The Neural Representation of Events Is Dominated by Elements that Are Most Reliably Present

2021 ◽  
pp. 1-15
Author(s):  
Konstantinos Bromis ◽  
Petar P. Raykov ◽  
Leah Wickens ◽  
Warrick Roseboom ◽  
Chris M. Bird
Keyword(s):  
Episodic Memory ◽  
Specific Activity ◽  
Activity Patterns ◽  
Neural Representation ◽  
The Novel ◽  
Experimental Paradigm ◽  
Multiple Events ◽  
The People ◽  
The Brain ◽  
Posterior Midline

Abstract An episodic memory is specific to an event that occurred at a particular time and place. However, the elements that comprise the event—the location, the people present, and their actions and goals—might be shared with numerous other similar events. Does the brain preferentially represent certain elements of a remembered event? If so, which elements dominate its neural representation: those that are shared across similar events, or the novel elements that define a specific event? We addressed these questions by using a novel experimental paradigm combined with fMRI. Multiple events were created involving conversations between two individuals using the format of a television chat show. Chat show “hosts” occurred repeatedly across multiple events, whereas the “guests” were unique to only one event. Before learning the conversations, participants were scanned while viewing images or names of the (famous) individuals to be used in the study to obtain person-specific activity patterns. After learning all the conversations over a week, participants were scanned for a second time while they recalled each event multiple times. We found that during recall, person-specific activity patterns within the posterior midline network were reinstated for the hosts of the shows but not the guests, and that reinstatement of the hosts was significantly stronger than the reinstatement of the guests. These findings demonstrate that it is the more generic, familiar, and predictable elements of an event that dominate its neural representation compared with the more idiosyncratic, event-defining, elements.

scholarly journals Intact finger representation within primary sensorimotor cortex of Musicians Dystonia

2021 ◽  
Author(s):  
Anna Sadnicka ◽  
Tobias Wiestler ◽  
Katherine Butler ◽  
Eckart Altenmueller ◽  
Mark John Edwards ◽  
...  
Keyword(s):  
Sensorimotor Cortex ◽  
Specific Activity ◽  
Activity Patterns ◽  
Neural Representation ◽  
Therapeutic Interventions ◽  
Reliable Technique ◽  
Spatial Shift ◽  
Spatial Measures ◽  
Primary Sensorimotor Cortex ◽  
Spatial Geometry

Musicians dystonia presents with a persistent deterioration of motor control during musical performance. A predominant hypothesis has been that this is underpinned by maladaptive neural changes to the somatotopic organisation of finger representations within primary somatosensory cortex. Here, we tested this hypothesis by investigating the finger-specific activity patterns in the primary somatosensory and motor cortex using functional magnetic resonance (fMRI) in nine musicians with dystonia and nine healthy musicians. A purpose-built keyboard device allowed fMRI characterisation of activity patterns elicited during passive extension and active finger presses of individual fingers. We analysed the data using both traditional spatial analysis and state-of-the art multivariate analyses. Our analysis reveals that digit representations in musicians were poorly captured by spatial measures. An optimised spatial metric found clear somatotopy but no difference in the spatial geometry between fingers. Representational similarity analysis was confirmed as a highly reliable technique and more consistent than all spatial metrics evaluated. Significantly, the dissimilarity architecture was equivalent for musicians with and without dystonia and no expansion or spatial shift of digit representation maps were found in the symptomatic group. Our results therefore suggest that the neural representation of generic finger maps in primary sensorimotor cortex is intact in Musicians dystonia. These results are against the idea that task-specific dystonia is associated with a distorted hand somatotopy and suggests that task-specific dystonia is due to a higher order disruption of skill encoding. Such a formulation can better explain the task-specific deficit and offers mechanistic insight for therapeutic interventions.

scholarly journals Prior knowledge promotes hippocampal separation but cortical assimilation in the left inferior frontal gyrus

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Oded Bein ◽  
Niv Reggev ◽  
Anat Maril
Keyword(s):  
Prior Knowledge ◽  
Inferior Frontal Gyrus ◽  
Activity Patterns ◽  
Neural Representation ◽  
The Novel ◽  
Left Inferior Frontal Gyrus ◽  
Specific Direction ◽  
Before And After ◽  
Novel Associations ◽  
Striking Contrast

