Changes in delta and theta oscillations in the brain indicate dynamic switching of attention between internal and external processing

AbstractIn recent years, several hierarchical extensions of well-known learning algorithms have been proposed. For example, when stimulus-action mappings vary across time or context, the brain may learn two or more stimulus-action mappings in separate modules, and additionally (at a hierarchically higher level) learn to appropriately switch between those modules. However, how the brain mechanistically coordinates neural communication to implement such hierarchical learning, remains unknown. Therefore, the current study tests a recent computational model that proposed how midfrontal theta oscillations implement such hierarchical learning via the principle of binding by synchrony (Sync model). More specifically, the Sync model employs bursts at theta frequency to flexibly bind appropriate task modules by synchrony. 64-channel EEG signal was recorded while 27 human subjects (Female: 21, Male: 6) performed a probabilistic reversal learning task. In line with the Sync model, post-feedback theta power showed a linear relationship with negative prediction errors, but not with positive prediction errors. This relationship was especially pronounced for subjects with better behavioral fit (measured via AIC) of the Sync model. Also consistent with Sync model simulations, theta phase-coupling between midfrontal electrodes and temporo-parietal electrodes was stronger after negative feedback. Our data suggest that the brain uses theta power and synchronization for flexibly switching between task rule modules, as is useful for example when multiple stimulus-action mappings must be retained and used.Significance StatementEveryday life requires flexibility in switching between several rules. A key question in understanding this ability is how the brain mechanistically coordinates such switches. The current study tests a recent computational framework (Sync model) that proposed how midfrontal theta oscillations coordinate activity in hierarchically lower task-related areas. In line with predictions of this Sync model, midfrontal theta power was stronger when rule switches were most likely (strong negative prediction error), especially in subjects who obtained a better model fit. Additionally, also theta phase connectivity between midfrontal and task-related areas was increased after negative feedback. Thus, the data provided support for the hypothesis that the brain uses theta power and synchronization for flexibly switching between rules.

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Probing Neural Networks for Dynamic Switches of Communication Pathways

10.1101/523522 ◽

2019 ◽

Author(s):

Holger Finger ◽

Richard Gast ◽

Christian Gerloff ◽

Andreas K. Engel ◽

Peter König

Keyword(s):

Neural Networks ◽

Human Brain ◽

Computational Model ◽

Broad Spectrum ◽

Dynamic Properties ◽

Dynamic Network ◽

Thought Processes ◽

Response Properties ◽

Dynamic Switching ◽

The Brain

AbstractDynamic communication and routing play important roles in the human brain to facilitate 2exibility in task solving and thought processes. Here, we present a network perturbation methodology that allows to investigate dynamic switching between different network pathways based on phase offsets between two external oscillatory drivers. We apply this method in a computational model of the human connectome with delay-coupled neural masses. To analyze dynamic switching of pathways, we define four new metrics that measure dynamic network response properties for pairs of stimulated nodes. Evaluating these metrics for all network pathways, we found a broad spectrum of pathways with distinct dynamic properties and switching behaviors. Specifically, we found that 60.1% of node pairs can switch their communication from one pathway to another depending on their phase offsets. This indicates that phase offsets and coupling delays play an important computational role for the dynamic switching between communication pathways in the brain.

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Respiration competes with theta for modulating parietal cortex neurons

10.1101/707331 ◽

2019 ◽

Author(s):

Felix Jung ◽

Yevgenij Yanovsky ◽

Jurij Brankačk ◽

Adriano BL Tort ◽

Andreas Draguhn

Keyword(s):

Neuronal Activity ◽

Parietal Cortex ◽

Field Potential ◽

Anterior Cingulate ◽

Theta Oscillations ◽

Network Activity ◽

Coupled Oscillations ◽

Neuronal Network Activity ◽

Posterior Parietal ◽

The Brain

AbstractRecent work has shown that nasal respiration entrains local field potential (LFP) and neuronal activity in widespread regions of the brain. This includes non-olfactory regions where respiration-coupled oscillations have been described in different mammals, such as rodents, cats and humans. They may, thus, constitute a global signal aiding interregional communication. Nevertheless, the brain produces other widespread slow rhythms, such as theta oscillations, which also mediate long-range synchronization of neuronal activity. It is completely unknown how these different signals interact to control neuronal network activity. In this work, we characterized respiration- and theta-coupled activity in the posterior parietal cortex of mice. Our results show that respiration-coupled and theta oscillations have different laminar profiles, in which respiration preferentially entrains LFPs and units in more superficial layers, whereas theta modulation does not differ across the parietal cortex. Interestingly, we find that the percentage of theta-modulated units increases in the absence of respiration-coupled oscillations, suggesting that both rhythms compete for modulating parietal cortex neurons. We further show through intracellular recordings that synaptic inhibition is likely to play a role in generating respiration-coupled oscillations at the membrane potential level. Finally, we provide anatomical and electrophysiological evidence of reciprocal monosynaptic connections between the anterior cingulate and posterior parietal cortices, suggesting a possible source of respiration-coupled activity in the parietal cortex.

