David J Brooks

..It is concluded that functional imaging provides a valuable adjunct to clinical assessment when judging the efficacy of neuroprotective approaches to PD...

..It is concluded that, although neuroimaging biomarkers provide valuable supportive data alongside clinical assessments, it is not possible to use them as surrogate markers...

..Finally, the value of functional imaging as a biomarker for following the progression of PD and for understanding mechanisms of dementia when present is debated...

..In addition, neuronal loss in PD is associated with microglial activation. The role of microglia in driving the disease process remains uncertain. This review presents and discusses current findings in these areas...

..The contribution of inflammatory processes to the pathology of PD is discussed, as are the various possible mechanisms that lead to coexistent dementia and depression...

..The mean daily dose of levodopa did not increase over the 5-year follow-up period. Long-term therapy with levodopa/DDCI and entacapone was well-tolerated...

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..e. levodopa/DDCI and entacapone). Stalevo was well tolerated and safe when substituted for levodopa DDCI preparations...

..Anti-amyloid strategies could be a relevant approach for slowing dementia in a number of DLB and PDD cases...

..In this review, the insight that PET has given us concerning the role of dopamine in motor control is presented, and the functional substrates underlying PD symptomatologies are discussed...

..PET currently has the greater spatial resolution and provides the added advantages that it also allows extra-striatal dopaminergic function to be monitored...

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..Finally, PET can detect widespread brain inflammation in PD. This review discusses the role of structural and functional imaging for diagnosing and managing different parkinsonian syndromes...

..Novel markers of amyloid plaque load will also help clarify the etiology of dementia in PD...

..It is concluded that in the future functional imaging will provide a valuable adjunct to clinical assessment when judging the efficacy of putative neuroprotective approaches to PD...

..Finally the discordance between the development of functional changes in PD and Braak staging is highlighted...

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..It is an early event in HD pathophysiology and could contribute to the impairment in neuropsychological performance in these patients...

..PK PET may be a useful marker of active subclinical disease and a means of investigating the efficacy of neuroprotection strategies in PGCs...

..The reference-to-target ratio and the Logan graphical approach were significantly less reliable and less sensitive...

..MMSE scores in AD subjects correlated with levels of cortical microglial activation but not with amyloid load. The inverse correlation between MMSE and microglial activation is compatible with a role of microglia in neuronal damage...

..These findings suggest that parkin patients and IPD patients with similar striatal dysfunction have different patterns of monoaminergic involvement, with more widespread dysfunction in IPD...

..Cortical reductions in D2 binding may contribute to the behavioural problems reported in parkin patients...

..86) but unacceptably low for VOI-derived VD estimates at the low doses of injected radioactivity (0.24/0.04). Our data can inform the choice of methodology for a given biological problem...

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..Parkin-positive patients appear to have a greater susceptibility to the exposure to dopaminergic medication than IPD patients, which in turn might be an indirect effect of their genetic mutation...

..In contrast, mesocortical dopaminergic transmission appears well preserved in early PD patients...

..11C](R)-PK11195 PET, therefore, may help in characterizing in vivo the underlying disease activity in PSP...

..Although subclinical reductions of striatal (18)F-dopa uptake are common in carriers of a single parkin mutation their slow rate of progression suggests that few if any of these will develop clinical parkinsonism...

..Achieving a normal striatal serotonin/dopamine transporter ratio following transplantation of fetal tissue or stem cells should be necessary to avoid the development of graft-induced dyskinesias...

..INTERPRETATION: This provides evidence that links sensitization of ventral striatal circuitry in humans to compulsive drug use...

..1%; levodopa, -22.9%; 95% CI, 4.24-13.3), but the decrease was significantly lower with ropinirole compared with levodopa (p < 0.001). Ropinirole is associated with slower progression of PD than levodopa as assessed by (18)F-dopa PET...

..To our knowledge, this is the first time such a centralized approach has been employed with (18)F-DOPA PET and this descriptive basic science article outlines the methods used...

..In contrast to PD, there was no evidence of early compensatory increases in regional 18F-dopa uptake...

