scholarly journals Selective control of working memory in prefrontal, parietal, and visual cortex

2020 ◽  
Author(s):  
Matthew F. Panichello ◽  
Timothy J. Buschman
Keyword(s):  
Working Memory ◽  
Prefrontal Cortex ◽  
Visual Cortex ◽  
Primary Role ◽  
Dependent Manner ◽  
Sensory Stimuli ◽  
Neural Recordings ◽  
Memory And Attention ◽  
Memory Representations ◽  
Selection Of

AbstractCognitive control guides behavior by controlling what, where, and how information is represented in the brain. Previous work has shown parietal and prefrontal cortex direct attention, which controls the representation of external sensory stimuli1,2. However, the neural mechanisms controlling the selection of representations held ‘in mind’, in working memory, are unknown. To address this, we trained two monkeys to switch between two tasks, requiring them to either select an item from a set of items held in working memory or attend to one stimulus from a set of visual stimuli. Simultaneous neural recordings in prefrontal, parietal, and visual cortex found prefrontal cortex played a primary role in selecting an item from working memory, representing selection before parietal and visual cortex. Surprisingly, a common population representation in prefrontal cortex encoded selection of an item in working memory and attention to an external stimulus, suggesting prefrontal cortex may act as a domain-general controller. Selection acted on memory representations in two ways. First, selection improved the accuracy of memory reports by enhancing the selected item’s representation in prefrontal and parietal cortex. Second, selection transformed memory representations in a task-dependent manner. Before selection, when both items were relevant to the task, the identity of each item was represented in an independent subspace of neural activity. After selection, the representation of only the selected item was transformed into a new subspace that was used to guide the animal’s behavioral report. Together, our results provide insight into how prefrontal cortex controls working memory representations, selectively enhancing and transforming them to support behavior.

scholarly journals The Neural Codes Underlying Internally Generated Representations in Visual Working Memory

2021 ◽  
pp. 1-16
Author(s):  
Qing Yu ◽  
Bradley R. Postle
Keyword(s):  
Working Memory ◽  
Visual Cortex ◽  
Visual Working Memory ◽  
Subjective Experience ◽  
Neural Representation ◽  
Delayed Recall ◽  
Early Visual Cortex ◽  
Memory Representations ◽  
Internal Sources ◽  
Scaling Analyses

Abstract Humans can construct rich subjective experience even when no information is available in the external world. Here, we investigated the neural representation of purely internally generated stimulus-like information during visual working memory. Participants performed delayed recall of oriented gratings embedded in noise with varying contrast during fMRI scanning. Their trialwise behavioral responses provided an estimate of their mental representation of the to-be-reported orientation. We used multivariate inverted encoding models to reconstruct the neural representations of orientation in reference to the response. We found that response orientation could be successfully reconstructed from activity in early visual cortex, even on 0% contrast trials when no orientation information was actually presented, suggesting the existence of a purely internally generated neural code in early visual cortex. In addition, cross-generalization and multidimensional scaling analyses demonstrated that information derived from internal sources was represented differently from typical working memory representations, which receive influences from both external and internal sources. Similar results were also observed in intraparietal sulcus, with slightly different cross-generalization patterns. These results suggest a potential mechanism for how externally driven and internally generated information is maintained in working memory.

scholarly journals Goal-directed and stimulus-driven selection of internal representations

2020 ◽  
Vol 117 (39) ◽  
pp. 24590-24598
Author(s):  
Freek van Ede ◽  
Alexander G. Board ◽  
Anna C. Nobre
Keyword(s):  
Working Memory ◽  
Feature Matching ◽  
Memory Performance ◽  
Sensory Information ◽  
Internal Representations ◽  
Memory Representations ◽  
External Stimuli ◽  
Selection Of ◽  
Do So

