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Recent advances in the analysis and control of spatio-temporal brain oscillations Antoine Chaillet L2S - CentraleSup´ elec - Univ. Paris Sud - Univ. Paris Saclay Institut Universitaire de France GdR BioComp, Bordeaux, 5/6/2018 A. Chaillet (L2S) Spatio-temporal oscillations attenuation GdR BioComp 2018 1 / 39
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Page 1: Recent advances in the analysis and control of spatio ...gdr-biocomp.fr/wp-content/uploads/2018/...Chaillet.pdf · Recent advances in the analysis and control of spatio-temporal brain

Recent advances in the analysis and control ofspatio-temporal brain oscillations

Antoine Chaillet

L2S - CentraleSupelec - Univ. Paris Sud - Univ. Paris SaclayInstitut Universitaire de France

GdR BioComp, Bordeaux, 5/6/2018

A. Chaillet (L2S) Spatio-temporal oscillations attenuation GdR BioComp 2018 1 / 39

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1 Context and motivations

2 Spatio-temporal rate model for STN-GPe

3 ISS for delayed spatio-temporal dynamics

4 Stabilization of STN-GPe by proportional feedback

5 Adaptive control for selective disruption

6 Conclusion and perspectives

A. Chaillet (L2S) Spatio-temporal oscillations attenuation GdR BioComp 2018 2 / 39

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1 Context and motivations

2 Spatio-temporal rate model for STN-GPe

3 ISS for delayed spatio-temporal dynamics

4 Stabilization of STN-GPe by proportional feedback

5 Adaptive control for selective disruption

6 Conclusion and perspectives

A. Chaillet (L2S) Spatio-temporal oscillations attenuation GdR BioComp 2018 3 / 39

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Control theory

Using measurements to impose a prescribedbehavior with limited human intervention

Traditional applications: mechanical, electrical,chemical systems

Intrinsically interdisciplinary

Key notion: the feedback loop.

A. Chaillet (L2S) Spatio-temporal oscillations attenuation GdR BioComp 2018 4 / 39

Page 5: Recent advances in the analysis and control of spatio ...gdr-biocomp.fr/wp-content/uploads/2018/...Chaillet.pdf · Recent advances in the analysis and control of spatio-temporal brain

Control theory

Using measurements to impose a prescribedbehavior with limited human intervention

Traditional applications: mechanical, electrical,chemical systems

Intrinsically interdisciplinary

Key notion: the feedback loop.

A. Chaillet (L2S) Spatio-temporal oscillations attenuation GdR BioComp 2018 4 / 39

Page 6: Recent advances in the analysis and control of spatio ...gdr-biocomp.fr/wp-content/uploads/2018/...Chaillet.pdf · Recent advances in the analysis and control of spatio-temporal brain

Control theory

Using measurements to impose a prescribedbehavior with limited human intervention

Traditional applications: mechanical, electrical,chemical systems

Intrinsically interdisciplinary

Key notion: the feedback loop.

A. Chaillet (L2S) Spatio-temporal oscillations attenuation GdR BioComp 2018 4 / 39

Page 7: Recent advances in the analysis and control of spatio ...gdr-biocomp.fr/wp-content/uploads/2018/...Chaillet.pdf · Recent advances in the analysis and control of spatio-temporal brain

Control theory

Using measurements to impose a prescribedbehavior with limited human intervention

Traditional applications: mechanical, electrical,chemical systems

Intrinsically interdisciplinary

Key notion: the feedback loop.

A. Chaillet (L2S) Spatio-temporal oscillations attenuation GdR BioComp 2018 4 / 39

Page 8: Recent advances in the analysis and control of spatio ...gdr-biocomp.fr/wp-content/uploads/2018/...Chaillet.pdf · Recent advances in the analysis and control of spatio-temporal brain

Basal ganglia

[Bolam et al. 2009]

Deep-brain nuclei involved in motor,cognitive, associative and mnemonicfunctions

I Striatum (Str)I Ext. segment globus pallidus (GPe)I Int. segment globus pallidus (GPi)I Subthalamic nucleus (STN)I Substantia nigra (SN)

Interact with cortex, thalamus, brainstem and spinal cord, and otherstructures.

A. Chaillet (L2S) Spatio-temporal oscillations attenuation GdR BioComp 2018 5 / 39

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Parkinson’s disease and basal ganglia activityBursting activity of STN and GPe neurons:

[Ammari et al. 2011]

Prominent 13− 30Hz (β-band) oscillations in local field potential(LFP) of parkinsonian STN and GPe:

I In parkinsonian patients:

[Hammond et al. 2007]

I In MPTP monkeys:

A. Chaillet (L2S) Spatio-temporal oscillations attenuation GdR BioComp 2018 6 / 39

Page 10: Recent advances in the analysis and control of spatio ...gdr-biocomp.fr/wp-content/uploads/2018/...Chaillet.pdf · Recent advances in the analysis and control of spatio-temporal brain

Parkinson’s disease and basal ganglia activityBursting activity of STN and GPe neurons:

[Ammari et al. 2011]

Prominent 13− 30Hz (β-band) oscillations in local field potential(LFP) of parkinsonian STN and GPe:

I In parkinsonian patients:

[Hammond et al. 2007]

I In MPTP monkeys:

A. Chaillet (L2S) Spatio-temporal oscillations attenuation GdR BioComp 2018 6 / 39

Page 11: Recent advances in the analysis and control of spatio ...gdr-biocomp.fr/wp-content/uploads/2018/...Chaillet.pdf · Recent advances in the analysis and control of spatio-temporal brain

Parkinson’s disease and basal ganglia activityBursting activity of STN and GPe neurons:

[Ammari et al. 2011]

Prominent 13− 30Hz (β-band) oscillations in local field potential(LFP) of parkinsonian STN and GPe:

I In parkinsonian patients:

[Hammond et al. 2007]I In MPTP monkeys:

A. Chaillet (L2S) Spatio-temporal oscillations attenuation GdR BioComp 2018 6 / 39

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Parkinson’s disease and basal ganglia activity

Reduction of β-oscillationscorrelates motor symptomsimprovement [Hammond et al.

2007, Little et al. 2012]

β-oscillations may decreaseduring Deep Brain Stimulation[Eusebio et al. 2013]

A. Chaillet (L2S) Spatio-temporal oscillations attenuation GdR BioComp 2018 7 / 39

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Parkinson’s disease and basal ganglia activity

Reduction of β-oscillationscorrelates motor symptomsimprovement [Hammond et al.

2007, Little et al. 2012]

β-oscillations may decreaseduring Deep Brain Stimulation[Eusebio et al. 2013]

A. Chaillet (L2S) Spatio-temporal oscillations attenuation GdR BioComp 2018 7 / 39

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Oscillations onset still debated

Parkinsonian symptoms mechanisms are notfully understood yet:

Pacemaker effect of the STN-GPe loop ?

Cortical endogenous oscillations ?

Striatal endogenous oscillations ?

[Bolam et al. 2009]

A. Chaillet (L2S) Spatio-temporal oscillations attenuation GdR BioComp 2018 8 / 39

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Oscillations onset still debated

Parkinsonian symptoms mechanisms are notfully understood yet:

Pacemaker effect of the STN-GPe loop ?

