A Gaussian Attractor Network for Memory and Recognition with Experience-Dependent Learning

2010 ◽  
Vol 22 (5) ◽  
pp. 1333-1357 ◽  
Author(s):  
Xiaolin Hu ◽  
Bo Zhang
Keyword(s):  
Learning Strategies ◽  
Visual Recognition ◽  
Memory Systems ◽  
Attractor Network ◽  
Attractor Networks ◽  
Testable Prediction ◽  
Attractor Dynamics ◽  
Dependent Learning ◽  
High Level ◽  
The Brain

Attractor networks are widely believed to underlie the memory systems of animals across different species. Existing models have succeeded in qualitatively modeling properties of attractor dynamics, but their computational abilities often suffer from poor representations for realistic complex patterns, spurious attractors, low storage capacity, and difficulty in identifying attractive fields of attractors. We propose a simple two-layer architecture, gaussian attractor network, which has no spurious attractors if patterns to be stored are uncorrelated and can store as many patterns as the number of neurons in the output layer. Meanwhile the attractive fields can be precisely quantified and manipulated. Equipped with experience-dependent unsupervised learning strategies, the network can exhibit both discrete and continuous attractor dynamics. A testable prediction based on numerical simulations is that there exist neurons in the brain that can discriminate two similar stimuli at first but cannot after extensive exposure to physically intermediate stimuli. Inspired by this network, we found that adding some local feedbacks to a well-known hierarchical visual recognition model, HMAX, can enable the model to reproduce some recent experimental results related to high-level visual perception.

scholarly journals Memory Dynamics in Attractor Networks

2015 ◽  
Vol 2015 ◽  
pp. 1-7 ◽  
Author(s):  
Guoqi Li ◽  
Kiruthika Ramanathan ◽  
Ning Ning ◽  
Luping Shi ◽  
Changyun Wen
Keyword(s):  
Energy Function ◽  
Stable Equilibrium ◽  
Equilibrium Points ◽  
Saddle Points ◽  
Memory Systems ◽  
Initial Stimulus ◽  
Attractor Network ◽  
Local Maxima ◽  
Attractor Networks ◽  
New Energy

As can be represented by neurons and their synaptic connections, attractor networks are widely believed to underlie biological memory systems and have been used extensively in recent years to model the storage and retrieval process of memory. In this paper, we propose a new energy function, which is nonnegative and attains zero values only at the desired memory patterns. An attractor network is designed based on the proposed energy function. It is shown that the desired memory patterns are stored as the stable equilibrium points of the attractor network. To retrieve a memory pattern, an initial stimulus input is presented to the network, and its states converge to one of stable equilibrium points. Consequently, the existence of the spurious points, that is, local maxima, saddle points, or other local minima which are undesired memory patterns, can be avoided. The simulation results show the effectiveness of the proposed method.

Cortical attractor dynamics and connectivity, stochasticity, psychiatric disorders, and aging

2020 ◽  
pp. 554-608
Author(s):  
Edmund T. Rolls
Keyword(s):  
Decision Making ◽  
Mental Disorders ◽  
Firing Rate ◽  
Psychiatric Disorders ◽  
Short Term Memory ◽  
Term Memory ◽  
Attractor Networks ◽  
Attractor Dynamics ◽  
The Stability ◽  
The Brain

In this chapter we consider how the operation of attractor networks in the brain is influenced by noise in the brain produced by the random firing times of neurons for a given mean firing rate; how this can in fact be beneficial to the operation of the brain; and how the stability of these systems and how they are influenced by noise in the brain is relevant to understanding a number of mental disorders. The concept of noise in attractor networks is important to understanding decision-making, short-term memory, and depression and schizophrenia, and this is described in this Chapter. It is a key aim of this book to increase understanding of the brain that is relevant not only to its operation in health, but also in disease, and how it may be possible to ameliorate some of the effects found in these mental and other disorders.

