Long-Term Plasticity at Excitatory Synapses on Aspinous Interneurons in Area CA1 Lacks Synaptic Specificity

Cowan, A. I., C. Stricker, L. J. Reece, and S. J. Redman. Long-term plasticity at excitatory synapses on aspinous interneurons in area CA1 lacks synaptic specificity. J. Neurophysiol. 79: 13–20, 1998. The synaptic specificity of long-term potentiation (LTP) was examined at synapses formed on aspinous dendrites of interneurons whose somata were located in the pyramidal cell layer of hippocampal area CA1. Intracellular recordings from slices prepared from rats were used to monitor excitatory postsynaptic potentials (EPSPs) elicited by extracellular stimulation in stratum radiatum. Two synaptic inputs were evoked at 0.5 Hz by stimulating axons adjacent to stratum pyramidale and s. lacunosum-moleculare. After obtaining baseline recordings (≥10 min), one of the EPSPs was conditioned. The protocol involved tetanic stimulation, sometimes combined with somatic depolarization. Low-frequency stimulation of the two pathways was then resumed and EPSPs were recorded for