Biology subjects

Kamijo, M.

Publications and source records attributed to Kamijo, M..

3 recordsLinked to original sources

bioRxiv2025

Rats spontaneously show categorical responses toward familiar or unfamiliar conspecifics in a habituation-dishabituation task using multiple habituation stimuli

Discriminating between familiar and unfamiliar conspecifics is a fundamental aspect of social recognition. Previous studies have shown that familiarity strongly influences rat social behavior, and that rats can be trained to discriminate between olfactory cues from cage-mates and non-cage-mates in a digging task. However, such discrimination did not occur in a lever-pressing task using live conspecifics as stimuli. In the present study, we investigated whether rats could discriminate social familiarity in a simple, less-demanding and naturalistic context using whole-animal stimuli. We employed a habituation-dishabituation paradigm in which multiple cage-mate or non-cage-mate individuals were presented during the habituation phase. We examined whether rats would habituate to the familiarity category among these multiple stimuli and subsequently show dishabituation when the stimulus class switched (cage-mate to non-cage-mate or vice versa). During the habituation phase, exploratory responses declined over successive sessions, suggesting habituation to the common element among multiple cage-mates or non-cage-mates, i.e., familiarity/unfamiliarity. When all subjects were considered together, clear dishabituation was not observed, indicating individual variation in habituation. However, a post-hoc analysis restricted to subjects showing sufficient habituation revealed significant dishabituation to the stimulus class switch. These findings suggest that rats can spontaneously classify multiple conspecifics according to their familiarity without training. Rats may flexibly employ different forms of social recognition and information such as individual identity or familiarity-based heuristics to guide adaptive social behavior in varying contexts. HighlightsO_LIWe tested familiarity discrimination in rats by habituation-dishabituation task C_LIO_LIMultiple cage-mate or non-cage-mate stimuli were presented during habituation C_LIO_LIExploratory responses decreased as habituation sessions progressed C_LIO_LIDishabituation occurred in individuals who exhibited sufficient habituation C_LIO_LIRats showed categorical responses toward familiarity or unfamiliarity C_LI

animal behavior and cognition↗

bioRxiv2024

Familiarity modulates preference for joint feeding with conspecifics in rats

Rats are highly social mammals that form social groups of various sizes. Interestingly, they are known to show prosocial behaviors, and are socially tolerant of other conspecifics as they feed together, but the specificity of their prosociality has not been fully understood. Here, we investigated what degree rats showed social choice, i.e., preferential joint feeding even with unfamiliar animals by performing a simple feeding site choice task. In the task, subjects were tested to choose between the feeding site where they fed with other rats (social option) or the other site where they could feed alone (solitary option). The results showed that social option choices increased particularly when the partner was a single non-cagemate rat. This result means that high social preference for other individuals occurs spontaneously, even when they are feeding with unfamiliar non-cagemates. This high degree of social tolerance would lead to the suppression of aggressive behavior as well as enhancement of affiliative relationships even in situations when the rats met with unfamiliar conspecifics for the first time. HighlightsO_LIRats are highly socially tolerant mammals as they feed with conspecifics together. C_LIO_LIWe explored how the presence of conspecifics affects feeding site choices in rats. C_LIO_LISocial choices increased when the partners were non-cagemates. C_LIO_LISocial choices decreased as the number of non-cagemates increased. C_LIO_LIJoint feeding with a single non-cagemate is observed particularly frequently. C_LI

animal behavior and cognition↗

bioRxiv2022

Discrimination of conspecific head orientations and learning set formation in Bengalese finches

Animals detect others gaze direction, such as predators, prey, and courtship mates, to enable adaptive behavior. However, head movements play a more significant role in gaze shifts in birds than eye movement because of the flat eye shape. Additionally, most birds with laterally placed eyes usually turn the lateral face to the target. Therefore, we used Bengalese finches to examine whether songbirds can discriminate between conspecific frontal and lateral faces and divide head orientations in different angles into two categories. In experiments, birds were trained by operant conditioning to discriminate stimuli consisting of conspecific frontal and lateral head images. Eight out of nine birds finished discrimination training and test sessions. The results indicate that Bengalese finches can discriminate gaze direction by the head orientations. Furthermore, as the number of stimuli set increased, fewer trials were needed to achieve the criteria, which suggests that birds have developed a learning set during the training. However, we did not find a clear discrimination boundary for head orientation categorization.

animal behavior and cognition↗