NEURAL CONTROL OF MOVEMENT: ENGINEERING THE RHYTHMS OF THE BRAIN

Transcription

1 NEURAL CONTROL OF MOVEMENT: ENGINEERING THE RHYTHMS OF THE BRAIN Madeleine Lowery School of Electrical and Electronic Engineering Centre for Biomedical Engineering University College Dublin

2 Parkinson s disease 2 nd most common neurological disorder 1-3 % of the population over 65 7 million individuals worldwide

3 Loss of dopamine in Parkinson s disease Imaging of dopaminergic activity in the Parkinsonian basal ganglia shown by fluorodopa PET. Dunnett and Björklund, Nature 399, 1999.

4 Deep Brain Stimulation (DBS) Stimulation electrode Subcutaneous extension wire Implanted stimulator Pulse amptlitude DBS waveform V Stimulating pulse Pulse duration Charge-balancing pulse Time

5 Deep Brain Stimulation (DBS) DBS OFF DBS ON

6 Modelling deep brain stimulation Macroscopic models System models Neural networks Single neurons Electric field

7 Electric field effects Scalp Skull Electrode Cerebrospinal fluid Grey and white matter brain tissue Nerves

8 Volume of neural tissue activated.975 quantile mean.25 quantile Grant and Lowery, IEEE Trans. Biomed. Eng., 21. Schmidt et al., IEEE Trans. Biomed. Eng., 213.

9 NETWORK EFFECTS White matter fiber architecture of the brain. Measured from diffusion spectral imaging (DSI).

10 NETWORK EFFECTS Interneurons Cortex Pyramidal tract neurons Soma Striatum AIS Axon GPe Thalamus Collateral STN GPi DBS LFP GABA Glutamate Electrode

11 Neural oscillations in Parkinson's disease Simulated STN local field potential Time (s) DBS ON Frequency (Hz) Recorded STN local field potential * DBS ON Frequency (Hz) *Clinical data recorded by Dr Hayriye Cagnan and Prof. Peter Brown, University of Oxford. DBS off DBS on DBS off DBS on Beta band power (normalised) DBS amplitude (arbitrary units) Simulated data Experimental data

12 Suppression of local field potential oscillations with DBS Variation with DBS parameters (pulse amplitude, duration and frequency) 1 Oscillation amplitude Pulse duration (ms) Amplitude (ma) 1 Oscillation amplitude Pulse duration (ms) Frequency (Hz) Oscillation amplitude Frequency (Hz) Amplitude (ma)

13 Suppression of low-frequency oscillations with high-frequency dither

14 Suppression of low-frequency oscillations with high-frequency dither DBS T.2 DBS on a α T y sec u 2 y arctan G( s) h ( s b) ks 2 y

15 Comparison with Clinical Data Comparison with clinical data DBS amplitude for tremor suppression (ma) Patient A Patient B Patient C Patient D Frequency of Stimulation (Hz) Beta (15-3 Hz) LFP power Patient #3 R 2 = Patient #1 R 2 = Patient #4 R 2 = Amplitude of stimulation (V) Patient #2 R 2 = Clinical data 1 (measured limb tremor) Model predictions Clinical LFP data (recorded at DBS electrode) Model prediction 1 Clinical patient data from Benabid et al., The Lancet, 337:43 46, Davidson, et al., IEEE Trans. Biomed. Eng. (214; 215)

16 Adaptive deep brain stimulation

17 Adaptive deep brain stimulation Local field potential EMG signal Muscle force and tremor

18 Adaptive deep brain stimulation Controller Local field potential EMG signal Muscle force and tremor

19 Conclusions Engineering the rhythms of the brain Understand and modify neural activity DBS suppresses neural oscillations Variation with stimulation parameters Adaptive DBS in near future

20 Acknowledgements UCD Neuromuscular Systems and Neural Engineering Lab Dr Peadar Grant Dr Guiyeom Kang Dr Clare Davidson Eleanor Dunn Prof. Annraoi de Paor Collaborators Dr Hayriye Cagnan and Prof. Peter Brown, University of Oxford. Dr Christian Schmidt and Prof. Ursula Van Rienen, University of Rostock.

21 Closed-loop control of DBS Strongly-coupled network Weakly-coupled network Increased synaptic gain to induce stronger oscillations Grant and Lowery, IEEE Trans. Neural Syst & Rehab Eng, 214

22 Neural oscillations in Parkinson's DBS ON DBS OFF Oscillatory activity recorded from GPi during and after bilateral STN DBS. From Andrea A. Kühn et al. J. Neurosci. 28;28:

23 Suppression of local field potential oscillations with DBS Variation with DBS parameters (pulse amplitude, duration and frequency) Normalised beta oscillation amplitude