Search results for "Content-addressable memory"
showing 9 items of 9 documents
The Sensory Neocortex and Associative Memory
2016
Most behaviors in mammals are directly or indirectly guided by prior experience and therefore depend on the ability of our brains to form memories. The ability to form an association between an initially possibly neutral sensory stimulus and its behavioral relevance is essential for our ability to navigate in a changing environment. The formation of a memory is a complex process involving many areas of the brain. In this chapter we review classic and recent work that has shed light on the specific contribution of sensory cortical areas to the formation of associative memories. We discuss synaptic and circuit mechanisms that mediate plastic adaptations of functional properties in individual …
The picture superiority effect in associative memory: A developmental study.
2018
We tested whether semantic relatedness between to-be-remembered items and item presentation format (pictorial vs. verbal) affects associative recall. Fifty-nine children (11-13 years old) and forty young adults (age 18-30) completed a learning and recall task for semantically related (e.g., padlock-key) and unrelated (e.g., lemon-piano) picture-picture, word-picture, and word-word pairs. The data revealed memory advantage for semantically related item pairs, and for pictures compared to words. A picture superiority effect was found exclusively for pure picture pairs. Despite pronounced differences in memory accuracy, the effect of semantic relatedness and the picture superiority effect were…
The formation of structurally relevant units in artificial grammar learning
2002
A total of 78 adult participants were asked to read a sample of strings generated by a finite state grammar and, immediately after reading each string, to mark the natural segmentation positions with a slash bar. They repeated the same task after a phase of familiarization with the material, which consisted, depending on the group involved, of learning items by rote, performing a short term matching task, or searching for the rules of the grammar. Participants formed the same number of cognitive units before and after the training phase, thus indicating that they did not tend to form increasingly large units. However, the number of different units reliably decreased, whatever the task that…
Pheromone-induced olfactory memory in newborn rabbits: Involvement of consolidation and reconsolidation processes.
2009
Mammary pheromone (MP)-induced odor memory is a new model of appetitive memory functioning early in a mammal, the newborn rabbit. Some properties of this associative memory are analyzed by the use of anisomycin as an amnesic agent. Long-term memory (LTM) was impaired by anisomycin delivered immediately, but not 4 h after either acquisition or reactivation. Thus, the results suggest that this form of neonatal memory requires both consolidation and reconsolidation. By extending these notions to appetitive memory, the results reveal that consolidation and reconsolidation processes are characteristics of associative memories of positive events not only in the adult, but also in the newborn.
Associative Memory Based on Double-Gating of Molecularly Linked Nanosystem Arrays: A Theoretical Scheme
2008
We discuss theoretically the properties of an associative memory (a system that can retrieve a stored pattern that is similar to the input pattern) based on the ideal conductive properties of a molecularly linked nanosystem array. Two schemes are considered for the memory based on the gate potential modulation of the drain-source current through the array. In the first scheme, the basic units of the electric circuit are nanosystems (e.g., nanoparticles) arranged in a series array. Each nanosystem is assumed to have two states of conductances, GM and Gm (GM ≫ Gm), that can be tuned externally by the gate and backgate potentials. The bit sequence associated with a given pattern is stored as t…
Information Processing Schemes Based on Monolayer Protected Metallic Nanoclusters
2011
Nanostructures are potentially useful as building blocks to complement future electronics because of their high versatility and packing densities. The fabrication and characterization of particular nanostructures and the use of new theoretical tools to describe their properties are receiving much attention. However, the integration of these individual systems into general schemes that could perform simple tasks is also necessary because modern electronics operation relies on the concerted action of many basic units. We review here new conceptual schemes that can allow information processing with ligand or monolayer protected metallic nanoclusters (MPCs) on the basis of the experimentally de…
Signal processing and frequency-dependent associative memory based on nanoswitches
2008
A signal processing concept based on nanoscale switches whose conductance can be tuned by an external stimulus between two (ON and OFF) states is proposed and analyzed theoretically. The building block of the system is formed by a metal nanoparticle linked to two electrodes by an organic ligand and a molecular switch. When we apply an alternating potential to the system of the same frequency as the periodic variation between the ON and OFF states induced on the switch, the net charge delivered by the system exhibits a sharp resonance. This resonance can be used to process an external signal by selectively extracting the weight of the different harmonics. In addition, a frequency-dependent a…
Machine Learning Methods for One-Session Ahead Prediction of Accesses to Page Categories
2004
This paper presents a comparison among several well-known machine learning techniques when they are used to carry out a one-session ahead prediction of page categories. We use records belonging to 18 different categories accessed by users on the citizen web portal Infoville XXI. Our first approach is focused on predicting the frequency of accesses (normalized to the unity) corresponding to the user’s next session. We have utilized Associative Memories (AMs), Classification and Regression Trees (CARTs), Multilayer Perceptrons (MLPs), and Support Vector Machines (SVMs). The Success Ratio (SR) averaged over all services is higher than 80% using any of these techniques. Nevertheless, given the …
The inhibitory effect of long-term associative representation on working memory
2020
Studies on how long-term memory affects working memory (WM) have found that long-term memory can enhance WM processing. However, these studies only use item memory as the representation of long-term memory. In addition to item memory, associative memory is also an essential part of long-term memory. The associative memory and item memory involve different cognitive mechanisms and brain areas. The purpose of the present study was to investigate how associative memory affects WM processing. Before the WM task, participants were asked to store 16 pairs of dissimilar pictures into long-term memory. The participants would obtain the associative memory of these pairs of pictures in the long-term …