Brain Interaction of Cognition and Emotion in Patients with Schizophrenia: experiments in search of a common brain mechanism using functional magnetic resonance imaging (fMRI)

Cognition and emotion are two basic functions of humans which subserve
recognizing inner and outer environment as well as goal directed behaviour in
order to react on certain changes of the environment. Many studies examined
human behaviour and the underlying brain mechanisms focusing only on one of
these functions, namely cognition or emotion. It has become clearer in the last
years that both functions are closely connected. Several approaches have been
used to look for the interaction of cognition and emotion, for example, the
emotional Stroop task, the influence of emotional valence or arousal on memory,
positive or negative feedback etc.
In patients with schizophrenia both functions can be disturbed. Core symptoms
of schizophrenia are besides the well known phenomena as hallucinations,
delusions and disorganisation changes in affect and mood, but also in cognitive
processes, for example working memory, attention, detection of perceptual
differences, or detection of emotions.
So, it seems to be important to examine the interaction between the two
functions in patients with schizophrenia focusing on the underlying brain
process using fMRI.
In fMRI studies it has been shown that there are many parameters which may
influence the results, for example the scanner itself, parameters of the
scanning sequences used, statistical methods or baseline conditions.
Furthermore the actual state of patients as well as medication may have an
influence on fMRI results. The here presented study therefore addresses not
only the disease process itself but also the effect of specific medication on
the fMRI results by restricting the population of patients with schizophrenia
to three groups, that is, medication free, use op haloperidol or clozapine.

To investigate whether patients with schizophrenia show reliable and consistent
brain activations as measured with fMRI to two different stimulation paradigms
and wether they differ in terms of the patterns or the intensity of activation
as compared to healthy controls.
a. Are there differences in activation of the prefrontal lobe, parietal lobe
and limbic regions between patients with schizophrenia and healthy controls
during a working memory paradigm comprising identiy of faces with emotional
faces.
b. Are there differences in activation of medial prefrontal regions, limbic
regions, the basal ganglia and the nucleus accumbens between patients with
schizophrenia and healthy controls during a time estimation task with faces
(positive or negative emotional expression) as feedback.

The paradigm comprises two neuropsychological tasks:
1. The first task comprises a working memory paradigm designed as an
event-related Sternberg-Paradigm. Each trial comprises the short presentation
of 2 or 3 faces (sample) followed by a delay of 6 seconds. Thereafter another
face will appear for 2 seconds (target). Subjects have to decide whether the
target face has been displayed in the sample or not. Faces will vary in
identity or in emotional expression, so the study has a 2 (identity vs.
emotion) x 2 (load) factorial design.
2. The second task comprises a time estimation task. Subjects are requested to
look at a blank screen. Starting from the appearance of an exclamation mark on
the screen subjects are asked to press a button when - following their
subjective estimation - one second has passed. They will receive feedback using
positive or negative emotional faces which signal the correctness of their
response. Using a "self-learning" algorithm time spans, which will be assigned
as correct or incorrect, are dependent of the performance of subjects. As
better a subject performs the task the narrower the time spans will get, and
the worse a subject performs the wider the time spans will get. This strategy
is chosen in order to guarantee the same amount of positive and negative
feedback signals.

None.

The experiment will be performed in one session lasting about 1.5 hours.
Patients and healthy controls will undergo an fMRI measurement. There will be
no specific risk due to the measurement if the standard safety instructions for
fMRI measurement are followed. The measurement is non-invasive and there is no
exposure to X-ray or radioactivity. Patients and healthy controls are forced to
lie into the tube of the scanner. Some of them may perceive this position as
uncomfortable. Further causes the fMRI measurements are noisy, and this may
cause in some subjects to experience a short lasting headache. Therefore
subjects will wear ear plug during the measurement, a standard safety procedure
during clinical MRI measurement. There are no other specific risks.