Model Organisms - Poulet

Question 1

Briefly describe the use of the cricket model in neuroscience

Answer 1

1. They have fewer and larger neurons that allow IC in vivo recording
2. they exhibit complex auditory related behaviour:
   - Only males vocalize by stridulation (sounds made by moving body parts), females respond by phonotactics (moving towards the voice). Females and males process voices (in form of chirps made of individual syllabi).

Question 2

Describe the phonotactics behaviour

Answer 2

It starts with hearing the stimulus -> recognizing its patterns -> localization command (steering) -> then phonotactics

Phonotactics depends on recognizing the pattern of chirps so that only species‘ related sounds are responded to. It also depends on the intensity of the stimulus.

Localization of sound to either left or right depends on steering (directing oneself) to individual pulses rather than the pattern.

Pattern recognition happens first then the localization of sound.

To study the phonotactics the trackball is used.

Question 3

Why during eliciting stridulations the cricket can‘t hear any outside noise or voices?

Answer 3

Anatomy: voice is encoded by the afferent auditory nerve that reaches the pre-thoracic ganglion and synapse with the Omega1 neurons.

Sensory information is processed in the brain, while motor information is processed in the thoracic ganglia (eg. the mesothoracic ganglia contains the CPG which gives the order to the wings to elicit the stridulations).

During stridulations, corollary discharge from the CPG inhibits both the auditory afferent and the Omega neurons.