Adaptive behavior relies on the selection of relevant sensory information from both the external environment and internal memory representations. In understanding external selection, a classic distinction is made between voluntary (goal-directed) and involuntary (stimulus-driven) guidance of attention. We have developed a task—the anti-retrocue task—to separate and examine voluntary and involuntary guidance of attention to internal representations in visual working memory. We show that both voluntary and involuntary factors influence memory performance but do so in distinct ways. Moreover, by tracking gaze biases linked to attentional focusing in memory, we provide direct evidence for an involuntary “retro-capture” effect whereby external stimuli involuntarily trigger the selection of feature-matching internal representations. We show that stimulus-driven and goal-directed influences compete for selection in memory, and that the balance of this competition—as reflected in oculomotor signatures of internal attention—predicts the quality of ensuing memory-guided behavior. Thus, goal-directed and stimulus-driven factors together determine the fate not only of perception, but also of internal representations in working memory.

scholarly journals Intraparietal sulcus maintains working memory representations of somatosensory categories in an adaptive, context-dependent manner

NeuroImage ◽  
2020 ◽  
Vol 221 ◽  
pp. 117146 ◽  
Author(s):  
Lisa Alexandria Velenosi ◽  
Yuan-Hao Wu ◽  
Timo Torsten Schmidt ◽  
Felix Blankenburg
Keyword(s):  
Working Memory ◽  
Dependent Manner ◽  
Intraparietal Sulcus ◽  
Memory Representations ◽  
Context Dependent

scholarly journals Time-invariant working memory representations in the presence of code-morphing in the lateral prefrontal cortex

2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Aishwarya Parthasarathy ◽  
Cheng Tang ◽  
Roger Herikstad ◽  
Loong Fah Cheong ◽  
Shih-Cheng Yen ◽  
...  
Keyword(s):  
Working Memory ◽  
Prefrontal Cortex ◽  
Dimensional Subspace ◽  
Neural Data ◽  
Neuronal Populations ◽  
Attractor Model ◽  
Memory Representations ◽  
Low Dimensional ◽  
Types Of Information ◽  
Time Invariant

Abstract Maintenance of working memory is thought to involve the activity of prefrontal neuronal populations with strong recurrent connections. However, it was recently shown that distractors evoke a morphing of the prefrontal population code, even when memories are maintained throughout the delay. How can a morphing code maintain time-invariant memory information? We hypothesized that dynamic prefrontal activity contains time-invariant memory information within a subspace of neural activity. Using an optimization algorithm, we found a low-dimensional subspace that contains time-invariant memory information. This information was reduced in trials where the animals made errors in the task, and was also found in periods of the trial not used to find the subspace. A bump attractor model replicated these properties, and provided predictions that were confirmed in the neural data. Our results suggest that the high-dimensional responses of prefrontal cortex contain subspaces where different types of information can be simultaneously encoded with minimal interference.

scholarly journals The Neurocognitive Cost of Enhancing Cognition with Methylphenidate: Improved Distractor Resistance but Impaired Updating

2017 ◽  
Vol 29 (4) ◽  
pp. 652-663 ◽  
Author(s):  
Sean James Fallon ◽  
Marieke E. van der Schaaf ◽  
Niels ter Huurne ◽  
Roshan Cools
Keyword(s):  
Working Memory ◽  
Cognitive Flexibility ◽  
Dependent Manner ◽  
Neural Signal ◽  
Specific Effects ◽  
Cognitive Stability ◽  
Paradoxical Effects ◽  
Memory Representations ◽  
The Stability ◽  
And Task

A balance has to be struck between supporting distractor-resistant representations in working memory and allowing those representations to be updated. Catecholamine, particularly dopamine, transmission has been proposed to modulate the balance between the stability and flexibility of working memory representations. However, it is unclear whether drugs that increase catecholamine transmission, such as methylphenidate, optimize this balance in a task-dependent manner or bias the system toward stability at the expense of flexibility (or vice versa). Here we demonstrate, using pharmacological fMRI, that methylphenidate improves the ability to resist distraction (cognitive stability) but impairs the ability to flexibly update items currently held in working memory (cognitive flexibility). These behavioral effects were accompanied by task-general effects in the striatum and opposite and task-specific effects on neural signal in the pFC. This suggests that methylphenidate exerts its cognitive enhancing and impairing effects through acting on the pFC, an effect likely associated with methylphenidate's action on the striatum. These findings highlight that methylphenidate acts as a double-edged sword, improving one cognitive function at the expense of another, while also elucidating the neurocognitive mechanisms underlying these paradoxical effects.

