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Motor Control of Phonotactic Behaviour

Motor Control of Phonotactic Behaviour

Measuring Phonotactic Walking with a Trackball System

Female crickets are attracted to the male’s song. When they approach a singing male, they have to solve two fundamental tasks: they need to recognise the species-specific song pattern, and they also need to localise the sound source. I developed a fast and sensitive trackball systems to analyse the female phonotactic walking behaviour. The cricket is tethered and positioned on top of the trackball, which floats in an airstream. While walking, the insect rotates the trackball; the movement of the ball is measured with an optical sensor and provides the walking speed and direction. When testing different sound patterns, the female will walk best to those, which resemble a male calling song.

Female cricket walking on a trackball

References:

  • Hedwig, B and JFA Poulet (2004) Complex auditory behaviour emerges from simple reactive steering. Nature 430: 781-785
  • Hedwig, B and JFA Poulet (2005) Mechanisms underlying phonotactic steering in the cricket Gryllus bimaculatus (de Geer) revealed with a fast trackball system. J Exp Biol 208: 915-927
  • Poulet, JFA and Hedwig B (2005) Auditory orientation in crickets: Pattern recognition controls reactive steering. PNAS, 102 (43): 15665-15669
  • Hedwig B (2017) Trackball systems for analysing cricket phonotaxis. In: Horch HW, Mito T, Ohuchi H, Popadić A, Noji S (eds), The Cricket as a Model Organism. Development, Regeneration and Behaviour. Springer Japan, Chapter 19, pp: 303-312

 

Highspeed Videos reveal Leg Trajectories

When orienting towards a male calling song, crickets rapidly walk and steer towards the direction of the sound signal. In order to understand the underlying motor control, we recorded their movements during phonotactic steering using a high speed video system and analysed the leg trajectories. During forward walking leg trajectories are basically parallel to the cricket’s long axis, but during acoustic steering especially the trajectories of the front and middle legs are tilted towards the side of the incoming sound. The neural mechanism by which the sound stimulus is transformed into a motor command for walking and steering is still a crucial unsolved question.

Phonotactic walking cricket

High speed video recordings of crickets walking on a trackball (left), leg trajectories when walking straight on (middle) and trajectories when steering to calling song from the right (right).

Watch the trajectories of phonotactic walking crickets online at: to be done

 References:

  • Witney AG and Hedwig B (2011) Kinematics of phonotactic steering in the walking cricket Gryllus bimaculatus (de Geer). JEB, 214: 69-79
  • Baden, T and Hedwig B (2008) Front leg movements and tibial motoneurons underlying auditory steering in the cricket (Gryllus bimaculatus, de Geer). J Exp Biol 211: 2123-2133. 

Pattern Recognition

What kind of neuronal network could the females use to recognise the species-specific song pattern of the singing males? An early hypothesis indicated a delay-line and coincidence detector mechanisms, in which an internal delay matches the period of the pulse pattern. We identified the neurons of such a pathway in the brain of crickets and characterised a non-spiking interneuron, which responds with a hyperpolarisation to each sound pulse and then generates a post-inhibitory rebound that matches the timing of the pulse pattern. This delayed activity coincides with the direct spike activity of the ascending interneuron and leads to the very specific response of feature detecting neurons – the “grandmother cells” for cricket auditory behaviour? This is an exciting field, and we now aim to link pattern recognition with the motor control of phonotactic behaviour.

B-LI5

References:

  • Schöneich S, Kostarakos K and Hedwig B (2015) An Auditory Feature Detection Circuit for Sound Pattern Recognition. Sci Adv 1(8) e1500325, doi: 10.1126/sciadv.1500325
  • Kostarakos K and Hedwig B (2015) Pattern recognition in field crickets: Concepts and neural evidence. J Comp Physiol A, 201:73-85, doi 10.1007/s00359-014-0949-4
  • Kostarakos K and Hedwig B (2012) Calling song recognition in female crickets: Temporal tuning of identified brain neurons matches behaviour. J Neuroscience 32:9601-9612