Cortical endogenous oscillations ?

Striatal endogenous oscillations ?

[Bolam et al. 2009]

A. Chaillet (L2S) Spatio-temporal oscillations attenuation GdR BioComp 2018 8 / 39

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Oscillations onset still debated

Parkinsonian symptoms mechanisms are notfully understood yet:

Pacemaker effect of the STN-GPe loop ?

Cortical endogenous oscillations ?

Striatal endogenous oscillations ?

[Bolam et al. 2009]

A. Chaillet (L2S) Spatio-temporal oscillations attenuation GdR BioComp 2018 8 / 39

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Disrupting pathological oscillationsTechnological solutions to steer brain populations dynamics

Deep Brain Stimulation [Benabid et al. 91]:

Optogenetics [Boyden et al. 2005]:

Acoustic neuromodulation[Eggermont & Tass 2015]

Sonogenetics[Ibsen et al. 2015]

Transcranial current stim.[Brittain et al. 2013]

Transcranial magnetic stim.[Strafella et al. 2004]

Magnetothermal stim.[Chen et al. 2015]

A. Chaillet (L2S) Spatio-temporal oscillations attenuation GdR BioComp 2018 9 / 39

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Disrupting pathological oscillationsTechnological solutions to steer brain populations dynamics

Deep Brain Stimulation [Benabid et al. 91]:

Optogenetics [Boyden et al. 2005]:

Acoustic neuromodulation[Eggermont & Tass 2015]

Sonogenetics[Ibsen et al. 2015]

Transcranial current stim.[Brittain et al. 2013]

Transcranial magnetic stim.[Strafella et al. 2004]

Magnetothermal stim.[Chen et al. 2015]

A. Chaillet (L2S) Spatio-temporal oscillations attenuation GdR BioComp 2018 9 / 39

Page 19: Recent advances in the analysis and control of spatio ...gdr-biocomp.fr/wp-content/uploads/2018/...Chaillet.pdf · Recent advances in the analysis and control of spatio-temporal brain

Disrupting pathological oscillationsTechnological solutions to steer brain populations dynamics

Deep Brain Stimulation [Benabid et al. 91]:

Optogenetics [Boyden et al. 2005]:

Acoustic neuromodulation[Eggermont & Tass 2015]

Sonogenetics[Ibsen et al. 2015]

Transcranial current stim.[Brittain et al. 2013]

Transcranial magnetic stim.[Strafella et al. 2004]

Magnetothermal stim.[Chen et al. 2015]

A. Chaillet (L2S) Spatio-temporal oscillations attenuation GdR BioComp 2018 9 / 39

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Some attempts towards closed-loop brain stimulation

Survey: [Carron et al. 2013]

A. Chaillet (L2S) Spatio-temporal oscillations attenuation GdR BioComp 2018 10 / 39

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Neuronal populations: rate models

Firing rate: instantaneous number of spikes per time unit

Mesoscopic modelsI Focus on populations rather than single neuronsI Allows analytical treatmentI Well-adapted to experimental constraints

Rely on Wilson & Cowan model [Wilson & Cowan 1972]

I Interconnection of an inhibitory and an excitatory populationsI Too much synaptic strength generates instability

Simulation analysis: [Gillies et al. 2002, Leblois et al. 2006]

Analytical conditions for oscillations onset: [Nevado-Holgado et al. 2010, Pavlides et al.

2012, Pasillas-Lepine 2013, Haidar et al. 2014].

A. Chaillet (L2S) Spatio-temporal oscillations attenuation GdR BioComp 2018 11 / 39

Page 22: Recent advances in the analysis and control of spatio ...gdr-biocomp.fr/wp-content/uploads/2018/...Chaillet.pdf · Recent advances in the analysis and control of spatio-temporal brain

Neuronal populations: rate models

Firing rate: instantaneous number of spikes per time unit

Mesoscopic modelsI Focus on populations rather than single neuronsI Allows analytical treatmentI Well-adapted to experimental constraints

Rely on Wilson & Cowan model [Wilson & Cowan 1972]

I Interconnection of an inhibitory and an excitatory populationsI Too much synaptic strength generates instability

Simulation analysis: [Gillies et al. 2002, Leblois et al. 2006]

Analytical conditions for oscillations onset: [Nevado-Holgado et al. 2010, Pavlides et al.

2012, Pasillas-Lepine 2013, Haidar et al. 2014].

A. Chaillet (L2S) Spatio-temporal oscillations attenuation GdR BioComp 2018 11 / 39

Page 23: Recent advances in the analysis and control of spatio ...gdr-biocomp.fr/wp-content/uploads/2018/...Chaillet.pdf · Recent advances in the analysis and control of spatio-temporal brain

Neuronal populations: rate models

Firing rate: instantaneous number of spikes per time unit

Mesoscopic modelsI Focus on populations rather than single neuronsI Allows analytical treatmentI Well-adapted to experimental constraints

Rely on Wilson & Cowan model [Wilson & Cowan 1972]

I Interconnection of an inhibitory and an excitatory populationsI Too much synaptic strength generates instability

Simulation analysis: [Gillies et al. 2002, Leblois et al. 2006]

Analytical conditions for oscillations onset: [Nevado-Holgado et al. 2010, Pavlides et al.

2012, Pasillas-Lepine 2013, Haidar et al. 2014].

A. Chaillet (L2S) Spatio-temporal oscillations attenuation GdR BioComp 2018 11 / 39

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Neuronal populations: limitations of existing models

Spatial heterogeneity needs to be considered:I Oscillations onset might be related to local neuronal organization

[Schwab et al., 2013]

I Spatial correlation could play a role in parkinsonian symptoms[Cagnan et al., 2015]

I Possible exploitation of multi-plot electrodes.

Techniques needed for analytical treatments of:I NonlinearitiesI Position-dependent delays.

A. Chaillet (L2S) Spatio-temporal oscillations attenuation GdR BioComp 2018 12 / 39

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1 Context and motivations

2 Spatio-temporal rate model for STN-GPe

3 ISS for delayed spatio-temporal dynamics

4 Stabilization of STN-GPe by proportional feedback

5 Adaptive control for selective disruption

6 Conclusion and perspectives

A. Chaillet (L2S) Spatio-temporal oscillations attenuation GdR BioComp 2018 13 / 39

Page 26: Recent advances in the analysis and control of spatio ...gdr-biocomp.fr/wp-content/uploads/2018/...Chaillet.pdf · Recent advances in the analysis and control of spatio-temporal brain

Spatio-temporal model of STN-GPe dynamics

Delayed neural fields:

τ1∂x1

∂t= −x1 + S1

2∑j=1

∫Ωw1j (r , r

′)xj (r′, t − dj (r , r

′))dr ′ + α(r)u(r , t)

(1a)

τ2∂x2

∂t= −x2 + S2

2∑j=1

∫Ωw2j (r , r

′)xj (r′, t − dj (r , r

′))dr ′

. (1b)

1: STN population (directly controlled), 2: GPe population (no control)

xi (r , t) rate of population i at time t and position r ∈ Ω

τi : decay rate

wij : synaptic weights distributions

Si : activation functions

di : delay distributions

α: impact of stimulation, u: control signal.

