1. ACTIVE SENSING Lecture 8 : Electric fish control loops ELECTRIC FISH

2. Course assistants Erez Simony: erez.simony@weizmann.ac.il Avi Saig: avi.saig@weizmann.ac.il Exercises Course list

3. Energy-emitting active sensing Geometry M. E. Nelson ֶ M. A. MacIver J Comp Physiol A (2006) 192: 573–586

4. Energy-emitting active sensing Frequency and duration ranges M. E. Nelson ֶ M. A. MacIver J Comp Physiol A (2006) 192: 573–586

5. Energy-emitting active sensing detection range M. E. Nelson ֶ M. A. MacIver J Comp Physiol A (2006) 192: 573–586 Bat (detecting musquitoes) Dolphin (typical prey) Electric fish (daphnia) Rat (contact range)

6. Daphnia signal characteristics Mechanosensory stimuli Low-frequency bioelectric fields Perturbations to the fish’s high-frequency electric field Daphnia 1 mm The prey:

7. Principle of active electrolocation M. E. Nelson

8. Prey capture behavior

9. Prey capture kinematics Distance to closest point on body surface acceleration Longitudinal velocity

10. emitted-energy active sensing Complications with conspicuousness Detection of energy by prey and predators confusion with peers

11. emitted-energy active sensing conspicuousness Detection of energy by prey and predators confusion with peers Adaptations specific to - technology war - ciphering - jamming avoidance

12. Technology war make the probe less conspicuous to the prey/predator. echolocating killer whales A  dolphins echolocating killer whales B  fish Dolphins can detect the ecolocating signals Fish cannot echolocating killer whales A use irregular short clicks echolocating killer whales B use continuous emission Example:

13. Technology war make the probe less conspicuous to the prey/predator. The prevalence of passive vision systems make it difficult for bioluminescence-based active photoreception to be a viable strategy in most ecological niches. Solution 2: In deep sea, vision is usually based on the blue-green portion of the spectrum. deep-sea dragonfish have two bioluminescent organs, one of which produces a near infrared wavelength of light that only they can see. Example 2: Solution 1: Flaslight fish open and close a “lid” to expose their light organ briefly

14. Ciphering keep a private signal that allows decoding the echo 1 st harmonic is weak and does not reach the peers 2 nd harmonic is loud and also echoed well These bats have evolved cells that respond to 1 st harmonic & delayed 2 nd harmonic Example: CF-FM echolocating bats pairing of 2 nd harmonic (source) & delayed 2 nd harmonic (echo) would include peer calls other ciphering tricks?

15. Jamming avoidance

16. Masashi Kawasaki Current Opinion in Neurobiology 1997, 7:473-479

17. Jamming avoidance WALTER METZNER, The Journal of Experimental Biology 202, 1365–1375 (1999)

18. emitted-energy active sensing conspicuousness Detection of energy by prey and predators confusion with peers Adaptations specific to - technology war - ciphering - jamming avoidance

19. Prey capture behavior

20. What is the control loop? how to design a prey-capture loop d F P d F P

21. What is the control loop? how to design a prey-capture loop d F P d F P

22. What is the control loop? how to design a prey-capture loop d F P K1K1 ? d F P

23. Prey capture kinematics Distance to closest point on body surface acceleration Longitudinal velocity