Biology subjects

Karigo, T.

Publications and source records attributed to Karigo, T..

3 recordsLinked to original sources

bioRxiv2023

Cholecystokinin is the follicle-stimulating hormone (FSH)-releasing hormone

In vertebrates, folliculogenesis and ovulation are regulated by two distinct pituitary gonadotropins: follicle-stimulating hormone (FSH) and luteinizing hormone (LH). Today, there is an intriguing consensus that a single hypothalamic neurohormone, gonadotropin-releasing hormone (GnRH), regulates the secretion of both FSH and LH, although the required timing and functions of FSH and LH are different. However, recent studies in vertebrates other than mammals indicate that the effect of GnRH on FSH is too weak to explain its regulation. Therefore, to challenge this "solo GnRH model," we aimed to identify the other gonadotropin regulator, FSH-releasing hormone (FSH-RH), in vertebrates. Here, by using the model teleost medaka, we successfully identified cholecystokinin as the FSH-RH. Our histological and in vitro analyses demonstrated that hypothalamic cholecystokinin-expressing neurons directly affect FSH cells through the cholecystokinin receptor, Cckbr1, thereby increasing the expression and release of FSH. Remarkably, the knockout of cholecystokinin ligand or cckbr1 minimized FSH expression and resulted in a complete failure of folliculogenesis. Our results challenge the longstanding consensus of the solo GnRH model in all vertebrates; instead, we propose the existence of a "dual GnRH model" group in vertebrates that utilizes both FSH-RH and LH-RH. The discovery of the FSH-RH in vertebrates opens not only a new era in neuroendocrinology but also possible applications involving vertebrate reproduction.

neuroscience↗

bioRxiv2022

An approximate line attractor in the hypothalamus that encodes an aggressive internal state

The hypothalamus plays a key role in regulating innate behaviors. It is widely believed to function as a system of labeled lines, containing behavior-specific neurons with characteristic transcriptomic and connectomic profiles. This view however fails to explain why, although activation of estrogen receptor-1 (Esr1) expressing neurons in the ventromedial hypothalamus (VMHvl) promotes aggression, few VMHvl neurons are tuned to attack. To address this paradox, we adopted an unsupervised dynamical systems framework to analyze population activity among VMHvlEsr1 neurons during aggression. We discovered that this activity contains an "integration" dimension exhibiting slow-ramping dynamics and persistent activity that correlates with escalating aggressiveness. These dynamics are implemented as an approximate line attractor in state space. Our analysis suggests a function for VMHvl to encode the intensity of behavior-relevant motive states using line attractors. This view reconciles observational and perturbational studies of VMHvl, and reveals a new mode of neural computation in the hypothalamus.

neuroscience↗

bioRxiv2020

The Mouse Action Recognition System (MARS): a software pipeline for automated analysis of social behaviors in mice

The study of naturalistic social behavior requires quantification of animals interactions. This is generally done through manual annotation--a highly time consuming and tedious process. Recent advances in computer vision enable tracking the pose (posture) of freely-behaving animals. However, automatically and accurately classifying complex social behaviors remains technically challenging. We introduce the Mouse Action Recognition System (MARS), an automated pipeline for pose estimation and behavior quantification in pairs of freely interacting mice. We compare MARSs annotations to human annotations and find that MARSs pose estimation and behavior classification achieve human-level performance. We also release the pose and annotation datasets used to train MARS, to serve as community benchmarks and resources. Finally, we introduce the Behavior Ensemble and Neural Trajectory Observatory (BENTO), a graphical user interface for analysis of multimodal neuroscience datasets. Together, MARS and BENTO provide an end-to-end pipeline for behavior data extraction and analysis, in a package that is user-friendly and easily modifiable.

neuroscience↗