Research techniques: Functional MRI

Whilst 'normal' magnetic resonance imaging capitalises on the behaviour of tissues in a magnetic field to produce a structural image of the brain, functional MRI can produce a dynamic map of brain activation over time. Activity by nerve cells triggers an increase in oxygenated blood flow in the activated part of the brain. This change in the oxygen supply is the signal measured by fMRI. Hence, by looking at the fMRI signal under different conditions it is possible to infer regionally specific aspects of brain function. For example, presenting subjects with speech stimuli via headphones inside the scanner causes an increase in the fMRI signal in the temporal lobes of the brain - site of the human auditory cortex.

Using fMRI we are investigating a range of important themes including social cognition, 'executive' brain function, auditory processing and time perception. The populations of individuals in which these themes are being investigated include people with schizophrenia, people with PTSD and homeless people.