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REVIEWS
THE HUMAN ORBITOFRONTAL CORTEX: LINKING REWARD TO HEDONIC EXPERIENCE
REINFORCERS
Positive reinforcers (rewards) increase the frequency of behaviour that leads to their acquisition. Negative reinforcers (punishers) decrease the frequency of behaviour that leads to their encounter and increase the frequency of behaviour that leads to their avoidance.
Morten L. Kringelbach
Abstract | Hedonic experience is arguably at the heart of what makes us human. In recent neuroimaging studies of the cortical networks that mediate hedonic experience in the human brain, the orbitofrontal cortex has emerged as the strongest candidate for linking food and other types of reward to hedonic experience. The orbitofrontal cortex is among the least understood regions of the human brain, but has been proposed to be involved in sensory integration, in representing the affective value of reinforcers, and in decision making and expectation. Here, the functional neuroanatomy of the human orbitofrontal cortex is described and a new integrated model of its functions proposed, including a possible role in the mediation of hedonic experience.
The human orbitofrontal cortex has received relatively little attention in studies of the prefrontal cortex, and many of its functions remain enigmatic. During primate evolution, the orbitofrontal cortex has developed considerably, and although some progress has been made through neurophysiological recordings in non-human primates, it is only during the past couple of years that evidence has converged from neuroimaging, neuropsychology and neurophysiology to allow a better understanding of the functions of the human orbitofrontal cortex. These studies indicate that the orbitofrontal cortex is a nexus for sensory integration, the modulation of autonomic reactions, and participation in learning, prediction and decision making for emotional and reward-related behaviours. The orbitofrontal cortex functions as part of various networks that include regions of the medial prefrontal cortex, hypothalamus, amygdala, insula/operculum and dopaminergic midbrain, and areas in the basal ganglia including the ventral and dorsal striatum.These additional areas have been investigated in detail in rodents and other animals, and have been described in other reviews1,2. Here, I focus on the functions of the human orbitofrontal cortex, as the phylogenetic
expansion and heterogeneous nature of this brain region mean that a full understanding of its functions must be informed by evidence from human neuro-imaging and neuropsychology studies.
Recently, neuroimaging studies have found that the...