Cerebral Microcirculation: a Review Emphasizing the Interrelationship of Local Blood Flow and Neuronal Function

Abstract

Excellent reviews of cerebral circulation have appeared over the past 30 years. 1-5 The more recent of these3, have dealt in great detail with a single aspect of the subject. The following account covers a much wider range of data gathered by a number of separate disciplines. In organization, it differs from its predecessors in that the material focuses on a single problem, namely, the control of blood flow to small neuronal units and the relation of flow to the function of these units. It is our intent to illustrate the great gaps in our knowledge and to point out the many areas of contradictory data which confront the general reader in different segments of the literature.A discussion of this sort can best be initiated by describing current concepts of the control of vascular diameter and blood flow in the brain. These two parameters are often loosely equated in the literature, although they do not necessarily move in parallel. For example, increases in vascular diameter may be accompanied by a decrease in blood pressure locally or systemically, resulting either in no change or in net decrease in flow. It therefore seems advisable to separate the data dealing with measurements of diameter from that concerning measurements of blood flow. Accordingly, we have subdivided sections one and two, concerned with neurogenic and chemical controls of cerebral circulation, into units discussing diameter first and then flow. Within the separate units a comparison of flow measurements and diameter measurements is made when relevant.Our interest in regional blood flow stems from the need to define the interdependence of local blood flow and neuronal function. A portion of this review deals with this aspect of the problem. As an aid to the reader we have included two diagrammatic representations with the text in order to illustrate more effectively the morphologic details under discussion. The figures further emphasize the dimensional differences between subunits of the cerebrovascular bed. Of particular interest is the spatial relation between cerebral capillaries and cellular components of the brain.Although certain generalizations can be made concerning the control of the blood flow to the brain as a whole, the many gaps and contradictions in the literature make it virtually impossible to discuss in broad terms the control of local flow to neurons in any given area. It is highly probable that local blood supply to the nutrient-hungry neuron greatly influences cellular function and * From the

Regulation of cerebral blood flow in humans: physiology and clinical implications of autoregulation

“…(indirectly) Roy and Sherrington, was confirmed in subsequent decades (175,178,534) (see review by Rosenblum) (491). This research may have been sparked by work from Fulton (186), who obtained evidence of NVC in the occipital cortex upon visual stimulation in a patient with a cortical defect, very similar to the work of Mosso (181,465).…”

Regulation of cerebral blood flow in humans: physiology and clinical implications of autoregulation

“…(indirectly) Roy and Sherrington, was confirmed in subsequent decades (175,178,534) (see review by Rosenblum) (491). This research may have been sparked by work from Fulton (186), who obtained evidence of NVC in the occipital cortex upon visual stimulation in a patient with a cortical defect, very similar to the work of Mosso (181,465).…”

Modification of Kaolin‐Induced Intracranial Hypertension at Various Time‐Periods after Superior Cervical Sympathectomy in Rabbits

“…As a consequence of this the VFP will be lowered (Edvinsson and West 1971). In addition, the sympathetic ganglionectomy causes the noradrenaline transmitter to leak from the degenerating nerve terminals (Lundberg 1970) thus constricting the brain vessels (Sokoloff 1959, Rosenblum 1965, Edvinsson et al 1971, which reduces the intracranial blood volume. These two different events and the suggested decline in traumatic brain edema (see West 1971) at this postoperative stage will act together and result in a low net VFP.…”

Changes in Continuously Recorded Intracranial Pressure of Conscious Rabbits at Different Time‐Periods after Superior Cervical Sympathectomy

“…The functional significance of the neurogenic vasomotor control of the pial vessels is poorly understood. At least the ability of the cervical sympathetic system to produce a vasoconstriction of the vessels upon stimulation is well demonstrated (Sokoloff 1959, Kety 1960, Sears and Blirliny 1960, Klosovskii 1963, Rosenblum 1965, Lazorthes ~t al. 1966.…”

Regulation of cerebral blood flow in humans: physiology and clinical implications of autoregulation

“…(indirectly) Roy and Sherrington, was confirmed in subsequent decades (175,178,534) (see review by Rosenblum) (491). This research may have been sparked by work from Fulton (186), who obtained evidence of NVC in the occipital cortex upon visual stimulation in a patient with a cortical defect, very similar to the work of Mosso (181,465).…”

Modification of Kaolin‐Induced Intracranial Hypertension at Various Time‐Periods after Superior Cervical Sympathectomy in Rabbits

“…As a consequence of this the VFP will be lowered (Edvinsson and West 1971). In addition, the sympathetic ganglionectomy causes the noradrenaline transmitter to leak from the degenerating nerve terminals (Lundberg 1970) thus constricting the brain vessels (Sokoloff 1959, Rosenblum 1965, Edvinsson et al 1971, which reduces the intracranial blood volume. These two different events and the suggested decline in traumatic brain edema (see West 1971) at this postoperative stage will act together and result in a low net VFP.…”

Changes in Continuously Recorded Intracranial Pressure of Conscious Rabbits at Different Time‐Periods after Superior Cervical Sympathectomy

“…The functional significance of the neurogenic vasomotor control of the pial vessels is poorly understood. At least the ability of the cervical sympathetic system to produce a vasoconstriction of the vessels upon stimulation is well demonstrated (Sokoloff 1959, Kety 1960, Sears and Blirliny 1960, Klosovskii 1963, Rosenblum 1965, Lazorthes ~t al. 1966.…”

Regulation of cerebral blood flow in humans: physiology and clinical implications of autoregulation

“…(indirectly) Roy and Sherrington, was confirmed in subsequent decades (175,178,534) (see review by Rosenblum) (491). This research may have been sparked by work from Fulton (186), who obtained evidence of NVC in the occipital cortex upon visual stimulation in a patient with a cortical defect, very similar to the work of Mosso (181,465).…”

Modification of Kaolin‐Induced Intracranial Hypertension at Various Time‐Periods after Superior Cervical Sympathectomy in Rabbits

“…As a consequence of this the VFP will be lowered (Edvinsson and West 1971). In addition, the sympathetic ganglionectomy causes the noradrenaline transmitter to leak from the degenerating nerve terminals (Lundberg 1970) thus constricting the brain vessels (Sokoloff 1959, Rosenblum 1965, Edvinsson et al 1971, which reduces the intracranial blood volume. These two different events and the suggested decline in traumatic brain edema (see West 1971) at this postoperative stage will act together and result in a low net VFP.…”

Changes in Continuously Recorded Intracranial Pressure of Conscious Rabbits at Different Time‐Periods after Superior Cervical Sympathectomy

“…The functional significance of the neurogenic vasomotor control of the pial vessels is poorly understood. At least the ability of the cervical sympathetic system to produce a vasoconstriction of the vessels upon stimulation is well demonstrated (Sokoloff 1959, Kety 1960, Sears and Blirliny 1960, Klosovskii 1963, Rosenblum 1965, Lazorthes ~t al. 1966.…”