Malcolm A. MacIver

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Animals can actively influence the content and quality of sensory information they acquire from the environment through the positioning of peripheral sensory surfaces. This study investigated receptor surface positioning during prey-capture behavior in weakly electric gymnotiform fish of the genus Apteronotus. Infrared video techniques and three-dimensional(More)
Sensory systems are faced with the task of extracting behaviorally relevant information from complex sensory environments. In general, sensory acquisition involves two aspects: the control of peripheral sensory surfaces to improve signal reception and the subsequent neural filtering of incoming sensory signals to extract and enhance signals of interest. The(More)
A defining feature of active sensing is the use of self-generated energy to probe the environment. Familiar biological examples include echolocation in bats and dolphins and active electrolocation in weakly electric fish. Organisms that utilize active sensing systems can potentially exert control over the characteristics of the probe energy, such as its(More)
A surprising feature of animal locomotion is that organisms typically produce substantial forces in directions other than what is necessary to move the animal through its environment, such as perpendicular to, or counter to, the direction of travel. The effect of these forces has been difficult to observe because they are often mutually opposing and(More)
Black ghost knifefish (Apteronotus albifrons) are nocturnal, weakly electric fish that feed on insect larvae and small crustaceans in the freshwater rivers of South America. In the absence of visual cues, prey detection and localization in this species is likely to rely on weak electrosensory and mechanosensory cues generated by the prey. In this paper, a(More)
Active sensing organisms, such as bats, dolphins, and weakly electric fish, generate a 3-D space for active sensation by emitting self-generated energy into the environment. For a weakly electric fish, we demonstrate that the electrosensory space for prey detection has an unusual, omnidirectional shape. We compare this sensory volume with the animal's motor(More)
We explore the capabilities of a robotic sensing system designed to locate objects underwater through active movement of an electric field emitter and sensor apparatus. The system is inspired by the biological phenomenon of active electrolocation, a sensing strategy found in two groups of freshwater fishes known to emit weak electric fields for target(More)
We present experimental results of thrust produced by a robotic propulsor, the design of which is inspired by the ribbon fin of the South American black ghost knifefish (Apteronotus albifrons). This remarkably nimble fish moves by oscillating its ribbon fin rays out of phase and thereby passing a traveling wave along the fin's length. Combinations of thrust(More)
The accurate tracking of an animal's movements and postures through time has broad applicability to questions in neuroethology and animal behavior. In this paper we describe methods for precision body modeling and model-based tracking of non-rigid animal movements without the use of external markers. We describe the process of obtaining high-fidelity(More)
South American electric knifefish are a leading model system within neurobiology. Recent efforts have focused on understanding their biomechanics and relating this to their neural processing strategies. Knifefish swim by means of an undulatory fin that runs most of the length of their body, affixed to the belly. Propelling themselves with this fin enables(More)