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M 19

SECOArD IhTERNATIONAL. CONGRESS OF MOVEMENT DISORDERS

PET: motor function and dysfunction

David J BROOKS

MRC Cyclotron Unit, Hammersmith Hospital, London, UK

I3y monitoring focal changes i n regional cerebral

hlootl flow (rCBF) while subjects perform

Ipitt ;idignns, PET can demonstrate the patterns of

tc$ion:ii cci-ebrol activation associated with

ekecuting, learning, and selecting motor actions.

11 c:in RISO reve;iI abnormalities in these patterns

o i iictiv:itioii i n patients with pyramidal and

chitapyraniidal syndromes or involuntary

inoveiiictits I n normal subjects paced

\tereotyped a m movements activate contralateral

setisminioror (SMC) and lateral preniotor (PMC)

cot tcs. c a ~ I : i l ;interior cingulate, supplementary

iinolor ;ire8 (SMA), lentiform nucleus, bilateral

piit-tetiil association areas, and ipsilateral

c'i'rehelluni. Free selection of movement results in

iiddittonid activation of rostra1 anterior cingtrlate

iind SMA, and dorsolateral prefrontal cortex.

I'atients with pyramidal tract dysfunction due

in it pi-evious stroke or amyotrophic lateral

derosis (ALS), show abnormal recruitment of

ipsilateral S M C when performing arm

iiiovemeiirs. ALS patients activate face as well as

l i ~ i i i ai-eiis of contralateral SMC, and show

tinpiitred iictiviition of cingulate. SMA. and

Ipret'i-onta! areas. Parkinson's disease (PD)

patients activate contralateral SMC and PMC

normally when performing internally generated

actions, and do not recruit ipsilateral SMC in

contrast to patients with pyramidal tract lesions.

These patients, however, show impaired

activation of contralateral lentiform nucleus,

SMA, anterior cingulate. and prefrontal cortex.

Ad ni i n i st trii t i o n of aponiorp h i n e res t i Its i n

\i~titIic;iiitIy incre;ised SMA 'tctiv;i[ioii i i i PD i n

p ; i ~ ~ l l e l with improvement 111 niotor (Itiic[ioii

P;iitcnts with involuntary movement

disorders show regional overactivity of selective

stritctitres. Dystonia patients abnormally activate

i lie co in t rii lateral len t i form nucleus when

cAIXLltiiig motor tasks while essential tremor

p;irients show abnormal bilateral cerebellar

;ictivity both i n the presence and absence of their

trctnior.

111 sitmm;iry, PET is a powerful too! for

tlcicrminiiig the inatitre of rhz cerebral networks

involved i n selecting and executing tiiotor actions

:iiiti demonstrating the functional disorder i n

these networks i n akinetic and hyperkinetic

syndromes.

Movement Disorders, Vol. 7, Supplement I (1992)