Theta and Gamma Power Increases and Alpha/Beta Power Decreases with Memory Load in an Attractor Network Model

2011 ◽  
Vol 23 (10) ◽  
pp. 3008-3020 ◽  
Author(s):  
Mikael Lundqvist ◽  
Pawel Herman ◽  
Anders Lansner
Keyword(s):  
Working Memory ◽  
Single Cell ◽  
Network Model ◽  
Memory Load ◽  
Cell Activity ◽  
Gamma Oscillations ◽  
Attractor Network ◽  
Beta Power ◽  
Gamma Power ◽  
Alpha Beta

Changes in oscillatory brain activity are strongly correlated with performance in cognitive tasks and modulations in specific frequency bands are associated with working memory tasks. Mesoscale network models allow the study of oscillations as an emergent feature of neuronal activity. Here we extend a previously developed attractor network model, shown to faithfully reproduce single-cell activity during retention and memory recall, with synaptic augmentation. This enables the network to function as a multi-item working memory by cyclic reactivation of up to six items. The reactivation happens at theta frequency, consistently with recent experimental findings, with increasing theta power for each additional item loaded in the network's memory. Furthermore, each memory reactivation is associated with gamma oscillations. Thus, single-cell spike trains as well as gamma oscillations in local groups are nested in the theta cycle. The network also exhibits an idling rhythm in the alpha/beta band associated with a noncoding global attractor. Put together, the resulting effect is increasing theta and gamma power and decreasing alpha/beta power with growing working memory load, rendering the network mechanisms involved a plausible explanation for this often reported behavior.

Gamma Oscillations Index Sustained Attention in a Brief Vigilance Task

2021 ◽  
Vol 65 (1) ◽  
pp. 546-550
Author(s):  
Lorraine Borghetti ◽  
Megan B. Morris ◽  
L. Jack Rhodes ◽  
Ashley R. Haubert ◽  
Bella Z. Veksler
Keyword(s):  
Sustained Attention ◽  
Gamma Oscillations ◽  
Time On Task ◽  
Potential Candidate ◽  
Theta Power ◽  
High Performers ◽  
Beta Power ◽  
Study Results ◽  
Gamma Power ◽  
Compensatory Effort

Sustained attention is an essential behavior in life, but often leads to performance decrements with time. Computational accounts of sustained attention suggest this is due to brief disruptions in goal-directed processing, or microlapses. Decreases in gamma spectral power are a potential candidate for indexing microlapses and discriminating between low and high performers in sustained attention tasks, while increases in beta, alpha, and theta power are expected to exhibit compensatory effort to offset fatigue. The current study tests these hypotheses in a 10-minute Psychomotor Vigilance Test, a context that eliminates confounds with measuring gamma frequencies. 34 participants ( Mage = 22.60; SDage = 4.08) volunteered in the study. Results suggested frontal gamma power declined with time-on-task, indicating reduction in central cognition. Beta power increased with time-on-task, suggesting compensatory effort; however, alpha and theta power did not increase. Additionally, gamma power discriminated between low and high performers, potentially suggesting motivational differences between the groups.

scholarly journals GSK3β inhibition restores cortical gamma oscillation and cognitive behavior in a mouse model of NMDA receptor hypofunction relevant to schizophrenia

2020 ◽  
Vol 45 (13) ◽  
pp. 2207-2218
Author(s):  
Kazuhito Nakao ◽  
Mahendra Singh ◽  
Kiran Sapkota ◽  
Bailey C. Hagler ◽  
Robert N. Hunter ◽  
...  
Keyword(s):  
Working Memory ◽  
Mouse Model ◽  
Spatial Working Memory ◽  
Gamma Oscillations ◽  
Gamma Oscillation ◽  
Mutant Mice ◽  
Patch Clamp Recording ◽  
Behavioral Deficits ◽  
Gamma Power ◽  
Sensory Evoked

Abstract Cortical gamma oscillations are believed to be involved in mental processes which are disturbed in schizophrenia. For example, the magnitudes of sensory-evoked oscillations, as measured by auditory steady-state responses (ASSRs) at 40 Hz, are robustly diminished, whereas the baseline gamma power is enhanced in schizophrenia. Such dual gamma oscillation abnormalities are also present in a mouse model of N-methyl-D-aspartate receptor hypofunction (Ppp1r2cre/Grin1 knockout mice). However, it is unclear whether the abnormal gamma oscillations are associated with dysfunction in schizophrenia. We found that glycogen synthase kinase-3 (GSK3) is overactivated in corticolimbic parvalbumin-positive GABAergic interneurons in Grin1 mutant mice. Here we addressed whether GSK3β inhibition reverses both abnormal gamma oscillations and behavioral deficits with high correlation by pharmacological and genetic approach. We demonstrated that the paralog selective-GSK3β inhibitor, but not GSK3α inhibitor, normalizes the diminished ASSRs, excessive baseline gamma power, and deficits in spatial working memory and prepulse inhibition (PPI) of acoustic startle in Grin1 mutant mice. Cell-type specific GSK3B knockdown, but not GSK3A knockdown, also reversed abnormal gamma oscillations and behavioral deficits. Moreover, GSK3B knockdown, but not GSK3A knockdown, reverses the mutants’ in vivo spike synchrony deficits. Finally, ex vivo patch-clamp recording from pairs of neighboring cortical pyramidal neurons showed a reduction of synchronous spontaneous inhibitory-postsynaptic-current events in mutants, which was reversed by GSK3β inhibition genetically and pharmacologically. Together, GSK3β inhibition in corticolimbic interneurons ameliorates the deficits in spatial working memory and PPI, presumably by restoration of synchronous GABA release, synchronous spike firing, and evoked-gamma power increase with lowered baseline power.