..Finally, our data provide evidence that long-term immunosuppression can be withdrawn without interfering with graft survival or the motor recovery induced by transplantation...

..Our observations suggest strategies for avoiding and treating graft-induced dyskinesias that result from cell therapies for Parkinson's disease with fetal tissue or stem cells...

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..These data suggest that pathologically activated microglia in AST and other areas related to cognitive function, maybe better predictors of clinical onset and stresses the importance of early cognitive assessment in HD...

..When assessing the efficacy of novel neuroprotective agents on nigrostriatal dysfunction in PD, (18)F-dopa PET could provide supplementary information concerning function of extrastriatal monoaminergic structures...

..Full quantification with an image-independent input should ideally be used in the evaluation of FMZ PET; at least in TLE, intrasubject correlations do not predict equivalent clinical usefulness...

..We present a comprehensive assessment of thalamic and basal ganglia volumetric and geometric data in both native and stereotaxic spaces. Probabilistic maps in MNI/ICBM152 space will allow accurate localization in group analyses...

..This study provides direct human in vivo evidence for changes in opioid receptor availability over a time course of hours following spontaneous seizures, emphasizing an important role of the opioid system in seizure control...

..Applications include probabilistic determination of location in group studies, automatic labeling of new scans, and detection of anatomical abnormalities in patients...

..Further longitudinal studies are needed to fully elucidate this link...

..Our data also show that the capacity to release normal DA levels in prefrontal areas after a pharmacological challenge is preserved in severe stages of the disease...

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..The absence of significant longitudinal changes suggests that microglia are activated early in the disease process, and levels then remain relatively static, possibly driving the disease via cytokine release...

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..This probably reflects both contributions from other affected brain structures and high variance in these measures...

..Patlak analysis of [11C]PIB binding was the least reproducible...

..The red nucleus, subthalamus, ventral thalamus and pineal gland were also eventually involved. These findings provide a further basis for understanding the complex pathophysiology of PD in vivo and complement pathological studies...

..The aim of this study was to investigate the effect of acute HCV infection upon cerebral function and microglial cell activation in HIV-infected individuals...

..They support the hypothesis that blockade of glutamate transmission may have a place in the management of disabling dyskinesias in Parkinson's disease...

..We therefore discuss a possible role for opioids in the pathophysiology of RLS with respect to sensory and motor symptoms...

..In this study, we investigate whether an inflammatory response to TBI persists, and whether this response relates to structural brain abnormalities and cognitive function...

..The subclinical loss of striatal dopamine storage capacity found in the PARK6 carriers implies that the unidentified gene on the short arm of chromosome 1 exhibits either haploinsufficency or a dominant negative effect...

..The regions implicated are the rostral raphe nuclei and its connections to limbic and cognitive areas. It is conceivable that 5-HT agents could help alleviate abnormal changes in BMI in PD...

..However, the two carriers scanned twice showed no progression over a 7-year period. The slower rate of disease progression in parkin patients may explain the near normal longevity of these patients with young onset parkinsonism...

..These findings confirm that striatal dopamine release is a component of movement sequencing and show that dopamine release can be detected in early Parkinson's disease during a behavioural manipulation...

..With over 300,000 patient-years of exposure, levodopa combined with entacapone can be considered safe and well tolerated...

..0059 +/- 0.0028) in the absence of this drug. These findings are compatible with clinical doses of tolcapone having a significant blocking effect on peripheral and central COMT but not DDC activity in PD...

..We conclude that aberrant opioid transmission is unlikely to be present in DYT1-PTD and altered opioid transmission is not a common mechanism underlying all disorders of involuntary movement...

..We interpret these relative increases in cerebellar activation as evidence for the presence of compensatory neural mechanisms in unmedicated PD patients...

..These findings suggest that in PD there is impairment of catecholamine release from peripheral sympathetic presynaptic terminals, which correlates with motor impairment...

..Our results suggest the atypical parkinsonian phenotype seen in African-Caribbean and Indian patients represents a levodopa-refractory form of PD separate from MSA or PSP in most patients...

