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AKB: Biologische Physik

AKB 70: Neurophysics

AKB 70.1: Hauptvortrag

Mittwoch, 9. März 2005, 09:45–10:15, TU H2013

Biophysics of Mechanosensory Localization: What, Where, and Why — •J. Leo van Hemmen — Physik Department, TU München, 85747 Garching bei München

Auditory localization means locating a sound source, an auditory object, through sound waves emanating from a source and exciting hair cells. There is a huge family of sensory detectors that all work through the same mechanism, the mechanosensory one. Audition is best known: Sound waves excite hair cells that then send their action potentials or spikes to the auditory system. Defining a ‘map’ to be a neuronal representation of the outside sensory world, we implicitly ask: What is a map and how does it arise? In addition to sound waves there are other mechanical means to generate a neuronal response at the detectors. A surface wave allows a sand scorpion to locate prey near to it in a desert. Water waves stimulate hair cells in superficial neuromasts (i.e., detectors at the skin) of, e.g., the clawed frog Xenopus and in both superficial and canal neuromasts of fish. It is fair to call the ensuing process mechanosensory localization and ask whether the underlying neuronal mechanisms exhibit any universality. In so doing we will present a theory as to ‘what, where, and why’.