Strain commonalities and differences in response-outcome decision making in mice

Abstract

The ability to select between actions that are more vs. less likely to be reinforced is necessary for survival and navigation of a changing environment. A task termed “response-outcome contingency degradation” can be used in the laboratory to determine whether rodents behave according to such goal-directed response strategies. In one iteration of this task, rodents are trained to perform two food-reinforced behaviors, then the predictive relationship between one instrumental response and the associated outcome is modified by providing the reinforcer associated with that response non-contingently. During a subsequent probe test, animals can select between the two trained responses. Preferential engagement of the behavior most likely to be reinforced is considered goal-directed, while non-selective responding is considered a failure in response-outcome conditioning, or “habitual.” This test has largely been used with rats, and less so with mice. Here we compiled data collected from several cohorts of mice tested in our lab between 2012-2015. Mice were bred on either a C57BL/6 or predominantly BALB/c strain background. We report that both strains of mice can use information acquired as a result of instrumental contingency degradation training to select amongst multiple response options the response most likely to be reinforced. Mice differ, however, during the training sessions when the familiar response-outcome contingency is being violated. BALB/c mice readily generate perseverative or habit-like response strategies when the only available response is unlikely to be reinforced, while C57BL/6 mice more readily inhibit responding. These findings provide evidence of strain differences in response strategies when an anticipated reinforcer is unlikely to be delivered.

Inter-individual variability amplified through breeding reveals control of reward-related action strategies by Melanocortin-4 Receptor in the dorsomedial striatum

“…We extracted response rates in bins to compare groups across time. Response rates increased as animals first experienced the contingency violation, resembling a so-called “extinction burst,” as previously reported in mice performing the same task 26 . All mice ultimately inhibited responding with time, though, importantly with Mc4r knockdown mice responding less overall (Fig.…”

Cell adhesion factors during adolescence support amygdalo-cortical connections and flexible action later in life

“…Meanwhile, the BLA represents specific outcome information that is motivationally significant and necessary for choosing between options 23 . The contingency violation in our task causes a transient "extinction burst," evidence of motivational salience 41 , so involvement of the BLA in subsequent response prioritization is perhaps unsurprising. Our findings indicate that BLA inputs to the PL help animals prioritize certain reward-seeking behaviors over others during memory retrieval epochs.…”

Encore: Behavioural animal models of stress, depression and mood disorders

“…Large behavioural and physiological differences exist between rodent strains. Significant differences have been observed in motor skills ( Brooks et al, 2004 ), cognitive and learning abilities ( Baron and Meltzer, 2001 ; Brooks et al, 2005 ; Codita et al, 2012 ), and baseline anxiety-like and depressive-like behaviours ( Pothion et al, 2004 ; Bothe et al, 2005 ; Zimmermann et al, 2016 ). Some strains differ in sensory processing which directs subsequent behaviour ( Bailey et al, 2006 ).…”

“…Initially, genetic variation between different strains prompted investigations into genetic and molecular vulnerability factors. This remains one of the focal points of neuropsychiatric research (Pothion et al, 2004;Einat, 2007;Zimmermann et al, 2016). Strain 10.3389/fnbeh.2022 investigations have recently been more focussed toward behavioural and neurophysiological stress responses.…”