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Induced Theta Activity as a Biomarker for a Morbid Effect of Alcoholism on the Brain in Long-Term Abstinent Alcoholics

Journal of Psychophysiology ◽

10.1027/0269-8803/a000089 ◽

2013 ◽

Vol 27 (2) ◽

pp. 76-83 ◽

Cited By ~ 5

Author(s):

Casey S. Gilmore ◽

George Fein

Keyword(s):

Brain Function ◽

Target Stimulus ◽

Brain Activity ◽

Theta Activity ◽

Theta Oscillations ◽

Time Frequency ◽

Related Information ◽

The Relationship ◽

The Brain

Event-related, target stimulus-phase-locked (evoked) brain activity in both the time and time-frequency (TF) domains (the P3b ERP; evoked theta oscillations) has been shown to be reduced in alcoholics. Recently, studies have suggested that there is alcohol-related information in the non-stimulus-phase-locked (induced) theta TF activity. We applied TF analysis to target stimulus event-related EEG recorded during an oddball task from 41 long-term abstinent alcoholics (LTAA) and 74 nonalcoholic controls (NAC) to investigate the relationship between P3b, evoked theta, and induced theta activity. Results showed that an event-related synchronization (ERS) of induced theta (1) was larger in LTAA compared to NAC, and (2) was sensitive to differences between LTAA and NAC groups that was independent of the differences accounted for by P3b amplitude or evoked theta. These findings suggest that increased induced theta ERS may likely be a biomarker for a morbid effect of alcohol abuse on brain function.

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Theta-burst stimulation entrains frequency-specific oscillatory responses

10.21203/rs.3.rs-308421/v2 ◽

2021 ◽

Author(s):

Ethan Solomon ◽

Michael Sperling ◽

Ashwini Sharan ◽

Paul Wanda ◽

Deborah Levy ◽

...

Keyword(s):

Cognitive Processes ◽

Neural Activity ◽

Brain Regions ◽

Theta Oscillations ◽

Theta Burst Stimulation ◽

Burst Stimulation ◽

Electrical Pulses ◽

Brain Architecture ◽

The Brain ◽

Theta Burst

Abstract Background: Brain stimulation has emerged as a powerful tool in human neuroscience, becoming integral to next-generation psychiatric and neurologic therapeutics. Theta-burst stimulation (TBS), in which electrical pulses are delivered in rhythmic bouts of 3-8 Hz, seeks to recapitulate neural activity seen endogenously during cognitive tasks. A growing literature suggests that TBS can be used to alter or enhance cognitive processes, but little is known about how these stimulation events influence underlying neural activity.Objective/Hypothesis: The goal of our study was to investigate the effect of direct electrical TBS on mesoscale neural activity in humans by asking (1) whether TBS evokes persistent theta oscillations in cortical areas, (2) whether these oscillations occur at the stimulated frequency, and (3) whether stimulation events propagate in a manner consistent with underlying functional and structural brain architecture.Methods: We recruited 20 neurosurgical epilepsy patients with indwelling electrodes and delivered direct cortical TBS at varying locations and frequencies. Simultaneous iEEG was recorded from non-stimulated electrodes and analyzed to understand how TBS influences mesoscale neural activity. Results: We found that TBS rapidly evoked theta rhythms in widespread brain regions, preferentially at the stimulation frequency, and that these oscillations persisted for hundreds of milliseconds post stimulation offset. Furthermore, the functional connectivity between recording and stimulation sites predicted the strength of theta response, suggesting that underlying brain architecture guides the flow of stimulation through the brain.Conclusions: By demonstrating that direct TBS induces frequency-specific oscillatory responses, our results suggest this technology can be used to directly and predictably influence the activity of cognitively-relevant brain networks.

