Figure 1.

Depression-relevant behaviours in Tph2KI mice. (a) (i) Increased tail-suspension immobility (depression-like behaviour, i.e. behavioural despair), (ii) increased latency to cross into lit area in the light-dark box test (anxiety-like behaviour) and (iii) increased male aggression during an encounter with an unknown male in a non-territorial arena (dyadic test) in the Tph2KI (knockin) mice (adapted from Beaulieu et al. [138]). (b) The Tph2KI mice also displayed increased anxiety in the marble burying test (adapted from Jacobsen et al. [83]). Given random access to various dilutions of sweetened condensed milk both WT and Tph2KI mice displayed inverted U-shaped lever-press responses to obtain the reward. (c) However, the Tph2KI mice manifested reduced lever-pressing for sweetened condensed milk, indicating an anhedonic phenotype in this paradigm (previous unpublished data). Filled circles denote knockin, open circles denote WT.