scholarly journals Slow manifolds within network dynamics encode working memory efficiently and robustly

2021 ◽  
Vol 17 (9) ◽  
pp. e1009366
Author(s):  
Elham Ghazizadeh ◽  
ShiNung Ching
Keyword(s):  
Working Memory ◽  
Systems Analysis ◽  
Neural Circuits ◽  
Memory Function ◽  
Memory Task ◽  
Network State ◽  
Dynamical Systems Analysis ◽  
Activation Profile ◽  
Robust To Noise ◽  
Over Time

Working memory is a cognitive function involving the storage and manipulation of latent information over brief intervals of time, thus making it crucial for context-dependent computation. Here, we use a top-down modeling approach to examine network-level mechanisms of working memory, an enigmatic issue and central topic of study in neuroscience. We optimize thousands of recurrent rate-based neural networks on a working memory task and then perform dynamical systems analysis on the ensuing optimized networks, wherein we find that four distinct dynamical mechanisms can emerge. In particular, we show the prevalence of a mechanism in which memories are encoded along slow stable manifolds in the network state space, leading to a phasic neuronal activation profile during memory periods. In contrast to mechanisms in which memories are directly encoded at stable attractors, these networks naturally forget stimuli over time. Despite this seeming functional disadvantage, they are more efficient in terms of how they leverage their attractor landscape and paradoxically, are considerably more robust to noise. Our results provide new hypotheses regarding how working memory function may be encoded within the dynamics of neural circuits.

scholarly journals Auditory and Visual Working Memory Are Differentially Related to Carotenoid Status in Preadolescent Children

2020 ◽  
Vol 4 (Supplement_2) ◽  
pp. 98-98
Author(s):  
Corinne Cannavale ◽  
Caitlyn Edwards ◽  
Ruyu Liu ◽  
Samantha Iwinski ◽  
Anne Walk ◽  
...  
Keyword(s):  
Working Memory ◽  
Visual Working Memory ◽  
Cognitive Abilities ◽  
Memory Function ◽  
Memory Task ◽  
Whole Body ◽  
Set Size ◽  
Preadolescent Children ◽  
Central Illinois ◽  
The Relationship

Abstract Objectives Carotenoids are plant pigments known to deposit in neural tissues including the hippocampus, a brain substrate that supports several memory forms. However, there is a dearth of knowledge regarding carotenoid status and working memory function in children. Accordingly, this study aimed to understand the relationship between macular and skin carotenoids to visual and auditory working memory (WM) function. Methods Seventy preadolescent children (7–12 years, 32 males) were recruited from the East-Central Illinois area. Auditory working memory was assessed using the story recall subtest of the Woodcock-Johnson IV Test of Cognitive Abilities. A subsample (N = 61, 27 males) completed a visual working memory task and reaction time was quantified to determine speed of memory processing at set sizes of 1 to 4 items. Macular pigment optical density (MPOD) was assessed using customized heterochromatic flicker photometry. Skin carotenoids were assessed using reflection spectroscopy (Veggie Meter). Hierarchical linear regressions were conducted to assess the relationship between carotenoid status and WM function, while controlling for age, sex, income, and whole-body % fat (DXA). Results Auditory WM was positively associated with skin carotenoids (b = 0.263, P = 0.039) but not MPOD (b = −0.044, P = 0.380). In contrast, MPOD was significantly associated with faster visual WM speed at set size 3 (b = −0.253, P = 0.039) and trending at set sizes of 1 (b = −0.225, P = 0.051), 2 (b = −0.171, P = 0.121), and 4 (b = −0.230, P = 0.055). Interestingly, skin carotenoids were not related to visual WM performance at either set size (all P’s > 0.300). Conclusions These results indicate that auditory and visual WM may be differentially related to carotenoids. While skin carotenoids encompass all carotenoids consumed in diet, lutein and zeaxanthin are the only carotenoids which deposit in the macula. Given that MPOD was only related to visual WM, this suggests lutein plays a larger role in these neural functions relative to auditory WM. Interestingly, MPOD's relationship with visual WM increased in strength with the more difficult trial type (i.e., increasing set size), indicating MPOD is related at higher levels of WM capacity. Funding Sources This study was funded by the Egg Nutrition Center.

