1,721,042 research outputs found
Jėgos treniruotės kaip priemonė pagerinti pažintines, motorines funkcijas ir smegenų sveikatą asmenims, turintiems lengvus kognityvinius sutrikimus.
No full textPromoting healthy aging is becoming one of the most important challenges for healthcare systems (Shen et al., 2023). Despite significant positive results from preclinical studies and substantial investment in aging technologies, there is still a lack of clinically validated interventions that can effectively slow down the rate of aging or the progression of diseases, (Chan et al., 2024; Dunne et al., 2021; Senczyszyn et al., 2023; H. Zhang et al., 2019). Biological aging is characterized by a decline in the integrity and functioning of the central nervous system, leading to a reduction in cognitive and motor abilities that may vary in severity among individuals (Gonzales et al., 2022; K. J. Liang & Carlson, 2020; Nyberg et al., 2020). A few years before the diagnosis of dementia, cognitive symptoms become apparent, indicating a pre-clinical stage known as mild cognitive impairment (MCI) (Cloutier et al., 2015; Dickerson et al., 2007; Grundman et al., 2004). The risk of progressing from MCI to dementia increases five to tenfold (Petersen et al., 1999; Petersen, 2016). On the other hand, growing evidence suggests that 30 – 40% of dementia cases are linked to modifiable risk factors, with physical inactivity among key factors such as lack of cognitive stimulation, excessive alcohol consumption, head injury, air pollution, less education, hypertension, and social isolation, underscoring the importance of regular physical activity in dementia prevention (Iraniparast et al., 2022; Livingston et al., 2017, 2020). Although various cognitive abilities deteriorate in middle and older age (Kirova et al., 2015), it is notable that executive functions (Chehrehnegar et al., 2022), including inhibitory control, set-shifting, and working memory (Eriksson et al., 2015; S. Kim et al., 2016; Sweeney, 2001), tend to deteriorate earlier than memory (Kirova et al., 2015) and general cognitive decline (Si et al., 2020), and this correlates with a decline in functional abilities affecting quality of life (Verreckt et al., 2022), social and psychological well-being (Tomaszewski Farias et al., 2009). Executive dysfunction may therefore represent a behavioral manifestation of early structural and functional brain changes, underscoring the need for effective interventions capable of modifying neurodegenerative trajectories – among which physical exercise is one of the most promising approaches. Despite significant progress in early diagnostic techniques and intervention strategies, it remains uncertain which type of intervention – behavioral or pharmacological can most effectively modify the course of neurodegeneration in brain regions affected by Alzheimer’s disease (AD) (Bisbe et al., 2020; Chantanachai et al., 2024; Ribarič, 2022; Y. Wang et al., 2023; M. Zhang et al., 2023). Neuroimaging research has demonstrated that atrophy in the frontal and temporal cortices, including the hippocampus, can begin several years before cognitive impairment becomes clinically apparent (Aramadaka et al., 2023; Flak et al., 2018; Kantarci, 2013; Wei et al., 2021). Moreover, the extent of this atrophy has been shown to correlate with the severity of cognitive decline at the time of MCI diagnosis (Devivo et al., 2019). Evidence from both neuroimaging and histopathological studies indicates that cortical atrophy in MCI is heterogeneous. However, the mechanisms of these differences remain unclear, as clinical findings have often been inconsistent (Tabatabaei‐Jafari et al., 2015). In addition, there is still a lack of data describing the progression of these structural changes with aging and identifying which brain areas are initially affected during the preclinical stages of MCI (Devivo et al., 2019; Nurdal et al., 2020). Alzheimer's lesions are most commonly seen in the frontal, temporal and parietal cortices may occur subclinically in older adults with normal cognitive function (Bjorkli et al., 2020). Changes in the posterior cingulate cortex are likely related to hippocampal lesions and cognitive function (Papma et al., 2017). The alterations in the interconnected systems may