scholarly journals Behavioural test battery for the Back of the Brain project

2021 ◽  
Author(s):  
Ro Julia Robotham ◽  
Sheila Kerry ◽  
Grace E Rice ◽  
Alex Leff ◽  
Matt Lambon Ralph ◽  
...  
Keyword(s):  
Visual Perception ◽  
Cerebral Artery ◽  
Visual Recognition ◽  
Posterior Cerebral Artery ◽  
Test Battery ◽  
Low Level ◽  
Symptom Profile ◽  
Behavioural Test ◽  
High Level ◽  
The Brain

Much of the patient literature on the visual recognition of faces, words and objects is based on single case studies of patients selected according to their symptom profile. The Back of the Brain project aims to provide novel insights into the cerebral and cortical architecture underlying visual recognition of complex stimuli by adopting a different approach. A large group of patients was recruited according to their lesion location (in the areas supplied by the posterior cerebral artery) rather than their symptomatology. All patients were assessed with the same battery of sensitive tests of visual perception enabling the identification of dissociations as well as associations between deficits in face, word and object recognition. This paper provides a detailed description of the extensive behavioural test battery that was developed for the Back of the Brain project and that enables assessment of low-level, intermediate and high-level visual perceptual abilities. •Extensive behavioural test battery for assessing low-level, intermediate and high-level visual perception in patients with posterior cerebral artery stroke •Method enabling direct comparison of visual face, word and object processing abilities in patients with posterior cerebral artery stroke

scholarly journals Visual category-driven differences in memory

2021 ◽  
Author(s):  
Adam Steel ◽  
Edward Silson
Keyword(s):  
Visual Cortex ◽  
Human Memory ◽  
Memory Systems ◽  
Neural Mechanisms ◽  
Neural Responses ◽  
Cortical Areas ◽  
Visual Areas ◽  
High Level ◽  
Human Categorization ◽  
The Brain

Categorizing classes of stimuli in the real-world is thought to underlie features of general intelligence, including our ability to infer identities of new objects, environments, and people never encountered before. Our understanding of human categorization, and the neural mechanisms that underlie this ability, was initially described in the context of visual perception. It is now broadly accepted that a network of high-level visual areas on the ventral and lateral surfaces of the brain exhibit some level of ‘domain (or category)-selective’ activity: preferential neural responses to visual stimuli of one category more than another (e.g., larger responses to faces compared to scenes or manipulable objects). Inspired by this robust and intuitive organization, recent studies have begun investigating the extent to which human memory systems also exhibit a category-selective organization. Surprisingly, this work has revealed strong evidence for the existence of category-selective areas in swaths of cortex previously considered to be domain-general. These results suggest that category-selectivity is a general organizing principle not only of visual cortex, but also for higher-level cortical areas involved in memory. In this chapter we review the evidence for the manifestation of visual category preferences in memory systems, and how this relates to the well-established category-selectivity exhibited within visual cortex.

Model-Based and Model-Free Social Cognition

2019 ◽  
Author(s):  
Leor M Hackel ◽  
Jeffrey Jordan Berg ◽  
Björn Lindström ◽  
David Amodio
Keyword(s):  
Reinforcement Learning ◽  
Social Cognition ◽  
Learning Strategies ◽  
Memory Systems ◽  
Learning Task ◽  
Financial Advisors ◽  
Model Based ◽  
Model Free ◽  
Systems Model ◽  
Task Assessment

Do habits play a role in our social impressions? To investigate the contribution of habits to the formation of social attitudes, we examined the roles of model-free and model-based reinforcement learning in social interactions—computations linked in past work to habit and planning, respectively. Participants in this study learned about novel individuals in a sequential reinforcement learning paradigm, choosing financial advisors who led them to high- or low-paying stocks. Results indicated that participants relied on both model-based and model-free learning, such that each independently predicted choice during the learning task and self-reported liking in a post-task assessment. Specifically, participants liked advisors who could provide large future rewards as well as advisors who had provided them with large rewards in the past. Moreover, participants varied in their use of model-based and model-free learning strategies, and this individual difference influenced the way in which learning related to self-reported attitudes: among participants who relied more on model-free learning, model-free social learning related more to post-task attitudes. We discuss implications for attitudes, trait impressions, and social behavior, as well as the role of habits in a memory systems model of social cognition.