Delayed recognition memory span in HIV-1 infection

1995 ◽  
Vol 1 (6) ◽  
pp. 575-580 ◽  
Author(s):  
Eileen M. Martin ◽  
David L. Pitrak ◽  
Kenneth J. Pursell ◽  
Kathleen M. Mullane ◽  
Richard M. Novak
Keyword(s):  
Substance Abuse ◽  
Working Memory ◽  
Substance Abusers ◽  
Memory Span ◽  
Memory Function ◽  
Memory Task ◽  
Basal Ganglia Disease ◽  
History Of ◽  
Delayed Recognition ◽  
Hiv Seropositive

AbstractWe administered a spatial version of the Delayed Recognition Span Test (DRST), a working memory task performed abnormally by patients with basal ganglia disease, to a group of 96 HIV-seropositive and 83 seronegative subjects with a high prevalence of substance abuse. For comparison purposes, we also administered the Symbol-Digit Modalities Test (SDMT) and the Trail Making Test (TMT), measures which detect HIV-related mental slowing efficiently in gay men but are nonspecifically impaired in subjects with a history of substance abuse. As predicted, scores on the TMT and the SDMT did not discriminate the groups, but HIV-seropositive subjects had significantly shorter spatial spans (p < .007) and DRST total scores (p < .005). These effects could not be attributed to differences in age, education, estimated intelligence, or psychological distress, because the groups were well matched on these variables. The DRST is a promising measure of HIV-related cognitive dysfunction in substance abusers, who are often nonspecifically impaired on psychomotor tasks. These preliminary data also indicate that working memory function should be studied further in HIV-seropositive subjects. (JINS, 1995, 1, 575–580.)

scholarly journals Degeneracy and stability in neural circuits of neuromodulators

2020 ◽  
Author(s):  
Chandan K. Behera ◽  
Alok Joshi ◽  
Da-Hui Wang ◽  
Trevor Sharp ◽  
KongFatt Wong-Lin
Keyword(s):  
Systems Analysis ◽  
Neural Circuits ◽  
Neural Circuit ◽  
Dopamine D2 Receptor ◽  
D2 Receptor ◽  
Network Activity ◽  
Activity Profile ◽  
Dynamical Systems Analysis ◽  
Parallel Circuits ◽  
Experimental Findings

AbstractDegenerate neural circuits perform the same function despite being structurally different. However, it is unclear whether neural circuits with interacting neuromodulator sources can themselves be degenerate while maintaining the same neuromodulator function. Here, we address this by computationally modelling the neural circuits of neuromodulators serotonin and dopamine, local glutamatergic and GABAergic interneurons, and their possible interactions, under reward/aversion-based conditioning tasks. We show that a single sparsely connected neural circuit model can recapitulate many separate experimental findings, but not all, suggesting multiple parallel circuits. Using simulations and dynamical systems analysis, we demonstrate that several different stable circuit architectures can produce the same observed network activity profile. Further, simulating dopamine (D2) receptor agonists in rewarding task can distinguish among sub-groups of these degenerate networks; a testable model prediction. Overall, this work suggests the plausibility of degeneracy within neuromodulator circuitry and has important implication for the stable and robust maintenance of neuromodulator functions.

scholarly journals Chemogenetic dissection of the primate prefronto-subcortical pathways for working memory and decision-making

2021 ◽  
Author(s):  
Kei Oyama ◽  
Yukiko Hori ◽  
Yuji Nagai ◽  
Naohisa Miyakawa ◽  
Koki Mimura ◽  
...  
Keyword(s):  
Decision Making ◽  
Working Memory ◽  
Neural Circuits ◽  
Spatial Working Memory ◽  
Memory Task ◽  
Projection Mapping ◽  
Impaired Performance ◽  
Brain Functions ◽  
Neuronal Projection

The primate prefrontal cortex (PFC) is situated at the core of higher brain functions by linking and cooperating with the caudate nucleus (CD) and mediodorsal thalamus (MD) via neural circuits. However, the distinctive roles of these prefronto-subcortical pathways remain elusive. Combining in vivo neuronal projection mapping with chemogenetic synaptic silencing, we reversibly dissected key pathways from PFC to the CD and MD individually in single monkeys. We found that silencing the bilateral PFC-MD projections, but not the PFC-CD projections, impaired performance in a spatial working memory task. Conversely, silencing the unilateral PFC-CD projection, but not the PFC-MD projection, altered preference in a free-choice task. These results revealed dissociable roles of the prefronto-subcortical pathways in working memory and decision-making, representing the technical advantage of imaging-guided pathway-selective chemogenetic manipulation for dissecting neural circuits underlying cognitive functions in primates.

