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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]
Magnetoencephalography – a technique for mapping brain activity by recording magnetic fields produced by electrical currents occurring naturally in the brain, using very sensitive magnetometers In research, MEG's primary use is the measurement of time courses of activity. MEG can resolve events with a precision of 10 milliseconds or faster ...
An alternative definition of CPP is: [1] = where: MAP is mean arterial pressure ICP is intracranial pressure JVP is jugular venous pressure. This definition may be more appropriate if considering the circulatory system in the brain as a Starling resistor, where an external pressure (in this case, the intracranial pressure) causes decreased blood flow through the vessels.
The midbrain is the shortest segment of the brainstem, measuring less than 2cm in length. It is situated mostly in the posterior cranial fossa, with its superior part extending above the tentorial notch. [2] The principal regions of the midbrain are the tectum, the cerebral aqueduct, tegmentum, and the cerebral peduncles.
More blood flows in to transport more glucose, also bringing in more oxygen in the form of oxygenated hemoglobin molecules in red blood cells. This is from both a higher rate of blood flow and an expansion of blood vessels. The blood-flow change is localized to within 2 or 3 mm of where the neural activity is.
Because measurable blood changes are slow (on the order of seconds), these methods are much worse at measuring the time-course of neural events, but are generally better at measuring the location. Traditional "activation studies" focus on determining distributed patterns of brain activity associated with specific tasks.
When significant, arteries can become narrowed enough to reduce blood flow. It contributes to the development of dementia, and has protein similarities to those found in Alzheimer's disease. [176] The brain, although protected by the blood–brain barrier, can be affected by infections including viruses, bacteria and fungi.
Posterior cerebral artery (PCA), which supplies blood to the posterior portion of the brain, including the occipital lobe, thalamus, and midbrain [5] Both the ACA and MCA originate from the cerebral portion of internal carotid artery , while PCA branches from the intersection of the posterior communicating artery and the anterior portion of the ...