..Our results provide further evidence of dopaminergic dysfunction in the hypothalamus in PD, and this may contribute to the development of sleep, endocrine and autonomic disorders...

..Further longitudinal studies are required to elucidate the significance of these findings as they may have important public health implications...

..In contrast, relief of parkinsonian tremor and axial symptoms is not related to striatal synaptic dopamine levels and presumably occurs via extrastriatal mechanisms...

..This is the first in vivo documentation of cortical dopaminergic deficiency in PSP. Reduced striatal (18)F-dopa uptake in susceptible relatives may predict later clinical disease...

..In summary, (18)F-dopa PET can be employed to objectively evaluate the effect of potential neuroprotective agents on dopaminergic function...

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..Its potential applications range from the automatic labeling of new scans to the detection of anatomical abnormalities in patients. Further data can be extracted from the atlas for the detailed analysis of individual structures...

..These findings imply that strategies to increase brain level of serotonin would be a rational approach for relieving fatigue symptoms in Parkinson's disease and may also be relevant to alleviating fatigue in other clinical conditions...

..This review focuses on these recent advances in neuroimaging technology and their use for the diagnosis and assessment of PD and other parkinsonian disorders...

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..This study provides evidence for differences in the distribution of reduced cortical [11C]flumazenil binding in homD90A compared with sALS patients. We hypothesize that this might reflect differences in cortical neuronal vulnerability...

..The other patient did not improve clinically or radiologically. Our results indicate that striatal transplantation in HD may be beneficial but further studies are needed to confirm this...

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..They are, therefore, a potential therapeutic target in both AD and its prodrome amnestic mild cognitive impairment (MCI)...

..This study aimed to investigate the contribution of the dopaminergic system to performance on two executive tasks using (18)F-6-fluorodopa positron emission tomography ((18)F-dopa PET) in PD subjects with early cognitive changes...

..To investigate the association between brain amyloid load in Alzheimer disease (AD) measured by [11C]PIB-PET, regional cerebral glucose metabolism (rCMRGlc) measured by [18F]FDG-PET, and cognition...

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..The criteria and each of the three imaging techniques mentioned above were reviewed, and the results of that meeting are presented...

..INTERPRETATION: In-vivo detection of increased [11C](R)-PK11195 binding in Alzheimer-type dementia, including mild and early forms, suggests that microglial activation is an early event in the pathogenesis of the disease...

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..Providing an indicator of disease activity, [11C](R)-PK11195 PET can thus be used to characterize the in vivo neuropathology of MSA...

..The rarity of reports of familial PSP may be attributed in part to an inability to detect subclinical disease in affected relatives who subsequently die before symptoms clinically develop...

..The underlying pathological mechanisms leading to tremor, coexistent dementia and depression in PD are considered and the role of imaging as a biomarker for testing neuroprotective agents debated...

..CONCLUSION: Our findings suggest dissociable effects of dopamine medication withdrawal on cognitive processes putatively mediated by dorsal and ventral striatal regions...

..This result indicates for the first time that in humans the mirror system is biologically tuned. This system appears to be the neural substrate for biological preference during action coding...

..This is the first direct evidence that STN stimulation significantly alters pallidal coupling with prefrontal, cingulate, and temporal cortices during performance of a task that requires response selection under competition...

..These data indicate that 18F-DOPA PET can be used with detailed, anatomically based ROIs as a tool for in vivo analysis of regional changes in monoamine neuron systems throughout the brain in Parkinson's disease and other disorders...

..Despite an ongoing disease process, grafted neurons can thus continue for a decade to store and release dopamine and give rise to substantial symptomatic relief...

..Patients with amnestic mild cognitive impairment (MCI) represent an important clinical group as they are at increased risk of developing Alzheimer disease (AD). (11)C-PIB PET is an in vivo marker of brain amyloid load...

..Our findings suggest that the two treatment methods may lead to symptomatic relief via both common and different sites of action...

..This could represent a shift to the declarative memory system in Parkinson's disease during performance of the TOL task, possibly resulting from insufficient working memory capacity within the frontostriatal system...

..This suggests, therefore, that Parkinson's disease is a monoaminergic neurodegenerative disorder...