scholarly journals Network Structure During Encoding Predicts Working Memory Performance

2018 ◽  
Author(s):  
Anirudh Wodeyar ◽  
Ramesh Srinivasan
Keyword(s):  
Working Memory ◽  
Graphical Model ◽  
Structural Characteristics ◽  
Brain Activity ◽  
Memory Performance ◽  
Memory Function ◽  
Brain Networks ◽  
Memory Task ◽  
Functional Clustering ◽  
Network Properties

ABSTRACTWorking memory operates through networks that integrate distributed modular brain activity. We characterize the structure of networks in different electroencephalographic frequency bands while individuals perform a working memory task. The objective was to identify network properties that support working memory function during the encoding, maintenance, and retrieval of memory. In each EEG frequency band, we estimated a complex-valued Gaussian graphical model to characterize the structure of brain networks using measures from graph theory. Critically, the structural characteristics of brain networks that facilitate performance are all established during encoding, suggesting that they reflect the effect of attention on the quality of the representation in working memory. Segregation of networks in the alpha and beta bands during encoding increased with accuracy. In the theta band, greater integration of functional clusters involving the temporal lobe with other cortical areas predicted faster response time, starting in the encoding interval and persisting throughout the task, indicating that functional clustering facilitates rapid memory manipulation.

scholarly journals Robust Working Memory through Short-Term Synaptic Plasticity

2022 ◽  
Author(s):  
Leo Kozachkov ◽  
John Tauber ◽  
Mikael Lundqvist ◽  
Scott L Brincat ◽  
Jean-Jacques Slotine ◽  
...  
Keyword(s):  
Neural Networks ◽  
Working Memory ◽  
Synaptic Plasticity ◽  
Recent Work ◽  
Recurrent Neural Networks ◽  
Memory Task ◽  
Short Term ◽  
Attractor Dynamics ◽  
Robust To Noise

Working memory has long been thought to arise from sustained spiking/attractor dynamics. However, recent work has suggested that short-term synaptic plasticity (STSP) may help maintain attractor states over gaps in time with little or no spiking. To determine if STSP endows additional functional advantages, we trained artificial recurrent neural networks (RNNs) with and without STSP to perform an object working memory task. We found that RNNs with and without STSP were both able to maintain memories over distractors presented in the middle of the memory delay. However, RNNs with STSP showed activity that was similar to that seen in the cortex of monkeys performing the same task. By contrast, RNNs without STSP showed activity that was less brain-like. Further, RNNs with STSP were more robust to noise and network degradation than RNNs without STSP. These results show that STSP can not only help maintain working memories, it also makes neural networks more robust.

scholarly journals Chemogenetic dissection of the primate prefronto-subcortical pathways for working memory and decision-making

2021 ◽  
Vol 7 (26) ◽  
pp. eabg4246
Author(s):  
Kei Oyama ◽  
Yukiko Hori ◽  
Yuji Nagai ◽  
Naohisa Miyakawa ◽  
Koki Mimura ◽  
...  
Keyword(s):  
Decision Making ◽  
Working Memory ◽  
Neural Circuits ◽  
Spatial Working Memory ◽  
Memory Task ◽  
Mediodorsal Thalamus ◽  
Projection Mapping ◽  
Impaired Performance ◽  
Brain Functions

The primate prefrontal cortex (PFC) is situated at the core of higher brain functions via neural circuits such as those linking the caudate nucleus and mediodorsal thalamus. However, the distinctive roles of these prefronto-subcortical pathways remain elusive. Combining in vivo neuronal projection mapping with chemogenetic synaptic silencing, we reversibly dissected key pathways from dorsolateral part of the PFC (dlPFC) to the dorsal caudate (dCD) and lateral mediodorsal thalamus (MDl) individually in single monkeys. We found that silencing the bilateral dlPFC-MDl projections, but not the dlPFC-dCD projections, impaired performance in a spatial working memory task. Conversely, silencing the unilateral dlPFC-dCD projection, but not the unilateral dlPFC-MDl projection, altered preference in a decision-making task. These results revealed dissociable roles of the prefronto-subcortical pathways in working memory and decision-making, representing the technical advantage of imaging-guided pathway-selective chemogenetic manipulation for dissecting neural circuits underlying cognitive functions in primates.

