scholarly journals Content-based Dissociation of Hippocampal Involvement in Prediction

2020 ◽  
Vol 32 (3) ◽  
pp. 527-545 ◽  
Author(s):  
Peter Kok ◽  
Lindsay I. Rait ◽  
Nicholas B. Turk-Browne

Recent work suggests that a key function of the hippocampus is to predict the future. This is thought to depend on its ability to bind inputs over time and space and to retrieve upcoming or missing inputs based on partial cues. In line with this, previous research has revealed prediction-related signals in the hippocampus for complex visual objects, such as fractals and abstract shapes. Implicit in such accounts is that these computations in the hippocampus reflect domain-general processes that apply across different types and modalities of stimuli. An alternative is that the hippocampus plays a more domain-specific role in predictive processing, with the type of stimuli being predicted determining its involvement. To investigate this, we compared hippocampal responses to auditory cues predicting abstract shapes (Experiment 1) versus oriented gratings (Experiment 2). We measured brain activity in male and female human participants using high-resolution fMRI, in combination with inverted encoding models to reconstruct shape and orientation information. Our results revealed that expectations about shape and orientation evoked distinct representations in the hippocampus. For complex shapes, the hippocampus represented which shape was expected, potentially serving as a source of top–down predictions. In contrast, for simple gratings, the hippocampus represented only unexpected orientations, more reminiscent of a prediction error. We discuss several potential explanations for this content-based dissociation in hippocampal function, concluding that the computational role of the hippocampus in predictive processing may depend on the nature and complexity of stimuli.

2019 ◽  
Author(s):  
Peter Kok ◽  
Lindsay I. Rait ◽  
Nicholas B. Turk-Browne

AbstractIt has recently become clear that one of the key functions of the hippocampus is to predict future inputs. In line with this, previous research has revealed prediction-related signals in the hippocampus for complex visual objects, such as fractals and abstract shapes. Based on this, it has been suggested that the hippocampus may generate perceptual expectations, especially when relying on rapidly learned predictive associations between arbitrary stimuli. However, it is currently unknown whether the hippocampus implements general-purpose computations that subserve all associative predictions, regardless of stimulus properties, or whether the involvement of the hippocampus is stimulus-dependent. To investigate this, we exposed male and female human participants to complex auditory cues predicting either the shape of a complex object (Experiment 1) or the orientation of a simple line grating (Experiment 2). We measured brain activity using high-resolution functional magnetic resonance imaging (fMRI), in combination with inverted encoding models to reconstruct shape and orientation representations in visual cortex and the hippocampus. Our results revealed that expectations about shape and orientation evoked distinct representations in the hippocampus. For complex shapes, the hippocampus represented which shape was expected, potentially serving as a source of top-down predictions. In contrast, for simple gratings, the hippocampus represented only unexpected orientations, more reminiscent of a prediction error. We discuss several potential explanations for this dissociation, concluding that the computational role of the hippocampus in predictive processing depends upon the nature and complexity of stimuli.Significance StatementTo deal with the noisy and ambiguous sensory signals received by our brain, it is crucial to use prior knowledge of the world to guide perception. Previous research suggests that the hippocampus is involved in predicting upcoming visual stimuli based on prior knowledge. In the current study, we show that hippocampal prediction is specific to expectations of complex objects, whereas for simple features the hippocampus generates an opposite prediction error signal instead. These findings demonstrate that the computational role of the hippocampus can be content-sensitive and refine our understanding of the involvement of memory systems in predictive processing.


Author(s):  
Jeremy I Skipper ◽  
Daniel R Lamett

AbstractThe role of the cerebellum in speech perception remains a mystery. Given its uniform architecture, we tested the hypothesis that it implements a domain-general predictive mechanism whose role in speech processing is determined by connectivity. We used standard and coactivation neuroimaging meta-analyses of speech perception studies without motor responses, with (n = 72) or without (n = 92) cerebellum activity. We compared these to speech production studies (n = 175). Results show multiple, distinct regions of perception- and production-related activity throughout the cerebellum with some overlap. Each task had distinct patterns of cortico-cerebellar connectivity. Perception regions/connections were associated with task-related terms mined from thousands of neuroimaging studies that were neither speech nor domain-specific but were prediction related. Finally, when the cerebellum was active, there was less cortical activity compared to when it was inactive, a marker of predictive processing. Results suggest that the cerebellum implements a domain-general mechanism related to prediction during passive speech perception.


