Functional Neuroimaging - Overview

Overview

Common methods of functional neuroimaging include

  • Positron emission tomography (PET),
  • Functional magnetic resonance imaging (fMRI),
  • multichannel electroencephalography (EEG),
  • magnetoencephalography (MEG),
  • near infrared spectroscopic imaging (NIRSI), and
  • Single photon emission computed tomography (SPECT)

PET, fMRI and NIRSI can measure localized changes in cerebral blood flow related to neural activity. These changes are referred to as activations. Regions of the brain which are activated when a subject performs a particular task may play a role in the neural computations which contribute to the behaviour. For instance, widespread activation of the occipital lobe is typically seen in tasks which involve visual stimulation (compared with tasks that do not). This part of the brain receives signals from the retina and is believed to play a role in visual perception.

Other methods of neuroimaging involve recording of electrical currents or magnetic fields, for example EEG and MEG. Different methods have different advantages for research; for instance, MEG measures brain activity with high temporal resolution (down to the millsecond level), but is limited in its ability to localize that activity. fMRI does a much better job of localizing brain activity for spatial resolution, but at the cost of speed.

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