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1.
Neurobiol Aging ; 136: 78-87, 2024 Apr.
Article in English | MEDLINE | ID: mdl-38330642

ABSTRACT

Assessments of action semantics consistently reveal markers of Parkinson's disease (PD). However, neurophysiological signatures of the domain remain under-examined in this population, especially under conditions that allow patients to process stimuli without stringent time constraints. Here we assessed event-related potentials and time-frequency modulations in healthy individuals (HPs) and PD patients during a delayed-response semantic judgment task involving related and unrelated action-picture pairs. Both groups had shorter response times for related than for unrelated trials, but they exhibited discrepant electrophysiological patterns. HPs presented significantly greater N400 amplitudes as well as theta enhancement and mu desynchronization for unrelated relative to related trials. Conversely, N400 and theta modulations were abolished in the patients, who further exhibited a contralateralized cluster in the mu range. None of these patterns were associated with the participants' cognitive status. Our results suggest that PD involves multidimensional neurophysiological disruptions during action-concept processing, even under task conditions that elicit canonical behavioral effects. New constraints thus emerge for translational neurocognitive models of the disease.


Subject(s)
Parkinson Disease , Semantics , Humans , Male , Female , Evoked Potentials/physiology , Electroencephalography , Parkinson Disease/psychology , Reaction Time/physiology
2.
Qual Quant ; : 1-25, 2023 Jan 10.
Article in English | MEDLINE | ID: mdl-36685055

ABSTRACT

This paper introduces a new method to describe and analyse multidimensional time series based on wavelets. The methodology considers the time series as observations of a functional random variable. The paper generalizes previous research on stock market networks by including asset returns and volume trading as the main variables to study the financial market. The methodology is applied to examine the dynamics and structure of the Nasdaq-100 stock market during the pandemic period 2019/12-2021/12 considering both asset returns and volume trading to model the behaviour of different assets that are part of the index, applying an algorithm that offers better performance than others applied in the clustering literature. The study detects four clusters of firms corresponding with companies sharing common economic activities. The structure of the network reveals a nonlinear relationship between the variables, and the study shows that the main macroeconomic events during the period affect each cluster with different intensity. The change in the patterns of returns and risks and the redistribution of wealth in a highly changing environment are emerging phenomena, which must necessarily be carefully analyzed by public policies, in order to avoid the appearance of bubbles and systemic shocks.

3.
NPJ Parkinsons Dis ; 8(1): 163, 2022 Nov 25.
Article in English | MEDLINE | ID: mdl-36434017

ABSTRACT

Action-concept outcomes are useful targets to identify Parkinson's disease (PD) patients and differentiate between those with and without mild cognitive impairment (PD-MCI, PD-nMCI). Yet, most approaches employ burdensome examiner-dependent tasks, limiting their utility. We introduce a framework capturing action-concept markers automatically in natural speech. Patients from both subgroups and controls retold an action-laden and a non-action-laden text (AT, nAT). In each retelling, we weighed action and non-action concepts through our automated Proximity-to-Reference-Semantic-Field (P-RSF) metric, for analysis via ANCOVAs (controlling for cognitive dysfunction) and support vector machines. Patients were differentiated from controls based on AT (but not nAT) P-RSF scores. The same occurred in PD-nMCI patients. Conversely, PD-MCI patients exhibited reduced P-RSF scores for both texts. Direct discrimination between patient subgroups was not systematic, but it yielded best outcomes via AT scores. Our approach outperformed classifiers based on corpus-derived embeddings. This framework opens scalable avenues to support PD diagnosis and phenotyping.

4.
Front Syst Neurosci ; 13: 47, 2019.
Article in English | MEDLINE | ID: mdl-31616259

ABSTRACT

In the anesthetized cat the correlation between the ongoing cord dorsum potentials (CDPs) recorded from different lumbar spinal segments has a non-random structure, suggesting relatively stable patterns of functional connectivity between the dorsal horn neuronal ensembles involved in the generation of these potentials. During the nociception induced by the intradermic injection of capsaicin, the patterns of segmental correlation between the spontaneous CDPs acquire other non-random configurations that are temporarily reversed to their pre-capsaicin state by the systemic injection of lidocaine, a procedure known to decrease the manifestation of neuropathic pain in both animals and humans. We have now extended these studies and utilized machine learning for the automatic extraction and selection of particular classes of CDPs according to their shapes and amplitudes. By using a Markovian analysis, we disclosed the transitions between the different kinds of CDPs induced by capsaicin and lidocaine and constructed a global model based on the changes in the behavior of the CDPs generated along the whole set of lumbar segments. This allowed the identification of the different states of functional connectivity within the whole ensemble of dorsal horn neurones attained during nociception and their transitory reversal by systemic administration of lidocaine in preparations with the intact neuroaxis and after spinalization. The present observations provide additional information on the state of self-organized criticality that leads to the adaptive behavior of the dorsal horn neuronal networks during nociception and antinociception both shaped by supraspinal descending influences.

