8 Mechanosensory Regulation of Invertebrate Motor Systems

Abstract

Organisms must obtain and integrate information about the internal and external environment to generate appropriate behaviors. In both invertebrate and vertebrate animals, specialized structures are present to ensure adequate detection of this information and its transmission to the central nervous system (CNS). Such structures that respond to physical deformations of the external or internal body surface are termed mechanoreceptors. Mechanoreceptors transduce touch, pressure, sound waves, and changes in acceleration from the external environment, as well as vascular pressure, muscle stretch, muscle tension, and joint position inside the body. Although the structures that detect these different modalities are specialized for their particular functions, there appears to be a convergence across species and modalities at the level of the ion channels that transduce mechanical stimuli (Goodman et al. 2004; Sukharev and Corey 2004; Syntichaki and Tavernarakis 2004; Lin and Corey 2005; Lumpkin and Bautista 2005; O’Hagan and Chalfie 2006; Schafer 2006).

Considerable research in both invertebrate and vertebrate systems has revealed a comparable conservation of the roles played by mechanosensory input to CNS motor circuits, as well as the mechanisms by which the CNS regulates transmission of mechanosensory input to these circuits (Buschges and El Manira 1998; Clarac et al. 2000; Cattaert et al. 2002; Torkelli and Panek 2002; Pearson 2004; Whitaker and Sternberg 2004; Buschges 2005; Samuel and Sengupta 2005; Rossignol et al. 2006). Invertebrate model systems have consistently contributed in pivotal ways to elucidating these issues, often because they provide better access for analysis at the level of individual, identified...