Summary: Kasanetz et al. (2010)

 Numerous studies have shown that brain physiology is modified in a numerous ways through chronic exposure to illegal substances (i.e. drugs of abuse). Since some individuals are more likely to become addicts than others, this raises the question of which neurobiological adaptations are associated with a shift from no-addict to addict. Kasanetz et al. (2010) noted that long-term depression (LTD) can be suppressed through self-administration of cocaine and this is related to synaptic plasticity in the region of the nucleus accumbens. They found that rats that are likely to become addicts have permanently impaired LTD, while rats that are unlikely to become addicts show progressive recovering in LTD. Kasanetz et al. (2010) suggest that the transition to addiction could be mediated by a persistently impaired LTD when drug seeking behaviour is made consistently resistant to modulation by possible environmental changes.