6.
Cortex ; 100: 111-126, 2018 03.
Article in English | MEDLINE | ID: mdl-28764852

ABSTRACT

The linguistic profile of Parkinson's disease (PD) is characterized by difficulties in processing units which denote bodily movements. However, the available evidence has low ecological validity, as it stems from atomistic tasks which are never encountered in real life. Here, we assessed whether such deficits also occur for meanings evoked by context-rich narratives, considering patients with and without mild cognitive impairment (PD-MCI and PD-nMCI, respectively) and matched controls for each group. Participants read two naturalistic stories (an action text and a neutral text) and responded to questions tapping the appraisal of verb-related and circumstantial information. In PD-MCI, impairments in the appraisal of action meanings emerged alongside difficulties in other categories, but they were unique in their independence from general cognitive dysfunction. However, in PD-nMCI, deficits were observed only for action meanings, irrespective of the patients' domain-general skills (executive functions and general cognitive state). Also, using multiple group discriminant function analyses, we found that appraisal of action meanings was the only discourse-level variable that robustly contributed to classifying PD-MCI patients from controls (with an accuracy of 88% for all participants and for each sample separately). Moreover, this variable actually superseded a sensitive executive battery in discriminating between PD-nMCI and controls (with a combined accuracy of 83% for all participants, correctly classifying 79.2% of patients and 87.5% of controls). In sum, action appraisal deficits seem to constitute both a hallmark of naturalistic discourse processing in PD and a sensitive subject-level marker for patients with and without MCI. Such findings highlight the relevance of ecological measures of embodied cognitive functions in the assessment of this population.


Subject(s)
Cognition/physiology , Cognitive Dysfunction/physiopathology , Executive Function/physiology , Parkinson Disease/physiopathology , Adult , Aged , Aged, 80 and over , Female , Humans , Language , Male , Middle Aged , Neuropsychological Tests
7.
Brain Lang ; 168: 37-46, 2017 May.
Article in English | MEDLINE | ID: mdl-28131052

ABSTRACT

Parkinson's disease (PD) patients show marked impairments in processing action verbs, and to a lesser extent, concrete (specially, manipulable) nouns. However, it is still unclear to what extent deficits in each of these categories are influenced by more general cognitive dysfunctions, and whether they are modulated by the words' implied motility. To examine these issues, we evaluated 49 non-demented PD patients and 49 healthy volunteers in an oral production task. The patients were divided into two groups depending on the presence or absence of mild cognitive impairment (PD-MCI and PD-nMCI, respectively). Participants named pictures of actions varying in motion content (low and high) and of objects varying in manipulability (low and high). The PD-MCI group showed deficits across all four categories. However, PD-nMCI patients exhibited a selective difficulty for high-motion action verbs. This finding corroborates and refines previous results suggesting that disturbances of action-related lexico-semantic information in PD constitute a sui generis alteration manifested early in the course of the disease's physiopathology. Moreover, it suggests that the grounding of action verbs on motor circuits could depend on fine-grained intracategorical semantic distinctions.


Subject(s)
Cognitive Dysfunction/psychology , Parkinson Disease/psychology , Semantics , Aged , Case-Control Studies , Cognitive Dysfunction/physiopathology , Female , Humans , Language , Male , Middle Aged , Motion , Parkinson Disease/physiopathology
8.
Rev Med Chil ; 144(6): 772-80, 2016 Jun.
Article in Spanish | MEDLINE | ID: mdl-27598498

ABSTRACT

The Chilean senate is discussing a proposal to decriminalize abortion in 3 causals. One of these is when the pregnancy occurs as a result of a rape. To be legally able to perform the abortion in this circumstance, a health care team must confirm the occurrence of the facts constituting the offence. Regardless of the patient’s will, the accusation will be reported to the justice. In our view, in its current status the proposed rule does not consider certain medicolegal and procedural topics. Those flaws may determine in certain scenarios critical problems, such as: a) a wrongful conviction as a consequence of a false allegation of rape; (b) some pregnant due to a rape will not have access to the abortion procedure; (c) some accusations of rape will not be accredited nor criminally sanctioned. Employing a fictional case, we illustrate how those scenarios can actually be seen in practice. We also emphasize the difficulties and limitations that the health care team will encounter if the project is approved under the current conditions. Finally, we encourage the professional societies implicated in the theme to contribute in the legislatorial debate. Therefore, we give a set of proposals aimed to improve the bill before it may be enacted as a law.


Subject(s)
Abortion, Legal/legislation & jurisprudence , Legislation, Medical , Rape/legislation & jurisprudence , Chile , Female , Humans , Male , Patient Care Team , Pregnancy
9.
J Food Sci Technol ; 51(7): 1421-7, 2014 Jul.
Article in English | MEDLINE | ID: mdl-24966441

ABSTRACT

Continuous flow and linear viscoelasticity rheology of chocolate coating is studied in this work using fat substitute gums (xanthan, GX). An alternative conching process, using a Rotor-Estator (RE) type impeller, is proposed. The objective is to obtain a chocolate coating material with improved flow properties. Characterization of the final material through particle size distribution (PSD), differential scanning calorimetry (DSC) and proximal analysis is reported. Particle size distribution of the final material showed less polydispersity and therefore, greater homogeneity; fusion points were also generated at around 20 °C assuming crystal type I (ß'2) and II (α). Moreover, the final material exhibited crossover points (higher structure material), whereas the commercial brand chocolate used for comparison did not. The best conditions to produce the coating were maturing of 36 h and 35 °C, showing crossover points around 76 Pa and a 0.505 solids particle dispersion (average particle diameter of 0.364 µm), and a fusion point at 20.04 °C with a ΔHf of 1.40 (J/g). The results indicate that xanthan gum is a good substitute for cocoa butter and provides stability to the final product.

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