Slide 27

PGN Neurons Inhibit One Another Through GABA-A Receptors

(A) Intracellular recordings in PGN neurons during the generation of spindle waves reveal that these cells not only are excited by thalamocortical neurons, but also inhibited by other PGN cells. Thus, barrages of postsynaptic potentials are often dominated by EPSPs initially (from the burst firing of thalamocortical cells) that give way to IPSPs (from the burst firing of neighboring PGN cells). 

(B) The activation of PGN cells with local application of glutamate results in the generation of IPSPs in another PGN cell. Changing the timing of this IPSP in relation to the generation of a rebound low threshold Ca2+ spike reveals that PGN to PGN inhibition can have a potent inhibitory effect on these Ca2+ spikes. 

see Bal, T., von Krosigk, M., and McCormick, D.A. (1995) Synaptic and membrane mechanisms underlying synchronized oscillations in the lateral geniculate nucleus in vitro. Journal of Physiology 483.3: 641-663. 

Bal, T., von Krosigk, M., and McCormick, D.A. (1995) Role of the perigeniculate nucleus in the generation of synchronized oscillations in vitro. Journal of Physiology 483.3: 665-685.