A N Penchev

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The effect of GABAergic blockade on the intensity-response function of frog ERG waves was investigated under two levels of background illumination in the mesopic and photopic range. GABAergic blockade by picrotoxin shifted the intensity-response curves to the left along the intensity axis and increased their slope under both backgrounds. The maximal gain(More)
The intensity-response function of the b-wave of the ERG in the retina of the turtle (Emys orbicularis) was investigated at two different background illuminations--0.01 and 10 lx, before and after blockade of the GABA-ergic transmission by 0.4 mmol/l picrotoxin (PT). A shift of the curve to the left along the intensity axis at both backgrounds was observed(More)
The effect of blockade of the GABA-ergic synapses in the frog retina by picrotoxin (PT) on ERG was studied under two conditions of background illumination (Ib): scotopic Ib with illumination level below 0.01 lx and mesopic Ib with illumination level of 2 lx. Under scotopic Ib PT produced a greater relative increase in the d-wave amplitude as compared to the(More)
The intensity-response--V/log I, function of the d-wave in the turtle ERG was investigated before and after blockade of the GABAergic transmission by 0.4 mmol/l picrotoxin (PT) under conditions of two adapting background illuminations--0.01 and 10 lx. After PT the d-wave V/log I curves showed a shift to the left along the intensity axis under both adapting(More)
The thresholds for identifying the orientation of line segments were studied with the following stimuli: a) single line segment (S1); b) two parallel line segments (S2) with or without longitudinal displacement; c) three parallel line segments (S3) with or without longitudinal displacement. The thresholds for the stimuli S2 and S3 are lower in comparison to(More)