The Use of Functional MRI to Study Appetite Control in the CNS

Figure 1

Brain reward centres: the hypothalamus (H), as a homeostatic gatekeeper, has numerous connections with higher brain centres which process salience and reward. The hypothalamus transmits to these higher centres information received from the periphery, such as nutritional status signalled via the postprandial release of gut hormones, and in turn modulates metabolic rate via the sympathetic nervous system. This sagittal section of the brain reveals the important areas involved in the hedonic control of eating behaviour; amygdale (Am): emotional and aversive processing; nucleus accumbens (Nac): anticipatory reward processing; ventral tegmental area (VTA): numerous dopaminergic projections to other limbic areas; ventral striatum (VS): motivation reward; expectancy and novelty processing; anterior cingulate cortex (ACC): decision making; orbitofrontal cortex (OFC): reward encoding; prefrontal cortex (PFC): translation of external and internal cues into behavioural responses; dorsolateral prefrontal cortex (DLPFC): self-control. Not shown is the insular cortex (a more lateral structure), which is also important in gustatory processing.