UC Irvine

The blood supply to several regions of the chick brain is rapidly decreased following reduction of visual input by monocular eyelid Suture. This decrease is not confined to the primary visual area (the optic lobe) contralateral to and innervated by the sutured eye but is also apparent in the indirectly innervated cerebral hemispheres contralateral to the treated eye. After periods of bilateral eyelid suture, exposure of a single eye to patterned light by suture removal results in a rapid increase of blood flow through contralateral cerebral regions directly or secondarily innervated by the exposed eye. This response appears to be more closely related to the intensity rather than to the information content of incident light. The ability to regulate regional cerebral blood flow is lost following reduction of brain catecholamine levels with reserpine. However, cerebral blood flow is still responsive to afferent sensory input, in the presence of a concentration of carbon dioxide sufficient to cause near maximal dilation of cerebral blood vessels. This suggests that variations of vascular supply to specific brain regions may in part be effected by direct autonomic nervous mechanisms regulating the diameter of blood vessels within the brain. © 1973.