Metastability and Eye Movements: A Dynamical‑Systems Interpretation

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  1. Why metastability is a natural language for gaze behavior The idea that perception, attention, and neural activity evolve through transiently stable states has deep roots in cognitive science and neuroscience. Concepts such as attractors , basins , noise‑induced transitions , and escape times appear in work on perceptual switching, decision‑making, and neural population dynamics (Kelso, 1995; Rabinovich et al., 2008; Deco & Jirsa, 2012). Eye movements, especially the alternation between fixations and saccades ,   fit remarkably well into this metastable picture. The Freidlin–Wentzell theory of rare events (Freidlin & Wentzell, 2012) provides a rigorous mathematical language for these intuitions. 2. Fixations as metastable states  Consider the gaze position X t as the state of a stochastic dynamical system. During a fixation the  gaze remains confined to a small region, microsaccades and noise generate small fluctuations, and the gaze tends to return...
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Relationship between the modified Rankin Scale and the Barthel Index in the process of functional recovery after stroke

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The modified Rankin Scale (mRS) and the Barthel Index (BI) are the most  
common clinimetrical instruments for measuring disability after stroke. 

 This study [here] investigated the relationship between the BI and the 

 mRS at multiple time points after stroke. 

The BI, which is a widely used instrument for longitudinal follow-up post-

 stroke, was used as  reference to determine the effect of time on the 

 sensitivity of the mRS in differentiating  functional recovery. 
Methods: Ninety-two patients with first stroke and hemispheric brain 

 lesion were evaluated using the BI and mRS at 10 days, 3 and 6 months. 

 The Kruskal-Wallis test was applied to examine median differences in BI 

 among the mRS levels at 10 days, 3 and 6 months with Dunn's correction 

 for multigroup comparison. The Mann and Whitney test was used to 

 compare median differences in BI scores between two aggregations of 

 mRS grades (mRS=0-2, mRS=3-5) at the same time periods after 

 stroke. 
Results: BI score distribution amongst mRS grades overlapped at 10 

 days, differentiating only between extreme grades (no disability vs severe 

 disability). At 3 months, independent patients with slight disability could be 

 distinguished from dependent patients with marked disability. At 6 

 months, grade 2 and 3 overlapped no more, differentiating independence 

 (class 0-2) from dependence (class 3-5). The largest transition to an 

 independent functional status occurred from grade 4, at 3 months.
Conclusion: Maximum sensitivity of mRS in differentiating functional 

 recovery is reached at six months post-stroke.



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