scholarly journals Theta Oscillations in Human Cortex During a Working-Memory Task: Evidence for Local Generators

2006 ◽  
Vol 95 (3) ◽  
pp. 1630-1638 ◽  
Author(s):  
S. Raghavachari ◽  
J. E. Lisman ◽  
M. Tully ◽  
J. R. Madsen ◽  
E. B. Bromfield ◽  
...  
Keyword(s):  
Working Memory ◽  
Sensory Processing ◽  
Memory Function ◽  
Memory Task ◽  
Large Data ◽  
Theta Oscillations ◽  
Resolution Method ◽  
Data Set ◽  
Human Cortex ◽  
Coordinate Regulation

Cortical theta appears important in sensory processing and memory. Intracanial electrode recordings provide a high spatial resolution method for studying such oscillations during cognitive tasks. Recent work revealed sites at which oscillations in the theta range (4–12 Hz) could be gated by a working-memory task: theta power was increased at task onset and continued until task offset. Using a large data set that has now been collected (10 participants/619 recording sites), we have sufficient sampling to determine how these gated sites are distributed in the cortex and how they are synchronized. A substantial fraction of sites in occipital/parietal (45/157) and temporal (23/280) cortices were gated by the task. Surprisingly, this aspect of working-memory function was virtually absent in frontal cortex (2/182). Coherence measures were used to analyze the synchronization of oscillations. We suspected that because of their coordinate regulation by the working-memory task, gated sites would have synchronized theta oscillations. We found that, whereas nearby gated sites (<20 mm) were often but not always coherent, distant gated sites were almost never coherent. Our results imply that there are local mechanisms for the generation of cortical theta.

Changes over time in frontotemporal activation during a working memory task in patients with schizophrenia

2007 ◽  
Vol 91 (1-3) ◽  
pp. 141-150 ◽  
Author(s):  
Robert Christian Wolf ◽  
Nenad Vasic ◽  
Annett Höse ◽  
Manfred Spitzer ◽  
Henrik Walter
Keyword(s):  
Working Memory ◽  
Memory Task ◽  
Changes Over Time ◽  
Over Time

scholarly journals History of Alcohol Consumption and HIV Status Related to Functional Connectivity Differences in the Brain During Working Memory Performance

2020 ◽  
Vol 18 (3) ◽  
pp. 181-193 ◽  
Author(s):  
Vaughn E. Bryant ◽  
Joseph M. Gullett ◽  
Eric C. Porges ◽  
Robert L. Cook ◽  
Kendall J. Bryant ◽  
...  
Keyword(s):  
Working Memory ◽  
Functional Connectivity ◽  
Alcohol Consumption ◽  
Memory Performance ◽  
Memory Function ◽  
Brain Networks ◽  
Memory Task ◽  
Hiv Positive ◽  
Hiv Status ◽  
Using Data

Background: Poorer working memory function has previously been associated with alcohol misuse, Human Immunodeficiency Virus (HIV) positive status, and risky behavior. Poorer working memory performance relates to alterations in specific brain networks. Objective: The current study examined if there was a relationship between brain networks involved in working memory and reported level of alcohol consumption during an individual’s period of heaviest use. Furthermore, we examined whether HIV status and the interaction between HIV and alcohol consumption was associated with differences in these brain networks. Methods: Fifty adults, 26 of whom were HIV positive, engaged in an n-back working memory task (0-back and 2-back trials) administered in a magnetic resonance imaging (MRI) scanner. The Kreek- McHugh-Schluger-Kellogg (KMSK) scale of alcohol consumption was used to characterize an individual’s period of heaviest use and correlates well with their risk for alcohol dependence. Connectivity analyses were conducted using data collected during n-back task. Results: Functional connectivity differences associated with greater alcohol consumption included negative connectivity, primarily from parietal attention networks to frontal networks. Greater alcohol consumption was also associated with positive connectivity from working memory nodes to the precuneus and paracingulate. HIV positive status was associated with more nodes of negative functional connectivity relative to alcohol consumption history alone, particularly in the frontoparietal networks. The HIV positive individuals with heavier drinking history related to negative fronto-parietal connectivity, along with positive connectivity from working memory nodes to mesolimbic regions. Conclusion: Findings allow for a better understanding of brain networks affected by HIV and alcohol and may provide avenues for interventions.

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