scholarly journals Visual working memory and attention in early visual cortex

2010 ◽  
Vol 6 (6) ◽  
pp. 1091-1091
Author(s):  
S. Offen ◽  
D. Schluppeck ◽  
D. J. Heeger
Keyword(s):  
Working Memory ◽  
Visual Cortex ◽  
Visual Working Memory ◽  
Memory And Attention ◽  
Early Visual Cortex

scholarly journals Naturalistic coding of working memory in primate prefrontal cortex

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.

scholarly journals Selection of Visual Objects in Perception and Working Memory One at a Time

2019 ◽  
Vol 30 (9) ◽  
pp. 1259-1272 ◽  
Author(s):  
Nina Thigpen ◽  
Nathan M. Petro ◽  
Jessica Oschwald ◽  
Klaus Oberauer ◽  
Andreas Keil
Keyword(s):  
Working Memory ◽  
Visual Cortex ◽  
Steady State ◽  
Visual Evoked Potential ◽  
Evoked Potential ◽  
External World ◽  
Visual Environment ◽  
Single Item ◽  
Visual Objects ◽  
Selection Of

How does the content of visual working memory influence the way we process the visual environment? We addressed this question using the steady-state visual evoked potential (SSVEP), which provides a discernible measure of visuocortical activation to multiple stimuli simultaneously. Fifty-six adults were asked to remember a set of two oriented gratings. During the retention interval, two frequency-tagged oriented gratings were presented to probe the visuocortical processing of matching versus mismatching orientations relative to the memory set. Matching probes prompted an increased visuocortical response, whereas mismatching stimuli were suppressed. This suggests that the visual cortex prioritizes attentional selection of memory-relevant features at the expense of non-memory-relevant features. When two memory items were probed simultaneously, visuocortical amplification alternated between the two stimuli at a rate of 3 Hz to 4 Hz, consistent with the rate of attentional sampling of sensory events from the external world. These results suggest a serial, single-item attentional sampling of remembered features.

The Nature of Task Set Representations in Working Memory

2017 ◽  
Vol 29 (11) ◽  
pp. 1950-1961 ◽  
Author(s):  
Atsushi Kikumoto ◽  
Ulrich Mayr
Keyword(s):  
Working Memory ◽  
Executive Control ◽  
Long Term Memory ◽  
Dependent Manner ◽  
Stimulus Response ◽  
Set Size ◽  
Memory Representations ◽  
Task Sets ◽  
Limited Process

Selection and preparation of action plans (task sets) is often assumed to occur in working memory (WM). Yet, the absence of consistent evidence that WM capacity and task selection efficiency is correlated raises questions about the functional relationship between these two aspects of executive control. We used the EEG-derived contralateral delay activity (CDA) to index the WM load of task sets. In Experiment 1, we found a CDA set size effect (2 vs. 4 stimulus–response [S-R] rules) for high-WM, but not for low-WM, individuals when S-R sets were novel. In contrast, when only four task sets were presented throughout the experiment, we observed a sustained yet set size-independent use of WM for high-WM participants. Moreover, Experiment 2 showed an increase of the CDA in situations with task conflict, and this effect was larger the more that participants experienced RT conflict effects. Combined, these results indicate that even highly familiar S-R settings are maintained in WM, albeit in a compressed manner, presumably through cues to long-term memory representations. Finally, participants with low-WM capacity represented even familiar tasks in a load-dependent manner, suggesting that the establishment of effective retrieval structures itself is a capacity-limited process.

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