Abstract An adaptive memory system rarely learns information tabula rasa, but rather builds on prior knowledge to facilitate learning. How prior knowledge influences the neural representation of novel associations remains unknown. Here, participants associated pairs of faces in two conditions: a famous, highly familiar face with a novel face or two novel faces while undergoing fMRI. We examine multivoxel activity patterns corresponding to individual faces before and after learning. The activity patterns representing members of famous-novel pairs becomes separated in the hippocampus, that is, more distinct from one another through learning, in striking contrast to paired novel faces that become similar. In the left inferior frontal gyrus, however, prior knowledge leads to integration, and in a specific direction: the representation of the novel face becomes similar to that of the famous face after learning, suggesting assimilation of new into old memories. We propose that hippocampal separation might resolve interference between existing and newly learned information, allowing cortical assimilation. Thus, associative learning with versus without prior knowledge relies on radically different computations.

Differential Modulation of CA1 and Dentate Gyrus Interneurons During Exploration of Novel Environments

2004 ◽  
Vol 91 (2) ◽  
pp. 863-872 ◽  
Author(s):  
Douglas Nitz ◽  
Bruce McNaughton
Keyword(s):  
Dentate Gyrus ◽  
Spatial Information ◽  
Specific Activity ◽  
Activity Patterns ◽  
Spatial Location ◽  
The Novel ◽  
Novel Environment ◽  
Principal Cells ◽  
Familiar Environment ◽  
Novel Environments

Parallel recordings of hippocampal principal cells and interneurons were obtained as rats foraged in familiar and adjacent, novel environments. Firing rates of each cell type were assessed as a function of spatial location. Many CA1 interneurons exhibited large decreases in activity in the novel compared with the familiar environment. Dentate gyrus interneurons, however, were much more likely to exhibit large increases in firing in the novel environment. Neither effect was correlated with basic interneuron discharge properties such as degree of theta modulation, baseline firing rate or degree of spatially modulated discharge. Both CA1 and dentate gyrus interneuron rate changes extended into regions of the familiar environment bordering the novel environment. Principal cells in CA1 and dentate gyrus exhibited similar patterns of place specific activity each being indicative of incorporation of novel spatial information into the spatial representation of the familiar environment. The data indicate that inhibitory networks in the CA1 and dentate gyrus areas are modulated in a divergent fashion during the acquisition of novel spatial information and that interneuron activities can be used to detect those regions of an environment subject to redistribution of principal cell spatial activity patterns.

Finding Concepts in Brain Patterns

2019 ◽  
pp. 547-575
Author(s):  
Elizabeth Musz ◽  
Sharon L. Thompson-Schill
Keyword(s):  
Real World ◽  
Functional Neuroimaging ◽  
Dimensional Space ◽  
Activity Patterns ◽  
Semantic Relatedness ◽  
Semantic Knowledge ◽  
Neural Representation ◽  
World Knowledge ◽  
Proximity Data ◽  
The Brain

Semantic memory is composed of one’s accumulated world knowledge. This includes one’s stored factual information about the real-world objects and animals, which enables one to recognize and interact with the things in one’s environment. How is this semantic information organized, and where is it stored in the brain? Newly developed functional neuroimaging (fMRI) methods have provided exciting and innovative approaches to studying these questions. In particular, several recent fMRI investigations have examined the neural bases of semantic knowledge using similarity-based approaches. In similarity models, data from direct (i.e., neural) and indirect (i.e., subjective, psychological) measurements are interpreted as proximity data that provide information about the relationships among object concepts in an abstract, high-dimensional space. Concepts are encoded as points in this conceptual space, such that the semantic relatedness between two concepts is determined by their distance from one another. Using this approach, neuroimaging studies have offered compelling insights to several open-ended questions about how object concepts are represented in the brain. This chapter briefly describes how similarity spaces are computed from both behavioral data and spatially distributed fMRI activity patterns. Then, it reviews empirical reports that relate observed neural similarity spaces to various models of semantic similarity. The chapter examines how these methods have both shaped and informed our current understanding of the neural representation of conceptual information about real-world objects.