A. Chaillet (L2S) Spatio-temporal oscillations attenuation GdR BioComp 2018 14 / 39

Page 27: Recent advances in the analysis and control of spatio ...gdr-biocomp.fr/wp-content/uploads/2018/...Chaillet.pdf · Recent advances in the analysis and control of spatio-temporal brain

Spatio-temporal model of STN-GPe dynamics

Delayed neural fields:

τ1∂x1

∂t= −x1 + S1

2∑j=1

∫Ωw1j (r , r

′)xj (r′, t − dj (r , r

′))dr ′ + α(r)u(r , t)

(1a)

τ2∂x2

∂t= −x2 + S2

2∑j=1

∫Ωw2j (r , r

′)xj (r′, t − dj (r , r

′))dr ′

. (1b)

1: STN population (directly controlled), 2: GPe population (no control)

xi (r , t) rate of population i at time t and position r ∈ Ω

τi : decay rate

wij : synaptic weights distributions

Si : activation functions

di : delay distributions

α: impact of stimulation, u: control signal.

A. Chaillet (L2S) Spatio-temporal oscillations attenuation GdR BioComp 2018 14 / 39

Page 28: Recent advances in the analysis and control of spatio ...gdr-biocomp.fr/wp-content/uploads/2018/...Chaillet.pdf · Recent advances in the analysis and control of spatio-temporal brain

Spatio-temporal model of STN-GPe dynamics

Delayed neural fields:

τ1∂x1

∂t= −x1 + S1

2∑j=1

∫Ωw1j (r , r

′)xj (r′, t − dj (r , r

′))dr ′ + α(r)u(r , t)

(1a)

τ2∂x2

∂t= −x2 + S2

2∑j=1

∫Ωw2j (r , r

′)xj (r′, t − dj (r , r

′))dr ′

. (1b)

1: STN population (directly controlled), 2: GPe population (no control)

xi (r , t) rate of population i at time t and position r ∈ Ω

τi : decay rate

wij : synaptic weights distributions

Si : activation functions

di : delay distributions

α: impact of stimulation, u: control signal.

A. Chaillet (L2S) Spatio-temporal oscillations attenuation GdR BioComp 2018 14 / 39

Page 29: Recent advances in the analysis and control of spatio ...gdr-biocomp.fr/wp-content/uploads/2018/...Chaillet.pdf · Recent advances in the analysis and control of spatio-temporal brain

Spatio-temporal model of STN-GPe dynamics

Delayed neural fields:

τ1∂x1

∂t= −x1 + S1

2∑j=1

∫Ωw1j (r , r

′)xj (r′, t − dj (r , r

′))dr ′ + α(r)u(r , t)

(1a)

τ2∂x2

∂t= −x2 + S2

2∑j=1

∫Ωw2j (r , r

′)xj (r′, t − dj (r , r

′))dr ′

. (1b)

1: STN population (directly controlled), 2: GPe population (no control)

xi (r , t) rate of population i at time t and position r ∈ Ω

τi : decay rate

wij : synaptic weights distributions

Si : activation functions

di : delay distributions

α: impact of stimulation, u: control signal.

A. Chaillet (L2S) Spatio-temporal oscillations attenuation GdR BioComp 2018 14 / 39

Page 30: Recent advances in the analysis and control of spatio ...gdr-biocomp.fr/wp-content/uploads/2018/...Chaillet.pdf · Recent advances in the analysis and control of spatio-temporal brain

Spatio-temporal model of STN-GPe dynamics

Delayed neural fields:

τ1∂x1

∂t= −x1 + S1

2∑j=1

∫Ωw1j (r , r

′)xj (r′, t − dj (r , r

′))dr ′ + α(r)u(r , t)

(1a)

τ2∂x2

∂t= −x2 + S2

2∑j=1

∫Ωw2j (r , r

′)xj (r′, t − dj (r , r

′))dr ′

. (1b)

1: STN population (directly controlled), 2: GPe population (no control)

xi (r , t) rate of population i at time t and position r ∈ Ω

τi : decay rate

wij : synaptic weights distributions

Si : activation functions

di : delay distributions

α: impact of stimulation, u: control signal.

A. Chaillet (L2S) Spatio-temporal oscillations attenuation GdR BioComp 2018 14 / 39

Page 31: Recent advances in the analysis and control of spatio ...gdr-biocomp.fr/wp-content/uploads/2018/...Chaillet.pdf · Recent advances in the analysis and control of spatio-temporal brain

Spatio-temporal model of STN-GPe dynamics

Delayed neural fields:

τ1∂x1

∂t= −x1 + S1

2∑j=1

∫Ωw1j (r , r

′)xj (r′, t − dj (r , r

′))dr ′ + α(r)u(r , t)

(1a)

τ2∂x2

∂t= −x2 + S2

2∑j=1

∫Ωw2j (r , r

′)xj (r′, t − dj (r , r

′))dr ′

. (1b)

1: STN population (directly controlled), 2: GPe population (no control)

xi (r , t) rate of population i at time t and position r ∈ Ω

τi : decay rate

wij : synaptic weights distributions

Si : activation functions

di : delay distributions

α: impact of stimulation, u: control signal.

A. Chaillet (L2S) Spatio-temporal oscillations attenuation GdR BioComp 2018 14 / 39

Page 32: Recent advances in the analysis and control of spatio ...gdr-biocomp.fr/wp-content/uploads/2018/...Chaillet.pdf · Recent advances in the analysis and control of spatio-temporal brain

Spatio-temporal model of STN-GPe dynamics

Delayed neural fields:

τ1∂x1

∂t= −x1 + S1

2∑j=1

∫Ωw1j (r , r

′)xj (r′, t − dj (r , r

′))dr ′ + α(r)u(r , t)

(1a)

τ2∂x2

∂t= −x2 + S2

2∑j=1

∫Ωw2j (r , r

′)xj (r′, t − dj (r , r

′))dr ′

. (1b)

1: STN population (directly controlled), 2: GPe population (no control)

xi (r , t) rate of population i at time t and position r ∈ Ω

τi : decay rate

wij : synaptic weights distributions

Si : activation functions

di : delay distributions

α: impact of stimulation, u: control signal.

A. Chaillet (L2S) Spatio-temporal oscillations attenuation GdR BioComp 2018 14 / 39

Page 33: Recent advances in the analysis and control of spatio ...gdr-biocomp.fr/wp-content/uploads/2018/...Chaillet.pdf · Recent advances in the analysis and control of spatio-temporal brain

Spatio-temporal model of STN-GPe dynamics

With parameters inspired from [Nevado-Holgado et al. 2010], generation ofspatio-temporal β-oscillations:

STN GPe(cm)

A. Chaillet (L2S) Spatio-temporal oscillations attenuation GdR BioComp 2018 15 / 39

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1 Context and motivations

2 Spatio-temporal rate model for STN-GPe

3 ISS for delayed spatio-temporal dynamics

4 Stabilization of STN-GPe by proportional feedback

5 Adaptive control for selective disruption

6 Conclusion and perspectives

A. Chaillet (L2S) Spatio-temporal oscillations attenuation GdR BioComp 2018 16 / 39

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Mathematical framework

System: x(t) = f (xt , p(t))

F := L2(Ω,Rn)

C := C ([−d ; 0],F)

f : C × U → Fx(t) ∈ F : at each fixed t, it is a function of the space variable

xt ∈ C: state segment. For each θ ∈ [−d ; 0], xt(θ) := x(t + θ).

p ∈ U : exogenous input.

