Stimulus deprivation and cerebral blood flow

Abstract

The effect of unilateral visual deprivation on the vascular system of brain regions has been studied in the chick where the visual pathways are totally crossed. We injected 1251-iodantipyrine or 1251-iodinated albumin into the hearts of chicks at various times after monocular eyelid suture or unilateral eye extirpation. Radioactivity within optic lobes and cerebral hemispheres was assayed, to estimate the velocity of blood flow or the plasma volume. As early as I hr after monocular deprivation by eyelid suture or by enucleation, significant deficits in the velocity of the circulation through the contralateral brain regions were observed. These effects were maintained for at least 6 days and were of similar magnitude in contralateral optic lobes (which are directly innervated by the optic nerve) and the contralateral cerebral hemispheres (which receive no primary innervation from the optic nerve). After I hr of either form of monocular deprivation, a reduced plasma volume was found in contralateral optic lobes but not in cerebral hemispheres. These data suggest that maintenance of optimal cerebral vascular supply may be dependent on a patterned sensory input to the btain. A deficiency in the complexity of cerebral afferentation in the young animal may impair adequate vascularity and thus retard maturation.

Experience and Plasticity in the Central Nervous System

“…Another difficulty is that the actual precursor to the macromolecule is intracellular, whereas the label is injected into the bloodstream, the peritoneal cavity, or the cerebrospinal fluid. Variations in regional blood flow [which is affected by sensory stimulation (54)], in uptake mechanisms across cell membranes, and in the pool of the unlabeled precursor (55) all complicate interpretation. In an attempt to avoid these difficulties, it has become the practice to normalize the results by calculating "relative activity," that is, the ratio of bound radioactivity to total radioactivity, bound and unbound, or of bound radioactivity to unbound radioactivity.…”

“…No significant regional differences in pool size were found between the two sides of the brain. This rules out the possibility that incorporation of the labeled base into macromolecules can be ascribed to asymmetric changes in pool sizeresu;lting, for example, from differences in cerebral blood flow, which can be affected by patterned visual stimulation (54). There are good grounds for supposing that both sides of the brain of the intact chick are trained when 512 input is restricted to one side (65).…”

Selective changes in the permeability of the blood‐brain barrier after pharmacological or surgical deafferentation

“…circulation can be adapted to metabolic and functional needs (Roy and Sherrington, 1890;Ingvar and Risberg, 1967;Sokoloff, 1961;Bondy and Davis, 1972;Bondy, 1973). We therefore decided to investigate changes in the permeability of the BBB to specific substances to see if selective alterations in brain uptake mechanisms occur under conditions known to reduce the rate of cerebral blood flow, such as eye removal (Bondy and Morelos, 1971). It was also of interest to compare the effects of surgical deafferentation to a functional pharmacological denervation induced by depletion of norepinephrine by reserpine.…”

Brain Blood Flow: Alteration by Prior Exposure to a Learned Task

“…Consequently, the metabolic changes caused by unilateral visual deprivation or stimulation are largely confined to regions contralateral to the treated eye. We have used this experimental system to show that reduction of visual input by eyelid suture results in a suppression of cerebral blood flow and glucose consumption (3). An increase in blood flow has also been demonstrated in regions contralateral to an eye receiving information relevant to feeding activity (4).…”