Behavioral paradigms for cognitive neuroscience in the common marmoset

SUMMARY/ABSTRACT Primates including humans evolved remarkable visual and cognitive functions compared to other mammals making it essential to utilize primate models specifically for studying high-level brain function. The common marmoset is one emerging primate model that holds immense experimental promise because of its small size (similar body size to a rat) and flat, surface-accessible cortex as opposed to most other monkey models which are significantly larger with highly folded brains. There remains concern, however, about the cognitive abilities of such a small monkey, such that there is a clear need for demonstrating marmoset high-level behavioral performance before studying brain circuits in marmosets. In this proposal, we directly address this overriding concern in the field by prescribing sophisticated task paradigms for the marmoset, addressing barriers to the marmoset’s widespread adoption in systems neuroscience. In Aim 1, we study cognitive flexibility by developing a rule-learning task that abstracts from the number and identity of visual items being compared. In Aim 2, we use a virtual foraging paradigm to study 3D visuospatial inference where marmosets have to recall high versus low value targets, predicting their locations from novel viewpoints. In both aims, we efficiently develop task paradigms using touchscreens in their housing unit, and then we subsequently validate in-lab performance using eye tracking under head-fixed conditions suitable for neuroscience experiments. Advancing the marmoset model in the field of cognitive neuroscience will lead to future inquiries elucidating neural mechanisms in high-level brain areas such as frontal cortex and the hippocampus and have implications for understanding cognitive impairments of visual memory and spatial navigation common to neurodegenerative diseases.