51st CiNet Monthly Seminar: Jun Kunimatsu “The function of the striatum tail in behavioral switching” (On-line for CiNet members only: Sign-up required)

CiNet Monthly Seminar

April 28, 2021

“The function of the striatum tail in behavioral switching”

Jun Kunimatsu
Assistant Professor
Faculty of Medicine, University of Tsukuba

Host : Nobuhiro Hagura

We can switch our choice immediately after the environment changes and this ability is critical for animals to survive. What neural mechanism underlies such switching behavior?
Previously, we showed that the striatum tail (STRt, caudal-ventral part of the putamen and caudate nucleus) contributes to the object choice behavior by encoding reward values of visual objects for a long time. We hypothesized that STRt is also related to context- dependent object choice because this area receives the signal from environment-sensitive brain areas, including the parahippocampal cortex. To address this hypothesis, we created an environment-based value task in which monkeys learned to reverse their choice of objects whenever the scene-environment changed. During this learning, medium spiny projection neurons (MSNs) in the striatum tail acquired object-value association, and did so prominently in one of the two scenes. In contrast, fast-spiking interneurons (FSIs) responded to the scenes selectively. When we locally blocked excitation of FSIs in the striatum tail, monkeys were no longer able to learn scene-selective object values. In summary, based on the scene-selective inhibition by FSIs, MSNs are separated into two groups, each encoding object values prominently in one scene, which enables scene- based object choices by the monkey.