scholarly journals Neural differentiation of incorrectly predicted memories

2016 ◽  
Author(s):  
Ghootae Kim ◽  
Kenneth A. Norman ◽  
Nicholas B. Turk-Browne
Keyword(s):  
Neural Differentiation ◽  
Computational Models ◽  
Activity Patterns ◽  
Neural Representation ◽  
Memory Representation ◽  
Neural Connections ◽  
Sequence Of Events ◽  
Network Simulations ◽  
The Brain ◽  
Target Memory

AbstractWhen an item is predicted in a particular context but the prediction is violated, memory for that item is weakened (Kim et al., 2014). Here we explore what happens when such previously mispredicted items are later re-encountered. According to prior neural network simulations, this sequence of events - misprediction and subsequent restudy - should lead to differentiation of the item's neural representation from the previous context (on which the misprediction was based). Specifically, misprediction weakens connections in the representation to features shared with the previous context, and restudy allows new features to be incorporated into the representation that are not shared with the previous context. This cycle of misprediction and restudy should have the net effect of moving the item‘s neural representation away from the neural representation of the previous context. We tested this hypothesis using fMRI, by tracking changes in item-specific BOLD activity patterns in the hippocampus, a key structure for representing memories and generating predictions. In left CA2/3/DG, we found greater neural differentiation for items that were repeatedly mispredicted and restudied compared to items from a control condition that was identical except without misprediction. We also measured prediction strength in a trial-by-trial fashion and found that greater misprediction for an item led to more differentiation, further supporting our hypothesis. Thus, the consequences of prediction error go beyond memory weakening: If the mispredicted item is restudied, the brain adaptively differentiates its memory representation to improve the accuracy of subsequent predictions and to shield it from further weakening.SignificanceCompetition between overlapping memories leads to weakening of non-target memories over time, making it easier to access target memories. However, a non-target memory in one context might become a target memory in another context. How do such memories get re-strengthened without increasing competition again? Computational models suggest that the brain handles this by reducing neural connections to the previous context and adding connections to new features that were not part of the previous context. The result is neural differentiation away from the previous context. Here provide support for this theory, using fMRI to track neural representations of individual memories in the hippocampus and how they change based on learning.

scholarly journals State dependence of adaptation of force output following movement observation

2013 ◽  
Vol 110 (5) ◽  
pp. 1246-1256 ◽  
Author(s):  
Paul A. Wanda ◽  
Gang Li ◽  
Kurt A. Thoroughman
Keyword(s):  
Action Observation ◽  
Motor Task ◽  
State Dependence ◽  
Lateral Force ◽  
Neural Representation ◽  
The Novel ◽  
Learning Effects ◽  
Force Output ◽  
State Dependent ◽  
The Brain

Humans readily learn to move through direct physical practice and by watching the movements of others. Some researchers have proposed that action observation can inform subsequent changes in control through the acquisition of a neural representation of the novel dynamics, but to date learning following observation has been described by kinematic metrics. Here we designed an experiment to consider the specificity of adaptation to novel dynamic perturbations at the level of force generation. We measured changes in temporal patterns of force output following either the performance or observation of movements perturbed by either position- or velocity-dependent dynamic environments to 1) establish whether previously described observational motor learning effects were attributable to changes in predictive limb control and 2) determine whether such adaptation reflected a learned dependence on limb states appropriate to the haptic environment. We found that subjects who observed perturbed movements produced significant compensatory changes in their lateral force output, despite never directly experiencing force perturbations firsthand while performing the motor task. The time series of observers' adapted force outputs suggested that the state dependence of observed dynamics shapes adaptation. We conclude that the brain can transform observation of kinematics into state-dependent adaptation of reach dynamics.