Associated norms [Faye & Faugeras 2010]:

‖x‖F :=√∫

Ω |x(s)|2ds for all x ∈ F

‖xt‖C := supθ∈[−d ;0] ‖x(t + θ)‖F for all xt ∈ C.

A. Chaillet (L2S) Spatio-temporal oscillations attenuation GdR BioComp 2018 17 / 39

Page 36: Recent advances in the analysis and control of spatio ...gdr-biocomp.fr/wp-content/uploads/2018/...Chaillet.pdf · Recent advances in the analysis and control of spatio-temporal brain

Mathematical framework

System: x(t) = f (xt , p(t))

F := L2(Ω,Rn)

C := C ([−d ; 0],F)

f : C × U → Fx(t) ∈ F : at each fixed t, it is a function of the space variable

xt ∈ C: state segment. For each θ ∈ [−d ; 0], xt(θ) := x(t + θ).

p ∈ U : exogenous input.

Associated norms [Faye & Faugeras 2010]:

‖x‖F :=√∫

Ω |x(s)|2ds for all x ∈ F

‖xt‖C := supθ∈[−d ;0] ‖x(t + θ)‖F for all xt ∈ C.

A. Chaillet (L2S) Spatio-temporal oscillations attenuation GdR BioComp 2018 17 / 39

Page 37: Recent advances in the analysis and control of spatio ...gdr-biocomp.fr/wp-content/uploads/2018/...Chaillet.pdf · Recent advances in the analysis and control of spatio-temporal brain

Mathematical framework

System: x(t) = f (xt , p(t))

F := L2(Ω,Rn)

C := C ([−d ; 0],F)

f : C × U → Fx(t) ∈ F : at each fixed t, it is a function of the space variable

xt ∈ C: state segment. For each θ ∈ [−d ; 0], xt(θ) := x(t + θ).

p ∈ U : exogenous input.

Associated norms [Faye & Faugeras 2010]:

‖x‖F :=√∫

Ω |x(s)|2ds for all x ∈ F

‖xt‖C := supθ∈[−d ;0] ‖x(t + θ)‖F for all xt ∈ C.

A. Chaillet (L2S) Spatio-temporal oscillations attenuation GdR BioComp 2018 17 / 39

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ISS for delayed spatio-temporal dynamics: definition

Definition: Input-to-state stability

The system (2) is ISS if there exist ν ∈ K∞ and β ∈ KL such that, forany x0 ∈ C and any p ∈ U ,

‖x(t)‖F ≤ β(‖x0‖C , t) + ν

(supτ∈[0;t]

‖p(τ)‖F

), ∀t ≥ 0.

Delayed spatio-temporal extension of ISS [Sontag]

In line with ISS for delay systems: [Pepe & Jiang 2006, Mazenc et al. 2008]

. . . and for infinite-dimensional systems: [Karafyllis & Jiang 2007,

Dashkovskiy & Mironchenko 2012].

A. Chaillet (L2S) Spatio-temporal oscillations attenuation GdR BioComp 2018 18 / 39

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ISS for delayed spatio-temporal dynamics: definition

Definition: Input-to-state stability

The system (2) is ISS if there exist ν ∈ K∞ and β ∈ KL such that, forany x0 ∈ C and any p ∈ U ,

‖x(t)‖F ≤ β(‖x0‖C , t) + ν

(supτ∈[0;t]

‖p(τ)‖F

), ∀t ≥ 0.

Delayed spatio-temporal extension of ISS [Sontag]

In line with ISS for delay systems: [Pepe & Jiang 2006, Mazenc et al. 2008]

. . . and for infinite-dimensional systems: [Karafyllis & Jiang 2007,

Dashkovskiy & Mironchenko 2012].

A. Chaillet (L2S) Spatio-temporal oscillations attenuation GdR BioComp 2018 18 / 39

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Lyapunov-Krasovskii condition for ISS

x(t) = f (xt , p(t)) (2)

Theorem: Lyapunov-Krasovskii function for ISS

Let α, α, α, γ ∈ K∞ and V ∈ C (C,R≥0). Assume that, given any x0 ∈ Cand any p ∈ U , solutions of (2) satisfy

α(‖x(t)‖F ) ≤ V (xt) ≤ α(‖xt‖C)

V (xt) ≥ γ(‖p(t)‖F ) ⇒ V |(2) ≤ −α(V (xt)).

Then the system (2) is ISS.

Proof similar to Sontag’s original result.

A. Chaillet (L2S) Spatio-temporal oscillations attenuation GdR BioComp 2018 19 / 39

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ISS small gain

x1(t) = f1(x1t , x2t , p1(t)) (3a)

x2(t) = f2(x2t , x1t , p2(t)) (3b)

Theorem: ISS small gain

Let αi , αi , αi , γi , χi ∈ K∞ and Vi : C (C,R≥0). Assume that, given any xi0 ∈ Cand any pi ∈ U ,

αi (‖xi (t)‖F ) ≤ Vi (xit) ≤ αi (‖xit‖C)

V1 ≥ max χ1(V2), γ1(‖p1(t)‖F ) ⇒ V1|(3a) ≤ −α1(V1)

V2 ≥ max χ2(V1), γ2(‖p2(t)‖F ) ⇒ V2|(3b) ≤ −α2(V2).

Then, under the small-gain condition χ1 χ2(s) < s, for all s > 0, the feedback

interconnection (3) is ISS.

Proof similar to [Jiang et al. 1996]

Similar results: [Karafyllis & Jiang 2007, Dashkovskiy & Mironchenko 2012].

A. Chaillet (L2S) Spatio-temporal oscillations attenuation GdR BioComp 2018 20 / 39

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ISS small gain

x1(t) = f1(x1t , x2t , p1(t)) (3a)

x2(t) = f2(x2t , x1t , p2(t)) (3b)

Theorem: ISS small gain

Let αi , αi , αi , γi , χi ∈ K∞ and Vi : C (C,R≥0). Assume that, given any xi0 ∈ Cand any pi ∈ U ,

αi (‖xi (t)‖F ) ≤ Vi (xit) ≤ αi (‖xit‖C)

V1 ≥ max χ1(V2), γ1(‖p1(t)‖F ) ⇒ V1|(3a) ≤ −α1(V1)

V2 ≥ max χ2(V1), γ2(‖p2(t)‖F ) ⇒ V2|(3b) ≤ −α2(V2).

Then, under the small-gain condition χ1 χ2(s) < s, for all s > 0, the feedback

interconnection (3) is ISS.

Proof similar to [Jiang et al. 1996]

Similar results: [Karafyllis & Jiang 2007, Dashkovskiy & Mironchenko 2012].

