Functional MRI during cognitive processing of food stimuli in chronically ill and recovered women with anorexia nervosa

Anorexia Nervosa (AN) is a psychiatric disease which has a poor outcome due to
lack of effective treatment. AN is characterized by obsessive fears and
behavior with regard to food, weight and shape, which are all under strong
cognitive control in patients. Although patients are constantly thinking of
food, they refuse to eat. The central regulation of food intake behaviour is
governed by different interacting brain systems. The homeostatic system
regulates the balance between energy intake and energy expenditure and is
affected by peripheral signals such as hormones. The hedonic system deals with
the reward value of (food) stimuli and has neural circuits which encode wanting
(incentive motivation) and liking (pleasantness). On top of these systems, the
cognitive control system can strongly modulate the decision to eat or to
refrain from eating. In contrast with the majority of people, patients with AN
are able to starve themselves by restricting their food intake and ignoring the
drive to eat.
The eating behavior of AN patients is usually studied by looking at 1 of these
systems. Since such studies have not been able to find a good explanation for
the ambivalence towards food seen in AN patients, in this study we will examine
the integration of these 3 systems.

To determine 1) the differences in the effects of food stimuli on the
activation of brain regions associated with energy homeostasis and reward
between women with chronic AN, women recovered from AN and healthy
normal-weight women, 2) the correlation between hormone concentrations and
these brain responses and 3) how variation in these brain responses correlates
with measures of cognitive functioning.

A cross-sectional experimental study. In the morning, subjects will undergo a
20 minute MRI scan. First, a perfusion MRI scan will be made. Second, a 15-min
functional MRI scan will be made, during which subjects will be shown images of
foods (varying in palatability) and of non-foods. During the functional scan,
participants rate their level of anxiety and their liking for the foods they
have been shown.

MRI during the presentation of food images.

The experiment is non-therapeutic to the subjects and will consist of one study
session. During screening, subjects will be asked to answer to questionnaires
on eating disorders, personality traits, depression and anxiety to rule out any
inflicting psychiatric morbidity. On the study day, length, weight and % body
fat will be measured by measuring height and weighing subjects on a TANITA (an
impedance measurement device). Furthermore, a single fasting blood sample will
be drawn to determine the concentrations of relevant hormones involved in food
intake regulation. After blood sampling, the subjects will be scanned once with
the use of an MRI scanner for 20 min, during which they will rate their anxiety
and desire to eat. The same functional MRI paradigm has been used with AN
patients in the Institute of Psychiatry in London and it poses no risk.
Functional MRI is a safe and non-invasive technique. The tasks used for
assessing cognitive functioning have been extensively used in AN patients and
are not considered to be a burden; they are even perceived as amusing to
perform. In summary, the risk associated with participation is assessed as
negligible and the burden as minimal.