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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Lifelong accumulation of amyloid in neurons may contribute to Alzheimer's Disease

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A research team at the Cognitive Neurology and Alzheimer’s Disease Center  - Northwestern University, Illinois, USA, found that the protein amyloid - a hallmark of this disease - begins to accumulate in the neurons of the brain since the age of 20 [see more here ]. Scientists believe that this is the first time that such changes were observed in the human brain of individuals so young. Prof. Changiz Gheula said:

Discovering that amyloid begins to accumulate so early in life is unprecedented. This is very significant. We know that amyloid, when present for long periods of time, is bad for you.

 For the study, brains of deceased people in the age range from 20 to 95 were considered. Specifically, the sample included twenty-one people with Alzheimer's disease aged between 60 and 95, sixteen people aged between 70 and 79 without dementia, and thirteen "normal" people aged between 20 and 66 years.   

The findings are published in the journal Brain [download the pdf]

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