Analytical Study of Violence Theme in Victoria Schwab’s This Savage Song

2019 ◽  
Keyword(s):  
Analytical Study ◽  
Research Paper ◽  
The Novel ◽  
Vicious Cycle ◽  
Aggressive Approach ◽  
Research Article ◽  
The People ◽  
The Social ◽  
Different Dimensions ◽  
The Right

This research article focuses on the theme of violence and its representation by the characters of the novel “This Savage Song” by Victoria Schwab. How violence is transmitted through genes to next generations and to what extent socio- psycho factors are involved in it, has also been discussed. Similarly, in what manner violent events and deeds by the parents affect the psychology of children and how it inculcates aggressive behaviour in their minds has been studied. What role is played by the parents in grooming the personality of children and ultimately their decisions to choose the right or wrong way has been argued. In the light of the theory of Judith Harris, this research paper highlights all the phenomena involved: How the social hierarchy controls the behaviour. In addition, the aggressive approach of the people in their lives has been analyzed in the light of the study of second theorist Thomas W Blume. As the novel is a unique representation of supernatural characters, the monsters, which are the products of some cruel deeds, this research paper brings out different dimensions of human sufferings with respect to these supernatural beings. Moreover, the researcher also discusses that, in what manner the curse of violence creates an inevitable vicious cycle of cruel monsters that makes the life of the characters turbulent and miserable.

Hubungan Intertekstual Novel Candra Kirana dan “Tjerita Panji Angreni”: Perspektif Riffaterre

ATAVISME ◽  
2020 ◽  
Vol 23 (1) ◽  
pp. 104-116
Author(s):  
Muhammad Rosyid H.W.
Keyword(s):  
Content Analysis ◽  
Gender Equality ◽  
The Novel ◽  
Main Character ◽  
The People

Penelitian ini bertujuan membahas hubungan intertekstual novel Candra Kirana karya Ajip Rosidi dengan "Tjerita Panji Angreni". Unsur apa saja dan bagaimana novel Candra Kirana memiliki hubungan intertekstual dengan "Tjerita Panji Angreni' sebagai teks hipogramnya adalah pertanyaan penelitian ini. Dalam menelaah hubungan intertekstual ini, penulis menggunakan teori intertekstual Michael Riffaterre yang menitikberatkan pada analisis isi dengan metode pembacaan heuristik dan hermeneutik. Temuan penelitian ini adalah bahwa novel Candra Kirana menunjukkan hubungan intertekstual dengan Tjerita Panji Angreni melalui unsur tema, citra tokoh, dan alur cerita. Meskipun demikian, novel Candra Kirana juga mentransformasikan makna-makna progresif yang berbeda dengan "Tjerita Panji Angreni", seperti makna nasionalisme yang berupa cinta akan kerajaan, makna kesetaraan gender yang berupa kesetiaan laki-laki, keberanian, kekuatan, perjuangan dan ketidakpasrahan perempuan, makna kerakyatan dengan pelibatan tokoh utama dari kalangan rakyat dan makna religiusitas yang berbentuk dasar niat Panji dalam mencari pasangan hidup.[Intertextuality on Novel Candra Kirana and "Tjerita Panji Angreni": Riffaterres Perspective] This research aims to discuss the intertextuality of Candra Kirana novel by Ajip Rosidi with "Tjerita Panji Angreni". What elements and to what extend Candra Kirana novel has an intertextual relationship with Tjerita Panji Angreni as the hipogram text were the questions of this research. In examining this intertextual relationship, the writer used Michael Riffaterre's intertextual theory which focused on content analysis with heuristic and hermeneutic readings. The findings of this study were that the novel Candra Kirana showed intertextuality with the "Tjerita Panji Angreni" through elements of themes, character images, and story lines. Even so, Candra Kirana's novel also transformed progressive meanings that differ from the Tjerita Panji Angreni such as the meaning of nationalism in the form of love for the kingdom, the meaning of gender equality in the form of male loyalty, courage, strength, struggle and women's insecurity, the meaning of populist with engagement the main character of the people and the meaning of religiosity in the form of Panji's intention in finding a life partner.Keywords: intertextuality; novel; "Tjerita Panji Angreni"

Life Lessons of the Pandemic ”Covid - 19”