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Speech encoding by coupled cortical theta and gamma oscillations

eLife ◽

10.7554/elife.06213 ◽

2015 ◽

Vol 4 ◽

Cited By ~ 75

Author(s):

Alexandre Hyafil ◽

Lorenzo Fontolan ◽

Claire Kabdebon ◽

Boris Gutkin ◽

Anne-Lise Giraud

Keyword(s):

Parallel Processing ◽

Auditory Cortex ◽

Sensory Analysis ◽

Gamma Oscillations ◽

Theta Oscillations ◽

Rhythmic Structure ◽

Speech Encoding ◽

Cortical Oscillations ◽

Slow Speech ◽

The Brain

Many environmental stimuli present a quasi-rhythmic structure at different timescales that the brain needs to decompose and integrate. Cortical oscillations have been proposed as instruments of sensory de-multiplexing, i.e., the parallel processing of different frequency streams in sensory signals. Yet their causal role in such a process has never been demonstrated. Here, we used a neural microcircuit model to address whether coupled theta–gamma oscillations, as observed in human auditory cortex, could underpin the multiscale sensory analysis of speech. We show that, in continuous speech, theta oscillations can flexibly track the syllabic rhythm and temporally organize the phoneme-level response of gamma neurons into a code that enables syllable identification. The tracking of slow speech fluctuations by theta oscillations, and its coupling to gamma-spiking activity both appeared as critical features for accurate speech encoding. These results demonstrate that cortical oscillations can be a key instrument of speech de-multiplexing, parsing, and encoding.

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Behavioral significance of hippocampal theta oscillations: looking elsewhere to find the right answers

Journal of Neurophysiology ◽

10.1152/jn.00358.2011 ◽

2011 ◽

Vol 106 (2) ◽

pp. 497-499 ◽

Cited By ~ 9

Author(s):

Calvin K. Young

Keyword(s):

Brain Structures ◽

Spike Timing ◽

Theta Oscillations ◽

Field Potentials ◽

Dynamic Coupling ◽

Theta Frequency ◽

Spike Timing Precision ◽

The Right ◽

Hippocampal Theta ◽

The Brain

The function of hippocampal theta oscillations has been subjected to constant speculation. Dynamic coupling of theta field potentials and spiking activity between the hippocampus and extra-hippocampal structures emphasizes the importance of theta-frequency oscillations in global spike-timing precision in the brain. Recent advances in understanding theta coupling between distant brain structures are discussed and explored in this article.

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Evidence for two distinct thalamocortical circuits in retrosplenial cortex

10.1101/2021.06.11.448056 ◽

2021 ◽

Author(s):

Eleonora Lomi ◽

Mathias L Mathiasen ◽

Han Yin Cheng ◽

Ningyu Zhang ◽

John P Aggleton ◽

...

Keyword(s):

Neural Coding ◽

Field Potential ◽

Retrosplenial Cortex ◽

Theta Oscillations ◽

Single Unit Activity ◽

Theta Band ◽

Potential Oscillations ◽

Anterior Thalamus ◽

Differential Weighting ◽

The Brain

Retrosplenial cortex (RSC) lies at the interface between perceptual and memory networks in the brain and mediates between these, although it is not yet known how. It has two distinct subregions, granular (gRSC) and dysgranular (dRSC). The present study investigated how these subregions differ with respect to their electrophysiology and connections, as a step towards understanding their functions. gRSC is more closely connected to the hippocampal system, in which theta-band local field potential oscillations are prominent. We therefore compared theta-rhythmic single-unit activity between the two RSC subregions and found, mostly in gRSC, a subpopulation of non-directional cells with spiking activity strongly entrained by theta oscillations, suggesting a stronger coupling of gRSC to the hippocampal system. We then used retrograde tracers to examine whether differences in neural coding between RSC subregions might reflect differential inputs from the anterior thalamus, which is a prominent source of RSC afferents. We found that gRSC and dRSC differ in their afferents from two AV subfields: dorsomedial (AVDM) and ventrolateral (AVVL). AVVL targets both gRSC and dRSC, while AVDM provides a selective projection to gRSC. These combined results suggest the existence of two distinct but interacting RSC subcircuits: one connecting AVDM to gRSC that may comprise part of the cognitive hippocampal system, and the other connecting AVVL to both RSC regions that may link hippocampal and perceptual regions. We suggest that these subcircuits are distinct to allow for differential weighting during integration of converging sensory and cognitive computations: an integration that may take place in thalamus, RSC or both.

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