reflect a pathophysiological process underlying the regional deterioration and specific patterns of cognitive changes observed in the aging brain (X. Liang et al., 2022). This may be important in identifying the mechanism and in defining new targets for intervention. It should be noted that there is still no evidence-based pharmacological treatment for MCI (Petersen et al., 2016), so promoting physical activity is probably the only viable means of improving cognitive function that can delay cognitive decline and reduce the risk of dementia among people with MCI (Geda et al., 2012; J. E. Lee & Lee, 2022). Therefore, in this context, there is a growing body of evidence supporting the importance of physical activity, particularly for older adults with MCI (Bisbe et al., 2020; Castellote-Caballero et al., 2024; Kuo et al., 2022). Studies have shown a convincing link between cognitive decline and the performance of motor tasks (Mirelman et al., 2014; Poirier et al., 2021; Toosizadeh et al., 2019) such as handgrip strength (Herold et al., 2022; Hesseberg et al., 2020), gait and balance (Levin et al., 2023; X. Liu et al., 2020; Montero-Odasso et al., 2014). This relationship is likely to be due to an age - related decline in nervous system function, which leads to impaired coordination between cognitive and motor activities (Jiang et al., 2019). In recent decades, numerous studies have confirmed that physical exercise does have a significant impact on brain structure and function (cognitive and physiological), particularly in older people (Chirles et al., 2017; Suzuki et al., 2013; Teixeira et al., 2018). Long-term studies show that older adults with active lifestyles maintain better cognitive function (Dieckelmann et al., 2023; X. Huang et al., 2022) compared to their sedentary peers (Merovitz-Budning, 2021; Sachdev et al., 2012). Moreover, physical activity (PA) levels are negatively correlated with the prevalence of AD, especially among individuals with a high genetic risk (de Frutos Lucas et al., 2023; de Frutos-Lucas et al., 2020; Gronek et al., 2019). A meta-analysis of randomized controlled trials of physical activity showed that regular physical activity (cardovascular training) improves reaction time, spatial processing, controlled processes, and executive functions in older people (S. Colcombe & Kramer, 2003; Demurtas et al., 2020; L. Zhang et al., 2020). In contrast, resistance training (RT) as an exercise paradigm for cognitive interventions has received much less attention. Nevertheless, positive results have been reported in RT research (Barry & Carson, 2004; Fiatarone Singh et al., 2014; Morrison et al., 2023; L. Zhang et al., 2020). Moreover, it has been observed that age-related muscle atrophy mainly affects the lower limbs, while the upper limb muscles remain relatively unaffected (Aagaard et al., 2010). Thus, lower limb strength and power are important determinants of physical functioning in older people and are related to general wellbeing (Beeri et al., 2021; J. Lee, 2020). Resistance training intervention studies have shown that even short-term physical activity can improve episodic memory (Cassilhas et al., 2007; Cavarretta et al., 2019; Herold et al., 2019; Papatsimpas et al., 2023) and executive function (Abonie et al., 2022; S. J. Colcombe et al., 2004; Feter et al., 2023). The fact that the brain is responsive to exercise suggests that peripheral muscle-mediated effects occurring during and/or after exercise can restore the structural and biochemical integrity of the brain (H.-J. Kim et al., 2022; Tao et al., 2019; Esiri & Chance, 2012; T. Liu-Ambrose et al., 2010; Coelho-Júnior et al., 2020; Sheoran et al., 2023). Exercise-induced muscle contraction can release myokines (L. S. Chow et al., 2022; Vints, Levin, et al., 2022), neurotrophic (Diniz et al., 2014; H.