Depression and mind control

Telling eye movements

The experiments focus on proactive cognitive control, i.e. the ability to focus attention on an expected event, mentally prepare for it, and plan an appropriate response. “It is our hypothesis that people with depression have difficulty doing just that,” says Duschek. “Because proactive control is exacting and requires a great deal of attention and working memory.”

This is the set task: a colored circle appears on the screen – mostly green or red – indicating whether the person should look at a face appearing to the side of the circle (mostly green) or look away from it (mostly red). The person mentally prepares for the expected requirement. Then an image of a facial expression with a green or red border appears. The border makes it clear which eye movement is actually required: looking at or away from the image. Looking away, known as an anti-saccade, is a prime example of cognitive control. This requires suppressing the automatic reaction (“Look!”) and actively making the eyes move in the opposite direction. These processes can be prepared in advance of the image's appearing, i.e. proactively controlled.

“It sounds complicated, but it's designed in a way that you'd respond correctly in three out of four cases,” says Duschek. The psychologists are particularly interested in the data from the EEG and fMRI, showing which areas of the brain become active, when, and to what extent. “We want to find out two things: first, the extent to which cognitive control is impaired in people with depression. And second, the role played by different facial expressions, i.e. whether controlling emotional information entails a particular challenge.”

Joy, fear, anger, sadness

Faces are particularly powerful stimuli. “Emotional facial expressions have proven valuable in psychological experiments because the human brain processes them particularly well and at lightning speed,” explains Duschek. “A sad or fearful face automatically and intuitively triggers an emotional response.” The psychologist suspects that people with depression find it particularly difficult to process negative emotional information such as sad faces.

In a second experiment, the team combined fearful and happy facial expressions with the words “fear” and “joy,” with the words either matching or contradicting the images. For example, a happy face was shown at the same time as the word “fear”. Test subjects with and without depression were asked to identify the facial expression but ignore the word. The result: people with depression made more mistakes, but only when the word and the face did not match. “This suggests that they have problems processing conflicts between different emotional information. Again, this is a problem of cognitive control,” says Duschek.

Distorted perceptions in depression

“People with depression often interpret situations differently,” reports Duschek. “This does not affect everyone equally, but sufferers show clear tendencies to view themselves, their environment, and the future in a more negative light.” By way of example the psychologist notes that many people are annoyed by an everyday argument for a brief moment, but will quickly let go of the negative thoughts and feelings. “People with depression tend to relate strongly to such an argument,” says Duschek. This can lead to brooding or spiraling thoughts, which then trigger negative feelings and other depressive symptoms.

“Blaming yourself for negative things and consequently experiencing feelings of guilt is very typical of depression,” notes Duschek. In this context, researchers need to distinguish between two levels: one concerns the content of thoughts, i.e., how or why those affected evaluate themselves and their environment negatively. Psychotherapy can address this content effectively. On the other hand, it is crucial to understand the fundamental mechanisms by which we control our thoughts and emotions and how this process can become impaired. This is precisely the subject of the present research project, designed to help us better understand the onset of depression.