2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Rosario Tomasello ◽  
Cora Kim ◽  
Felix R. Dreyer ◽  
Luigi Grisoni ◽  
Friedemann Pulvermüller

Abstract During everyday social interaction, gestures are a fundamental part of human communication. The communicative pragmatic role of hand gestures and their interaction with spoken language has been documented at the earliest stage of language development, in which two types of indexical gestures are most prominent: the pointing gesture for directing attention to objects and the give-me gesture for making requests. Here we study, in adult human participants, the neurophysiological signatures of gestural-linguistic acts of communicating the pragmatic intentions of naming and requesting by simultaneously presenting written words and gestures. Already at ~150 ms, brain responses diverged between naming and request actions expressed by word-gesture combination, whereas the same gestures presented in isolation elicited their earliest neurophysiological dissociations significantly later (at ~210 ms). There was an early enhancement of request-evoked brain activity as compared with naming, which was due to sources in the frontocentral cortex, consistent with access to action knowledge in request understanding. In addition, an enhanced N400-like response indicated late semantic integration of gesture-language interaction. The present study demonstrates that word-gesture combinations used to express communicative pragmatic intentions speed up the brain correlates of comprehension processes – compared with gesture-only understanding – thereby calling into question current serial linguistic models viewing pragmatic function decoding at the end of a language comprehension cascade. Instead, information about the social-interactive role of communicative acts is processed instantaneously.


2017 ◽  
Author(s):  
Michael B. Bone ◽  
Marie St-Laurent ◽  
Christa Dang ◽  
Douglas A. McQuiggan ◽  
Jennifer D. Ryan ◽  
...  

AbstractHalf a century ago, Donald Hebb posited that mental imagery is a constructive process that emulates perception. Specifically, Hebb claimed that visual imagery results from the reactivation of neural activity associated with viewing images. He also argued that neural reactivation and imagery benefit from the re-enactment of eye movement patterns that first occurred at viewing (fixation reinstatement). To investigate these claims, we applied multivariate pattern analyses to functional MRI (fMRI) and eye-tracking data collected while healthy human participants repeatedly viewed and visualized complex images. We observed that the specificity of neural reactivation correlated positively with vivid imagery and with memory for stimulus image details. Moreover, neural reactivation correlated positively with fixation reinstatement, meaning that image-specific eye movements accompanied image-specific patterns of brain activity during visualization. These findings support the conception of mental imagery as a simulation of perception, and provide evidence of the supportive role of eye-movement in neural reactivation.


2021 ◽  
Author(s):  
Silvia EP Bruzzone ◽  
Leonardo Bonetti ◽  
Tiina Paunio ◽  
Katri Kantojarvi ◽  
Marina Kliuchko ◽  
...  

Predictive processing of sounds depends on the constant updating of priors based on exposure to posteriors, which through repeated exposure mediates learning. The result of such corrections to the model is seen in musicians, whose lifelong training results in measurable plasticity of audio-motor brain anatomy and functionality. It has been suggested that the plasticity of auditory predictive processes depends on the interaction between the environment and the individual genetic substrate. However, empirical evidence to this is still missing. BDNF is a critical genetic factor affecting learning and plasticity, and its widely studied functional variant Val66Met single-nucleotide polymorphism offers a unique opportunity to investigate neuroplastic functional changes occurring upon a years-long training. We hypothesised that BDNF gene variations would be driving neuroplasticity of the auditory cortex in musically trained human participants. To this goal, musicians and non-musicians were recruited and divided in Val/Val and Met carriers and their brain activity measured with magnetoencephalography (MEG) while they listened to a regular auditory sequence containing different types of prediction errors. The auditory cortex responses to prediction errors was enhanced in Val/Val carriers who underwent intensive musical training, compared to Met and non-musicians. Our results point at a role of gene-regulated neurotrophic factors in the neural adaptations of auditory processing after long-term training.


