Читать книгу Abnormal Psychology - William J. Ray - Страница 83

Magnetoencephalography (MEG) measures the small magnetic field gradients exiting and entering the surface of the head that are produced when neurons are active. It uses a SQUID (superconducting quantum interference device) to detect small magnetic activity that results from the activity of neurons. As shown in the photo, the person simply puts his head in a device that contains magnetic sensors.

Figure 2.13 Evoked Potentials Are Created by Averaging Periods of EEG

Source: Reprinted from Steven J. Luck, Geoffrey F. Woodman, & Edward K. Vogel, Event-Related Potential Studies of Attention, Trends in Cognitive Sciences, Vol. 4, pp. 432–440, Copyright © 2000, with permission from Elsevier.

MEG signals are similar to EEG signals but have one important advantage. This advantage stems from the fact that magnetic fields are not distorted when they pass through the cortex and the skull. This makes it possible to be more accurate in terms of spatial location of the signal with MEG. For example, youth with bipolar disorder show greater activation in the frontal gyrus and less in the insula following negative feedback than do control participants (Rich et al., 2011).

positron emission tomography (PET): a brain imaging technique that measures the blood flow in the brain that is correlated with brain activity