2020 ◽  
Vol 11 (SPL1) ◽  
pp. 469-471 ◽  
Author(s):  
Bhagyashri Vijay Chaudhari ◽  
Priya P. Chawle
Keyword(s):  
Public Health ◽  
Review Article ◽  
Public Health Emergency ◽  
The Novel ◽  
Global Public Health ◽  
Strange Situation ◽  
Republic Of China ◽  
Lifetime History ◽  
The People ◽  
Life Lessons

“A lesson learned the hard way is a lesson learned for a lifetime.” Every bad situation hurts; however, it sure does teach us something a lesson. In the same manner of a new lesson for Human lifetime, history is observing 'The Novel COVID-19 ’, a very horrible and strange situation created due to fighting with a microscopic enemy. WHO on 11 February 2020 has announced a name for new disease as - 19 and has declared as a global public health emergency and subsequently as pandemic because of its widespread. This began as an outbreak in December 2019, with its in Wuhan, the People Republic of China has emerged as a public health emergency of international concern. is the group of a virus with non-segmented, single-stranded and positive RNA genome. This bad situation of pandemic creates new scenes in the life of people in a different manner, which will be going to be life lessons for them. Such lessons should be kept in mind for the safety of living beings and many more things. In this narrative review article, reference was taken from a different article published in various databases which include the view of different authors and writers on the "Lessons to be from Corona".

scholarly journals A novel PET tracer 18F-deoxy-thiamine: synthesis, metabolic kinetics, and evaluation on cerebral thiamine metabolism status

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Changpeng Wang ◽  
Siwei Zhang ◽  
Yuefei Zou ◽  
Hongzhao Ma ◽  
Donglang Jiang ◽  
...  
Keyword(s):  
High Performance ◽  
Specific Activity ◽  
High Accumulation ◽  
Metabolic Kinetics ◽  
Thiamine Metabolism ◽  
Pet Tracer ◽  
The Status ◽  
The Brain

Abstract Background Some neuropsychological diseases are associated with abnormal thiamine metabolism, including Korsakoff–Wernicke syndrome and Alzheimer’s disease. However, in vivo detection of the status of brain thiamine metabolism is still unavailable and needs to be developed. Methods A novel PET tracer of 18F-deoxy-thiamine was synthesized using an automated module via a two-step route. The main quality control parameters, such as specific activity and radiochemical purity, were evaluated by high-performance liquid chromatography (HPLC). Radiochemical concentration was determined by radioactivity calibrator. Metabolic kinetics and the level of 18F-deoxy-thiamine in brains of mice and marmosets were studied by micro-positron emission tomography/computed tomography (PET/CT). In vivo stability, renal excretion rate, and biodistribution of 18F-deoxy-thiamine in the mice were assayed using HPLC and γ-counter, respectively. Also, the correlation between the retention of cerebral 18F-deoxy-thiamine in 60 min after injection as represented by the area under the curve (AUC) and blood thiamine levels was investigated. Results The 18F-deoxy-thiamine was stable both in vitro and in vivo. The uptake and clearance of 18F-deoxy-thiamine were quick in the mice. It reached the max standard uptake value (SUVmax) of 4.61 ± 0.53 in the liver within 1 min, 18.67 ± 7.04 in the kidney within half a minute. The SUV dropped to 0.72 ± 0.05 and 0.77 ± 0.35 after 60 min of injection in the liver and kidney, respectively. After injection, kidney, liver, and pancreas exhibited high accumulation level of 18F-deoxy-thiamine, while brain, muscle, fat, and gonad showed low accumulation concentration, consistent with previous reports on thiamine distribution in mice. Within 90 min after injection, the level of 18F-deoxy-thiamine in the brain of C57BL/6 mice with thiamine deficiency (TD) was 1.9 times higher than that in control mice, and was 3.1 times higher in ICR mice with TD than that in control mice. The AUC of the tracer in the brain of marmosets within 60 min was 29.33 ± 5.15 and negatively correlated with blood thiamine diphosphate levels (r = − 0.985, p = 0.015). Conclusion The 18F-deoxy-thiamine meets the requirements for ideal PET tracer for in vivo detecting the status of cerebral thiamine metabolism.

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