2016 ◽  
Vol 86 (3-4) ◽  
pp. 127-151 ◽  
Author(s):  
Zeshan Ali ◽  
Zhenbin Wang ◽  
Rai Muhammad Amir ◽  
Shoaib Younas ◽  
Asif Wali ◽  
...  

While the use of vinegar to fi ght against infections and other crucial conditions dates back to Hippocrates, recent research has found that vinegar consumption has a positive effect on biomarkers for diabetes, cancer, and heart diseases. Different types of vinegar have been used in the world during different time periods. Vinegar is produced by a fermentation process. Foods with a high content of carbohydrates are a good source of vinegar. Review of the results of different studies performed on vinegar components reveals that the daily use of these components has a healthy impact on the physiological and chemical structure of the human body. During the era of Hippocrates, people used vinegar as a medicine to treat wounds, which means that vinegar is one of the ancient foods used as folk medicine. The purpose of the current review paper is to provide a detailed summary of the outcome of previous studies emphasizing the role of vinegar in treatment of different diseases both in acute and chronic conditions, its in vivo mechanism and the active role of different bacteria.


2007 ◽  
Author(s):  
P. S. Kavanagh ◽  
G. J. O. Fletcher ◽  
B. J. Ellis
Keyword(s):  

1984 ◽  
Vol 52 (02) ◽  
pp. 172-175 ◽  
Author(s):  
P R Kelsey ◽  
K J Stevenson ◽  
L Poller

SummaryLiposomes of pure phospholipids were used in a modified APTT test system and the role of phosphatidyl serine (PS) in determining the sensitivity of the test system to the presence of lupus anticoagulants was assessed. Six consecutive patients with lupus anticoagulants and seven haemophiliacs with anticoagulants directed at specific coagulation factors, were studied. Increasing the concentration of phospholipid in the test system markedly reduced the sensitivity to lupus anticoagulants but had marginal effect on the specific factor inhibitors. The same effect was achieved when the content of PS alone was increased in a vehicle liposome of constant composition.The results suggest that the lupus anticoagulants can best be detected by a screening method using an APTT test with a reagent of low PS content. The use of a reagent rich in PS will largely abolish the lupus anticoagulant’s effect on the APTT. An approach using the two different types of reagent may facilitate differentiation of lupus inhibitors from other types of anticoagulant.


2019 ◽  
Vol 28 (1) ◽  
pp. 19-27
Author(s):  
Ja. O. Petik

The connection of the modern psychology and formal systems remains an important direction of research. This paper is centered on philosophical problems surrounding relations between mental and logic. Main attention is given to philosophy of logic but certain ideas are introduced that can be incorporated into the practical philosophical logic. The definition and properties of basic modal logic and descending ones which are used in study of mental activity are in view. The defining role of philosophical interpretation of modality for the particular formal system used for research in the field of psychological states of agents is postulated. Different semantics of modal logic are studied. The hypothesis about the connection of research in cognitive psychology (semantics of brain activity) and formal systems connected to research of psychological states is stated.


2020 ◽  
pp. 97-110
Author(s):  
E. N. Mikhailova ◽  
V. A. Telegina

The article is devoted to the study of evaluative tools used in modern French media in order to form the media image of a representative of the political elite. The techniques used in the creation of a memorial media portrait of Jacques Chirac (1932—2019), President of France from 1995 to 2007 are considered. The research material was the most prestigious French print media of various political orientations, published in late September — early October 2019 in connection with the death of the ex-President of the French Republic. The relevance of the research topic is dictated by the close attention of modern linguistics to axiological phenomena, differently presented in different types of discursive practices. The novelty of the study is due to the appeal to the analysis of the complex of evaluation tools used in the French print media when characterizing the former leader of the state during the nation’s farewell period. The estimated potential of the title of the article and its influence on the formation of the estimated vector of the entire text of the publication are shown. A systematic analysis of the assessment expression means, reflected in the memorial media portrait of the politician, is given. The factors that influenced the peculiarities of their use in this type of media portrait are revealed.


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