[The negative side of emotions: addiction to drugs of abuse].
BACKGROUND
According to the model of emotions, feelings have their origin in the conscious perception of body changes produced in response to an emotional stimulus. These changes are perceived thanks to the fact that they are represented in the brain by the interoceptive system. During abstinence, addicts experience intense feelings of ill-being that drive them to consume drugs. The purpose of this review is to discuss the role played by the interoceptive system, and more especially the insular cortex, in the perception of the negative feelings that characterise abstinence.


METHODS
The continuous processing of interoceptive signals in the insular cortex is what accounts for the conscious appreciation of the body changes that accompany an emotional state. Temporary inactivation of the insular cortex suppresses the search for drugs in addicted rats. Neuroimaging studies reveal an increase in the neuronal activity in the insular cortex and in other areas of the brain while addicts are experiencing the craving to consume drugs. Likewise, nicotine addicts who suffer a brain injury that affects the insular cortex give up smoking easily because they lose the desire to do it. The temporary suppression of neuronal activity in the insular cortex in human addicts by means of non-invasive techniques could be a new therapy to treat the craving to consume drugs.


CONCLUSIONS
The insular cortex is essential in the perception of the emotional states and in orienting behaviour to match the needs of the body. New therapies that have the insular cortex as their target could be developed to mitigate craving.
Contreras
M
M
Departamento de Fisiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile. mecontre@puc.cl
Ceric
F
F
Torrealba
F
F
D000818:Animals; D016739:Behavior, Addictive / Q000503:physiopathology / Q000523:psychology; D002540:Cerebral Cortex / Q000033:anatomy & histology / Q000502:physiology; D004644:Emotions / Q000502:physiology*; D006801:Humans; D013287:Illicit Drugs; D019966:Substance-Related Disorders / Q000503:physiopathology* / Q000523:psychology* / Q000628:therapy
D013287:Illicit Drugs