Table 2.

Behavioural phenotype upon ΔFosB induction in dynorphin+neurons of nucleus accumbens and dorsal striatum^a.

stimulus	phenotype
cocaine	increased locomotor responses to acute administration
	increased locomotor sensitization to repeated administration
	increased conditioned place preference at lower doses
	increased acquisition of cocaine self-administration at lower doses
	increased incentive motivation in progressive ratio procedure
morphine	increased conditioned place preference at lower drug doses
	increased development of physical dependence and withdrawal
	decreased initial analgesic responses, enhanced tolerance
alcohol	increased anxiolytic responses
wheel running	increased wheel running
sucrose	increased incentive for sucrose in progressive ratio procedure
high fat	increased anxiety-like responses upon withdrawal of high-fat diet
sex	increased sexual behaviour

^aThe phenotypes described in this table are established upon inducible overexpression of ΔFosB in bitransgenic mice where ΔFosB expression is targeted to dynorphin+neurons of the nucleus accumbens and dorsal striatum; several-fold lower levels of ΔFosB are seen in hippocampus and frontal cortex. In many cases, the phenotype has been directly linked to ΔFosB expression in nucleus accumbens per se by use of viral-mediated gene transfer.