1. |
2. |
3. |
4. |
5. Interocular symmetry in dynamic retinal vessel analysis among healthy adultsMichael Mendes Wefelnberg, Freerk T. Baumann, Henning Guthoff, Damir Zubac, 2026, izvirni znanstveni članek Povzetek: Dynamic retinal vessel analysis is a non-invasive approach for assessing retinal microvascular endothelial function, yet the extent to which eye selection, interocular variability, and systemic physiological factors influence dynamic retinal vessel analyzer (DRVA)-derived biomarkers remains insufficiently defined. This prospective methodological study aimed to evaluate the interocular symmetry and absolute and relative reliability of arterial flicker-induced dilation (aFID), venular flicker-induced dilation (vFID), and arteriolar constriction (aCON), and to determine whether these parameters are moderated by eye dominance, peak oxygen uptake (V̇O₂ peak), or intraocular pressure (IOP) in healthy individuals. Twenty apparently healthy adults completed two laboratory visits. During the first visit, aerobic capacity was assessed by cardiopulmonary exercise testing until volitional exhaustion. During the second visit, IOP, resting blood pressure, eye dominance, and retinal vascular endothelial function were assessed using DRVA in both eyes in randomized order. Interocular differences were examined using paired comparisons, Bland–Altman analysis, reliability statistics, and linear mixed-effects models accounting for bilateral measurements within participants. No significant differences were observed between the left and right eyes for aFID, vFID, or aCON. Bland–Altman analysis showed no systematic interocular bias across DRVA-derived parameters, although the limits of agreement were widest for aFID, indicating greater interocular variability. Relative reliability was highest for vFID, followed by aCON, whereas aFID showed only fair agreement. Similarly, absolute reliability analyses identified vFID as the most stable biomarker, with the lowest coefficient of variation, while aFID demonstrated the greatest variability. Linear mixed-effects models showed no significant moderating effects of eye dominance, V̇O₂ peak, or IOP on aFID, vFID, or aCON. These findings suggest that retinal vascular endothelial responses measured by DRVA are not systematically influenced by eye dominance or selected systemic physiological factors in healthy young adults. However, given the observed interocular variability, particularly for aFID, assessment of both eyes should be considered in clinical and research settings to improve measurement precision and reproducibility.
Ključne besede: Microvascula rcirculation, retina, oxygen kinetics, microcirculation, circulation, flow mediated dilation
Objavljeno v DiRROS: 13.05.2026; Ogledov: 33; Prenosov: 18
 Celotno besedilo (1,52 MB)
Gradivo ima več datotek! Več... |
6. |
7. |
8. |
9. Spinal mechanisms in post-activation potentiation : facilitation of presynaptic inhibition contrasts h-reflex amplitude reductionMiloš Kalc, Aleš Holobar, Matej Kramberger, Nina Murks, Jakob Škarabot, 2026, izvirni znanstveni članek Povzetek: This study invesƟgated the spinal neural mechanisms underlying post‐acƟvaƟon potenƟaƟon in ten16healthy young males (21.9 ± 4.8 years). ParƟcipants performed a 10‐second maximal isometric17plantarflexion, aŌer which we measured twitch torque and assessed spinal excitability using the18soleus H‐reflex, D1 presynapƟc inhibiƟon and heteronymous Ia facilitaƟon (HF). High‐density surface19EMG was decomposed to track single motor unit responses. The condiƟoning contracƟon increased20twitch torque by 12.2 Nm (p < 0.001) immediately and returning to baseline within nine minutes. This21mechanical potenƟaƟon was accompanied by a 29% reducƟon in H‐reflex amplitude (p < 0.001),22which recovered within three minutes. Paradoxically, neurophysiological indices of presynapƟc23inhibiƟon, D1 and HF were significantly increased (D1: p<0.017; HF: p<0.001), resulƟng in spinal24facilitaƟon. Single MU analysis revealed increased discharge probability, parƟcularly in higher‐25threshold units indicaƟng overall spinal facilitaƟon. These results demonstrate that post‐acƟvaƟon26potenƟaƟon involves a complex dissociaƟon: H‐reflex pathway inhibiƟon along with facilitaƟon of27presynapƟc spinal mechanisms. This paradox can be explained by either post‐acƟvaƟon depression28(caused by depleƟon of neurotransmiƩer at the Ia–motoneuron synapse) or muscle thixotropy, a29contracƟon history‐dependent decrease in muscle spindle sensiƟvity, which reduces the efficacy of30the Ia afferent volley independently of spinal inhibitory mechanisms. Our findings highlight a31dissociaƟon between spinal presynapƟc facilitaƟon and the decreased H‐reflex, underscoring the32need for future studies to explicitly test the roles of post‐acƟvaƟon depression and muscle thixotropy33aŌer condiƟoning contracƟons.
