Changes of visual evoked potentials in experimental occlusion of superior sagittal sinus in the cat.]

In the model of experimental occlusion of superior sagittal sinus (SSS) in 6 cats, the authors examined cerebral cortex activity by means of visual evoked potentials (VEP). They found shortening of latency of P2 wave potential in relation to the control by 5.5-13.3 msec, appearing after 4-6 hours following occlusion. Simultaneous cerebrospinal fluid pressure measurement indicated an increase in pressure following SSS occlusion from the control medium value 6.8 mmHg to 12-13 mmHg. Visual cortex in cat (area 17) is situated along the posterior portion of SSS. The occlusion of this vessel results in local haemostasis, which is likely to affect the physico-chemical properties of visual cortex cells, especially in the slow conducting system X (X cells can be found exclusively in area 17). The partial disappearance of this system activity results in reducing the signal and noticeable shortening of latency to peak P2 wave of VEP.