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

2018 ◽  
Author(s):  
Matthias Stangl ◽  
Ingmar Kanitscheider ◽  
Martin Riemer ◽  
Ila Fiete ◽  
Thomas Wolbers
Keyword(s):  
Path Integration ◽  
Age Groups ◽  
Motion Cues ◽  
Elapsed Time ◽  
Integration Error ◽  
Age Related ◽  
Langevin Diffusion ◽  
Self Motion ◽  
Velocity Input ◽  
Shed Light

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.

scholarly journals Functional correlates of the lateral and medial entorhinal cortex: objects, path integration and local–global reference frames

2014 ◽  
Vol 369 (1635) ◽  
pp. 20130369 ◽  
Author(s):  
James J. Knierim ◽  
Joshua P. Neunuebel ◽  
Sachin S. Deshmukh
Keyword(s):  
Entorhinal Cortex ◽  
Path Integration ◽  
Sensory Input ◽  
Reference Frames ◽  
External Input ◽  
Frame Of Reference ◽  
Medial Entorhinal Cortex ◽  
Motion Cues ◽  
Cortical Input ◽  
Self Motion

The hippocampus receives its major cortical input from the medial entorhinal cortex (MEC) and the lateral entorhinal cortex (LEC). It is commonly believed that the MEC provides spatial input to the hippocampus, whereas the LEC provides non-spatial input. We review new data which suggest that this simple dichotomy between ‘where’ versus ‘what’ needs revision. We propose a refinement of this model, which is more complex than the simple spatial–non-spatial dichotomy. MEC is proposed to be involved in path integration computations based on a global frame of reference, primarily using internally generated, self-motion cues and external input about environmental boundaries and scenes; it provides the hippocampus with a coordinate system that underlies the spatial context of an experience. LEC is proposed to process information about individual items and locations based on a local frame of reference, primarily using external sensory input; it provides the hippocampus with information about the content of an experience.

scholarly journals Both visual and idiothetic cues contribute to head direction cell stability during navigation along complex routes

2011 ◽  
Vol 105 (6) ◽  
pp. 2989-3001 ◽  
Author(s):  
Ryan M. Yoder ◽  
Benjamin J. Clark ◽  
Joel E. Brown ◽  
Mignon V. Lamia ◽  
Stephane Valerio ◽  
...  
Keyword(s):  
Visual Information ◽  
Path Integration ◽  
Visual Cues ◽  
Cell Activity ◽  
Neural Representation ◽  
Head Direction ◽  
Motion Cues ◽  
Cell Stability ◽  
Self Motion ◽  
The Relationship

Successful navigation requires a constantly updated neural representation of directional heading, which is conveyed by head direction (HD) cells. The HD signal is predominantly controlled by visual landmarks, but when familiar landmarks are unavailable, self-motion cues are able to control the HD signal via path integration. Previous studies of the relationship between HD cell activity and path integration have been limited to two or more arenas located in the same room, a drawback for interpretation because the same visual cues may have been perceptible across arenas. To address this issue, we tested the relationship between HD cell activity and path integration by recording HD cells while rats navigated within a 14-unit T-maze and in a multiroom maze that consisted of unique arenas that were located in different rooms but connected by a passageway. In the 14-unit T-maze, the HD signal remained relatively stable between the start and goal boxes, with the preferred firing directions usually shifting <45° during maze traversal. In the multiroom maze in light, the preferred firing directions also remained relatively constant between rooms, but with greater variability than in the 14-unit maze. In darkness, HD cell preferred firing directions showed marginally more variability between rooms than in the lighted condition. Overall, the results indicate that self-motion cues are capable of maintaining the HD cell signal in the absence of familiar visual cues, although there are limits to its accuracy. In addition, visual information, even when unfamiliar, can increase the precision of directional perception.

Inference of perceptual priors from path dynamics of passive self-motion

2015 ◽  
Vol 113 (5) ◽  
pp. 1400-1413 ◽  
Author(s):  
Mario Prsa ◽  
Danilo Jimenez-Rezende ◽  
Olaf Blanke
Keyword(s):  
Path Integration ◽  
Bayesian Estimator ◽  
Whole Body ◽  
Movement Trajectory ◽  
Motion Cues ◽  
Movement Dynamics ◽  
History Of ◽  
Average Size ◽  
Self Motion ◽  
Over Time

