Brain Networks Responsible for Self-Agency: An fMRI Study

This study will examine how people consider their actions to be under their own control or not. The term to describe this feeling of being in control of one's own actions is called "agency." The sense of agency becomes impaired in disorders such as schizophrenia, in which people may feel, for example, as if someone else is controlling their thoughts.

Healthy, right-handed normal volunteers 18 years of age and older may be eligible for this study. Candidates are screened with a medical history, neurological examination, pregnancy test for women of childbearing age, and magnetic resonance imaging (MRI) scan. MRI uses a strong magnetic field and radio waves to obtain images of body organs and tissues. During the procedure, the subject lies on a table that can slide in and out of the scanner (a metal cylinder surrounded by a magnetic field) and may be asked to lie still for up to 30 minutes at a time.

Participants undergo functional MRI (fMRI). This procedure is the same as a regular MRI, except it is done while the subject performs tasks. This enables researchers to learn about changes in brain regions involved in those tasks. The fMRI scan for this study takes about 90 minutes.

Before beginning the fMRI procedure, subjects receive training using a Cyber glove device. This device allows the researchers to measure the subject's finger movements and display them on a screen for the subject to view. The subjects are asked to make hand movements by slowly opening and closing the hand while watching the computer displaying an artificial hand. During the movements, the subjects' level of control is adjusted and they are asked to describe how much control they think they have over the hand on the screen. When the subjects become comfortable using the Cyber glove, they enter the MRI scanner to begin the test scan.

For the fMRI, subjects are given visual instruction on when to begin opening and closing their right hand. They move continuously for a 30-second block and then have a 20-second rest period. This is repeated, with subjects provided different levels of control over the displayed hand in each block. The entire test consists of four runs, each run consisting of 12 blocks lasting about 10 minutes. When the fMRI scanning is finished, the brain is scanned once more using regular MRI.