Regional cerebral blood flow and visual attention in the awake isolated cerebrium of the pretrigeminal cat.

The effect of visual stimulation on cerebral blood flow (CBFJ was studied in five cats with brainstem transection at the pretrigeminal level. The CBF was measured in the occipital and fron- tal cortex b,y external monitoring of the clearance of la3Xe. As a visual stimulus, a feather duster moving for 2 min in front of the cat's eyes was used. This stimulus evoked an increase of CBF. In the occipital cortex the CBF increase was greater and comparable to that evoked by elevation of the arterial pCO,. Both in the occipital and frontal, cortex the CBF response was positively correlated with the intensity of the ocular-following reflex and the cortical EEG arousal. It is con- cluded that the CBF increase was correlated with the degree of atten- tion paid by the cat to the visual stimulus.