The monitoring of one's own spatial orientation depends on the ability to estimate successive self-motion cues accurately. This process has become to be known as path integration. A feature of sequential cue estimation, in general, is that the history of previously experienced stimuli, or priors, biases perception. Here, we investigate how during angular path integration, the prior imparted by the displacement path dynamics affects the translation of vestibular sensations into perceptual estimates. Subjects received successive whole-body yaw rotations and were instructed to report their position within a virtual scene after each rotation. The overall movement trajectory either followed a parabolic path or was devoid of explicit dynamics. In the latter case, estimates were biased toward the average stimulus prior and were well captured by an optimal Bayesian estimator model fit to the data. However, the use of parabolic paths reduced perceptual uncertainty, and a decrease of the average size of bias and thus the weight of the average stimulus prior were observed over time. The produced estimates were, in fact, better accounted for by a model where a prediction of rotation magnitude is inferred from the underlying path dynamics on each trial. Therefore, when passively displaced, we seem to be able to build, over time, from sequential vestibular measurements an internal model of the vehicle's movement dynamics. Our findings suggest that in ecological conditions, vestibular afference can be internally predicted, even when self-motion is not actively generated by the observer, thereby augmenting both the accuracy and precision of displacement perception.

scholarly journals Estimation of self-motion duration and distance in rodents

2016 ◽  
Vol 3 (5) ◽  
pp. 160118 ◽  
Author(s):  
Magdalena Kautzky ◽  
Kay Thurley
Keyword(s):  
Path Integration ◽  
Spatial Navigation ◽  
Distance Estimation ◽  
Mongolian Gerbils ◽  
Integration Path ◽  
Virtual Reality Environment ◽  
Motion Cues ◽  
Heading Direction ◽  
Temporal And Spatial ◽  
Self Motion

Spatial orientation and navigation rely on information about landmarks and self-motion cues gained from multi-sensory sources. In this study, we focused on self-motion and examined the capability of rodents to extract and make use of information about own movement, i.e. path integration. Path integration has been investigated in depth in insects and humans. Demonstrations in rodents, however, mostly stem from experiments on heading direction; less is known about distance estimation. We introduce a novel behavioural paradigm that allows for probing temporal and spatial contributions to path integration. The paradigm is a bisection task comprising movement in a virtual reality environment in combination with either timing the duration ran or estimating the distance covered. We performed experiments with Mongolian gerbils and could show that the animals can keep track of time and distance during spatial navigation.

Observations of the Morphological Evolution of Neuronal Intranuclear Rods in the Human Substantia Nigra Across the Age Spectrum

2019 ◽  
Vol 152 (Supplement_1) ◽  
pp. S76-S76
Author(s):  
Osama Khan ◽  
Mario Capitano ◽  
Susan Fan ◽  
John Woulfe
Keyword(s):  
Observational Study ◽  
Middle Ages ◽  
Morphological Evolution ◽  
Age Groups ◽  
Distinct Type ◽  
Elderly Subjects ◽  
Cellular Mechanisms ◽  
Age Related ◽  
Shed Light

Abstract Objectives Parkinson’s disease (PD) is a neurodegenerative disease characterized by a depletion of dopaminergic neurons in the substansia nigra (SN). Loss of SN neurons occurs at a rate of up to 10% per decade in nonpathological aging. Other age-related changes in nigral neurons include accumulation of intranuclear inclusions called Marinesco bodies (MBs). MBs have been shown to associate with a distinct type of neuronal intranuclear body called the intranuclear rod (INR). At what point in the aging process INRs develop, and when they give rise to MBs, are questions that remain unanswered. In this observational study, we set out to determine whether SN INRs display changes in their morphology across the human age spectrum. Methods The laboratory information system was searched for hospital and forensic autopsies conducted from 2010-2017 that had midbrain sections taken. Ten slides were cut from each of 11 age groups from ages ranging from 1 month to 80 years of age. Sections were immunostained with glucocorticoid receptor (GR) to identify INRs. Results There was a progressive age-associated transition in INR morphology from long, linear intranuclear structures in the youngest age groups (infants), to shorter linear structures at middle ages, culminating in small, dot-like juxtanucleolar structures in elderly subjects. A proportion of short INRs displayed contact with MBs in the middle age groups. Conclusion We demonstrated a striking progressive, age-dependent alteration in INR morphology. These results suggest that INRs give rise to MBs in the SN during middle ages. As a follow-up of this preliminary observational study, quantitative analysis of INR frequency and size is currently being performed in our lab. Ultimately, we plan to expand our cases for the creation of a human SN tissue microarray, which we hope will shed light on the cellular mechanisms of neuronal ageing and degeneration in the SN.

