8 - Neuroimaging

Summary

Introduction

Neuroimaging studies have provided new insights in neural brain circuits and neuroreceptor functions of eating disorders and as a consequence have contributed to a change of the conceptual framework of the pathophysiology and aetiology of eating disorders. Most research has been collected for the two distinct DSM–IV defined eating disorders: anorexia (AN) and bulimia nervosa (BN). To our knowledge only three studies have specifically investigated teenagers with an eating disorder (Gordon et al., 1997; Chowdhury et al., 2003; Wagner et al., 2003), although in many studies a wide age range of the participants is found, including adolescents. This chapter is substantially based on findings in adulthood. Task and provocation using eating disorder-related stimulus material have been used to unravel the disorder-specific neural circuits. However, eating disorders show a high psychiatric comorbidity including depression, anxiety and obsessive-compulsive disorders. Therefore, overlap with other psychiatric disorders is likely and may impact on the interpretation of the findings.

Neural basis of hunger, satiety and reward value of food

Motivation for food intake and eating behaviour is not only dependent on internal factors sensing recent energy intake and energy homeostasis, but is also determined by the incentive value (‘wanting’) and hedonic pleasure (‘liking’) of food (Fig. 8.1). Motivational aspects of food intake involve higher mental processes such as emotional, motivational and cognitive processing, which are poorly understood (see also Mercer, Chapter 2).