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 (CBF) was studied in five cats with brainstem transection at the pretrigeminal level. The CBF was measured in the occipital and frontal cortex by external monitoring of the clearance of 133Xe. 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 pCO2. 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 concluded that the CBF increase was correlated with the degree of attention paid by the cat to the visual stimulus.