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Communication in Brain System – Cold Spring Harbor – May, 2004

Mental Processes and Brain Activation Lab. INSERM U280, Lyon, France bertrand@lyon.inserm.fr. Modulation of local and long-distance beta/gamma oscillatory synchronization observed in human intracranial recordings. O. Bertrand.

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Communication in Brain System – Cold Spring Harbor – May, 2004

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  1. Mental Processes and Brain Activation Lab. INSERM U280, Lyon, France bertrand@lyon.inserm.fr Modulation of local and long-distance beta/gamma oscillatory synchronization observed in human intracranial recordings O. Bertrand Communication in Brain System – Cold Spring Harbor – May, 2004

  2. beta/gamma oscillatory synchronization perception, attention, learning, memory, sensory-motor integration, … Working hypothesis Oscillatory synchronization could be a general mechanism for the dynamic cooperation of neural networks underlying various sensory and cognitive processes effective coupling / de-coupling of brain regions by synchronization / de-synchronization Tallon-Baudry & Bertrand 1999, Varela et al. 2001, Engel & Singer 2001

  3. Human intracranial recordings depth electrodes in epileptic patients during pre-surgical functional evaluation • Visual working memory task • Auditory discrimination task collaboration with C. Fischer, Neurological Hospital, Lyon

  4. T-F • • • T-F averaging power averaging ERP induced gamma T-F 2 evoked gamma +µV Hz Hz 0 2 -µV ms ms Wavelet-based time-frequency analysis Bertrand et al. 1996

  5. Visual short-term memory

  6. lateral occipital sulcus fusiform gyrus memory condition S2=S1? delay S1 S2 control condition dimming? Visual memory task - intracranial recordings Tallon-Baudry, Bertrand, Fischer, J. Neurosci., 2001

  7. lateral occipital sulcus fusiform gyrus 100 Hz 60 40 30 20 15 -400 0 400 800 1200 1400 ms Visual memory task – gamma / beta oscillations memory S1 S1 control Tallon-Baudry, Bertrand, Fischer, J. Neurosci., 2001

  8. power complex value (ampl. & phase) N trials chan#1 trial 1 synchrony factor = modulus of the mean vector (ranging from 0 to 1) chan#2 phase difference Synchrony 1 chan#1 freq. trial N 0 chan#2 time time Phase-synchrony detection in the time-frequency domain Lachaux et al. 1999 Tallon-Baudry, Bertrand, Fischer 2001

  9. lateral occipital sulcus fusiform gyrus 2 µV 0 2 -µV S1 S1 synchrony factor 1 synchronization during memory retention 0 S1 Visual memory task – phase synchronization S1 S1 Tallon-Baudry, Bertrand, Fischer, J. Neurosci., 2001

  10. lateral occipital sulcus fusiform gyrus 2 µV 0 2 -µV S1 S1 Visual memory task – phase synchronization S1 S1 beta synchronization during memory retention randomization statistics (yellow: p<0.05) Tallon-Baudry, Bertrand, Fischer, J. Neurosci., 2001

  11. Auditory frequency discrimination

  12. Frequency discrimination task distractor 1080 Hz button press target 1040 Hz STD 1000 Hz ISI : 1.4 s 50 ms tones

  13. ERPs HG PT HG H1 pat. NG HG PT STG PT standard tones Heschl’s Gyrus (HG) Planum Temporale (PT) Frequency discrimination – intracranial recordings

  14. evoked off induced HG on PT induced response 40 - 80 Hz profile pat. NG HG evoked response PT Frequency discrimination task

  15. evoked off induced HG on PT induced response 40 - 80 Hz profile pat. NG HG PT Frequency discrimination task induced response

  16. HG PT induced response pat. NG evoked HG induced (220 ms) induced response PT 26-40Hz low-gamma Frequency discrimination task evoked off induced (170ms) on 40-80Hz high-gamma

  17. evoked HG PT HG induced 26 - 40 Hz depth profile PT 10 mm evoked Frequency discrimination task induced 40 - 80 Hz depth profile pat. NG induced response

  18. distractor 1080 Hz target 1040 Hz STD 1000 Hz ISI : 1.4 s 50 ms tones early STD late STD increased attention Frequency discrimination task

  19. 1400 ms (early) . . . . . . STD Target STD STD (late) Frequency discrimination task Effect of attention on induced gamma 24-40 Hz pat. CG

  20. Heschl’s gyrus Superior temporal gyrus Planum Temporale patient #2 patient #1 Frequency discrimination task 25-70 Hz 130-300 ms

  21. primary area secondary areas no attention effect modulation by attention Frequency discrimination task 2 gamma foci in the auditory cortex 25-80 Hz 130-300 ms 5 patients late vs early standard tones

  22. high-gamma (40-80 Hz) synchronized low-gamma (25-30 Hz) Multiple foci of induced gamma oscillations HG1 PT 130 - 500 ms STG amplitude and phase-synchrony modulated by attention

  23. Local and large-scale oscillatory synchronization • multiple gamma (25-40, 40-80 Hz) and beta (15-25 Hz) sites • local synchrony in the vicinity of the electrodes • beta when evoked response and gamma • task-modulated medium-scale gamma synchrony (30 Hz) • task-modulated long-distance beta synchrony (15-20 Hz) • The same neural population can switch from gamma to beta oscillatory modes, each one being related to distinct functional processes: encoding, target selection, maintenance in memory

  24. INSERM Lyon Neurological Hosp. Lyon CNRS Paris Mental Processes and Brain Activation Lab. INSERM U280, Lyon, France bertrand@lyon.inserm.fr Aurélie Bidet-Caulet, Françoise Bauchet Pierre-Emmanuel Aguera Jean-Philippe Lachaux Catherine Fischer Catherine Tallon-Baudry

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