Formation and synaptic control of active transient working memory representations

AbstractNeural representations of working memory maintain information temporarily and make it accessible for processing. This is most feasible in active, spiking representations. State-of-the-art modeling frameworks, however, reproduce working memory representations that are either transient but non-active or active but non-transient. Here, we analyze a biologically motivated working memory model which shows that synaptic short-term plasticity and noise emerging from spiking networks can jointly produce a working memory representation that is both active and transient. We investigate the effect of a synaptic signaling mechanism whose dysregulation is related to schizophrenia and show how it controls transient working memory duration through presynaptic, astrocytic and postsynaptic elements. Our findings shed light on the computational capabilities of healthy working memory function and offer a possible mechanistic explanation for how molecular alterations observed in psychiatric diseases such as schizophrenia can lead to working memory impairments.

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Working memory content is distorted by its use in perceptual comparisons

10.31234/osf.io/96axn ◽

2020 ◽

Author(s):

Keisuke Fukuda ◽

April Emily Pereira ◽

Joseph M. Saito ◽

Ty Yi Tang ◽

Hiroyuki Tsubomi ◽

...

Keyword(s):

Working Memory ◽

Individual Differences ◽

Computational Modeling ◽

Visual Information ◽

Dynamic Environment ◽

Memory Bias ◽

General Mechanism ◽

Memory Representation ◽

Memory Representations ◽

Memory Content

Visual information around us is rarely static. To carry out a task in such a dynamic environment, we often have to compare current visual input with our working memory representation of the immediate past. However, little is known about what happens to a working memory (WM) representation when it is compared with perceptual input. Here, we tested university students and found that perceptual comparisons retroactively bias working memory representations toward subjectively-similar perceptual inputs. Furthermore, using computational modeling and individual differences analyses, we found that representational integration between WM representations and perceptually-similar input underlies this similarity-induced memory bias. Together, our findings highlight a novel source of WM distortion and suggest a general mechanism that determines how WM representations interact with new perceptual input.

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Naturalistic coding of working memory in primate prefrontal cortex

10.1101/2020.06.19.162446 ◽

2020 ◽

Author(s):

Megan Roussy ◽

Rogelio Luna ◽

Lyndon Duong ◽

Benjamin Corrigan ◽

Roberto A. Gulli ◽

...

Keyword(s):

Working Memory ◽

Prefrontal Cortex ◽

Memory Performance ◽

Memory Function ◽

Nmda Receptor Antagonist ◽

Inhibitory Neurons ◽

Natural Behavior ◽

Neuronal Populations ◽

Memory Representations ◽

Decoding Accuracy

SummaryThe primate lateral prefrontal cortex (LPFC) is considered fundamental for temporarily maintaining and manipulating mental representations that serve behavior, a cognitive function known as working memory1. Studies in non-human primates have shown that LPFC lesions impair working memory2 and that LPFC neuronal activity encodes working memory representations3. However, such studies have used simple displays and constrained gaze while subjects held information in working memory3, which put into question their ethological validity4,5. Currently, it remains unclear whether LPFC microcircuits can support working memory function during natural behavior. We tested macaque monkeys in a working memory navigation task in a life-like virtual environment while their gaze was unconstrained. We show that LPFC neuronal populations robustly encode working memory representations in these conditions. Furthermore, low doses of the NMDA receptor antagonist, ketamine, impaired working memory performance while sparing perceptual and motor skills. Ketamine decreased the firing of narrow spiking inhibitory interneurons and increased the firing of broad spiking cells reducing population decoding accuracy for remembered locations. Our results show that primate LPFC generates robust neural codes for working memory in naturalistic settings and that such codes rely upon a fine balance between the activation of excitatory and inhibitory neurons.

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Distractor inhibition contributes to retroactive attentional orienting within working memory: Evidence by lateralized alpha oscillations in the EEG

10.1101/235069 ◽

2017 ◽

Cited By ~ 2

Author(s):

Daniel Schneider ◽

Anna Barth ◽

Henrike Haase ◽

Clayton Hickey ◽

Edmund Wascher

Keyword(s):

Working Memory ◽

Memory Representation ◽

Alpha Power ◽

Attentional Orienting ◽

Cognitive Mechanisms ◽

Storage And Retrieval ◽

Irrelevant Item ◽

Memory Representations ◽

The Cost ◽

Memory Resources

AbstractShifts of attention within mental representations based on retroactive cues (retro-cues) facilitate performance in working memory tasks. It was suggested that this retro-cue benefit is related to the concentration of working memory resources on a subset of representations, thereby improving storage and retrieval at the cost of non-cued items. However, the attentional mechanisms underlying this updating of working memory representations remain unknown. Here, we present EEG data for distinguishing between target enhancement and distractor suppression processes in the context of retroactive attentional orienting. Therefore, we used a working memory paradigm with retro-cues indicating a shift of attention to either a lateralized or non-lateralized item. There was an increase of posterior alpha power contralateral compared to ipsilateral to the irrelevant item when a non-lateralized mental representation was cued and a contralateral suppression of posterior alpha power when a lateralized item had to be selected. This suggests that both inhibition of the non-cued information and enhancement of the target representation are important features of attentional orienting within working memory. By further presenting cues to either remember or to forget a working memory representation, we give a first impression of these retroactive attentional sub-processes as two separable cognitive mechanisms.

