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Action verbs are critically embodied in motor brain networks. In Parkinson's disease (PD), damage to the latter compromises access to such words. However, patients are not fully incapable of processing them, as their performance is far from floor level. Here we tested the hypothesis that action-verb processing in PD may rely on alternative disembodied semantic circuits. Seventeen PD patients and 15 healthy controls listened to action verbs and nouns during functional MRI scanning. Using cluster-mass analysis with a permutation test, we assessed task-related functional connectivity considering seeds differentially engaged by action and non-action words (namely, putamen and M1 versus posterior superior temporal lobe, respectively). The putamen seed showed reduced connectivity within the basal ganglia in patients for both lexical categories. However, only action verbs recruited different cortical networks in each group. Specifically, the M1 seed exhibited more anterior connectivity for controls and more posterior connectivity for patients, with no differences in the temporal seed. Moreover, the patients' level of basal ganglia atrophy positively correlated with their reliance on M1-posterior connectivity during action-verb processing. PD patients seem to have processed action verbs via non-motor cortical networks subserving amodal semantics. Such circuits may afford alternative pathways to process words when default embodied mechanisms are disturbed. Moreover, the greater the level of basal ganglia atrophy, the greater the patients' reliance on this alternative route. Our findings offer new insights into differential neurofunctional mechanisms recruited to process action semantics in PD.

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We previously identified in two families with early onset Parkinson's Disease (PD) from the isolated population of Antioquia (Colombia), a parkin Cys212Tyr substitution caused by a G736A mutation. This mutation was subsequently observed in a Spanish family, suggesting that it could have been taken to Antioquia by Spanish immigrants. Here we screened for the G736A mutation in additional Antioquian early onset PD cases and used haplotype analysis to investigate the relationship between Spanish and Antioquian G736A chromosomes. We confirmed the occurrence of an extensive founder effect in Antioquia. Thirteen individuals (10 homozygotes) from seven nuclear families were identified with the G736A mutation. Genealogical investigations demonstrated the existence of shared ancestors between six of these families four to five generations ago and no evidence of Spanish ancestry during this period. A second parkin mutation (a duplication of exon 3), was detected in the three G736A heterozygote carriers. Haplotype data exclude a recent common ancestry between the Spanish and Antioquian patients studied here and is consistent with the introduction of the G736A mutation in Antioquia during early colonial times (about 16 generations ago).

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Our objective was to estimate the prevalence of Parkinson's disease (PD) and Parkinsonism (Ps) in Antioquia (Colombia), using the Capture-Recapture method. The two biggest institutions for attending neurological patients in Antioquia were selected as sources for the use of the Capture-Recapture method. Prevalences of PD (PPD) and Ps (PPs) were estimated according to the following expression: PPD (or PPs) = n/Nl105. The number of cases (n) of PD (or Ps), n = a + b + c + d, where a = cases identified from the two sources, b = cases identified only in the first source, c = cases identified only in the second source, and d = nondetected cases from any source = bc/a. The projected Antioquian population for the year 2000 was used as denominator. Information obtained between January 1, 1996, and December 31, 2000, was reviewed in order to identify the clinical records of all patients that fulfilled the Ps or PD criteria. General prevalence of PD in Antioquia was 30.7/100.000 (C195% = 29.2-32.2), and that of Ps was 42.1/100.000 (CI95% = 40.3-43.8). Prevalence of PD in people older than 50 years was 176.4/100.000 (CI95% = 166.6-186.3) and that of Ps was of 339.6/100.000 (C195% = 326.0-353.2). Ps and PD prevalences in Antioquia were lower than the figures reported by the National Neuroepidemiologic Study (470/100.000) and similar to the estimated prevalence of these diseases in Caucasian populations (80 to 270/100.000). These findings evidence the great variability of PD prevalence in different regions; therefore, a nationwide study is necessary to determine the prevalence of PD and Ps in Colombia.

Mutations in parkin are implicated in the pathogenesis of autosomal recessive juvenile parkinsonism (AR-JP) disease. We show that homozygote Cys212Tyr parkin mutation in AR-JP patients renders lymphocytes sensitive to dopamine, iron and hydrogen peroxide stimuli. Indeed, dopamine-induced apoptosis by four alternative mechanisms converging on caspase-3 activation and apoptotic morphology: (1) NF-kappaB-dependent pathway; mitochondrial dysfunction either by (2) H(2)O(2) or (3) hydroxyl exposure and (4) increase of unfolded-protein stress. We also demonstrate that 17beta-estradiol and testosterone prevent homozygote lymphocytes from oxidative stressors-evoked apoptosis. These results may contribute to understanding the relationship between genetic and environmental factors and iron in AR-JP.