AI Insight
This study examined whether extrinsic motivation (working for tangible rewards) and intrinsic motivation (self-driven behaviors without external rewards) represent distinct processes by testing three mouse strains on different motivation tasks. BALB/c mice showed low intrinsic motivation in a foraging task but high extrinsic motivation when working for rewards, while other strains showed different patterns. These opposing profiles within the same strain demonstrate that intrinsic and extrinsic motivation are separable behavioral processes that cannot be measured on a single motivational scale.
Why it matters
The findings suggest that motivational deficits in psychiatric and neurodegenerative disorders may affect intrinsic and extrinsic motivation differently, which could explain why current treatments often fail to address motivational symptoms. This work indicates that effective therapies may need to target these distinct motivational systems separately rather than treating motivation as a unified construct.
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⚠️ Preprint – Noch nicht peer-reviewed
Dieser Artikel wurde noch nicht von unabhängigen Experten begutachtet. Die Ergebnisse sind vorläufig und sollten mit Vorsicht interpretiert werden.
Motivational deficit is a prevalent symptom across a wide range of neurodegenerative and neuropsychiatric disorders. Despite its clinical importance, first-line treatments for these disorders fail to effectively treat this symptom domain. In animal models, motivation is typically assessed in the context of extrinsic reward, where reward is delivered for completing an effortful action. However, many motivated behaviours occur in the absence of a tangible reward and are instead driven by intrinsic motivation. Previous work has shown that an extrinsic motivation task (effort for reward (EfR)) and an intrinsic motivation task (effort based forage (EBF) task) show opposing responses to a range of pharmacological manipulations. However, it is not clear whether intrinsic and extrinsic motivation dissociate in the context of endogenous behavioural variation. We therefore investigated whether these tasks were sensitive to behavioural variation across three different strains of mice (C57Bl/6JJRi, 129S2/SvPasOrlRj and BALB/cJRi) and whether strain profiles diverged across tasks. Here, we found that BALB/c mice showed the lowest levels of foraging in the EBF task, indicative of a low intrinsic motivational state but showed the highest levels of high effort responding in the EfR task, indicative of a high extrinsic motivational state. These differences were not driven by an anxiety-related phenotype and were therefore indicative of a motivation phenotype divergence across tasks. This work highlights the importance of moving away from considering motivation on a single axis, as findings can diverge depending on the nature of the motivational process. This has important implications for both phenotypic interpretation and the development of treatments targeting motivational dysfunction.