A. Chaillet (L2S) Spatio-temporal oscillations attenuation GdR BioComp 2018 20 / 39

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ISS small gain

x1(t) = f1(x1t , x2t , p1(t)) (3a)

x2(t) = f2(x2t , x1t , p2(t)) (3b)

Theorem: ISS small gain

Let αi , αi , αi , γi , χi ∈ K∞ and Vi : C (C,R≥0). Assume that, given any xi0 ∈ Cand any pi ∈ U ,

αi (‖xi (t)‖F ) ≤ Vi (xit) ≤ αi (‖xit‖C)

V1 ≥ max χ1(V2), γ1(‖p1(t)‖F ) ⇒ V1|(3a) ≤ −α1(V1)

V2 ≥ max χ2(V1), γ2(‖p2(t)‖F ) ⇒ V2|(3b) ≤ −α2(V2).

Then, under the small-gain condition χ1 χ2(s) < s, for all s > 0, the feedback

interconnection (3) is ISS.

Proof similar to [Jiang et al. 1996]

Similar results: [Karafyllis & Jiang 2007, Dashkovskiy & Mironchenko 2012].

A. Chaillet (L2S) Spatio-temporal oscillations attenuation GdR BioComp 2018 20 / 39

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ISS small gain

x1(t) = f1(x1t , x2t , p1(t)) (3a)

x2(t) = f2(x2t , x1t , p2(t)) (3b)

Theorem: ISS small gain

Let αi , αi , αi , γi , χi ∈ K∞ and Vi : C (C,R≥0). Assume that, given any xi0 ∈ Cand any pi ∈ U ,

αi (‖xi (t)‖F ) ≤ Vi (xit) ≤ αi (‖xit‖C)

V1 ≥ max χ1(V2), γ1(‖p1(t)‖F ) ⇒ V1|(3a) ≤ −α1(V1)

V2 ≥ max χ2(V1), γ2(‖p2(t)‖F ) ⇒ V2|(3b) ≤ −α2(V2).

Then, under the small-gain condition χ1 χ2(s) < s, for all s > 0, the feedback

interconnection (3) is ISS.

Proof similar to [Jiang et al. 1996]

Similar results: [Karafyllis & Jiang 2007, Dashkovskiy & Mironchenko 2012].

A. Chaillet (L2S) Spatio-temporal oscillations attenuation GdR BioComp 2018 20 / 39

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1 Context and motivations

2 Spatio-temporal rate model for STN-GPe

3 ISS for delayed spatio-temporal dynamics

4 Stabilization of STN-GPe by proportional feedback

5 Adaptive control for selective disruption

6 Conclusion and perspectives

A. Chaillet (L2S) Spatio-temporal oscillations attenuation GdR BioComp 2018 21 / 39

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Proportional feedback on STN

Control input: u(r , t) = −kx1(r , t):

Similar control in an averagedmodel: [Haidar et al. 2016]

No measurement or control onGPe required.

A. Chaillet (L2S) Spatio-temporal oscillations attenuation GdR BioComp 2018 22 / 39

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Stabilizability by proportional feedback

τ1∂x1

∂t= −x1 + S1

2∑j=1

∫Ωw1j (r, r

′)xj (r′, t − dj (r, r

′))dr′ + α(r)u(r, t) + p1(r, t)

τ2∂x2

∂t= −x2 + S2

2∑j=1

∫Ωw2j (r, r

′)xj (r′, t−dj (r, r

′))dr′ + p2(r, t)

.

Theorem: ISS stabilization [Detorakis et al. 2015]

Assume that Si are nondecreasing and `i -Lipschitz. If∫Ω

∫Ωw22(r , r ′)2dr ′dr <

1

`2(4)

then there exists k∗ > 0 such that, for any k ≥ k∗, the proportionalfeedback u(r , t) = −kx1(r , t) makes the coupled neural fields ISS.

(4) imposes that oscillations are not endogenous to GPe (weakinternal coupling: in line with neurophysiology literature)

No precise knowledge of parameters required.

A. Chaillet (L2S) Spatio-temporal oscillations attenuation GdR BioComp 2018 23 / 39

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Stabilizability by proportional feedback

τ1∂x1

∂t= −x1 + S1

2∑j=1

∫Ωw1j (r, r

′)xj (r′, t − dj (r, r

′))dr′ + α(r)u(r, t) + p1(r, t)

τ2∂x2

∂t= −x2 + S2

2∑j=1

∫Ωw2j (r, r

′)xj (r′, t−dj (r, r

′))dr′ + p2(r, t)

.

Theorem: ISS stabilization [Detorakis et al. 2015]

Assume that Si are nondecreasing and `i -Lipschitz. If∫Ω

∫Ωw22(r , r ′)2dr ′dr <

1

`2(4)

then there exists k∗ > 0 such that, for any k ≥ k∗, the proportionalfeedback u(r , t) = −kx1(r , t) makes the coupled neural fields ISS.

(4) imposes that oscillations are not endogenous to GPe (weakinternal coupling: in line with neurophysiology literature)

No precise knowledge of parameters required.

A. Chaillet (L2S) Spatio-temporal oscillations attenuation GdR BioComp 2018 23 / 39

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Stabilizability by proportional feedback

τ1∂x1

∂t= −x1 + S1

2∑j=1

∫Ωw1j (r, r

′)xj (r′, t − dj (r, r

′))dr′ + α(r)u(r, t) + p1(r, t)

τ2∂x2

∂t= −x2 + S2

2∑j=1

∫Ωw2j (r, r

′)xj (r′, t−dj (r, r

′))dr′ + p2(r, t)

.

Theorem: ISS stabilization [Detorakis et al. 2015]

Assume that Si are nondecreasing and `i -Lipschitz. If∫Ω

∫Ωw22(r , r ′)2dr ′dr <

1

`2(4)

then there exists k∗ > 0 such that, for any k ≥ k∗, the proportionalfeedback u(r , t) = −kx1(r , t) makes the coupled neural fields ISS.

(4) imposes that oscillations are not endogenous to GPe (weakinternal coupling: in line with neurophysiology literature)

No precise knowledge of parameters required.

A. Chaillet (L2S) Spatio-temporal oscillations attenuation GdR BioComp 2018 23 / 39

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Stabilizability by proportional feedback

τ1∂x1

∂t= −x1 + S1

2∑j=1

∫Ωw1j (r, r

′)xj (r′, t − dj (r, r

′))dr′ + α(r)u(r, t) + p1(r, t)

τ2∂x2

∂t= −x2 + S2

2∑j=1

∫Ωw2j (r, r

′)xj (r′, t−dj (r, r

′))dr′ + p2(r, t)

.

Theorem: ISS stabilization [Detorakis et al. 2015]

Assume that Si are nondecreasing and `i -Lipschitz. If∫Ω

∫Ωw22(r , r ′)2dr ′dr <

1

`2(4)

then there exists k∗ > 0 such that, for any k ≥ k∗, the proportionalfeedback u(r , t) = −kx1(r , t) makes the coupled neural fields ISS.

