons arborize mainly within the pyramidal cell layer (b; rad). The size of gephyrin clusters associated with parvalbumin-positive presynaptic boutons was assessed in pyr. Blue, TO-PRO nuclear stain. Scale bar in a, 20 μm, in b, 4 μm. (c) No significant difference in parvalbumin-associated gephyrin cluster sizes is observed in pyr between stimulated and non-stimulated slice cultures 3 h after rMS (control, n=8 cultures; rMS, n=7 cultures; averaged data from three visual fields per culture; Mann–Whitney test). (d,e) The mean size and number of all gephyrin clusters are not significantly different in pyr. In the rad a significant reduction in gephyrin cluster sizes and numbers is observed after stimulation in the same set of cultures (control, n=8 cultures; rMS, n=7 cultures; averaged data from three visual fields per culture; Mann–Whitney test). (f) Paired recordings of parvalbumin-positive interneurons and CA1 pyramidal neurons were carried out in slice cultures prepared from GAD67-GFP mice. Parvalbumin-positive interneurons in pyr can be readily identified by the GFP signal in these preparations. Scale bar, 10 μm. (g–j) No major changes in inhibitory synaptic strength, efficacy and connectivity are observed in these experiments (control; n=6 connected pairs in four cultures, one connected pair excluded from analysis since series resistance changed significantly during recordings and reached ⩾30 MΩ; seven of nine probed pairs connected; rMS, n=5 connected pairs in three cultures; five of six probed pairs connected; Mann–Whitney test). Individual data points are indicated by grey dots. Values represent mean±s.e.m. (**P<0.01; ns, not significant differences).