scholarly journals The neural correlates of two forms of spiritual love: an EEG study

2016 ◽  
Author(s):  
E. S. Louise Faber
Keyword(s):  
Neural Activity ◽  
Emotional Experience ◽  
Gamma Oscillations ◽  
Neural Correlates ◽  
Spiritual Practices ◽  
Loving Kindness ◽  
Beta Power ◽  
Delta Activity ◽  
Gamma Power ◽  
The Brain

AbstractSpiritual practices are gaining an increasingly wider audience as a means to enhance positive affect in healthy individuals and to treat neurological disorders such as anxiety and depression. The current study aimed to examine the neural correlates of two different forms of love generated by spiritual practices using EEG; love generated during a loving kindness meditation performed by Buddhist meditators, and love generated during prayer, in a separate group of participants from a Christian-based faith. The loving kindness meditation was associated with significant increases in delta, alpha 1, alpha 2 and beta power compared to baseline, while prayer induced significant increases in power of alpha 1 and gamma oscillations, together with an increase in the gamma: theta ratio. An increase in delta activity occurred during the loving kindness meditation but not during prayer. In contrast increases in theta, alpha 1, alpha 2, beta and gamma power were observed when comparing both types of practice to baseline, suggesting that increases in these frequency bands are the neural correlates of spiritual love, independent of the type of practice used to attain the state of this type of love. These findings show that both spiritual love practices are associated with widespread changes in neural activity across the brain, in particular at frequency ranges that have been implicated in positive emotional experience, integration of distributed neural activity, and changes in short-term and longterm neural circuitry.

scholarly journals Across-Area Synchronization Supports Feature Integration in a Biophysical Network Model of Working Memory

2021 ◽  
Vol 15 ◽  
Author(s):  
Joao Barbosa ◽  
Vahan Babushkin ◽  
Ainsley Temudo ◽  
Kartik K. Sreenivasan ◽  
Albert Compte
Keyword(s):  
Working Memory ◽  
Network Model ◽  
Feedback Inhibition ◽  
Memory Function ◽  
Explanatory Power ◽  
Phase Relationship ◽  
Gamma Oscillations ◽  
Feature Binding ◽  
Recurrent Excitation ◽  
Rate Coding

Working memory function is severely limited. One key limitation that constrains the ability to maintain multiple items in working memory simultaneously is so-called swap errors. These errors occur when an inaccurate response is in fact accurate relative to a non-target stimulus, reflecting the failure to maintain the appropriate association or “binding” between the features that define one object (e.g., color and location). The mechanisms underlying feature binding in working memory remain unknown. Here, we tested the hypothesis that features are bound in memory through synchrony across feature-specific neural assemblies. We built a biophysical neural network model composed of two one-dimensional attractor networks – one for color and one for location – simulating feature storage in different cortical areas. Within each area, gamma oscillations were induced during bump attractor activity through the interplay of fast recurrent excitation and slower feedback inhibition. As a result, different memorized items were held at different phases of the network’s oscillation. These two areas were then reciprocally connected via weak cortico-cortical excitation, accomplishing binding between color and location through the synchronization of pairs of bumps across the two areas. Encoding and decoding of color-location associations was accomplished through rate coding, overcoming a long-standing limitation of binding through synchrony. In some simulations, swap errors arose: “color bumps” abruptly changed their phase relationship with “location bumps.” This model, which leverages the explanatory power of similar attractor models, specifies a plausible mechanism for feature binding and makes specific predictions about swap errors that are testable at behavioral and neurophysiological levels.

