1. Adaptation 1.Adaptation – examples and definitions 2.Adaptation as efficient coding 3.A tradeoff between sensitivity and efficiency 4.Adaptation and perception 5.Adaptation occurs over multiple timescales 6.Adaptation involves multiple mechanisms

2. Mori, Sasakura, & Kuhara, 2007 Adaptation with 302 neurons C. elegans

3. Adaptation with thousands (?) of neurons

4. Rhodes, Jeffery, Watson, Clifford, & Nakayama 2003 human psychophysics exposed to compressive distortionexposed to expansive distortion Adaptation with millions (?) of neurons

5. How does this explain that? Why might this be useful? stimulus Smirnakis & Meister, 1997

6. Adaptation 1.Adaptation – examples and definitions 2.Adaptation as efficient coding 3.A tradeoff between sensitivity and efficiency 4.Adaptation and perception 5.Adaptation occurs over multiple timescales 6.Adaptation involves multiple mechanisms

7. The idea of efficient coding 1. Each neuron should use all parts of its dynamic range with roughly equal frequency. 2. Information encoded in the spike train of one neuron should not be duplicated in the spike train of another neuron.

8. 1. Each neuron should use all parts of its dynamic range with roughly equal frequency. The idea of efficient coding

9. Encoding a natural distribution efficiently Dunn and Rieke, 2006

10. Laughlin 1981 redrawn in Wark & Fairhall 2007 Encoding a natural distribution efficiently Equal areas of probability density should correspond to equal segments of dynamic range.

11. Laughlin 1981 redrawn in Wark & Fairhall 2007 Changing stimulus statistics

12. Laughlin 1981 redrawn in Wark & Fairhall 2007 Changing stimulus statistics

13. Laughlin 1981 redrawn in Wark & Fairhall 2007 Efficient coding of a changing distribution

14. Adaptation

15. 1.Adaptation – examples and definitions 2.Adaptation as efficient coding 3.A tradeoff between sensitivity and efficiency 4.Adaptation and perception 5.Adaptation occurs over multiple timescales 6.Adaptation involves multiple mechanisms

16. Enroth-Cudgell & Lennie, 1975 An example: light adaptation in the retina cat RGC

17. spatial integrator high redundancy spatial edge detector low redundancy An adaptive change in receptive field low luminance (low signal-to-noise) high luminance (high signal-to-noise)

18. An adaptive change in receptive field temporal edge detector low redundancy high luminance (high signal-to-noise) temporal integrator high redundancy low luminance (low signal-to-noise)

19. Adaptation 1.Adaptation – examples and definitions 2.Adaptation as efficient coding 3.A tradeoff between sensitivity and efficiency 4.Adaptation and perception 5.Adaptation occurs over multiple timescales 6.Adaptation involves multiple mechanisms

20. Repulsive perceptual adaptation

21. http://homepages.inf.ed.ac.uk/jbednar/tae.html Repulsive perceptual adaptation

22. Bacon & Murphey 1984 see http://www.biol.sc.edu/~vogt/courses/neuro/neurolabs.html The cricket cercal system

23. cell 1cell 2cell 3cell 4 wind direction (degrees) r / r max Theunissen & Miller 1991 Salinas & Abbott 1994 v

24. Attractive neural adaptation macaque MT adapting stimulus adapting stimulus ○ before ● after Kohn and Movshon, 2004

25. Attractive neural adaptation can explain repulsive perceptual adaptation

26. Adaptation 1.Adaptation – examples and definitions 2.Adaptation as efficient coding 3.A tradeoff between sensitivity and efficiency 4.Adaptation and perception 5.Adaptation occurs over multiple timescales 6.Adaptation involves multiple mechanisms

27. Adaptation on many timescales in the same neuron Smirnakis et al. 1997 salamander RGC

28. Adaptation on many timescales in the same neuron velocity Fairhall et al. 2001 blowfly H1

29. Adaptation on many timescales in the same neuron single exponential process cascade of exponential processes Drew and Abbott, 2006 model

30. Adaptation

31. 1.Adaptation – examples and definitions 2.Adaptation as efficient coding 3.A tradeoff between sensitivity and efficiency 4.Adaptation and perception 5.Adaptation occurs over multiple timescales 6.Adaptation involves multiple mechanisms

32. Mechanisms of adaptation: intrinsic mechanisms Lancaster and Nicoll, 1987 VmVm I inj

33. Mechanisms of adaptation: synaptic mechanisms Tsodyks & Markram 1997

34. Mechanisms of adaptation: circuit mechanisms Hosoya et al., 2005

35. Costs of adaptation Adaptation worsens the ability of a system to encode the absolute magnitude of a stimulus. Noise in the signals controlling gain can produce noisy fluctuations in gain. inputoutput