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Neural evidence for categorical biases in working memory for location and orientation

10.1101/2020.12.15.422978 ◽

2020 ◽

Author(s):

Gi-Yeul Bae

Keyword(s):

Working Memory ◽

Computational Models ◽

Spatial Working Memory ◽

Memory Representation ◽

Response Preparation ◽

Behavioral Measures ◽

Eeg Data ◽

Categorical Structure ◽

Memory Representations ◽

Preparation Strategy

AbstractPrevious research demonstrated that visual working memory exhibits biases with respect to the categorical structure of the stimulus space. However, a majority of those studies used behavioral measures of working memory, and it is not clear whether the working memory representations per se are influenced by the categorical structure or whether the biases arise in decision or response processes during the report. Here, I applied a multivariate decoding technique to EEG data collected during working memory tasks to determine whether neural activity associated with the working memory representation is categorically biased prior to the report. I found that the decoding of spatial working memory was biased away from the nearest cardinal location, consistent with the biases observed in the behavioral responses. In a follow-up experiment which was designed to prevent the use of a response preparation strategy, I found that the decoding still exhibited categorical biases. Together, these results provide neural evidence that working memory representations themselves are categorically biased, imposing important constraints on the computational models of working memory representations.

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The Cultural Foundation of Human Memory

Annual Review of Psychology ◽

10.1146/annurev-psych-070920-023638 ◽

2021 ◽

Vol 72 (1) ◽

pp. 151-179 ◽

Cited By ~ 2

Author(s):

Qi Wang

Keyword(s):

Working Memory ◽

Episodic Memory ◽

Memory Function ◽

Human Memory ◽

Memory Representation ◽

Future Directions ◽

Memory Research ◽

Cultural Elements ◽

Mind And Brain ◽

The Mind

Human memory, as a product of the mind and brain, is inherently private and personal. Yet, arising from the interaction between the organism and its ecology in the course of phylogeny and ontogeny, human memory is also profoundly collective and cultural. In this review, I discuss the cultural foundation of human memory. I start by briefly reflecting on the conception of memory against a historical and cultural background. I then detail a model of a culturally saturated mnemonic system in which cultural elements constitute and condition various processes of remembering, focusing on memory representation, perceptual encoding, memory function, memory reconstruction, memory expression, and memory socialization. Then I discuss research on working memory, episodic memory, and autobiographical memory as examples that further demonstrate how cultural elements shape the processes and consequences of remembering and lay the foundation for human memory. I conclude by outlining some important future directions in memory research.

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Inhibition-of-return-like effects in working memory? A preregistered replication study of Johnson et al . (2013)

Royal Society Open Science ◽

10.1098/rsos.210254 ◽

2021 ◽

Vol 8 (7) ◽

pp. 210254

Author(s):

Naomi Langerock ◽

Giuliana Sposito ◽

Caro Hautekiet ◽

Evie Vergauwe

Keyword(s):

Working Memory ◽

Cognitive Psychology ◽

Inhibition Of Return ◽

Replication Study ◽

Memory Representation ◽

Central Concept ◽

Inhibitory Processes ◽

Look Back ◽

Memory Inhibition ◽

Memory Representations

The present study concerns a preregistered replication of the study conducted by Johnson et al . (Johnson et al. 2013 Psychol. Sci. 24 , 1104–1112 ( doi:10.1177/0956797612466414 )), in which they showed an inhibition-of-return-like effect in working memory. Inhibition of return is a well-known phenomenon observed in the field of perception and refers to the observation that it takes longer to look back at a location which has recently been explored than to look at an unexplored location. Working memory is a central concept in the field of cognitive psychology and refers to the capacity to process and maintain information simultaneously over short periods of time. Johnson's study applied the inhibition of return paradigm to the concept of working memory. Their results showed that it is harder to access a working memory representation that had just been thought of, i.e. refreshed, in comparison to an unrefreshed working memory representation. Contrary to this study of Johnson et al ., who observed refreshing to result in inhibitory processes, most studies on refreshing have described its effect as increasing/prolonging the level of activation of the memory representations. In an attempt to integrate these opposite patterns produced by ‘refreshing’, we started by replicating one of the studies on the inhibition of return in working memory reported by Johnson et al .

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A Self-Organizing Short-Term Dynamical Memory Network

10.1101/144683 ◽

2017 ◽

Cited By ~ 2

Author(s):

Callie Federer ◽

Joel Zylberberg

Keyword(s):

Working Memory ◽

Biological Networks ◽

Null Space ◽

Memory Function ◽

Connectivity Matrix ◽

Prior Work ◽

Neural Activities ◽

Synaptic Noise ◽

Memory Representations ◽

External Stimuli

AbstractWorking memory requires information about external stimuli to be represented in the brain even after those stimuli go away. This information is encoded in the activities of neurons, and neural activities change over timescales of tens of milliseconds. Information in working memory, however, is retained for tens of seconds, suggesting the question of how time-varying neural activities maintain stable representations. Prior work shows that, if the neural dynamics are in the ‘null space’ of the representation - so that changes to neural activity do not affect the downstream read-out of stimulus information - then information can be retained for periods much longer than the time-scale of individual-neuronal activities. The prior work, however, requires precisely constructed synaptic connectivity matrices, without explaining how this would arise in a biological neural network. To identify mechanisms through which biological networks can self-organize to learn memory function, we derived biologically plausible synaptic plasticity rules that dynamically modify the connectivity matrix to enable information storing. Networks implementing this plasticity rule can successfully learn to form memory representations even if only 10% of the synapses are plastic, they are robust to synaptic noise, and they can represent information about multiple stimuli.

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