Impaired mesial frontal and putamen activation in Parkinson's disease: A positron emission tomography study

Abstract

Selection of movement in normal subjects has been shown to involve the premotor, supplementary motor, anterior cingulate, posterior parietal, and dorsolateral prefrontal areas. In Parkinson's disease (PD), the primary pathological change is degeneration of the nigrostriatal dopaminergic projections, and this is associated with difficulty in initiating actions. We wished to investigate the effect of the nigral abnormality in PD on cortical activation during movement. Using C15O2 and positron emission tomography (PET), we studied regional cerebral blood flow in 6 patients with PD and 6 control subjects while they performed motor tasks. Subjects were scanned while at rest, while repeatedly moving a joystick forward, and while freely choosing which of four possible directions to move the joystick. Significant increases in regional cerebral blood flow were determined with covariance analysis. In normal subjects, compared to the rest condition, the free-choice task activated the left primary sensorimotor cortex, left premotor cortex, left putamen, right dorsolateral prefrontal cortex and supplementary motor area, anterior cingulate area, and parietal association areas bilaterally. In the patients with PD, for the free-choice task, compared with the rest condition, there was significant activation in the left sensorimotor and premotor cortices but there was impaired activation of the contralateral putamen, the anterior cingulate, supplementary motor area, and dorsolateral prefrontal cortex. Impaired activation of the medial frontal areas may account for the difficulties PD patients have in initiating movements.

Mapping brain function in freely moving subjects

“…akasthesia, tardive dyskinesia, chorea), cataplexy in narcolepsy, compulsions (e.g. hand washing) in obsessive compulsive disorder, or the study of brain activation during motor activity in deficits syndromes such as Parkinson's disease [114][115][116]. In addition, more multidimensional behavioral challenges could be studied, such as brain activation during social encounters in subjects with different subtypes of schizophrenia or autism, procedural memory in subtypes of dementia, maternal-infant bonding, or structured versus unstructured play activity in subjects with attention deficit disorder.…”

Basal ganglia network mediates the control of movement amplitude

“…This ®nding by itself, however, leaves ambiguity about the anatomical source(s) of the de®cit and thus whether the intact BG are really involved in planning movement extent. Although PD is associated with a relatively circumscribed dopaminergic dennervation of the BG motor circuit' (Wichmann & DeLong, 1996; but see Braak & Braak, 2000), functional abnormalities have been observed not only in the BG and in the frontal cortical areas that are primary recipients of BG out¯ow (Playford et al, 1992;Jahanshahi et al, 1995), but also in other structures including the brainstem, the parietal cortex and the cerebellum (Catalan et al, 1999;Rascol et al, 1997). As a consequence, impaired use of the extent precue in PD could re¯ect a dysfunction of other CNS networks independent of or secondary to the abnormal BG out¯ow known to be associated with PD.…”

Cortical Regions Involved in the Generation of Musical Structures during Improvisation in Pianists

“…Willed actions involve ''free'' choice as well as attention, conscious awareness, and intentionality (Jahanshahi & Frith, 1998). By studying tasks such as finger or hand movements (Lau, Rogers, Ramnani, & Passingham, 2004;Frith, 2000;Playford et al, 1992;Deiber et al, 1991) or number generation (Jahanshahi, Dirnberger, Fuller, & Frith, 2000), and by comparing pseudorandom generation of responses with stereotyped actions, a number of cortical regions involved in free selection have been characterized. These include the dorsolateral prefrontal cortex (DLPFC), medial and lateral premotor areas, and the anterior cingulate cortex.…”