scholarly journals A novel dephosphorylation targeting chimera selectively promoting tau removal in tauopathies

2021 ◽  
Vol 6 (1) ◽  
Author(s):  
Jie Zheng ◽  
Na Tian ◽  
Fei Liu ◽  
Yidian Zhang ◽  
Jingfen Su ◽  
...  
Keyword(s):  
Neurodegenerative Disorders ◽  
Protein Phosphatase ◽  
High Efficiency ◽  
Microtubule Assembly ◽  
Hyperphosphorylated Tau ◽  
Phosphatase 2A ◽  
Dependent Learning ◽  
The Brain

AbstractIntraneuronal accumulation of hyperphosphorylated tau is a hallmark pathology shown in over twenty neurodegenerative disorders, collectively termed as tauopathies, including the most common Alzheimer’s disease (AD). Therefore, selectively removing or reducing hyperphosphorylated tau is promising for therapies of AD and other tauopathies. Here, we designed and synthesized a novel DEPhosphorylation TArgeting Chimera (DEPTAC) to specifically facilitate the binding of tau to Bα-subunit-containing protein phosphatase 2A (PP2A-Bα), the most active tau phosphatase in the brain. The DEPTAC exhibited high efficiency in dephosphorylating tau at multiple AD-associated sites and preventing tau accumulation both in vitro and in vivo. Further studies revealed that DEPTAC significantly improved microtubule assembly, neurite plasticity, and hippocampus-dependent learning and memory in transgenic mice with inducible overexpression of truncated and neurotoxic human tau N368. Our data provide a strategy for selective removal of the hyperphosphorylated tau, which sheds new light for the targeted therapy of AD and related-tauopathies.

scholarly journals A neurocognitive model of ideological thinking

2021 ◽  
pp. 1-15
Author(s):  
Leor Zmigrod
Keyword(s):  
Empirical Evidence ◽  
Motivational Factors ◽  
Cognitive Systems ◽  
Social Forces ◽  
Low Level ◽  
Cognitive Principles ◽  
High Level ◽  
Ideological Attitudes ◽  
The Brain

Abstract Ideological behavior has traditionally been viewed as a product of social forces. Nonetheless, an emerging science suggests that ideological worldviews can also be understood in terms of neural and cognitive principles. The article proposes a neurocognitive model of ideological thinking, arguing that ideological worldviews may be manifestations of individuals’ perceptual and cognitive systems. This model makes two claims. First, there are neurocognitive antecedents to ideological thinking: the brain’s low-level neurocognitive dispositions influence its receptivity to ideological doctrines. Second, there are neurocognitive consequences to ideological engagement: strong exposure and adherence to ideological doctrines can shape perceptual and cognitive systems. This article details the neurocognitive model of ideological thinking and synthesizes the empirical evidence in support of its claims. The model postulates that there are bidirectional processes between the brain and the ideological environment, and so it can address the roles of situational and motivational factors in ideologically motivated action. This endeavor highlights that an interdisciplinary neurocognitive approach to ideologies can facilitate biologically informed accounts of the ideological brain and thus reveal who is most susceptible to extreme and authoritarian ideologies. By investigating the relationships between low-level perceptual processes and high-level ideological attitudes, we can develop a better grasp of our collective history as well as the mechanisms that may structure our political futures.

scholarly journals Perceptual decisions are biased toward relevant prior choices

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Helen Feigin ◽  
Shira Baror ◽  
Moshe Bar ◽  
Adam Zaidel
Keyword(s):  
Sensory Information ◽  
Irrelevant Stimulus ◽  
Stimulus Feature ◽  
Serial Dependence ◽  
Low Level ◽  
Subsequent Test ◽  
Key Factor ◽  
High Level ◽  
Motor Actions ◽  
The Brain

