scholarly journals Postdiction: when temporal regularity drives space perception through pre-stimulus alpha oscillations

eNeuro ◽  
2021 ◽  
pp. ENEURO.0030-21.2021
Author(s):  
Laetitia Grabot ◽  
Christoph Kayser ◽  
Virginie van Wassenhove
2021 ◽  
Author(s):  
Laetitia Grabot ◽  
Christoph Kayser ◽  
Virginie van Wassenhove

AbstractDuring postdiction, the last stimulus of a sequence changes the perception of the preceding ones: in the rabbit illusion, a three-flash series presented regularly in time, but not in space, is – illusory - perceived as spatially regular. Such a reorganization of (spatial) perception could be driven by internal priors, e.g. favoring slow motion for the rabbit illusion. Although postdiction is a ubiquitous phenomenon, its neural underpinnings remain poorly understood. Here, we focused on the role of priors during postdiction and hypothesized that these could be reflected by alpha oscillations (8-12Hz), previously observed to correlate with idiosyncratic biases. We presented human participants with ambiguous visual stimuli that elicited the rabbit illusion on about half the trials, allowing us to contrast MEG-EEG brain responses to the same physical events causing distinct percepts. Given that a strong prior will increase the overall probability of perceiving the illusion, we used the percentage of perceived illusion as a proxy for an individual’s prior. We found that high fronto-parietal alpha power was associated with perceiving the sequence according to individual biases: participants with high susceptibility to the illusion would report the illusion, while participants with low susceptibility would report the veridical sequence. Additionally, we found that pre-stimulus alpha phase in occipital and frontal areas dissociated illusory from non-illusory trials. These results point to a dissociated relation of the power and timing of alpha band activity to illusory perception, with power reflecting prior expectations and phase influencing behavioral performance, potentially due to the modulation of sensory uncertainty.Significance StatementLate events may sometimes influence how earlier events are perceived, as if the arrow of time was reversed in the brain. This surprising phenomenon, called postdiction, is observed in the rabbit illusion, and highlights a predominant mechanism for perceptual processes. Perception builds up from the combination of prior expectations with incoming sensory evidence, which takes time. We showed that pre-stimulus neural activity, and more specifically alpha oscillations (8-12Hz), play a double role in postdiction. Fronto-parietal alpha power reflects individual prior expectation, while occipital and frontal alpha phase predicts illusory perception. Postdiction might actually be a means of compensating for the neural delays inherent in perceptual processes, so that the arrow of perceptual time matches the arrow of physical time.


Author(s):  
Joanna Ganczarek ◽  
Vezio Ruggieri ◽  
Marta Olivetti Belardinelli ◽  
Daniele Nardi

1911 ◽  
Vol 8 (1) ◽  
pp. 31-31
Author(s):  
No authorship indicated
Keyword(s):  