The Preliminary Investigation of Multi-Level Working Memory in Predicting Anxiety/Depressive Symptomatology in Childhood/Adolescence

2019 ◽  
Author(s):  
Brian Kavanaugh ◽  
Alexa Fryc ◽  
Simona Temereanca Ibanescu ◽  
Eric Tirrell ◽  
Lindsay Oberman ◽  
...  
Keyword(s):  
Working Memory ◽  
Depressive Symptomatology ◽  
Preliminary Investigation ◽  
Gamma Oscillations ◽  
Composite Score ◽  
Clinical Markers ◽  
Measurement Variability ◽  
Parent Questionnaire ◽  
Gamma Power ◽  
Multi Level

Prior research in working memory (WM) has been hampered by measurement variability and a lack of integration of neural and clinical markers. This study sought to examine whether a multi-level composite of WM with neural, cognitive, and behavioral levels could predict childhood affective symptomatology in seventeen children and adolescents receiving outpatient mental health services. WM-related theta/gamma oscillations at the F3 electrode were measured via electroencephalography (EEG) recording during a spatial WM task. Other measures included a neuropsychological measure of WM, parent questionnaire assessing WM, and self-reported affective symptoms. Gamma power and theta-gamma coupling, but not theta power, predicted high WM demands performance (i.e., 16-19% of variance). Two composite scores were created consisting of gamma power or theta-gamma coupling, clinical WM measure performance, and parent-reported WM symptoms. These multi-level composite score predicted self-reported depressive (22-32% of variance) symptoms, while only the gamma-version of the composite predicted anxious symptoms (39% of variance compared to 12% of variance). A WM composite score consisting of neural, cognitive, and behavioral levels predicted the severity of childhood affective symptomatology. WM, like other EFs, is highly complex and may be most appropriately measured in clinical and research settings with a combination of neural, cognitive, and behavioral measures.

scholarly journals Early alpha/beta oscillations reflect the formation of face-related expectations in the brain

PLoS ONE ◽  
2021 ◽  
Vol 16 (7) ◽  
pp. e0255116
Author(s):  
Marlen A. Roehe ◽  
Daniel S. Kluger ◽  
Svea C. Y. Schroeder ◽  
Lena M. Schliephake ◽  
Jens Boelte ◽  
...  
Keyword(s):  
Event Related Potentials ◽  
Face Images ◽  
Power Enhancement ◽  
Contrast Enhanced ◽  
Beta Power ◽  
Gamma Power ◽  
Statistical Regularities ◽  
Related Potentials ◽  
Alpha Beta ◽  
The Brain

Although statistical regularities in the environment often go explicitly unnoticed, traces of implicit learning are evident in our neural activity. Recent perspectives have offered evidence that both pre-stimulus oscillations and peri-stimulus event-related potentials are reliable biomarkers of implicit expectations arising from statistical learning. What remains ambiguous, however, is the origination and development of these implicit expectations. To address this lack of knowledge and determine the temporal constraints of expectation formation, pre-stimulus increases in alpha/beta power were investigated alongside a reduction in the N170 and a suppression in peri-/post-stimulus gamma power. Electroencephalography was acquired from naive participants who engaged in a gender classification task. Participants were uninformed, that eight face images were sorted into four reoccurring pairs which were pseudorandomly hidden amongst randomly occurring face images. We found a reduced N170 for statistically expected images at left parietal and temporo-parietal electrodes. Furthermore, enhanced gamma power following the presentation of random images emphasized the bottom-up processing of these arbitrary occurrences. In contrast, enhanced alpha/beta power was evident pre-stimulus for expected relative to random faces. A particularly interesting finding was the early onset of alpha/beta power enhancement which peaked immediately after the depiction of the predictive face. Hence, our findings propose an approximate timeframe throughout which consistent traces of enhanced alpha/beta power illustrate the early prioritisation of top-down processes to facilitate the development of implicitly cued face-related expectations.

Spectral Properties of Induced and Evoked Gamma Oscillations in Human Early Visual Cortex to Moving and Stationary Stimuli

2009 ◽  
Vol 102 (2) ◽  
pp. 1241-1253 ◽  
Author(s):  
J. B. Swettenham ◽  
S. D. Muthukumaraswamy ◽  
K. D. Singh
Keyword(s):  
Visual Cortex ◽  
Stimulus Presentation ◽  
Gamma Oscillations ◽  
Induced Response ◽  
Stimulus Motion ◽  
Time Frequency ◽  
Beta Power ◽  
Visual Areas ◽  
Gamma Power ◽  
Early Visual Cortex

In two experiments, magnetoencephalography (MEG) was used to investigate the effects of motion on gamma oscillations in human early visual cortex. When presented centrally, but not peripherally, stationary and moving gratings elicited several evoked and induced response components in early visual cortex. Time-frequency analysis revealed two nonphase locked gamma power increases—an initial, rapidly adapting response and one sustained throughout stimulus presentation and varying in frequency across observers from 28 to 64 Hz. Stimulus motion raised the sustained gamma oscillation frequency by a mean of ∼10 Hz. The largest motion-induced frequency increases were in those observers with the lowest gamma response frequencies for stationary stimuli, suggesting a possible saturation mechanism. Moderate gamma amplitude increases to moving versus stationary stimuli were also observed but were not correlated with the magnitude of the frequency increase. At the same site in visual cortex, sustained alpha/beta power reductions and an onset evoked response were observed, but these effects did not change significantly with the presence of motion and did not correlate with the magnitude of gamma power changes. These findings suggest that early visual areas encode moving and stationary percepts via activity at higher and lower gamma frequencies, respectively.

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