scholarly journals Sources of path integration error in young and aging humans

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Matthias Stangl ◽  
Ingmar Kanitscheider ◽  
Martin Riemer ◽  
Ila Fiete ◽  
Thomas Wolbers
2018 ◽  
Author(s):  
Matthias Stangl ◽  
Ingmar Kanitscheider ◽  
Martin Riemer ◽  
Ila Fiete ◽  
Thomas Wolbers

AbstractPath integration is a vital function in navigation: it enables the continuous tracking of one’s position in space by integrating self-motion cues. Path integration abilities vary across individuals but tend to deteriorate in old age. The specific causes of path integration errors, however, remain poorly characterized. Here, we combined tests of path integration performance with a novel analysis based on the Langevin diffusion equation, which allowed us to decompose errors into distinct causes that can corrupt path integration computations. Across age groups, the dominant errors were due to noise and a bias in speed estimation. Noise-driven errors accumulated with travel distance not elapsed time, suggesting that the dominant noise originates in the velocity input rather than within the integrator. Age-related declines were traced primarily to a growth in this unbiased noise. Together, these findings shed light on the contributors to path integration error and the mechanisms underlying age-related navigational deficits.


2012 ◽  
Author(s):  
Xiaoli Chen ◽  
Timothy P. McNamara ◽  
Jonathan W. Kelly
Keyword(s):  

2006 ◽  
Author(s):  
Xiaoang Irene Wan ◽  
Ranxiao Frances Wang ◽  
James A. Crowell

2020 ◽  
Vol 26 (3) ◽  
pp. 171-176
Author(s):  
Ilya M. Sobol ◽  
Boris V. Shukhman

AbstractA crude Monte Carlo (MC) method allows to calculate integrals over a d-dimensional cube. As the number N of integration nodes becomes large, the rate of probable error of the MC method decreases as {O(1/\sqrt{N})}. The use of quasi-random points instead of random points in the MC algorithm converts it to the quasi-Monte Carlo (QMC) method. The asymptotic error estimate of QMC integration of d-dimensional functions contains a multiplier {1/N}. However, the multiplier {(\ln N)^{d}} is also a part of the error estimate, which makes it virtually useless. We have proved that, in the general case, the QMC error estimate is not limited to the factor {1/N}. However, our numerical experiments show that using quasi-random points of Sobol sequences with {N=2^{m}} with natural m makes the integration error approximately proportional to {1/N}. In our numerical experiments, {d\leq 15}, and we used {N\leq 2^{40}} points generated by the SOBOLSEQ16384 code published in 2011. In this code, {d\leq 2^{14}} and {N\leq 2^{63}}.


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