Cage-induced stereotypic behaviour in laboratory mice covaries with nucleus accumbens FosB/DeltaFosB expression (2015)

Behav Brain Res. 2015 Dec 27. pii: S0166-4328(15)30344-2. doi: 10.1016/j.bbr.2015.12.035.

Phillips D1, Choleris E1, Ervin KS1, Fureix C2, Harper L3, Reynolds K4, Niel L5, Mason GJ6.


Stereotypic behaviour (SB) occurs in certain human disorders (e.g. autism), and animals treated with stimulants or raised in impoverished conditions, including laboratory mice in standard cages.

Dysfunctional cortico-basal ganglia pathways have been implicated in these examples, but for cage-induced forms of SB, the relative roles of ventral versus dorsal striatum have not been fully ascertained.

Here, we used immunohistochemical staining of FosB and ΔFosB to assess long-term activation within the nucleus accumbens and caudate-putamen of C57BL/6 mice. Housed in typical laboratory cages, these mice spontaneously developed different degrees of route-tracing, bar-mouthing and other forms of SB (spending 0% to over 50% of their active time budgets in this behaviour).

The most highly stereotypic mice showed the most elevated FosB/ΔFosB activity in the nucleus accumbens. No such patterns occurred in the caudate-putamen.

The cage-induced SB common in standard-housed mice thus involves elevated activity within the ventral striatum, suggesting an aetiology closer to compulsive gambling, eating and drug-seeking than to classic amphetamine stereotypies and other behaviours induced by motor loop over-activation.

KEYWORDS: Stereotypic behaviour; abnormal repetitive behaviour; caudate-putamen; nucleus accumbens; stereotypy; striatum; transcription factor; ΔFosB