COGS 2160 Chapter Notes - Chapter CS 4.5 (pp.108-113): Pulse Oximetry, Brain Structure And Function, Visual Cortex
Document Summary
Local integration ii: neural activity and the bold signal. Functional neuroimaging allows us to study the workings of the brain at the level of neural systems and large-scale neural circuits. Allows us to study the behaviour of large populations of neurons. Blood flow to a particular region of the brain increases when cellular activity in that region increases. Increase in blood flow = increase in oxygen. Degree of oxygen consumption does not increase in proportion to the increase in blood supply. Increase in blood oxygen level can be detected in the powerful magnetic field created by mri scanner, since oxygenated and deoxygenated blood have different magnetic properties. Difference is known as bold (blood oxygen level dependent) contrast fmri measures the bold contrast neuroscientists study the behaviour of individual neurons through single-cell recordings. When a neuron fires it sends a signal to the other neurons to which it is connected. Signal is the result of processing internal to the neuron.