Switching and Coordination of Survival Actions in the Human Hypothalamus

709 

Abstract Submission 

Jaejoong Kim¹, Dean Mobbs²

¹University of Minnesota, Saint Paul, MN, ²California Institute of Technology, Pasadena, CA

Jaejoong Kim  
University of Minnesota
Saint Paul, MN

Dean Mobbs  
California Institute of Technology
Pasadena, CA

Comparative research suggests that the hypothalamus is critical in switching between survival states such as a switching between hunting and escaping. However, it is unclear if this is the case in humans due to the lack of naturalistic experimental paradigms that can investigate this question and the difficulty of investigating hypothalamic neural signals.

Here, we introduce a gamified experimental paradigm where volunteers switch between hunting and escape in response to encounters with a continuously-moving virtual predator and prey. Given the small size and low tissue contrast of the hypothalamus, we used deep learning-based segmentation to identify individual-specific hypothalamus and its subnuclei as well as imaging sequence optimized for hypothalamic signal acquisition. Computational modeling of continuous hunting and escaping behaviors was done to identify the latent process of generating these survival behaviors. Multi-voxel pattern analysis (MVPA), as well as the Multi-voxel connectivity analysis, was performed to investigate region-level encoding and network-level encoding of switching between hunting and escaping behavior in the hypothalamus. Finally, model-based functional MRI analysis was applied to investigate how the hypothalamic switching signal is associated with the optimal survival movement generation process.

Across two experiments, the winning model of the Bayesian model comparison showed that an agent utilizes an internal model of moving virtual prey or predator to guide an appropriate movement decision during both hunting and escaping behavior. Decoding of model parameter space showed that internal movement generation processes were highly specific to each task (p<0.001 in t-test against chance level). In experiment 2, multi-voxel pattern analyses showed that the hypothalamus, hippocampus and periaqueductal gray encode switching of survival states while not encoding simple motor switching outside of the survival context (all p<0.05 in t-test against chance level). Furthermore, multi-voxel connectivity analyses revealed a network including the hypothalamus as encoding survival switching and how the hypothalamus is connected to other regions in this network (network-based statistic; p<0.001). Finally, model-based fMRI analyses showed that a strong hypothalamic multi-voxel switching signal is predictive of optimal behavioral coordination after switching, especially when this signal was synchronized with multi-voxel switching signals in the amygdala (mixed-effect linear regression; p<0.001).

These findings extend understanding of the human hypothalamus from a region that regulates our internal bodily states to a region that switches survival states and coordinates strategic survival behaviors.

Emotion and Motivation Other ¹

Activation (eg. BOLD task-fMRI)

Connectivity (eg. functional, effective, structural)

Multivariate Approaches

Motor Behavior Other ²

Computational Neuroscience

Emotions

Experimental Design

Modeling

MRI

Multivariate