(4) imposes that oscillations are not endogenous to GPe (weakinternal coupling: in line with neurophysiology literature)

No precise knowledge of parameters required.

A. Chaillet (L2S) Spatio-temporal oscillations attenuation GdR BioComp 2018 23 / 39

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Stabilizability by proportional feedbackSketch of proof

1 Show that GPe is ISS under condition (4) with

V2(x2t) :=τ2

2

∫Ω

x2(r , t)2dr +

∫Ω

β(r)

∫Ω

∫ 0

−d2(r,r′)

ecθx2(r ′, t + θ)2dθdr ′dr .

2 Show that, for k large enough, STN is ISS with arbitrarily smallISS-gain with

V1(x1t) :=τ1

2

∫Ω

x1(r , t)2dr +τ1

2#Ω

∫Ω

∫Ω

∫ 0

−d1(r,r′)

eθx1(r ′, t + θ)2dθdr ′dr .

3 Invoke small-gain theorem.

A. Chaillet (L2S) Spatio-temporal oscillations attenuation GdR BioComp 2018 24 / 39

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Stabilizability by proportional feedbackSketch of proof

1 Show that GPe is ISS under condition (4) with

V2(x2t) :=τ2

2

∫Ω

x2(r , t)2dr +

∫Ω

β(r)

∫Ω

∫ 0

−d2(r,r′)

ecθx2(r ′, t + θ)2dθdr ′dr .

2 Show that, for k large enough, STN is ISS with arbitrarily smallISS-gain with

V1(x1t) :=τ1

2

∫Ω

x1(r , t)2dr +τ1

2#Ω

∫Ω

∫Ω

∫ 0

−d1(r,r′)

eθx1(r ′, t + θ)2dθdr ′dr .

3 Invoke small-gain theorem.

A. Chaillet (L2S) Spatio-temporal oscillations attenuation GdR BioComp 2018 24 / 39

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Stabilizability by proportional feedbackSketch of proof

1 Show that GPe is ISS under condition (4) with

V2(x2t) :=τ2

2

∫Ω

x2(r , t)2dr +

∫Ω

β(r)

∫Ω

∫ 0

−d2(r,r′)

ecθx2(r ′, t + θ)2dθdr ′dr .

2 Show that, for k large enough, STN is ISS with arbitrarily smallISS-gain with

V1(x1t) :=τ1

2

∫Ω

x1(r , t)2dr +τ1

2#Ω

∫Ω

∫Ω

∫ 0

−d1(r,r′)

eθx1(r ′, t + θ)2dθdr ′dr .

3 Invoke small-gain theorem.

A. Chaillet (L2S) Spatio-temporal oscillations attenuation GdR BioComp 2018 24 / 39

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Stabilizability by proportional feedbackSimulations

0 0.5 1Time (s)

0

50

100

150

200Fr

eque

ncy

(sp/

s)

0 0.5 1Time (s)

-250

-200

-150

-100

-50

0

50

100

150

200

u(r,t

)

Efficient attenuation of pathological oscillations

using proportional feedback on STN.

A. Chaillet (L2S) Spatio-temporal oscillations attenuation GdR BioComp 2018 25 / 39

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Robustness to feedback delays

Estimation of STN activity requires acquisition and computation time:

u(r , t) = −kx1(r , t−dc(r)).

Proposition: Robustness to feedback delays [Chaillet et al. 2017]

Under the same assumptions, consider any k ≥ k∗ and assume that S1 isbounded. Then there exists a function ν ∈ K∞ such that

lim supt→∞

‖x(t)‖F ≤ ν(

supr∈Ω

dc(r)

).

Magnitude of remaining oscillations “proportional” toacquisition/processing delays

Does not provide much information for large feedback delays. . .

Requires a bounded activation function on the STN.

A. Chaillet (L2S) Spatio-temporal oscillations attenuation GdR BioComp 2018 26 / 39

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Robustness to feedback delays

Estimation of STN activity requires acquisition and computation time:

u(r , t) = −kx1(r , t−dc(r)).

Proposition: Robustness to feedback delays [Chaillet et al. 2017]

Under the same assumptions, consider any k ≥ k∗ and assume that S1 isbounded. Then there exists a function ν ∈ K∞ such that

lim supt→∞

‖x(t)‖F ≤ ν(

supr∈Ω

dc(r)

).

Magnitude of remaining oscillations “proportional” toacquisition/processing delays

Does not provide much information for large feedback delays. . .

Requires a bounded activation function on the STN.

A. Chaillet (L2S) Spatio-temporal oscillations attenuation GdR BioComp 2018 26 / 39

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Robustness to feedback delaysSketch of proof

1 See the difference between the delayed and the non-delayed controlinputs as a disturbance:

p1(r , t) = −k(x1(r , t − dc(r))− x1(r , t)

).

2 Show that this quantity is bounded by a linear function of dc usingboundedness of S1

3 Exploit the “asymptotic gain property” induced by ISS.

A. Chaillet (L2S) Spatio-temporal oscillations attenuation GdR BioComp 2018 27 / 39

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Robustness to feedback delaysSketch of proof

1 See the difference between the delayed and the non-delayed controlinputs as a disturbance:

p1(r , t) = −k(x1(r , t − dc(r))− x1(r , t)

).

2 Show that this quantity is bounded by a linear function of dc usingboundedness of S1

3 Exploit the “asymptotic gain property” induced by ISS.

A. Chaillet (L2S) Spatio-temporal oscillations attenuation GdR BioComp 2018 27 / 39

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Robustness to feedback delaysSketch of proof

1 See the difference between the delayed and the non-delayed controlinputs as a disturbance:

p1(r , t) = −k(x1(r , t − dc(r))− x1(r , t)

).

2 Show that this quantity is bounded by a linear function of dc usingboundedness of S1

3 Exploit the “asymptotic gain property” induced by ISS.

A. Chaillet (L2S) Spatio-temporal oscillations attenuation GdR BioComp 2018 27 / 39

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Robustness to feedback delaysSimulations

0 0.5 1Time (s)

0

50

100

150

200

Freq

uenc

y (s

p/s)

0 0.5 1Time (s)

0

50

100

150

200

Freq

uenc

y (s

p/s)

STN and GPe mean activity with acquisition/processing delays

of 10ms (left) and 5ms (right).

1 3 5 7 8 9 10 13 15 20Delay (ms)

0

50

100

150

200

250

Max

imum

Osc

illat

ions

Am

plit

ude

kc =12kc =6

kc =2

STN oscillations magnitude as a

function of acquisition/processing

delays.

A. Chaillet (L2S) Spatio-temporal oscillations attenuation GdR BioComp 2018 28 / 39

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Robustness to feedback delaysSimulations

0 0.5 1Time (s)

0

50

100

150

200

Freq

uenc

y (s

p/s)

0 0.5 1Time (s)

0

50

100

150

200

Freq

uenc

y (s

p/s)

STN and GPe mean activity with acquisition/processing delays

of 10ms (left) and 5ms (right).

1 3 5 7 8 9 10 13 15 20Delay (ms)

0

50

100

150

200

250

Max

imum

Osc

illat

ions

Am

plit

ude

kc =12kc =6

kc =2

STN oscillations magnitude as a

function of acquisition/processing

delays.

