1. Dynamic changes of somatosensory evoked potentials in rats and humans during wake-sleep states Institute of Cognitive Science, National Cheng Kung University 國立成功大學 認知科學所 蕭富仁 (Fu-Zen Shaw)

2. Biological rhythm Rhythms are ubiquitous in the mammalian CNS. They also span a broad range of frequencies, from 100 Hz EEG to once per year (0.00000003 Hz) for many seasonal behaviors. They also influence the physiological states (respiratory and cardiac rhythms). The earth is a rhythmic environment. Brains have evolved a variety of systems for rhythmic control. (e.g., waking and sleep, cardiac rhythm, breathing cycle)

6. Brain rhythms Alpha rhythm (8-13 Hz) appears at the occipital cortex when eyes close. [resting condition] {rolandic mu rhythm; temporal tau rhythm} Beta rhythm (13-30 Hz) is associated with alertness. Gamma rhythm (30-80 Hz) is related to sensory integration and feature binding. Theta rhythm (4-8 or 4-10 Hz) Delta rhythm (0.5-4 or 1-4 Hz) Sleep spindle (12-15 Hz or 7-15 Hz) {sigma rhythm} K complex (<0.5 Hz) {(very) slow oscillation}

7. Brain activities with eye-open and eye-close states

8. 清醒 - 睡眠之腦電波特性 (ultradian rhythm)

9. Ogilvie, Sleep Med. Rev., 5, 247-270, 2001. Successive EEG changes throughout the sleep onset period

10. Characteristic patterns of the brain activities in the neocortex and hippocampus Buzsaki, Neuroscience, 31, 551-70, 1989. Gottesmann, Neurosci. Biobehav. Rev., 16, 31-8, 1992. Steriade et al., Science, 262, 679-85, 1993. Steriade, Neuroscience, 101, 243-76, 2000. AwakeNon-REM sleepREM sleep Stage 1Stage 2Stage 3-4 CortexAlpha wave Gamma wave Spindle K complex Delta wave Theta wave Gamma wave HippocampusTheta wave HVS High-voltage spike (HVS) with high-frequency ripple (~200 Hz) Theta wave

11. Brain rhythms in wake-sleep states Shaw et al., Sleep, 29, 276-284, 2006.

12. Somatosensory pathway & Somatotopography

13. SEP changes during wake-sleep states Shaw et al., Sleep, 29, 276-284, 2006.

14. Frequency response of EPs Castro-Alamancos, Prog. Neurobiol., 74, 213-247, 2004.

15. Augmenting response in cortical neurons during 80-150 ms inter- stimulus intervals Castro-Alamancos and Connors, Science, 272, 274-277, 1996.

16. Short-term plasticity: Augmenting response in cortical neurons by 10-Hz stimulation Steriade, Trends Neurosci., 22, 337- 345, 1999.

17. Frequency response of SEPs in wake-sleep states Shaw et al., Sleep, 29, 276-284, 2006.

18. SEP changes in sleep and absence epilepsy Shaw et al., Sleep, 29, 276-284, 2006.

19. Binding problem & winner-take-all strategy

21. Two gamma responses: evoked vs. induced Tallon-Baudry and Bertrand, Trends Cog. Sci., 3, 151-162, 1999.

23. Eevoked auditory gamma activity during wake-sleep states Llinas and Ribary, Proc. Natl. Acad. Sci. USA, 90, 2078-2081, 1993. Evoked responses Spontaneous

24. Evoked visual gamma activity in various brain areas Schurmann et al., NeuroReport, 8, 531-534, 1997.

25. Evoked auditory gamma activity in various brain areas Basar et al., IEEE Eng. Bio. Med., 14, 400-410, 1995. Shaw and Chew, Brain Res., 983: 152-161, 2003.

26. Shaw and Chew, Brain Res., 983: 152-163, 2003. Gamma responses of the rat’s SEPs in wake-sleep states

27. Shaw and Chew, Brain Res., 983: 152-163, 2003.

28. Changes of cortical somatosensory evoked potentials using medial nerve stimulation during wake-sleep states

29. + - P1 N1 1 2 *P <.05 vs S2; #P <.05 vs SWS; +P <.05 vs REM by Student-Newman-Keuls test.

31. Theta wave analysis

32. SEP changes in sleep spindles

34. Stickgold, Nat. Neurosci., 10, 540-542, 2007.

36. Miller, Science, 315, 1360-1363, 2007.

39. Maquet, Science, 294, 1048-1052, 2001. The role of sleep in brain plasticity Dual process: SWS is favorable to explicit memory traces REM sleep is involved in implicit memory consolidation Double-step process: Consolidation of memory traces requires SWS followed by REM sleep Two-stage processes to external stimulation: SWS (sleep spindle) is beneficial for enhancement of inputs, and REM sleep for integrating/binding inputs.

40. Acknowledgement National Cheng Kung University S.-F. Liang ( 梁勝富 ) National Taiwan University C.-T. Yen ( 嚴震東 ) Graduate Students J.-H. Chew ( 周佳禾 ) S.-Y. Lee ( 李姝瑩 ) T.-Y. Chuang ( 莊子宜 )