Ključne besede: HDsEMG, Ia afference, soleus, heteroniumous Ia facilitation, spinal reflex, muscle contraction, neural mechanisms, performance enhancement
Objavljeno v DiRROS: 12.05.2026; Ogledov: 52; Prenosov: 26
Celotno besedilo (12,07 MB)
Gradivo ima več datotek! Več... |
10. Uporaba mobilnega nevroslikanja pri Parkinsonovi bolezni : izsledki projektov TwinBrain in BrainSpinUroš Marušič, 2026, objavljeni znanstveni prispevek na konferenci Povzetek: Mobile Brain/Body Imaging (MoBI) predstavlja sodoben pristop mobilnega nevroslikanja, ki omogoča sočasno spremljanje možganske aktivnosti, mišične aktivacije in gibalnega vedenja med dejanskim izvajanjem funkcionalnih nalog. V raziskovanju Parkinsonove bolezni je tak pristop posebej pomemben, saj klasične laboratorijske in slikovne metode pogosto ne zajamejo ustrezno nevrofizioloških procesov, ki spremljajo hojo, ravnotežje in kognitivno-motorično integracijo. Projekt TwinBrain je bil zasnovan za preučevanje zgodnjih nevrofizioloških, živčno-mišičnih in biomehanskih označevalcev Parkinsonove bolezni v ekološko veljavnih okoliščinah. Protokol vključuje mobilni 128-kanalni EEG, visokoločljivostni EMG in nosljive inercialne senzorje med nalogami hoje, ravnotežja in razvoja sile, tudi v pogojih dvojne naloge. Doslej objavljeni izsledki kažejo, da se pri osebah z zgodnjo Parkinsonovo boleznijo že pojavljajo značilne spremembe v strategijah posturalnega nadzora, v spektralnih značilnostih EEG ter v kortiko-mišični funkcionalni povezljivosti. V drugem delu prispevka bo govora o projektu BrainSpin, ki se je začel 1. januarja 2026, in bo v obdobju 2026–2028 longitudinalno preučeval učinke namiznega tenisa pri osebah s Parkinsonovo boleznijo. Dosedanja literatura kaže, da je namizni tenis varna, izvedljiva in potencialno učinkovita oblika večdimenzionalne vadbe, ki lahko prispeva k izboljšanju motoričnih simptomov, ravnotežja, vsakodnevnega funkcioniranja in nekaterih kognitivnih ter psihosocialnih izidov. V prihodnje bi lahko prav povezava med intervencijskimi programi in mobilnim nevroslikanjem omogočila boljše razumevanje nevralnih mehanizmov rehabilitacije pri Parkinsonovi bolezni.
Ključne besede: Parkinsonova bolezen, mobilno nevroslikanje, Mobile Brain/Body imaging, dvojna naloga, namizni tenis
Objavljeno v DiRROS: 11.05.2026; Ogledov: 53; Prenosov: 30
Celotno besedilo (2,82 MB)
Gradivo ima več datotek! Več... |
