Biology subjects

Doi, T.

Publications and source records attributed to Doi, T..

4 recordsLinked to original sources

bioRxiv2023

Wistar rats raised in an affectionate environment display lifesaving-like behaviors while distinguishing life from death

It is generally believed that humans are the only species that values life. However, it is not well understood whether animals have a nature that values life. In this study, we attempted to determine whether male Wistar rats have this nature. Normally-reared rats did not show lifesaving-like actions towards anesthesia-induced comatose rats, although they seemed to distinguish life from death. Considering the possibility that different rearing conditions may foster a life-valuing nature, male Wistar rat pups were reared in several ways: normal rearing, loving rearing (LR; rats reared as if they were cute pets), rearing in an enriched environment, reared with gentle stroking of the back, and normal rearing of offspring of rats raised under LR conditions. When placed in an anxiety-producing environment, only LR rats escaped into the hands of the person who reared them, indicating attachment. Only the LR rats displayed lifesaving-like actions towards unknown comatose rats or drowning pups. LR rats also stopped attacks by biting ICR mice that were attacking C57BL/6 mice. Thus, rearing in an affectionate environment may foster a life-valuing nature, even in rats, suggesting that the valuing of life may be neither innate nor human-specific.

animal behavior and cognition↗

bioRxiv2022

Neural Representations of Post-Decision Choice Confidence and Reward Expectation in the Caudate Nucleus and Frontal Eye Field

Performance monitoring that supports ongoing behavioral adjustments is often examined in the context of either choice confidence for perceptual decisions (i.e., "did I get it right?") or reward expectation for reward-based decisions (i.e., "what reward will I receive?"). However, our understanding of how the brain encodes these distinct evaluative signals remains limited because they are easily conflated, particularly in commonly used two-alternative tasks with symmetric rewards for correct choices. Previously we reported behavioral and neural results related to decision formation by monkeys performing a visual motion discrimination task with asymmetric rewards (Doi et al., 2020; Fan et al., 2020). Here we leveraged this task design to partially decouple trial-by-trial estimates of choice confidence and reward expectation and examine their impacts on behavior and their representations in the caudate nucleus (part of the striatum in the basal ganglia) and the frontal eye field (FEF, in prefrontal cortex). We found that these evaluative signals had infrequent, but consistent, effects on the behavior of well-trained monkeys. We also identified distinguishable representations of the two types of signals in FEF and caudate neurons, including different distribution patterns, time courses, and relationships to behavior in the two brain areas. These results suggest that the cortico-striatal decision network may use diverse evaluative signals for performance monitoring and add to our understanding of the different roles of the FEF and caudate nucleus in decision-related computations.

neuroscience↗

bioRxiv2020

Specialization of mid-tier stages of dorsal and ventral pathways in stereoscopic processing

The division of labor between the dorsal and ventral visual pathways is an influential model of parallel information processing in the cerebral cortex. However, direct comparison of the two pathways at the single-neuron resolution has been scarce. Here we compare how MT and V4, mid-tier areas of the two pathways in the monkey, process binocular disparity, a powerful cue for depth perception and visually guided actions. We report a novel tradeoff where MT neurons transmit disparity signals quickly and robustly, whereas V4 neurons markedly transform the nature of the signals with extra time to solve the stereo correspondence problem. Therefore, signaling speed and robustness are traded for computational complexity. The key factor in this tradeoff was the shape of disparity tuning: V4 neurons had more even-symmetric tuning than MT neurons. Moreover, this correlation between tuning shape and signal transformation was present across individual neurons within both MT and V4. Overall, our results reveal both distinct signaling advantages and common tuning-curve features of the dorsal and ventral pathways in stereoscopic processing.

neuroscience↗

bioRxiv2019

The caudate nucleus contributes causally to decisions that combine noisy visual evidence and reward context

Our decisions often need to balance what we observe and what we desire. However, our understanding of how and where in the brain such decisions are made remains limited. A prime candidate for integrating sensory observations and desired rewards, and a focus of many modeling studies, is the basal ganglia pathway, which is known to make separate contributions to perceptual decisions that require the interpretation of uncertain sensory evidence and value-based decisions that select among outcome options 1-16. Here we report direct evidence for a causal role for a major input station of the basal ganglia, the caudate nucleus, in incorporating reward context and uncertain visual evidence to guide adaptive decision-making. In monkeys making saccadic decisions based on visual motion evidence and asymmetric reward-choice associations 17, single caudate neurons encoded information about both the visual evidence and the asymmetric rewards. Electrical microstimulation at caudate sites with task-modulated activity during motion viewing affected how the visual and reward information was used to form the decision. The microstimulation effects included coordinated changes in multiple computational components of the decision process, mimicking the monkeys voluntary adjustments in response to the asymmetric reward contexts. These results imply that the caudate nucleus plays key roles in coordinating the deliberative decision process that balances external evidence and internal preferences to guide adaptive behavior.

neuroscience↗