Intrinsic Dynamics and Neural Implementation of a Hypothalamic Line Attractor Encoding an Internal Behavioral State

Area of Science:

• Neuroscience
• Computational Neuroscience
• Systems Neuroscience

Background:

• Line attractors are hypothesized neural population dynamics that encode continuous variables.
• Direct evidence for mammalian line attractors has been limited by experimental challenges.

Purpose of the Study:

• To investigate line attractor dynamics in estrogen receptor type 1 (Esr1)-expressing neurons in the ventrolateral ventromedial hypothalamus (VMHvl).
• To determine if these dynamics encode the intensity of internal aggressive states.
• To experimentally perturb and characterize the neural circuit mechanisms underlying this line attractor.

Main Methods:

• Utilized 2-photon calcium imaging and holographic optogenetics in head-fixed mice observing aggression.
• Performed on-manifold and off-manifold perturbations of Esr1+ VMHvl neurons.
• Analyzed functional connectivity and performed mechanistic modeling.

Main Results:

• Esr1+ VMHvl neurons exhibit line attractor dynamics during observed aggression.
• Perturbations confirmed integration and persistent activity as intrinsic properties driving attractor dynamics.
• Functional connectivity among neurons correlated with attractor stability, requiring dense subnetworks and slow neurotransmission.

Conclusions:

• Esr1+ VMHvl neurons implement a line attractor encoding aggression intensity.
• This study provides direct evidence and mechanistic insights into a behaviorally relevant mammalian line attractor.
• Bridges circuit and manifold paradigms in understanding neural dynamics.