-J. Kim et al., 2022) and anti-inflammatory factors (Fang et al., 2022; Molina-Sotomayor et al., 2020), which have been associated with the observed improvements in cognitive function and increased neuroplasticity, neurogenesis, and synaptogenesis (Brenner et al., 2023; Fang et al., 2022; Foster et al., 2011; Fragala et al., 2019; Herold et al., 2019; C. Liu et al., 2023; Vints, Levin, et al., 2022). The main aim of this study was to investigate the effects of physical activity, in particular 12 weeks of resistance training (RT), on cognitive function in older adults. In addition, we aimed to investigate and evaluate the effects of RT on individual cognitive functions such as executive function, delayed memory, and attention. We also aimed to investigate the effects of progressive RT on the volume and cortical thickness of selected brain regions and their associations with exerciseinduced changes in cognitive functioning. Based on findings from previous reviews and behavioral studies on aging (Cleeland et al., 2019; Michely et al., 2018; Nelson et al., 2022; Tsapanou et al., 2019; Voss et al., 2013; L. Zhao et al., 2021) we focused specifically on substructures of the prefrontal cortex (PFC) and substructures of the medial temporal lobe structures surrounding the hippocampus. These include: (1) the rostral middle frontal gyrus, which plays a crucial role in attentional reorientation, working memory, speech, and language comprehension (Briggs et al., 2021); (2) the superior frontal gyrus, which is thought to contribute to higher cognitive functions, particularly working memory (Hone-Blanchet et al., 2022; Kokudai et al., 2021; Nissim et al., 2017; Tisserand et al., 2002) and episodic memory (involving the inferior temporal and parahippocampal cortex); (3) the entorhinal and parahippocampal areas (Devivo et al., 2019; Tsapanou et al., 2019), which are crucial in mediating signaling between the hippocampus and the prefrontal cortex (Eichenbaum, 2017), and (4) the inferior parietal cortex, which is essential for mathematical operations and it is involved in language processing (P. Liang et al., 2012). We hypothesized that cortical thickness in the frontal (superior frontal and rostral middle frontal) (Hone-Blanchet et al., 2022), parietal (inferior parietal), entorhinal and temporal (inferior temporal and parahippocampal) regions would correlate with interconnected subcortical brain structures (e.g. hippocampus) (Erickson et al., 2011; Hillerer et al., 2019; Olesen et al., 2020; Tao et al., 2019; Wilckens et al., 2021). We also sought to compare the effects of RT with those observed over time in the control group. Furthermore, we hypothesized that the effect of RT would be more pronounced in older adults at high-risk of MCI compared to low-risk of MCI adults. This study opens the door to a deeper understanding of how RT may promote cognitive resilience in the trajectory of healthy aging. CONCLUSIONS 1) The 12-week resistance training intervention did not produce statistically significant improvements in cognitive functions, including inhibitory control and memory. However, participants at higher risk of mild cognitive impairment (MCI) demonstrated a more pronounced tendency toward positive change compared to those at lower risk. No significant differences were observed between the experimental and control groups. 2) The 12 weeks of resistance training produced limited effects on cortical thickness in regions vulnerable to age-related gray matter atrophy. No statistically significant differences in neurometabolite concentrations were observed in the left hippocampus, left primary sensorimotor cortex (SM1), right dorsolateral prefrontal cortex (DLPFC) between high- and low-risk MCI groups following the intervention. 3) After the intervention, the high-risk MCI group demonstrated a significant reduction in sway speed, indicating improved balance control under challenging dual-task conditions. No significant balance changes were observed in the lowrisk group. 4) No statistically significant differences in ¹H-MRS neurometabolites (tNAA/tCr, tCho/tCr, mIns/tCr) were found between the high-risk and low-risk MCI groups in brain regions associated with cognitive functions and balance control
Causal involvement of DLPFC during bimanual coordination in older adults - an rTMS study
