Mapping of functional changes associated with administration of substances of abuse in the rat

The [14C]2-deoxyglucose method allows us to investigate whether a drug affects cerebral functional activity in selected brain regions or along discrete neural pathways. Employment of the method in laboratory animals has shown that substances of abuse produce a wide variety of cerebral functional changes which depend upon a number of different variables including the kind of substance, the dose, the modality of administration, and the context. In spite of such a variability, different substances of abuse, when injected in a rat at doses, or with modalities effective in inducing self-administration, have in common the property of selectively modifying glucose utilization of the nucleus accumbens, in particular in the shell portion. It is likely that the change reflects a functional change of a neural circuitry which mediates motivational properties associated with addiction.