scholarly journals Activity Strength within Optic Flow-Sensitive Cortical Regions Is Associated with Visual Path Integration Accuracy in Aged Adults

2021 ◽  
Vol 11 (2) ◽  
pp. 245
Author(s):  
Lauren Zajac ◽  
Ronald Killiany
Keyword(s):  
Motion Perception ◽  
Optic Flow ◽  
Path Integration ◽  
Visual Motion ◽  
Spatial Navigation ◽  
Motion Processing ◽  
Global Pattern ◽  
Age Related ◽  
Cortical Regions ◽  
Self Motion

Spatial navigation is a cognitive skill fundamental to successful interaction with our environment, and aging is associated with weaknesses in this skill. Identifying mechanisms underlying individual differences in navigation ability in aged adults is important to understanding these age-related weaknesses. One understudied factor involved in spatial navigation is self-motion perception. Important to self-motion perception is optic flow–the global pattern of visual motion experienced while moving through our environment. A set of optic flow-sensitive (OF-sensitive) cortical regions was defined in a group of young (n = 29) and aged (n = 22) adults. Brain activity was measured in this set of OF-sensitive regions and control regions using functional magnetic resonance imaging while participants performed visual path integration (VPI) and turn counting (TC) tasks. Aged adults had stronger activity in RMT+ during both tasks compared to young adults. Stronger activity in the OF-sensitive regions LMT+ and RpVIP during VPI, not TC, was associated with greater VPI accuracy in aged adults. The activity strength in these two OF-sensitive regions measured during VPI explained 42% of the variance in VPI task performance in aged adults. The results of this study provide novel support for global motion processing as a mechanism underlying visual path integration in normal aging.

Immigrant Youth in Germany

2013 ◽  
Vol 18 (3) ◽  
pp. 158-168 ◽  
Author(s):  
Emily Frankenberg ◽  
Katharina Kupper ◽  
Ruth Wagner ◽  
Stephan Bongard
Keyword(s):  
School System ◽  
Large Scale ◽  
Age Groups ◽  
Well Being ◽  
Ethnic Discrimination ◽  
Emotional And Behavioral Problems ◽  
Sociocultural Adaptation ◽  
Age Related ◽  
German School ◽  
Transcultural Adaptation

This paper reviews research on young migrants in Germany. Particular attention is given to the question of how Germany’s history of migration, immigration policies, and public attitude toward migrants influence the transcultural adaptation of children and adolescents from different ethnic backgrounds. We combine past research with the results of new empirical studies in order to shed light on migrants’ psychological and sociocultural adaptation. Studies comparing young migrants and their German peers in terms of psychological well-being, life satisfaction, and mental health outcome suggest higher rates of emotional and behavioral problems among migrants of most age groups. With regard to adolescent populations between the ages of 14 and 17 years, however, the existence of differences between migrants and natives appears to be less clear. Research has also yielded inconsistent findings regarding the time trajectory of transcultural adaptation among adolescents. The coincidence of acculturation and age-related change is discussed as a possible source of these inconsistencies. Further, we provide an overview of risk and protective factors such as conflicting role expectations and ethnic discrimination, which may cause heightened vulnerability to adverse adaptation outcomes in some groups. Large-scale studies have repeatedly shown migrants of all age groups to be less successful within the German school system, indicating poor sociocultural adaptation. Possible explanations, such as the idiosyncrasies of the German school system, are presented. Our own studies contribute to the understanding of young migrants’ adaptation process by showing that it is their orientation to German culture, rather than the acculturation strategy of integration, that leads to the most positive psychological and sociocultural outcomes. The paper concludes by discussing implications for future cross-cultural research on young migrants and by suggesting recommendations for multicultural policies.

The influence of osteopathic correction on the rate of various rhythms of the body

2019 ◽  
pp. 64-71 ◽  
Author(s):  
A. E. Chernikova ◽  
Yu. P. Potekhina
Keyword(s):  
Heart Rate ◽  
Respiratory Rate ◽  
Age Groups ◽  
Biomechanical Properties ◽  
Dispersion Analysis ◽  
The Body ◽  
Body Tissues ◽  
Age Related ◽  
Significant Difference ◽  
Before And After