A. Chaillet (L2S) Spatio-temporal oscillations attenuation GdR BioComp 2018 28 / 39

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Homogeneous control signal

In practice (e.g. optogenetics), the whole STN receives the samestimulation signal: u(t) = −

∫Ω α′(r)x1(r , t)dr .

Measure of heterogeneity: H(q) :=√∫

Ω

∫Ω(q(r)− q(r ′))2dr ′dr .

Proposition: Homogeneous feedback [Chaillet et al. 2017]

Under the same assumptions, consider any k ≥ k∗. Assume that theactivation functions Si are bounded and that the delay distributions di arehomogeneous (di (r , r

′) = d∗i ). Then there exist ν1, ν2 ∈ K∞ such that

lim supt→∞

‖x(t)‖F ≤ ν1 (H(w11) +H(w12)) + ν2 (H(α)) .

Magnitude of remaining oscillations “proportional” to heterogeneityof STN synaptic weights and stimulation impact

Requires space-independent delays.

A. Chaillet (L2S) Spatio-temporal oscillations attenuation GdR BioComp 2018 29 / 39

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Homogeneous control signal

In practice (e.g. optogenetics), the whole STN receives the samestimulation signal: u(t) = −

∫Ω α′(r)x1(r , t)dr .

Measure of heterogeneity: H(q) :=√∫

Ω

∫Ω(q(r)− q(r ′))2dr ′dr .

Proposition: Homogeneous feedback [Chaillet et al. 2017]

Under the same assumptions, consider any k ≥ k∗. Assume that theactivation functions Si are bounded and that the delay distributions di arehomogeneous (di (r , r

′) = d∗i ). Then there exist ν1, ν2 ∈ K∞ such that

lim supt→∞

‖x(t)‖F ≤ ν1 (H(w11) +H(w12)) + ν2 (H(α)) .

Magnitude of remaining oscillations “proportional” to heterogeneityof STN synaptic weights and stimulation impact

Requires space-independent delays.

A. Chaillet (L2S) Spatio-temporal oscillations attenuation GdR BioComp 2018 29 / 39

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Homogeneous control signal

In practice (e.g. optogenetics), the whole STN receives the samestimulation signal: u(t) = −

∫Ω α′(r)x1(r , t)dr .

Measure of heterogeneity: H(q) :=√∫

Ω

∫Ω(q(r)− q(r ′))2dr ′dr .

Proposition: Homogeneous feedback [Chaillet et al. 2017]

Under the same assumptions, consider any k ≥ k∗. Assume that theactivation functions Si are bounded and that the delay distributions di arehomogeneous (di (r , r

′) = d∗i ). Then there exist ν1, ν2 ∈ K∞ such that

lim supt→∞

‖x(t)‖F ≤ ν1 (H(w11) +H(w12)) + ν2 (H(α)) .

Magnitude of remaining oscillations “proportional” to heterogeneityof STN synaptic weights and stimulation impact

Requires space-independent delays.

A. Chaillet (L2S) Spatio-temporal oscillations attenuation GdR BioComp 2018 29 / 39

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Homogeneous control signal

In practice (e.g. optogenetics), the whole STN receives the samestimulation signal: u(t) = −

∫Ω α′(r)x1(r , t)dr .

Measure of heterogeneity: H(q) :=√∫

Ω

∫Ω(q(r)− q(r ′))2dr ′dr .

Proposition: Homogeneous feedback [Chaillet et al. 2017]

Under the same assumptions, consider any k ≥ k∗. Assume that theactivation functions Si are bounded and that the delay distributions di arehomogeneous (di (r , r

′) = d∗i ). Then there exist ν1, ν2 ∈ K∞ such that

lim supt→∞

‖x(t)‖F ≤ ν1 (H(w11) +H(w12)) + ν2 (H(α)) .

Magnitude of remaining oscillations “proportional” to heterogeneityof STN synaptic weights and stimulation impact

Requires space-independent delays.

A. Chaillet (L2S) Spatio-temporal oscillations attenuation GdR BioComp 2018 29 / 39

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Homogeneous control signalSketch of proof

1 Considering W (x1(t)) = H1(x1(t))2, show that

H(x1(t)) ≤ H(x1(t0))e−(t−t0)/τ∗1 + c (H(w11) +H(w12) +H(α)) .

2 Evaluate the difference between the nominal and uniform control laws:∫Ω

(∫Ωα′(r ′)x1(t, r ′)dr ′ − x1(t, r)

)2

dr ≤ cH(x1(t))2.

3 Exploit the “asymptotic gain property” induced by ISS.

A. Chaillet (L2S) Spatio-temporal oscillations attenuation GdR BioComp 2018 30 / 39

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Homogeneous control signalSketch of proof

1 Considering W (x1(t)) = H1(x1(t))2, show that

H(x1(t)) ≤ H(x1(t0))e−(t−t0)/τ∗1 + c (H(w11) +H(w12) +H(α)) .

2 Evaluate the difference between the nominal and uniform control laws:∫Ω

(∫Ωα′(r ′)x1(t, r ′)dr ′ − x1(t, r)

)2

dr ≤ cH(x1(t))2.

3 Exploit the “asymptotic gain property” induced by ISS.

A. Chaillet (L2S) Spatio-temporal oscillations attenuation GdR BioComp 2018 30 / 39

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Homogeneous control signalSketch of proof

1 Considering W (x1(t)) = H1(x1(t))2, show that

H(x1(t)) ≤ H(x1(t0))e−(t−t0)/τ∗1 + c (H(w11) +H(w12) +H(α)) .

2 Evaluate the difference between the nominal and uniform control laws:∫Ω

(∫Ωα′(r ′)x1(t, r ′)dr ′ − x1(t, r)

)2

dr ≤ cH(x1(t))2.

3 Exploit the “asymptotic gain property” induced by ISS.

A. Chaillet (L2S) Spatio-temporal oscillations attenuation GdR BioComp 2018 30 / 39

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Homogeneous control signalSimulations

0 0.5 1Time (s)

0

50

100

150

200Fr

eque

ncy

(sp/

s)

0 0.5 1Time (s)

-250

-200

-150

-100

-50

0

50

100

150

200

u(r,t

)

Efficient attenuation of pathological oscillations

using homogeneous feedback on STN.

A. Chaillet (L2S) Spatio-temporal oscillations attenuation GdR BioComp 2018 31 / 39

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1 Context and motivations

2 Spatio-temporal rate model for STN-GPe

3 ISS for delayed spatio-temporal dynamics

4 Stabilization of STN-GPe by proportional feedback

5 Adaptive control for selective disruption

6 Conclusion and perspectives

A. Chaillet (L2S) Spatio-temporal oscillations attenuation GdR BioComp 2018 32 / 39

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Selective disruption in a targeted frequency band

Unlike β-oscillations, transient γ-oscillations(30-80Hz) in STN are believed to be pro-kinetic

The proportional stimulation attenuates alloscillations, regardless of their frequency

A possible solution: adaptive control.