AbstractPerceptual decisions are biased by recent perceptual history—a phenomenon termed 'serial dependence.' Here, we investigated what aspects of perceptual decisions lead to serial dependence, and disambiguated the influences of low-level sensory information, prior choices and motor actions. Participants discriminated whether a brief visual stimulus lay to left/right of the screen center. Following a series of biased ‘prior’ location discriminations, subsequent ‘test’ location discriminations were biased toward the prior choices, even when these were reported via different motor actions (using different keys), and when the prior and test stimuli differed in color. By contrast, prior discriminations about an irrelevant stimulus feature (color) did not substantially influence subsequent location discriminations, even though these were reported via the same motor actions. Additionally, when color (not location) was discriminated, a bias in prior stimulus locations no longer influenced subsequent location discriminations. Although low-level stimuli and motor actions did not trigger serial-dependence on their own, similarity of these features across discriminations boosted the effect. These findings suggest that relevance across perceptual decisions is a key factor for serial dependence. Accordingly, serial dependence likely reflects a high-level mechanism by which the brain predicts and interprets new incoming sensory information in accordance with relevant prior choices.

Vascular responses of dura mater

1989 ◽  
Vol 257 (1) ◽  
pp. H157-H161 ◽  
Author(s):  
F. M. Faraci ◽  
K. A. Kadel ◽  
D. D. Heistad
Keyword(s):  
Blood Flow ◽  
Substance P ◽  
Dura Mater ◽  
Sympathetic Nerves ◽  
Vascular Headache ◽  
Vascular Responses ◽  
Anesthetized Dogs ◽  
High Level ◽  
The Brain ◽  
Increased Blood Flow

The goal of this study was to examine vascular responses of the dura mater. Microspheres were used to measure blood flow to the dura and brain in anesthetized dogs. Under control conditions, blood flow to the dura was 38 +/- 3 (SE) ml.min-1.100 g-1. Values for blood flow to the dura obtained with simultaneous injection of 15- and 50-microns microspheres were similar, which suggests that shunting of 15-microns spheres was minimal. Left atrial infusion of substance P (100 ng.kg-1.min-1) and serotonin (40 micrograms.kg-1.min-1), two agonists that have been reported to increase vascular permeability in the dura, increased blood flow to the dura two- to threefold. Adenosine (iv) produced vasodilatation in the dura. Adenosine and serotonin did not affect cerebral blood flow, but substance P increased blood flow to the brain by approximately 40%. Seizures, which produce pronounced dilatation of cerebral vessels despite activation of sympathetic nerves, produced vasoconstriction in the dura. Thus 1) the dura is perfused at a relatively high level of blood flow under normal conditions and is very responsive to vasoactive stimuli, and 2) substance P and serotonin, which have been implicated in the pathogenesis of vascular headache, produce pronounced vasodilator responses in the dura mater.

Multiple Memory Systems and Their Support of Language

2014 ◽  
Vol 24 (2) ◽  
pp. 64-73 ◽  
Author(s):  
Jake Kurczek ◽  
Natalie Vanderveen ◽  
Melissa C. Duff
Keyword(s):  
Memory Impairment ◽  
Language Use ◽  
Declarative Memory ◽  
Memory Systems ◽  
Memory And Learning ◽  
Multiple Memory Systems ◽  
History Of Research ◽  
Language And Communication ◽  
History Of ◽  
The Brain

There is a long history of research linking the various forms of memory to different aspects of language. Clinically, we see this memory-language connection in the prevalence of language and communication deficits in populations that have concomitant impairments in memory and learning. In this article, we provide an overview of how the demands of language use and processing are supported by multiple memory systems in the brain, including working memory, declarative memory and nondeclarative memory, and how disruptions in different forms of memory may affect language. While not an exhaustive review of the literature, special attention is paid to populations who speech-language pathologists (SLPs) routinely serve. The goal of this review is to provide a resource for clinicians working with clients with disorders in memory and learning in helping to understand and anticipate the range of disruptions in language and communication that can arise as a consequence of memory impairment. We also hope this is a catalyst for more research on the contribution of multiple memory systems to language and communication.

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