No full textThe role of the dorsolateral prefrontal cortex (DLPFC) in the regulation of bimanual coordination appears to become crucial with aging. Age-related changes in the involvement of the DLPFC in bimanual coordination were studied by using disruptive repetitive TMS (rTMS), inducing a transient lesion in this brain structure. Neurophysiological as well as behavioral effects of suppressing DLPFC during the preparation and execution of a bimanual task were studied in 41 healthy adults (young and old). Specifically, we combined short-train rTMS with single pulse TMS to examine the effect of DLPFC suppression on the interhemispheric projection to the contralateral primary motor cortex (M1) during motor preparation. Findings revealed that compromised interhemispheric DLPFC-M1 disinhibition during motor preparation in older adults resulted in less accurate bimanual performance. The altered DLPFC-M1 interaction in older adults appeared to result from a decline in local inhibitory mechanisms in the DLPFC. In addition, the induction of DLPFC suppression affected task accuracy, but not movement stability in both age groups. Taken together, these results suggest that DLPFC acts as a key regulator in the control of bimanual movement coordination
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
Modulation of neuroplasticity in the development of novel rehabilitation strategies: Underlying mechanisms and motor control
No full textHet doel van dit doctoraatsproefschrift was om na te gaan in welke
mate centrale en/of perifere elektrische stimulatie kan leiden tot
veranderingen in neuroplasticiteit en of deze stimulatie het functieherstel
van spieren en/of zenuwen kan bevorderen bij personen met
neurodegeneratieve aandoeningen. Bij patiënten met multiple sclerose (MS)
verloopt de revalidatie vaak moeizaam. Naast psychologische klachten zijn
de voornaamste symptomen: vermoeidheid, verlies van kracht, spasticiteit,
gevoelsstoornissen en motorische coördinatieproblemen. Vanuit
therapeutisch perspectief zijn we vooral geïnteresseerd in een eenvoudige en
betaalbare revalidatietherapie die minimaal belastend is voor de patiënt en
die leidt tot positieve langetermijneffecten. Elektrostimulatietherapie wordt
reeds jaren gebruikt voor allerlei doeleinden, gaande van het verminderen
van chronische pijn tot het actief houden van spieren die niet meer worden
gebruikt (vb. bij coma patiënten). Tot op vandaag weten we zeer weinig
over de effecten van (langdurige) elektrotherapie bij patiënten met MS. MS
wordt gekenmerkt door een verminderde elektrische signaaloverdracht van
de zenuwen ten gevolge van de aantasting van de myelineschede. Het idee
van dit doctoraatproefschrift bestaat erin dat we met behulp van
elektrotherapie de abnormale impulsgeleiding weer tot een optimaal/normaal
niveau willen brengen. Vanuit voorgaand onderzoek weten we immers dat er
een verband is tussen een aangetaste impulsgeleiding en sensorimotorische
klachten bij MS patiënten. We verwachten dan ook dat wanneer de therapie
‘werkt’ deze klachten zullen verminderen. Daarnaast zijn we vooral
geïnteresseerd in wat de onderliggende mechanismen zijn die deze
sensorimotorische veranderingen teweegbrengen. Op basis van
veelbelovende resultaten uit voorgaande studies kwamen twee types van
elektrotherapie in aanmerking om de impulsgeleiding te optimaliseren,
namelijk Transcutaneous Electrical Nerve Stimulation (TENS) en Transcranial
Direct Current Stimulation (tDCS). Bij zowel TENS als tDCS wordt er een
nauwelijks voelbare elektrische stroom opgewekt tussen twee elektroden die
zijn aangebracht op de huid. Het verschil tussen beide interventies is dat de
elektroden bij TENS op de aangetaste spier/zenuw worden aangebracht en
bij tDCS op de schedellocatie waaronder zich het hersengebied bevindt dat
gekoppeld is aan de aangetaste spier. Onderzoek toonde aan dat beide
therapieën (stroomvorm, frequentie, amplitude, etc.) de prikkelbaarheid van
het centrale zenuwstelsel kunnen beïnvloeden indien de juiste parameters
worden gebruikt. Met andere woorden, ze kunnen ervoor zorgen dat een
zenuwcel makkelijker kan geactiveerd worden en bijgevolg makkelijker een
elektrisch signaal kan doorgeven. Met TENS kunnen we de sensorische
zenuwcellen stimuleren. Via deze sensorische zenuwcellen verkrijgen we
informatie over allerhande prikkels, bijvoorbeeld over de vorm, de textuur of
de grootte van een object. Vervolgens kunnen we op basis van deze
sensorische informatie een actie ondernemen zoals bijvoorbeeld het
aansturen van bepaalde spieren via motorische zenuwcellen om het object vast te pakken. Het vergemakkelijken van het aansturen van motorische
zenuwcellen kunnen we beïnvloeden met tDCS.