[Bolam et al. 2009]

A. Chaillet (L2S) Spatio-temporal oscillations attenuation GdR BioComp 2018 33 / 39

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Selective disruption in a targeted frequency band

Unlike β-oscillations, transient γ-oscillations(30-80Hz) in STN are believed to be pro-kinetic

The proportional stimulation attenuates alloscillations, regardless of their frequency

A possible solution: adaptive control.

[Bolam et al. 2009]

A. Chaillet (L2S) Spatio-temporal oscillations attenuation GdR BioComp 2018 33 / 39

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Selective disruption in a targeted frequency band

Unlike β-oscillations, transient γ-oscillations(30-80Hz) in STN are believed to be pro-kinetic

The proportional stimulation attenuates alloscillations, regardless of their frequency

A possible solution: adaptive control.

[Bolam et al. 2009]

A. Chaillet (L2S) Spatio-temporal oscillations attenuation GdR BioComp 2018 33 / 39

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Adaptive control for selective disruption

Modification of the stimulation law:

u = −kx1

τ k = z − εk.

z : intensity of STN activity in the β-band

ε > 0: parameter inducing decrease of the gain k when opportune

τ : time constant defining the response speed to pathologicaloscillations.

A. Chaillet (L2S) Spatio-temporal oscillations attenuation GdR BioComp 2018 34 / 39

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Adaptive control for selective disruptionAveraged model (no spatial dynamics):

τ1x1(t) = −x1(t) + S1

(c11x1(t − δ11)− c12x2(t − δ12) + u(t)

)(5a)

τ2x2(t) = −x2(t) + S2

(c21x1(t − δ21)− c22x2(t − δ22)

). (5b)

Theorem: Adaptive control [Or lowski et al. 2018]

Let Si be bounded and with maximum slope `i > 0 and assume thatc22 < 1/`2. Then there exists ν ∈ K∞ such that, given any ε > 0, thesolutions of (5) in closed loop with the adaptive law u = −kx1 withτ k = |x1| − εk satisfy

lim supt→∞

|x(t)| ≤ ν(ε).

Arbitrary reduction of oscillations

Ongoing work: τ k = z − εk and extension to neural fields.

A. Chaillet (L2S) Spatio-temporal oscillations attenuation GdR BioComp 2018 35 / 39

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Adaptive control for selective disruptionAveraged model (no spatial dynamics):

τ1x1(t) = −x1(t) + S1

(c11x1(t − δ11)− c12x2(t − δ12) + u(t)

)(5a)

τ2x2(t) = −x2(t) + S2

(c21x1(t − δ21)− c22x2(t − δ22)

). (5b)

Theorem: Adaptive control [Or lowski et al. 2018]

Let Si be bounded and with maximum slope `i > 0 and assume thatc22 < 1/`2. Then there exists ν ∈ K∞ such that, given any ε > 0, thesolutions of (5) in closed loop with the adaptive law u = −kx1 withτ k = |x1| − εk satisfy

lim supt→∞

|x(t)| ≤ ν(ε).

Arbitrary reduction of oscillations

Ongoing work: τ k = z − εk and extension to neural fields.

A. Chaillet (L2S) Spatio-temporal oscillations attenuation GdR BioComp 2018 35 / 39

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Adaptive control for selective disruptionAveraged model (no spatial dynamics):

τ1x1(t) = −x1(t) + S1

(c11x1(t − δ11)− c12x2(t − δ12) + u(t)

)(5a)

τ2x2(t) = −x2(t) + S2

(c21x1(t − δ21)− c22x2(t − δ22)

). (5b)

Theorem: Adaptive control [Or lowski et al. 2018]

Let Si be bounded and with maximum slope `i > 0 and assume thatc22 < 1/`2. Then there exists ν ∈ K∞ such that, given any ε > 0, thesolutions of (5) in closed loop with the adaptive law u = −kx1 withτ k = |x1| − εk satisfy

lim supt→∞

|x(t)| ≤ ν(ε).

Arbitrary reduction of oscillations

Ongoing work: τ k = z − εk and extension to neural fields.

A. Chaillet (L2S) Spatio-temporal oscillations attenuation GdR BioComp 2018 35 / 39

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Adaptive control for selective disruptionAveraged model (no spatial dynamics):

τ1x1(t) = −x1(t) + S1

(c11x1(t − δ11)− c12x2(t − δ12) + u(t)

)(5a)

τ2x2(t) = −x2(t) + S2

(c21x1(t − δ21)− c22x2(t − δ22)

). (5b)

Theorem: Adaptive control [Or lowski et al. 2018]

Let Si be bounded and with maximum slope `i > 0 and assume thatc22 < 1/`2. Then there exists ν ∈ K∞ such that, given any ε > 0, thesolutions of (5) in closed loop with the adaptive law u = −kx1 withτ k = |x1| − εk satisfy

lim supt→∞

|x(t)| ≤ ν(ε).

Arbitrary reduction of oscillations

Ongoing work: τ k = z − εk and extension to neural fields.

A. Chaillet (L2S) Spatio-temporal oscillations attenuation GdR BioComp 2018 35 / 39

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Adaptive control for selective disruptionSimulation: delayed neural fields

A. Chaillet (L2S) Spatio-temporal oscillations attenuation GdR BioComp 2018 36 / 39

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1 Context and motivations

2 Spatio-temporal rate model for STN-GPe

3 ISS for delayed spatio-temporal dynamics

4 Stabilization of STN-GPe by proportional feedback

5 Adaptive control for selective disruption

6 Conclusion and perspectives

A. Chaillet (L2S) Spatio-temporal oscillations attenuation GdR BioComp 2018 37 / 39

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Conclusion and perspectives

What we have so far:I A framework for ISS of delayed spatio-temporal dynamicsI A spatio-temporal model of STN-GPe generating β-oscillationsI A condition for robust stabilizability by proportional feedback on STNI An adaptive strategy for selective oscillations disruption.

What remains to be done:I Increased robustness to acquisition/processing delays: in the spirit of

[Haidar et al. 2016]I More precise modeling of actuator dynamicsI Indirect (cortical) stimulationI Experimental validation.

A. Chaillet (L2S) Spatio-temporal oscillations attenuation GdR BioComp 2018 38 / 39

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Conclusion and perspectives

What we have so far:I A framework for ISS of delayed spatio-temporal dynamicsI A spatio-temporal model of STN-GPe generating β-oscillationsI A condition for robust stabilizability by proportional feedback on STNI An adaptive strategy for selective oscillations disruption.

What remains to be done:I Increased robustness to acquisition/processing delays: in the spirit of

[Haidar et al. 2016]I More precise modeling of actuator dynamicsI Indirect (cortical) stimulationI Experimental validation.

A. Chaillet (L2S) Spatio-temporal oscillations attenuation GdR BioComp 2018 38 / 39

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Many thanks to my collaborators

Georgios Detorakis (L2S)

Jakub Or lowski (L2S)

Stephane Palfi (H. Mondor hospital)

Suhan Senova (H. Mondor hospital)

Mario Sigalotti (INRIA - JLL laboratory)

Alain Destexhe (CNRS - UNIC).

A. Chaillet (L2S) Spatio-temporal oscillations attenuation GdR BioComp 2018 39 / 39


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