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Cerebral blood flow (CBF) is the blood supply to the brain in a given period of time. [8] In an adult, CBF is typically 750 millilitres per minute or 15.8 ± 5.7% of the cardiac output. [9] This equates to an average perfusion of 50 to 54 millilitres of blood per 100 grams of brain tissue per minute. [10] [11] [12]
Electrophysiology [2] is the branch of physiology that pertains broadly to the flow of ions (ion current) in biological tissues and, in particular, to the electrical recording techniques that enable the measurement of this flow.
In both white and gray matter, cerebral blood volume decreases by about 0.50% per year with increasing age. [4] Intracranial hematoma and Intracerebral hemorrhage (ICH) will cause an increase in cerebral blood volume. [5] Ischemic stroke will cause a substantial reduction in cerebral blood volume. [6]
Changes in brain activity are closely coupled with changes in blood flow in those areas, and knowing this has proved useful in mapping brain functions in humans. The measurement of haemodynamic response, in a clinical setting, can be used to create images of the brain in which especially active and inactive regions are shown as distinct from ...
The cranium encloses a fixed-volume space that holds three components: blood, cerebrospinal fluid (CSF), and very soft tissue (the brain). While both the blood and CSF have poor compression capacity, the brain is easily compressible. Every increase of ICP can cause a change in tissue perfusion and an increase in stroke events.
HCN4 is the main isoform expressed in the sinoatrial node, but low levels of HCN1 and HCN2 have also been reported.The current through HCN channels, called the pacemaker current (I f), plays a key role in the generation and modulation of cardiac rhythmicity, [13] as they are responsible for the spontaneous depolarization in pacemaker action potentials in the heart.
The breakdown of the tight endothelial junctions that make up the blood–brain barrier causes extravasation of fluid, ions, and plasma proteins, such as albumin, into the brain parenchyma. [18] Accumulation of extracellular fluid increases brain volume and then intracranial pressure causing the symptoms of cerebral edema.
Electroencephalography (EEG) [1] is a method to record an electrogram of the spontaneous electrical activity of the brain.The biosignals detected by EEG have been shown to represent the postsynaptic potentials of pyramidal neurons in the neocortex and allocortex. [2]