2019 ◽  
pp. 98-100
Author(s):  
Д. М. Кудайбердиева

Аннотация. В данной статье рассматривается проблема восприятия городской среды студентами из города и сельской местности. Обозначены определения терминов «среда», «пространственная среда», «городская среда». Проведено экспериментальное сравнительное исследование особенностей восприятия города Бишкек городскими и сельскими студентами в количестве 50 человек. Статья содержит результаты проведенного анализа исследования. Выявлены различия и сходства в восприятии города Бишкек у студентов двух групп. В контексте восприятия города изучена неудовлетворенность прошлым и настоящим временем, трудности языкового барьера у студентов из сельской местности. Также было выявлено, что актуальной для студентов обеих групп является потребность в социальных контактах, общении, включенности в социум. Полученные результаты будут иметь пользу в проведении воспитательной работы со студентами из сельской местности, в оказании поддержки им в период адаптации с учетом особенностей восприятия города студентами. Ключевые слова. среда, городская среда, восприятие пространства, городские студенты, сельские студенты, восприятие города Бишкек, неудовлетворенность прошлым и настоящим, языковой барьер, учеба в городе, сходства и различия в восприятии города. Аннотация. Бул макалада шаардык жана айылдан келген студенттердин шаардык чөйрөнү кабыл алуу көйгөйү каралган. «Чөйрө», «мейкиндик чөйрө», «шаардык чөйрө» терминдеринин түшүнүктөрү келтирилген. 50 адамдан турган шаардык жана айылдык студенттердин Бишкек шаарын кабыл алуу өзгөчөлүктөрүнө эксперименталдык салыштырма изилдөө жүргүзүлгөн. Макалада изилдөөнүн анализ жыйынтыктары камтылган. Эки студенттик топторунун Бишкек шаарын кабыл алуусунун айырмачылыктары жана окшоштуктары белгиленген. Шаарды кабыл алуу контекстинде өткөн жана учур чактарга канагаттанбоо, тил барьеринин кыйынчылыктары изилденди. Ошондой эле студенттердин эки тобуна актуалдуу болуп социалдык катнаштарга, баарлашууга, коомго кошулуу муктаждыгы белгиленүүдө. Алынган жыйынтыктар студенттердин шаарды кабыл алуу өзгөчөлүктөрүнө эске алып, айылдан келген студенттерге адаптация убагында колдоо көрсөтүү максатында тарбиялык иштерди жүргүзүүдө жардам берет. Түйүндүү сөздөр. Чөйрө, шаардык чөйрө, мейкиндикти кабыл алуу, шаардык студенттер, айылдык студенттер, Бишкек шаарын кабыл алуу, өткөн жана учур чакка канагаттанбоо, тил барьери, шаарда окуу, шаарды кабыл алуусунун айырмачылыктары жана окшоштуктары. Annotation. This article addresses the problem of perception of the urban environment by students from the city and countryside. The definitions of the terms “environment”, “spatial environment”, and “urban environment” are indicated. An experimental comparative study of the characteristics of the perception of the city of Bishkek by urban and rural students in the amount of 50 people was conducted. The article contains the results of the analysis of the study. The differences and similarities in the perception of the city of Bishkek among students of the two groups are revealed. In the context of the perception of the city, dissatisfaction with the past and the present has been studied, and the difficulties of the language barrier among students from rural areas. It was also revealed that the need for social contacts, communication, inclusion in society is relevant for students of both groups. The results will have the benefit of conducting educational work with students from rural areas, in providing support to them during the adaptation period, taking into account the peculiarities of the perception of the city by students. Кeywords. Environment, urban environment, space perception, urban students, rural students, perception of the city of Bishkek, dissatisfaction with the past and the present, language barrier, studying in the city, similarities and differences in the perception of the city.


Author(s):  
Daniel Schneider ◽  
Sophie K. Herbst ◽  
Laura‐Isabelle Klatt ◽  
Malte Wöstmann
Keyword(s):  

2011 ◽  
Vol 31 (18) ◽  
pp. 6674-6683 ◽  
Author(s):  
C. Marzano ◽  
M. Ferrara ◽  
F. Mauro ◽  
F. Moroni ◽  
M. Gorgoni ◽  
...  

2000 ◽  
Vol 84 (2) ◽  
pp. 1107-1111 ◽  
Author(s):  
Jörg Lewald ◽  
Hans-Otto Karnath

We investigated the effect of vestibular stimulation on the lateralization of dichotic sound by cold-water irrigation of the external auditory canal in human subjects. Subjects adjusted the interaural level difference of the auditory stimulus to the subjective median plane of the head. In those subjects in whom dizziness and nystagmus indicated sufficient vestibular stimulation, these adjustments were significantly shifted toward the cooled ear compared with the control condition (irrigation with water at body temperature); i.e., vestibular stimulation induced a shift of the sound image toward the nonstimulated side. The mean magnitude of the shift was 7.3 dB immediately after vestibular stimulation and decreased to 2.5 dB after 5 min. As shown by an additional control experiment, this effect cannot be attributed to a unilateral hearing loss induced by cooling of the auditory periphery. The results indicate the involvement of vestibular afferent information in the perception of sound location during movements of the head and/or the whole body. We thus hypothesize that vestibular information is used by central-nervous mechanisms generating a world-centered representation of auditory space.


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