Читать книгу The Handy Psychology Answer Book - Lisa J. Cohen - Страница 215

As technology continues to advance, more and more sophisticated techniques to study the brain have become available. Similar to EEG, magnetoencephalography (MEG) measures brain activity at the scalp, only it measures magnetic rather than electrical activity. Another non-invasive method, near-infrared spectroscopy (NIRS) uses a light source to measure changes in the amount of oxygen in the blood. More invasive techniques are also used. In deep brain stimulation (DBS), electrodes are implanted directly into the brain. These depth electrodes can monitor and stimulate electrical activity in very small areas of the brain. Because deep brain stimulation involves brain surgery, it is only performed as part of the surgical treatment of patients with brain diseases such as Parkinson’s disease or epilepsy. In non-human animals, however, electrodes are frequently implanted in the brain to measure the behavior of specific brain regions or even single neurons during various experimental conditions.

How many neurons are in a voxel?

Avoxel is the smallest unit of measurement of an fMRI. It is a three-dimensional cube. In MRI scans, the smallest unit of measurement is called a pixel. A voxel is approximately 2.5 millimeters on each side. Each voxel covers approximately one million neurons (or brain cells).