In a breakthrough study published in Nature, scientists have discovered that the African weakly electric fish, Gnathonemus petersii, can harness the electrical pulses of nearby fish to sharpen its perception of the environment. The findings not only shed light on collective active sensing in nature but also offer potential applications for artificial sensing and robotics.
Study: Collective sensing in electric fish. Image Credit: MP cz/Shutterstock.com
By analyzing neural activity, behavior, and computational models, researchers found that these fish extend their sensing range, improve object detection, and enhance information processing by using signals from their peers. This study helps lay the groundwork for new approaches in designing autonomous systems that mimic biological group sensing mechanisms.
Understanding Active Sensing
Active sensing refers to the process by which organisms emit energy, such as sound or electrical pulses, to explore their surroundings. Well-known examples include dolphins and bats, which use echolocation to navigate and detect prey. Similarly, certain fish species generate electric organ discharges (EODs) to probe their environment.
Previous research on active sensing has largely focused on interference, such as electric fish adjusting their frequencies to avoid jamming. In contrast, engineered systems often benefit from multiple emitters working together. While it has been suggested that dolphins and bats might "eavesdrop" on signals from others, direct evidence has been lacking—until now.
This study provides clear proof that pulse-type electric fish actively use the emissions of nearby fish to improve their own object detection and electrolocation.
How Gnathonemus Petersii Uses Conspecific EODs
The researchers investigated how Gnathonemus petersii enhances its sensing abilities by detecting electric pulses from conspecifics (members of the same species). Computer simulations revealed that conspecific emissions significantly increase the detection range of objects, particularly when the fish are positioned perpendicularly to each other. This effect occurs because pulses from conspecifics decay more gradually than self-emitted pulses.
Neural recordings in the electrosensory lobe confirmed that these conspecific pulses trigger responses similar to self-generated signals. Behavioral experiments further demonstrated that fish can use these pulses to localize and interpret objects—even without knowing the precise location of the other fish. This suggests that collective sensing strengthens individual perception.
Effects on Object Detection, Discrimination, and Information Transmission
To understand how conspecific EODs influence object detection and discrimination, researchers conducted experiments using ‘virtual’ objects. Fish responses were measured under different EOD conditions, and artificial EOD mimics were introduced to isolate the effect of external pulses. The findings revealed a significant increase in object detection range when EOD mimics were active, especially when aligned perpendicularly to the fish. Larger simulated conspecifics further extended this range, validating predictions from computational modeling.
In a separate experiment, fish were trained to associate specific object properties with rewards or deterrents, demonstrating that they could discriminate objects using only conspecific EOD mimics. Their performance was comparable to using self-generated pulses, indicating that external EODs provide sufficient information for object recognition.
To study information transmission, researchers recorded neural activity from the electrosensory lateral line lobe (ELL). Although sensitivity to conspecific pulses was slightly reduced (~25 %) compared to self-generated pulses, ELL neurons effectively processed both. Under conditions mimicking social interactions, neurons encoded information from self and conspecific pulses in distinct time windows. Population-level analyses confirmed that self and conspecific signals were represented largely independently in the brain.
These findings challenge the assumption that corollary discharge signals—which help prioritize self-generated sensory inputs—completely block conspecific signals. Instead, social groups appear to enhance electrosensory information processing by integrating multiple EOD sources, improving overall environmental perception.
The Broader Implications of Collective Sensing
This study uncovers a unique form of collective active sensing in Gnathonemus petersii, where conspecific EODs improve perception without increasing energy expenditure or predator risk. Unlike other collective sensing systems, this mechanism allows group members to instantly share sensory information. Conspecific pulses extend electrolocation range, aid in object discrimination, and may function as an early warning system.
The researchers suggest that the fish’s neural circuits, including its enlarged cerebellum, may help predict the effects of conspecific EODs, enabling joint sensing within a group. These insights could have broader implications for neuroscience, artificial sensing systems, and autonomous robotics, offering new ways to design technologies that leverage group behavior for enhanced environmental perception and information processing.
Conclusion
This study provides compelling evidence that Gnathonemus petersii uses collective active sensing to enhance its electrolocation abilities. By integrating conspecific electric pulses, these fish extend their detection range, improve object discrimination, and refine sensory information processing—without additional energy costs or heightened predator exposure.
Neural recordings suggest that the fish’s cerebellum-like circuitry supports the integration of self and conspecific signals, advancing our understanding of social sensory systems in animals. These findings may also inspire developments in artificial sensing and robotics, demonstrating how biological systems efficiently leverage group behavior to improve perception.
Journal Reference
Pedraja, F., & Sawtell, N. B. (2024). Collective sensing in electric fish. Nature, 628(8006), 139–144. DOI:10.1038/s41586-024-07157-x https://www.nature.com/articles/s41586-024-07157-x
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