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The Movement System

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Basal Ganglia

Interconnected nuclei Caudate

Putamen

Globus pallidus Nucleus accumbens

Olfactory tubercle

Motor & non-

Corpus striatum Caudate

Putamen

Globus pallidus Striatum

Caudate

Putamen

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Striatum

CaudateHead bulges

into lat.

Ventricle

Degenerativediseases, akaHuntingtons,bulge is lost

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Caudate

Head anteriorhorn

Tail inferiorhorn

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Striatum

2 types of neuronsSpiny projection neurons

Silent at rest

Discharge when stimulated

Lost in Huntingtons Chorea

i.e. lose output of striatum

Aspiny - interneurons

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Spiny Neuron Inputs

CorticalDistal dendrites

Local inputs

Proximal dendrites

Soma

Inputs nearer to cellbody modulate far

inputs.

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Input to Striatum

Direct Corticostriate

projection Almost all cortical areas

3 distinct zones Sensorimotor

Putamen

Associative Caudate

Limbic Nucleus accumbens

Indirect

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Output from Striatum

Substantia Nigra Globus pallidus

Nucleus accumbens

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Globus Pallidus & Substantia Nigra

Globus pallidus Arm & leg

representation

Substantia nigra Head & neck

representation

Multipolar projectionneurons

90% input fromstriatum

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Striatopallidal Pathways Direct

Striatum to internal segment

of globus pallidus &substantia nigra parsreticulata

Disinhibits thalamus Increase motor activity Hyperkinesia Huntingtons

chorea

Indirect Striatum to external globus

pallidus to subthalamicnucleus to GPi & SNr

Inhibit thalamus Decrease motor activity

Enhanced activation Parkinsons hypokinesia

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GPi/SNr Output

Major output Thalamus

Ventral anterior

Ventral lateral

Dorsomeidal Intralaminar

Fields of Forel

Minor output S.C.

Habenular nucleus

Reticular formation Spinal cord

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Subthalamic Nucleus

Inputs Cortex

Motor, premotor,supplementary motor

areas

GPe

Thalamus

SNc

Dorsal Nucleus ofRaphe

Reticular input

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Subthalamic Nucleus Outputs

GPeGPi

SNr Lesions

Ballism Violent, involuntary

movements

Deep Brain StimTreatment of

Parkinsons

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Corticostriatothalamocortical Loops

5 parallel loopsMotor

Oculomotor

Dorsolateral prefrontalLateral orbitofrontal

Limbic

Cortical area -> striatum -> globus pallidus-> thalamus -> back to cortical area

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Motor Loop

PutamenArm, leg, face

inputs

Target location

Limb kinematics

Muscle pattern

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Oculomotor Loop

Caudate nucleus Eye movements

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Dorsolateral Prefrontal Loop

Caudate nucleus

DLPC Possibly unique to

humans

Damage schizophrenia

TMS treat

depression

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Lateral Orbitofrontal Loop

Caudate nucleus

Lateral orbitofrontalPlanning complex

behaviors

Personality

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Limbic Loop

Caudate, Putamen,Nucleusaccumbens,

olfactory tubercle

Implicated in

schizophrenia

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Split Circuitry

Closed loopsPrevious loops

Open loops

Allows for crosscommunication

Affects a corticalarea that does notproject to striatum

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Basal Ganglia Functions Motor

Automatic execution oflearned motor plan

Preparation for

movement Cortically initiated

Damage slower, less

automatic, lessaccurate movements Presumably from

cortical mechanism only

Tics & Tourettes

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Basal Ganglia Functions

Gating Sensory Information for MotorControl

Hypokinesia Parkinsons

Decreased input of sensory information

Hyperkinesia Huntingtons

Increased access to sensory information

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Basal Ganglia Functions Cognitive

Dorsolateral prefrontal loop Deficits

Spatial memory

Episodic memory Semantic information

Schizophrenia

Huntingtons chorea cognitive disturbances

Parkinsons disease cognitive disturbances

Lateral Orbitofrontal loop

Lesions Obsessive-compulsive disorder (OCD)

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Basal Ganglia Functions

Emotional/MotivationLimbic loop

Schizophrenia

Depression

Basal ganglia

Decrease in size in bipolar disorder

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Basal Ganglia: Clinical Correlates

Hyperkinetic disorders (continued)Athetosis

Greek for without position

Slow, writhing, continuous, worm-like movementsof the fingers.

Lesion of putamen

Ballism Greek for jump

Violent involuntary movements of the limbs

Often one side of body hemiballismus

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Basal Ganglia: Clinical Correlates

Hyperkinetic disorders (continued)

Dystonia

Greek for bad tone

Twisting, slow, contorting, involuntary movement

Sustained and repetitive

Focal

One body part, e.g. hand

Writers cramp Segmental

2 or more adjacent body parts, e.g. head and neck

Torticollis involuntary turning/tilting of head

Generalized

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Basal Ganglia: Clinical Correlates Hyperkinetic disorders (continued)

Tic Brief, sudden, rapid, intermittent movements or

sounds.

Simple Contractions of only one group of muscles, e.g. eyeblinks

Complex Coordinated sequence of movements, e.g. eyeblink and

shoulder shrug

Transient days to weeks

Chronic months to years

Prelude to Tourettes

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Basal Ganglia: Clinical Correlates Hyperkinetic disorders (continued)

Tourettes Motor and verbal tics.

Shrunken caudate

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