In de eerste 3 studies beschreven in dit doctoraatproefschrift werden
de effecten van een lange-termijn TENS therapie (stimulatie gedurende 3
weken, 1 uur per dag) op de handspieren onderzocht. Uit deze studies
kunnen we concluderen dat TENS de gevoeligheid kon verbeteren bij MS
patiënten met sensorische problemen. De patiënten konden met een grotere
gevoeligheid prikkels waarnemen. Bovendien verbeterde de gevoeligheid tot
op een niveau dat vergelijkbaar was met dat van gezonde leeftijdsgenoten
en was het effect nog steeds aanwezig tot minstens 3 weken na het
beëindigen van de therapie. Opmerkelijk was dat niet alleen de gevoeligheid
van de gestimuleerde spier/zenuw verbeterde, maar ook deze van de
naburige spieren. Naast het onderzoeken van deze functionele
veranderingen zijn we behulp van transcraniële magnetische stimulatie
(TMS) nagegaan welke neuroplastische veranderingen werden vastgesteld
na TENS. Met TMS kunnen we het activiteitspatroon (facilitatie/inhibitie) van
de motorische hersengebieden in kaart brengen. Je krijgt als het ware een
‘map’ van hersenactiviteit. Verschillende interventies zoals bijvoorbeeld
leren, immobilisatie en sensorische stimulatie kunnen leiden tot
veranderingen van deze maps. Onze resultaten toonden aan dat de maps na
TENS groter werden bij gezonde personen en kleiner werden bij MS
patiënten in vergelijking met de maps die werden gemeten vóór de TENS
behandeling. Dit doet ons vermoeden dat de richting van neuroplastische
veranderingen gestuurd wordt door het al dan niet aanwezig zijn van een
bepaalde pathologie. Uit voorgaand onderzoek bleek dat hersenactiviteit bij
MS patiënten een uitgesproken globaal patroon vertoont, dat mogelijk
veroorzaakt wordt door de aantasting van inhibitorische connecties in de
hersenen. Mogelijk zorgt TENS voor een normalisatie van deze
hersenactiviteit door in te grijpen op deze inhibitorische connecties en leidt
dit proces bijgevolg tot een normalisatie van de hersenactiviteit in het
betreffende hersengebied. Deze verklaring is echter voorbarig en dient
verder onderzocht te worden.
Naast de evaluatie van een langdurige interventie met TENS werd
het effect van anodale tDCS op neuroplastische veranderingen (studie 4) en
motorische prestatie (studie 5) nagegaan bij MS patiënten. Tot op heden
werden bij MS patiënten enkel effecten van tDCS op pijnklachten en
sensorische klachten geëvalueerd, met positieve resultaten tot gevolg. In dit
doctoraatsproefschrift hebben we aangetoond dat een 20 minuten durende
interventie met anodale tDCS leidde tot neuroplastische veranderingen in de
motorische cortex van MS patiënten. Meer specifiek werd er een toename
van de corticospinale output vastgesteld na anodale tDCS. Dit wil zeggen dat
er globaal gezien minder energie nodig is om dit hersengebied te activeren
na tDCS. Gebaseerd op de bevindingen van gelijkaardige onderzoeken
uitgevoerd bij andere neurodegeneratieve populaties zouden we kunnen
verwachten dat anodale tDCS motorische prestaties en/of leertaken zal faciliteren. Deze hypothese hebben we getoetst in studie 5, waarin we het
effect van tDCS gekoppeld met een motorische leertaak op motorische
prestatie zijn nagegaan bij MS patiënten. Uit onze resultaten bleek dat een
sessie van tDCS gekoppeld aan training van een taak echter niet leidde tot
een verhoogde motorische prestatie. Verder onderzoek is aangewezen om na
te gaan wat de factoren zijn die de uitkomst van de therapie bepalen. We
vermoeden dat zowel factoren die eigen zijn aan de patiënt (vb. anatomische
en genetische factoren), stimulatieparameters (herhaaldelijke sessies,
stimulatie intensiteit, elektroden plaatsing) en hun interactie een belangrijke
rol spelen. In studie 6 hebben we de parameter stimulatieintensiteit dieper
onderzocht. Onze resultaten toonden bij gezonde personen aan dat de
stimulatie intensiteit een cruciale rol speelde in het faciliteren van een
motorische leertaak. Meer bepaald, stelden we een significante verbetering
vast van de motorische prestatie wanneer een motorische leertaak werd
gekoppeld met tDCS aan een hogere intensiteit (studie 6).
Aan de hand van dit doctoraatsproefschrift kunnen we besluiten dat
zowel perifere als centrale elektrostimulatie de revalidatie van
neurodegeneratieve aandoeningen zoals MS kan faciliteren. Naast
veranderingen in de organisatie van corticale netwerken en het verhogen
van de prikkelbaarheid van de gestimuleerde hersenstructuren, hebben we
kunnen vaststellen dat zowel perifere als centrale stimulatie tot significante
veranderingen in sensorimotorische prestatie kan leiden. Toekomstig
onderzoek zal moeten uitwijzen welke (combinatie van) factoren bepalend
zijn voor het slagen van de therapie. Onze resultaten tonen alvast aan dat
een langdurige therapie aangewezen is voor het induceren van
langetermijneffecten en dat intensiteit van de stimulatie cruciaal is voor het
bekomen van deze effecten
- …
