Biology subjects

Li, L.-y.

Publications and source records attributed to Li, L.-y..

4 recordsLinked to original sources

bioRxiv2025

Rank- and Threat-Dependent Social Modulation of Innate Defensive Behaviors

Fear and defense are among the most fundamental survival behaviors and are profoundly influenced by the social environment in group-living animals. However, it remains poorly understood how social context--and particularly dominance hierarchy, a defining feature of many social species--modulates defensive strategies under ethologically relevant conditions. To address this question, we investigated the social modulation of innate fear in mice exposed to two ethologically relevant threats: a transient visual looming stimulus and a sustained predatory threat posed by a live rat. We found that social presence alleviated threat-induced stress and modulated defensive behaviors in a rank- and threat-specific manner. During looming exposure, it reduced immediate defensive responses and alleviated post-looming anxiety, with dominants showing greater benefit. During rat exposure, it promoted a shift from passive to active defense, again most prominently in dominants. These behavioral changes were accompanied by reorganization of transitions between defensive states, indicating that social hierarchy shapes both the expression and temporal organization of innate defensive behaviors. Conversely, threat exposure strengthened social engagement, with dominant mice exhibiting more proactive social behaviors and subordinate mice responding more readily to dominant social initiations. Together, these findings demonstrate how dominance hierarchy modulates defensive responses to distinct naturalistic threats and, in turn, how threat experience shapes social behavior, providing a behavioral framework for probing the neural basis of socially modulated innate fear.

neuroscience↗

bioRxiv2025

Economic and Social Modulations of Innate Decision-Making in Mice Exposed to Visual Threats

When confronted by predators, animals make innate decisions with rapid reaction times--a trait shaped by natural selection to maximize survival. However, rapid reactions are effective only when grounded in accurate judgments and appropriate choices, which often require cognitive control. To address how such choices are shaped, we developed a behavioral paradigm to investigate how threat intensity, reward value, and social hierarchy shape decision-making in foraging mice exposed to overhead visual threats. Using a machine learning-based approach, we classified defensive responses into four distinct decision types. Mice showed rapid habituation to repeated looming threats, with substantial inter-individual variability in the rate of habituation. Across both early and late phases of habituation, threat intensity emerged as the primary determinant of decision-making, strongly biasing behavior toward escape. In contrast, the influence of reward value was context-dependent and became evident primarily in the late phase: under low-threat conditions, higher reward value suppressed defensive responses, consistent with value-based decision theory; whereas under high-threat conditions, higher reward value promoted escape, potentially reflecting heightened vigilance. Innate decision-making was further modulated by social hierarchy, with dominant mice showing greater vigilance and a stronger bias toward risk-averse behaviors, while subordinates were more reward-driven. To understand the underlying decision-making process, we developed a drift-diffusion leaky integrator model that successfully captures how threat intensity, reward value, and vigilance interact to shape defensive decisions. Together, these findings reveal how economic and social factors modulate innate decisions and provide a computational framework for understanding the interplay between instinctive reactions and cognitive control.

neuroscience↗

bioRxiv2024

Population coding of predator imminence in the hypothalamus

Hypothalamic VMHdmSF1 neurons are activated by predator cues and are necessary and sufficient for instinctive defensive responses. However, such data do not distinguish which features of a predator encounter are encoded by VMHdmSF1 neural activity. To address this issue, we imaged VMHdmSF1 neurons at single-cell resolution in freely behaving mice exposed to a natural predator in varying contexts. Our results reveal that VMHdmSF1 neurons do not represent different defensive behaviors, but rather encode predator identity and multiple predator-evoked internal states, including threat-evoked fear/anxiety; neophobia or arousal; predator imminence; and safety. Notably, threat and safety are encoded bi-directionally by anti-correlated subpopulations. Finally, individual differences in predator defensiveness are correlated with differences in VMHdmSF1 response dynamics. Thus, different threat-related internal state variables are encoded by distinct neuronal subpopulations within a genetically defined, anatomically restricted hypothalamic cell class. HighlightsO_LIDistinct subsets of VMHdmSF1 neurons encode multiple predator-evoked internal states. C_LIO_LIAnti-correlated subsets encode safety vs. threat in a bi-directional manner C_LIO_LIA population code for predator imminence is identified using a novel assay C_LIO_LIVMHdmSF1 dynamics correlate with individual variation in predator defensiveness. C_LI

neuroscience↗

bioRxiv2024

Feature-independent Encoding of Visual Salience inthe Mouse Superior Colliculus

Detecting conspicuous stimuli in a visual scene is crucial for animal survival, yet it remains debated how the brain encodes visual saliency. Here we investigate how visual saliency is represented in the superficial superior colliculus (sSC) of awake mice using two-photon calcium imaging. We report on a preference-independent saliency map in the sSC. Specifically, salient stimuli evoke stronger responses in both excitatory and inhibitory neurons compared to uniform stimuli, with similar encoding patterns observed in both neuron types. The largest response occurs when a salient stimulus is positioned at the receptive field center, with contextual effects extending [~]40{degrees} away from the center. The response amplitude correlates well with the saliency strength of stimuli and is not influenced by the orientation or motion direction preferences of neurons. However, saliency encoding does depend on specific visual features. Furthermore, neurons involved in saliency encoding exhibit weak orientation or direction selectivity, suggesting a complementary relationship between the saliency map and the feature map.

neuroscience↗