EFFECTS OF GABA ANTAGONIST BICUCULLINE ON THE ORIENTATION TUNING CHARACTER OF RELAY CELLS IN DORSAL LATERAL GENICULATE ATE NUCLEUS(dLGN)
GABA拮抗剂荷包牡丹碱对猫外膝体神经元方位调谐特性的影响

Responses to sinusoidal drifting gratings of different spatial frequencies (SF) anddifferent orientations were recorded form cat's orientation sensitive neurons in lamina A and Alof the dorsal latelal geniculate nucleus (dLGN) with multimicrocapillary electtrodes andmicroiontophoresis technique. We quantitahvely measured and compared orientation sensitive biases (OB>0.1) of those Cells (38 total) before and after microiontophoresis of bicuculline, aGABA antagonist.The orientation sensitive biases at low SF near the Cell's preferred SF reduced significantly,but no remarkable change for dLGN neurons near their cut-off SF Wasdetected afterbicuculline applied.The results showed that the orientation sensitivity of dLGN neurons,measured tosinusoidal drifting gratings just near the Cell's cut-off spatial freqence,might be contributed bythe excitatory inputs of retina ganglion cells,but not by the inhibitory mechanism within thedLGN.keywods: Orientation tuning character Bicuculline Receptive field Dorsal lateral geniculate nuclesus Cat