MS04 - OTHE-01

Information theory, fitness, and semantics in biological information processing

Tuesday, July 15 at 4:00pm

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Andrew Eckford (Department of Electrical Engineering and Computer Science, York University, Toronto)

Description:

Shannon's information theory has been used to describe the gain of evolutionary fitness that an organism obtains from sensing and processing environmental information. However, the semantics of the information are important to the organism - for example, the presence of predators, or nutrients, are more important to the organism than other sensory details. Moreover, organisms sense and act, and their actions affect the sensing task. It is an important open question how to incorporate meaning and action into the Shannon information framework. This mini-symposium will consider recent results at the intersection of fitness, semantics, and information theory, and to facilitate discussion and future research on this important topic. A breakthrough in this direction would provide quantitative methods for predicting the behaviour of organisms and for understanding biological information processing. Moreover, while this mini-symposium focuses on biology, similar questions are presently being investigated in the mainstream information theory community, indicating the timeliness of this topic.

Massimiliano Pierobon

University of Nebraska-Lincoln

"On the Usefulness and Subjectivity of Life-supporting Information"

In recent years, the exploration of information flow within biological systems has become a groundbreaking approach for delving into the complex mechanisms at play in the life sciences. This approach serves a dual purpose: it not only provides a quantitative grasp of how biological systems store, transmit, sense, receive, and process information across various scales and contexts, but it also paves the way for designing and engineering systems that either mimic or are integrated with biochemical environments. At this interdisciplinary juncture, bridging the gap between diverse fields of expertise presents numerous challenges. These range from developing a shared vocabulary to addressing the limitations of applying theories and concepts across different contexts and assumptions. In our talk, we will share insights and lessons from organizing the Workshop on Information, Communication, and Coding Theory in Biology sponsored by the US National Science Foundation. We'll highlight cutting-edge interdisciplinary research areas and the major challenges that lie ahead. Our discussion will then delve into our research contributions, focusing on how communication theory can accurately describe biological processes and introducing the concept of subjective information as a new metric for biological information. We will also present practical applications derived from our research, offering recommendations for best practices and sharing personal anecdotes from our journey. This talk aims to illuminate the path forward for interdisciplinary collaboration in understanding and harnessing the principles of information flow in biological systems.

Alexander Moffett

Northeastern University

"Evolution of Environmental Sensing"

Organisms sense and respond to environmental cues, allowing for within-lifetime adaptation to an ever-changing world. A growing body of work has sought to connect the accuracy of environmental sensing with fitness, with the fitness value of information emerging as a key concept. Despite the progress made in this direction, we still lack a good understanding of how environmental sensing evolves in necessarily finite populations with metabolically costly sensory machinery. We attempt to construct a model capable of addressing these gaps in understanding, using concepts from rate-distortion theory and population genetics.

Andrew Eckford

York University

"Kelly Bets and Single-Letter Codes: Optimal Information Processing in Natural Systems"

In an information-processing investment game, such as the growth of a population of organisms in a changing environment, Kelly betting maximizes the expected log rate of growth. In this talk, we show that Kelly bets are closely related to optimal single-letter codes (i.e., they can achieve the rate-distortion bound with equality). Thus, natural information processing systems with limited computational resources can achieve information-theoretically optimal performance. We show that the rate-distortion tradeoff for an investment game has a simple linear bound, and that the bound is achievable at the point where the corresponding single-letter code is optimal. Moreover, since evolution is expected to optimize an organism's information processing capabilities, this bound allows prediction of biological behaviour. Examples illustrating the results in simplified biological scenarios are presented.

Peter Thomas

Case Western Reserve University

"Tradeoffs in the energetic value of neuromodulation in a closed-loop neuromechanical system"

Rhythmic motor behaviors controlled by neuromechanical systems, consisting of central neural circuitry, biomechanics, and sensory feedback, show efficiency in energy expenditure. The biomechanical elements (e.g., muscles) are modulated by peripheral neuromodulation which may improve their strength and speed properties. However, there are relatively few studies on neuromodulatory control of muscle function and metabolic mechanical efficiency in neuromechanical systems. To investigate the role of neuromodulation on the system’s mechanical efficiency, we consider a neuromuscular model of motor patterns for feeding in the marine mollusk Aplysia californica. By incorporating muscle energetics and neuromodulatory effects into the model, we demonstrate tradeoffs in the energy efficiency of Aplysia’s rhythmic swallowing behavior as a function of the level of neuromodulation. A robust efficiency optimum arises from an intermediate level of neuromodulation, and excessive neuromodulation may be inefficient and disadvantageous to an animal’s metabolism. This optimum emerges from physiological constraints imposed upon serotonergic modulation trajectories on the energy efficiency landscape. Our results may lead to experimentally testable hypotheses of the role of neuromodulation in rhythmic motor control.

#SMB2025 Follow

Annual Meeting for the Society for Mathematical Biology, 2025.