A Preliminary Model For The Role Of The Basal Ganglia In Natural Motor Control And Motor Programming

A preliminary model for the role of the basal ganglia in natural motor control and motor programming MURI Meeting, June 4th, 2002 Steve Massaquoi, Zhi-Hong Mao, Eugene Lim, Munther Dahleh, and Eric Feron

Massachusetts Institute of Technology

Modeling the lower (motor) loop of the basal ganglia in movement • Our model produced reasonable representations of normal and abnormal basal ganglionic functions in lower loop – Cruise movement generation – Dysfunctions in Parkinson’s disease and dystonia

Proposed role of the basal ganglia in regulating cruise movement velocity

-

θ target (t )

+

+

1

+

s

Basal ganglionic − cortical interaction

Neuronal integrator

θ command (t ) θcommand (t )

Plant

Movement

Muscular-skeletal system

θ )(t ) θ (t

θ (t ) θ (t )

Model simulator structure

1.5

2 1.5 V e lo c it y

P o s it io n

1

0.5

1 0.5 0

0

-0 . 5 0

0.5

1

1.5

2

Tim e (s e c )

B G s ig n a ls

10

5

0 0.5

1 Tim e (s e c )

0.5

1 Tim e (s e c )

15

0

0

1.5

2

1.5

2

Dysfunction of the basal ganglia in Parkinson’s disease • Signs of Parkinson’s disease – Tremor at rest – Slowness of movement (bradykinesia) – Rigidity of body

Model simulator structure

1.5

2

1 V e lo c it y

P o s it io n

1

0.5

0

-1

0

-2 0

0.5

1

1.5

2

0

0.5

Tim e (s e c )

1

1.5

2

Tim e (s e c )

15

1 .5

2 1.5 V e lo c it y

P o s it io n

10

0 .5

1 0.5 0

0

-0 . 5 0

0.5

1

1 .5

2

Tim e (s e c )

5

0 0

0.5

1 Tim e (s e c )

1.5

10

5

2 0 0

0.5

1 Tim e (s e c )

0

0.5

1 Tim e (s e c )

15

B G s ig n a ls

B G s ig n a ls

1

1 .5

2

1.5

2

Dysfunction of the basal ganglia in dystonia • Signs of dystonia – Abnormal posture and tremor

Model simulator structure

2

2 1.5 1

V e lo c it y

P o s it io n

1.5

1

0.5

0.5

0

0

-0 . 5 0

1

2

3

0

1

Tim e (s e c )

2

Tim e (s e c ) 1.5

2

15

1.5 V e lo c it y

P o s it io n

1

0.5

1 0.5 0

10 0

-0 . 5 0

0.5

1

1.5

2

Tim e (s e c )

0 0

1

2

10

5

3 0

Tim e (s e c )

0

0.5

1 Tim e (s e c )

0

0.5

1 Tim e (s e c )

15

5 B G s ig n a ls

B G s ig n a ls

3

1.5

2

1.5

2

Modeling the lower (motor) loop of the basal ganglia in movement • Our model produced reasonable representations of normal and abnormal basal ganglionic functions in lower loop – Cruise movement generation – Dysfunctions in Parkinson’s disease and dystonia

Role of the higher (cognitive) loop of the basal ganglia in programmed behavioral tasks • Conflict resolution over access to limited cognitive resources • Switching, brain states transition, and sequence generation • Circuit in higher loop is the same as in lower loop • A toy example

Conclusions and future work • Conclusions – The model is very simple – The model is consistent with the neuronal anatomy of the basal ganglia – The same circuit in the model is able to control cruise movement, to reproduce signs in the Parkinson’s disease and dystonia, and to execute programmed behavioral tasks

• Future work – Self tuning (learning) through reinforcement – Learning cooperative behavior