Ventral subicular lesion impairs pro-social empathy-like behavior in adult Wistar rats

In search of prosociality in rodents: A scoping review

Studying prosociality in rodents can provide insight into brain mechanisms potentially related to neurodevelopmental disorders known to impact social behaviors (e.g., autism spectrum disorder). While many studies have been published suggesting promising models, current knowledge remains scattered, including potential factors mediating prosocial behaviors in rodents. Prosocial behavior is characterized by an action done to benefit another or promote their well-being. The goal of this scoping review is to characterize current findings regarding prosocial paradigms in rodents, highlight current gaps in reporting, and identify factors shown to be important in mediating prosocial responses in rodents. Five databases were consulted in search of relevant studies published between 2000 and 2020 (APA PsycInfo, Embase, MEDLINE, Scopus, Web of Science). An update using a semi-supervised machine learning approach (ASReview) was then conducted to collect studies from 2021-2023. In total, 80 articles were included. Findings were the following: (1) Three categories of prosocial paradigm were extracted: cooperation, helping, and sharing tasks, (2) Rodents showed the ability to perform prosocial actions in all three categories, (3) Significant gaps in reported methodologies (e.g., failure to report animals' characteristics, housing conditions, and/or experimental protocol) and mediating factors (e.g., sex, strain, housing, food restriction) were found, and (4) Behaviors are determinant when investigating prosociality in rodents, however many studies omitted to include such analyses. Together these results inform future studies on the impact of mediating factors and the importance of behavioral analyses on the expression of prosocial behaviors in rodents.

Crosstalk between the subiculum and sleep-wake regulation: A review

The circuitry underlying the initiation, maintenance, and coordination of wakefulness, rapid eye movement sleep, and non-rapid eye movement sleep is not thoroughly understood. Sleep is thought to arise due to decreased activity in the ascending reticular arousal system, which originates in the brainstem and awakens the thalamus and cortex during wakefulness. Despite the conventional association of sleep-wake states with hippocampal rhythms, the mutual influence of the hippocampal formation in regulating vigilance states has been largely neglected. Here, we focus on the subiculum, the main output region of the hippocampal formation. The subiculum, particulary the ventral part, sends extensive monosynaptic projections to crucial regions implicated in sleep-wake regulation, including the thalamus, lateral hypothalamus, tuberomammillary nucleus, basal forebrain, ventrolateral preoptic nucleus, ventrolateral tegmental area, and suprachiasmatic nucleus. Additionally, second-order projections from the subiculum are received by the laterodorsal tegmental nucleus, locus coeruleus, and median raphe nucleus, suggesting the potential involvement of the subiculum in the regulation of the sleep-wake cycle. We also discuss alterations in the subiculum observed in individuals with sleep disorders and in sleep-deprived mice, underscoring the significance of investigating neuronal communication between the subiculum and pathways promoting both sleep and wakefulness.

The subiculum role on learning and memory tasks using rats and mice: A scoping review

This scoping review aimed to systematically identify and summarize data related to subiculum involvement in learning and memory behavioral tasks in rats and mice. Following a systematic strategy based on PICO and PRISMA guidelines, we searched five indexed databases (PubMed, Web of Science, EMBASE, Scopus, and PsycInfo) using a standardized search strategy to identify peer-reviewed articles published in English (pre-registration: osf.io/hm5ea). We identified 31 articles investigating the role of the subiculum in spatial, working, and recognition memories (n = 11), memories related to addiction models (n = 9), aversive memories (n = 7), and memories related to appetitive learning (n = 5). We highlight a dissociation in the dorsoventral axis of the subiculum with many studies exploring the ventral subiculum (n = 21) but only a few exploring the dorsal one (n = 10). We also observe the necessity of more data including mice, female animals, genetic tools, and better statistical approaches for replication purposes and research refinement. These findings provide a broad framework of the subiculum involvement in learning and memory, showing essential questions that can be explored by further studies.