Functional magnetic resonance imaging (fMRI) has provided the opportunity to safely investigate the workings of the human
brain. This paper focuses on its use in the field of human appetitive behaviour and its impact in obesity research. In the present
absence of any safe or e
ff
ective centrally acting appetite suppressants, a bette
r understanding of how appetite is controlled is vital
for the development of new antiobesity pharmacotherapies. Early functional imaging techniques revealed an attenuation of brain
reward area activity in response to visual food stimuli when humans are fed—in other words, the physiological state of hunger
somehow increases the appeal value of food. Later studies have inv
estigated the action of appetite modulating hormones on the
fMRI signal, showing how the attenuation of brain reward region activity that follows feeding can be recreated in the fasted state by
the administration of anorectic gut hormones. Furthermore, di
ff
erences in brain activity between obese and lean individuals have
provided clues about the possible aetiology of overeating. The hypothalamus acts as a central gateway modulating homeostatic and
nonhomeostatic drives to eat. As fMRI techniques constantly improve, functional data regarding the role of this small but hugely
important structure in appetite control is emerging.