Buck, J. R. | Search bioRxiv

bioRxiv2026

Modeling echolocation as an active pursuit of information via infotaxis

Echolocation is a closed-loop active sensing modality in which animals not only choose how they move to acquire information, but also actively modulate incoming sensory (echo) information by shaping the acoustic signals they emit to probe the environment. While many models describe how echolocating animals react to prior echoes by adjusting subsequent behavior, few explicitly model how they cognitively reason about information embedded in echoes when determining future actions. Here, we extend "infotaxis," an information-greedy algorithm originally developed for olfactory search, to sonar sensing by formulating an echolocating agent searching for a single target under sensory uncertainty characterized by probabilities of miss and false alarm. Through analytical and computational analyses, we show that the characteristic exploration-exploitation balance of infotaxis also emerges in echolocation, and that the efficiency and reliability of infotaxis search depend strongly on sensory information quality. Compared with a maximum a posteriori agent that always directs the beam to the most probable target location, the infotaxis agent consistently completes searches with fewer pings and greater robustness to sensory uncertainty. These results highlight information as a powerful concept for understanding active sensing and developing models for sonar-guided autonomy in both biological and engineered systems.

animal behavior and cognition↗

bioRxiv2024

DAMP-inducing Peptide Nanofibers and PAMP Combination Adjuvants Boost Functional Lung Tissue-resident Memory CD4+ T Cell Responses

Vaccine adjuvants are typically composed of pathogen-associated molecular patterns (PAMPs) or danger-associated molecular patterns (DAMPs) that activate innate immune cells. Advances in basic immunology have demonstrated the need for various types of protective immunity, which are difficult to achieve with a single adjuvant. The FDA approval of multiple PAMP-DAMP combinations for clinical use has led to an increased momentum in the area in recent years. Here we report the use of DAMP-inducing peptide nanofibers (PNFs) and CL429 (PAMP) combinations as subunit boosters for Bacille Calmette-Guerin (BCG). We demonstrate that pulmonary boosting with PNFs and CL429 enhances the lung-resident memory phenotype, effector cytokine profiles, and transcription factor bias of antigen-specific CD4+T cell populations compared to PNFs alone. Importantly, the combination significantly improved the frequency of tissue-resident memory T (TRM) cells which, have been shown to provide superior protection compared to circulating memory T cells. Interestingly, the T helper (Th) subset profile was driven in part driven by the route of vaccination resulting in a Th17 bias via a mucosal route or a Th1 bias when delivered intravenously. We show that following pulmonary administration, lung-resident antigen presenting cells (APCs) efficiently internalize PNFs and upregulate important co-stimulatory markers that drive T cell priming and activation. Our findings suggest that heterologous booster vaccines composed of DAMP-inducing PNFs and PAMP combinations can engage innate and adaptive immunity for generating TRM cells that protect against TB and potentially other respiratory diseases.

bioengineering↗