Introduction. An osteopathic examination determines the rate, the amplitude and the strength of the main rhythms (cardiac, respiratory and cranial). However, there are relatively few studies in the available literature dedicated to the influence of osteopathic correction (OC) on the characteristics of these rhythms.Goal of research — to study the influence of OC on the rate characteristics of various rhythms of the human body.Materials and methods. 88 adult osteopathic patients aged from 18 to 81 years were examined, among them 30 men and 58 women. All patients received general osteopathic examination. The rate of the cranial rhythm (RCR), respiratory rate (RR) heart rate (HR), the mobility of the nervous processes (MNP) and the connective tissue mobility (CTM) were assessed before and after the OC session.Results. Since age varied greatly in the examined group, a correlation analysis of age-related changes of the assessed rhythms was carried out. Only the CTM correlated with age (r=–0,28; p<0,05) in a statistically significant way. The rank dispersion analysis of Kruskal–Wallis also showed statistically significant difference in this indicator in different age groups (p=0,043). With the increase of years, the CTM decreases gradually. After the OC, the CTM, increased in a statistically significant way (p<0,0001). The RCR varied from 5 to 12 cycles/min in the examined group, which corresponded to the norm. After the OC, the RCR has increased in a statistically significant way (p<0,0001), the MNP has also increased (p<0,0001). The initial heart rate in the subjects varied from 56 to 94 beats/min, and in 15 % it exceeded the norm. After the OC the heart rate corresponded to the norm in all patients. The heart rate and the respiratory rate significantly decreased after the OC (р<0,0001).Conclusion. The described biorhythm changes after the OC session may be indicative of the improvement of the nervous regulation, of the normalization of the autonomic balance, of the improvement of the biomechanical properties of body tissues and of the increase of their mobility. The assessed parameters can be measured quickly without any additional equipment and can be used in order to study the results of the OC.

Age related volume of cadaver-prostates in Bangladesh

1970 ◽  
Vol 4 (2) ◽  
pp. 74-77
Author(s):  
Rukshana Ahmed ◽  
Shamim Ara
Keyword(s):  
Prostate Gland ◽  
Age Groups ◽  
Clinical Settings ◽  
Cross Sectional ◽  
Medical College ◽  
Age Related ◽  
Group A ◽  
Key Words Prostate ◽  
The Mean ◽  
Group B

Pathological changes in the prostate gland occur commonly with advancing age including inflammation, atrophy, hyperplasia and carcinoma and a change in volume is also evident. Estimation of volume of prostate may be useful in a variety of clinical settings. A cross-sectional descriptive study was designed to see the changes in volume of the prostate with advancing age and done in the Department of Anatomy, Dhaka Medical College, Dhaka from August 2006 to June 2007. The study was performed on 70 post-mortem human prostates collected from the unclaimed dead bodies that were under examination in the Department of Forensic Medicine, Dhaka Medical College, Dhaka. The samples were divided into three age groups; group A (10-20 years), group B (21-40 years) and group C (41-70 years). Volume of the sample was measured by using the ellipsoid formula. The mean ± SD volume of prostate was 7.68 ± 3.64 cm3 in group A, 10.61 ± 3.99 cm3 in group B and 15.40 ± 6.31 cm3 in group C. Mean difference in volume between group A and group C, group B and group C were statistically significant (p<0.001). Statistically significant positive correlation was found between age and volume of prostate (r = + 0.579, p < 0.001). Key Words: Prostate; volume; Bangladeshi. DOI: 10.3329/imcj.v4i2.6501Ibrahim Med. Coll. J. 2010; 4(2): 74-77

The Adult as Foe or Friend?: Childism in Guus Kuijer's Criticism and Fiction

2013 ◽  
Vol 6 (2) ◽  
pp. 205-217 ◽  
Author(s):  
Vanessa Joosen
Keyword(s):  
Children's Literature ◽  
Children’S Literature ◽  
Age Groups ◽  
Children's Books ◽  
Children’S Books ◽  
Memorial Award ◽  
Adult Reader ◽  
Shed Light ◽  
Selection Of

Compared to the attention that children's literature scholars have paid to the construction of childhood in children's literature and the role of adults as authors, mediators and readers of children's books, few researchers have made a systematic study of adults as characters in children's books. This article analyses the construction of adulthood in a selection of texts by the Dutch author and Astrid Lindgren Memorial Award winner Guus Kuijer and connects them with Elisabeth Young-Bruehl's recent concept of ‘childism’ – a form of prejudice targeted against children. Whereas Kuijer published a severe critique of adulthood in Het geminachte kind [The despised child] (1980), in his literary works he explores a variety of positions that adults can take towards children, with varying degrees of childist features. Such a systematic and comparative analysis of the way grown-ups are characterised in children's texts helps to shed light on a didactic potential that materialises in different adult subject positions. After all, not only literary and artistic aspects of children's literature may be aimed at the adult reader (as well as the child), but also the didactic aspect of children's books can cross over between different age groups.

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