Foreword for the special issue on Multimodal and Sensorimotor Bionics

Abstract

Animals are quite efficient at discerning “objects” that appear in their surroundings, exceeding by far what technical systems have been able to replicate. Evolution has equipped animals with several modalities such as vision, hearing, and haptics to exploit different physical means of information representation: electromagnetic spectrum (vision), pressure waves (hearing), forces (haptics, tactile sensing), gravity (vestibular system), hydrodynamic velocity and pressure field (lateral-line system), etc. It is precisely the combination of these different sensing modalities that allows biological systems to attain their high level of accuracy and dependability in sensing their surroundings. A few words on the notions of multimodal and multisensory are in order (Stein et al 2010). A lateral line, for instance, consists of many sensors (neuromasts) all over the body. The conglomeration of all neuromasts allows a fish, say, a pike, to localize or even determine the shape of a roach in its neighborhood. Only through the total input of all neuromasts can the pike accomplish the localization task with the lateral line as a truly “multisensory” modality. In clear water the pike can then both “see” the roach and perceive it through its lateral-line system, a multimodal experience. How do all these modalities, with their specific, physically different transmission techniques, function? How does the brain generate “objects” as neuronal representations