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. Author manuscript; available in PMC: 2015 Jan 8.
Published in final edited form as: Neuron. 2013 Dec 19;81(1):61–68. doi: 10.1016/j.neuron.2013.10.031

FIGURE 4. Fast-spiking parvalbumin interneurons preferentially inhibit Type A neurons.

FIGURE 4

(A) Simultaneous recordings of IPSCs in a Type A and B neuron during optogenetic stimulation of callosal inputs. Cells were voltage clamped at +10mV. (B) Peak IPSC amplitude (left) and inhibitory charge transfer (right) were larger in Type A neurons compared to simultaneously recorded Type B neurons (respectively, n=11 pairs). (C) We made simultaneous current clamp (CC) recordings from a fast-spiking interneuron (FSIN, green) and voltage clamp recordings from either a Type A or B neuron. Current was injected to elicit FSIN spiking while recording from the pyramidal neuron in voltage clamp at +10 mV (VC10). (D) The connection probability from FSINs was greater onto Type A neurons than Type B neurons (n=23 pairs).(E) Experimental design: We recorded simultaneously from a Type A and B neuron in PV::Cre mice injected with virus to drive Cre-dependent ChR2-EYFP expression (yellow, left). During optogenetic stimulation of ChR2-expressing PV interneurons, we recorded simultaneous IPSCs in Type A and B neurons (bottom right). (F) PV interneuron-mediated IPSC peak amplitude (left) and inhibitory charge transfer (right) were greater in Type A than Type B neurons (n=5 pairs). (G) Normalized, averaged EPSPs in Type A and B neurons following optogenetic stimulation of callosal inputs. Type A neurons (red) repolarize faster (arrow marks repolarization).(H) The decay time constant of callosally-evoked EPSPs is faster in Type A neurons (n=11 pairs). See also Fig. S4.