Abstract-1
Head direction (HD) cells in the anterodorsal thalamic nuclei form the brain’s internal compass, and are often modeled as a ring attractor maintaining azimuth coding by leveraging continuous visual and inertial sensory input. Here, we test how the common experimental preparation of head-fixed animals alters this code. Complete head-fixation that creates vestibular conflict disrupts both unit and population encoding of head direction, while selectively constraining head-on-body movements either in real or virtual reality uniquely impairs HD population activity. More specifically, attractor dynamics is altered in head-restrained mice during periods of immobility, but remarkably recover several hundred milliseconds prior to locomotion onset. The rescue preceding movement onset suggests that an efference copy or prediction of a re-afferent signal is necessary to maintain HD network activity during head restraint. A computational model recapitulates these effects by perturbing lateral connectivity among HD neurons. More generally, the results indicate that the HD network is a context- and state-dependent predictive estimator, stabilized by forthcoming self-motion signals. The classic ring-attractor models should be revised to integrate context-dependent dynamics with prospective motor signals, offering a more complete account of how the brain’s compass remains stable across both naturalistic and constrained conditions.
Alexandr Pak, Janna Aarse, Heng Wei Zhu, Jean-Paul Noel, Simón Carrillo Segura, André A. Fenton, Dora Angelaki. Active locomotion predictively rescues head direction attractor dynamics in head-fixed mice. bioRxiv, 2026-01. [LINK]
Abstract-2
Stereo olfaction, the difference in odor concentration between the two nostrils, has been shown to affect a variety of animal behaviors, including olfactory search. However, it is unknown whether stereo olfaction can enable the formation of allocentric spatial representations. Here, recording from head direction (HD) cells in the anterior dorsal nucleus of the thalamus in blind mice—a model system for studying olfaction-dependent allocentric spatial representations—we find that inhibiting stereo olfaction, by blocking olfactory processing in one nostril or merging the airflow going to both nostrils, drastically impairs head direction coding. To assess the behavioral impact of impaired HD cell tuning caused by loss of stereo olfaction, we developed a closed-loop head direction preference assay, in which a mouse received medial forebrain bundle reward stimulation upon orientating its head in a specific direction. We find that inhibiting stereo olfaction significantly impairs performance in the HD preference assay. These results reveal that stereo olfaction is required for mice to use smell to form a stable allocentric spatial representation of head direction.
Kadjita Asumbisa, Adrien Peyrache & Stuart Trenholm. Stereo olfaction underlies stable coding of head direction in blind mice. Nature Communications, 2024-04. [LINK]
Speaker: Yuhang Zhu
Time: 9:00 am, 2026/06/29
Location: CIBR A622
