Laminar origins of inhibitory synaptic inputs to pyramidal neurons of the rat neocortex

The Journal of Physiology
A NicollB W Connors

Abstract

1. Inhibitory neuron-pyramidal cell interactions were investigated in slices of rat somatosensory cortex in which excitatory synaptic transmission was blocked with bath-applied glutamate receptor antagonists. Local inhibitory neurons were excited by focal pressure ejections of small (approximately 40 pl) volumes of 1-10 mM acetylcholine. 2. The frequency of inhibitory postsynaptic potentials (IPSPs) ("responses per trial' or R/T) declined as the stimulation distance was increased. Inhibitory inputs were most prevalent in layer II/III regular spiking (RS) pyramidal neurons (30 cells) where median R/T was 0.020. In layer V, the median R/T was 0.024 for RS neurons (25 cells), but significantly lower for burst-firing (IB) neurons (17 cells), where median R/T was 0.007 (P = 0.039). 3. IPSPs in individual layer V pyramidal cells were recorded with CsCl electrodes. In eight neurons, spontaneous picrotoxin-sensitive IPSPs were recorded and found to display a wide range of 10-90% rise times (1-34 ms), not correlated with amplitude (0.2-18 mV). For a further ten pyramidal neurons, extracellular stimulating electrodes were placed simultaneously in layers II/III and V/VI in order to evoke pairs of IPSPs whose waveforms were averaged and co...Continue Reading

Citations

Jun 9, 2005·Brain Research. Developmental Brain Research·Richard A DeFazio, John J Hablitz
Apr 7, 2005·Hearing Research·Jeremy G TurnerDonald M Caspary
Feb 1, 2012·Cerebral Cortex·Rogier B PoorthuisHuibert D Mansvelder
May 7, 2005·Proceedings. Biological Sciences·Julian M L Budd
Aug 21, 2009·Journal of Neurophysiology·Andrew M TanBryan C Hains

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