Electrolocation based on tail-bending movements in weakly electric fish

Abstract

Weakly electric fish generate an electric field with their electric organ to navigate in space, detect objects and communicate with conspecifics. Several studies have examined how electric fish identify objects with their electroreceptors and use electric images for electrolocation. It has been argued that sensor readings from electroreceptors along the rostrocaudal line allow fish to determine the location of a target object. It is well known that the ratio between the maximal slope and the maximal amplitude of the electric image can allow the discrimination of object distances, regardless of object size and conductivity. In order to understand the temporal pattern of electric images, we used a model of electric field perturbation. Using the model, we suggest that the temporal pattern generated at an electrosensor during tail bending is another cue that can be used by the fish to discriminate object distances. The time course of electric sensor signals from a specific electroreceptor when tail-bending movements are applied can provide information about the lateral distance of a target object.

Sensory flow shaped by active sensing: sensorimotor strategies in electric fish

“…As a consequence, the EI is subject to large (predictive) distortions influencing both intensity and contrast (Bacher, 1983;Caputi, 2004;Chen et al, 2005;Engelmann et al, 2008;Heiligenberg, 1975;von der Emde et al, 2008). The analysis of these distortions over time could be used to determine the lateral distance to an object (Sim and Kim, 2011).…”

“…Although a number of studies have investigated the spatial formation of EIs and the influence of objects within a static electric scene (for a review, see Caputi and Budelli, 2006), information about spatiotemporal EI dynamics is sparse (Babineau et al, 2007;Chen et al, 2005;Hofmann et al, 2013;Sim and Kim, 2011;Sim and Kim, 2012).…”

“…The available data are based on simplified motions, e.g. va-et-vient motion or idealized tail bending motion (Babineau et al, 2007;Hofmann et al, 2013;Sim and Kim, 2011;Sim and Kim, 2012), on reduced and thus simplified artificial trajectories (Chen et al, 2005), or on actual sequences of behavioral recordings (Assad et al, 1999;MacIver et al, 1997;Nelson and MacIver, 1999). Similar to the approach of Assad and MacIver, we here use a natural object scanning behavior sequence of G. petersii to calculate and examine the electric flow for mormyrids for the first time (Fig.7A-C).…”

“…Avoiding these complexities by analyzing simplified behaviors, initial progress has been made towards better characterizations of electric flow and potential electrosensory cues contained in flow generated through simple behaviors. Using artificial and highly stereotyped tail movements, it was suggested that the ratio between tEI slope during bending the tail towards and away from an object might serve as a measure for lateral object distance (Sim and Kim, 2011). Furthermore, in va-et-vient movements, the calculation of a temporal slopeamplitude ratio (tSAR) based on the tEI was recently documented to be a suitable measure for lateral object distance (Hofmann et al, 2013;Sim and Kim, 2012).…”

“…Bastian, 1995;Bastian, 1999;Sawtell, 2010). Coincidence of these centrally Lannoo and Lannoo, 1993;MacIver et al, 2001;Pusch et al, 2008 Relative motion (va-et-vient) Shift spatiotemporal dynamics of sensory input towards the dynamic range of the sensory system, generation of temporal slopes Babineau et al, 2007;Hofmann et al, 2013;Sim and Kim, 2012;Stamper et al, 2012;Toerring and Belbenoit, 1979 Relative motion (tail bending) Change in contrast, calculation of lateral distance by temporal slope ratio Bacher, 1983;Behrend, 1984;Heiligenberg, 1975;Stamper et al, 2012;Sim and Kim, 2011 Control the amount of change of the incoming sensory input Arnegard and Carlson, 2005;von der Emde, 1992 In the left column, text in parentheses indicates exemplary probing motor acts that can be attributed to the strategy. Studies where aspects of these behaviors have been addressed are shown to the right.…”