scholarly journals Stochastic Resonance Mediates the State-Dependent Effect of Periodic Stimulation on Cortical Alpha Oscillations

2017 ◽  
Author(s):  
Jérémie Lefebvre ◽  
Flavio Frohlich ◽  
Axel Hutt
Keyword(s):  
Stochastic Resonance ◽  
Rhythmic Activity ◽  
Oscillatory Activity ◽  
Alpha Oscillations ◽  
State Dependent ◽  
Periodic Stimulation ◽  
Brain States ◽  
Behavioral States ◽  
Thalamocortical System ◽  
And Task

ABSTRACTBrain stimulation can be used to engage and modulate rhythmic activity in cortical networks. However, the outcomes have been shown to be impacted by behavioral states and endogenous brain fluctuations. To better understand how this intrinsic oscillatory activity controls the brain’s susceptibility to stimulation, we analyzed a computational model of the thalamocortical system in both the rest and task states, to identify the mechanisms by which endogenous alpha oscillations (8Hz-12Hz) are impacted by periodic stimulation. Our analysis shows that the differences between different brain states can be explained by a passage through a bifurcation combined to stochastic resonance - a mechanism whereby irregular fluctuations amplify the response of a nonlinear system to weak signals. Indeed, our findings suggest that modulating brain oscillations is best achieved in states of low endogenous rhythmic activity, and that irregular state-dependent fluctuations in thalamic inputs shape the susceptibility of cortical population to periodic stimulation.

scholarly journals Stochastic resonance mediates the state-dependent effect of periodic stimulation on cortical alpha oscillations

eLife ◽  
2017 ◽  
Vol 6 ◽  
Author(s):  
Jérémie Lefebvre ◽  
Axel Hutt ◽  
Flavio Frohlich
Keyword(s):  
Stochastic Resonance ◽  
Brain Stimulation ◽  
Brain Activity ◽  
Rhythmic Activity ◽  
Oscillatory Activity ◽  
Alpha Oscillations ◽  
State Dependent ◽  
Periodic Stimulation ◽  
Brain States ◽  
Cortical System

Brain stimulation can be used to engage and modulate rhythmic activity in brain networks. However, the outcomes of brain stimulation are shaped by behavioral states and endogenous fluctuations in brain activity. To better understand how this intrinsic oscillatory activity controls the susceptibility of the brain to stimulation, we analyzed a computational model of the thalamo-cortical system in two distinct states (rest and task-engaged) to identify the mechanisms by which endogenous alpha oscillations (8Hz–12Hz) are modulated by periodic stimulation. Our analysis shows that the different responses to stimulation observed experimentally in these brain states can be explained by a passage through a bifurcation combined with stochastic resonance — a mechanism by which irregular fluctuations amplify the response of a nonlinear system to weak periodic signals. Indeed, our findings suggest that modulation of brain oscillations is best achieved in states of low endogenous rhythmic activity, and that irregular state-dependent fluctuations in thalamic inputs shape the susceptibility of cortical population to periodic stimulation.

Rhythmic Constraints on Hippocampal Processing: State and Phase-Related Fluctuations of Synaptic Excitability During Theta and the Slow Oscillation

2008 ◽  
Vol 99 (2) ◽  
pp. 888-899 ◽  
Author(s):  
Kurt P. Schall ◽  
Jon Kerber ◽  
Clayton T. Dickson
Keyword(s):  
Medial Temporal Lobe ◽  
Evoked Potential ◽  
Rhythmic Activity ◽  
Slow Oscillation ◽  
Perforant Path ◽  
Oscillatory Activity ◽  
Deep Sleep ◽  
Differential Effects ◽  
Input Processing ◽  
State Dependent

Coordinated patterns of state-dependent synchronized oscillatory activity have been suggested to play differential roles in both the encoding and consolidation phases of hippocampal-dependent memories. Previous studies have concentrated on the mutually exclusive patterns of theta and sharp-wave/ripple activity because these were thought to be the only collective oscillatory patterns expressed in the hippocampus. Recently we (and others) have described a novel rhythmic activity expressed during anesthesia and deep sleep, the hippocampal slow oscillation (SO). In an attempt to describe the differential effects of theta and the SO on processing in the hippocampal circuit, we performed evoked potential analysis of two major pathways (the commissural and perforant) in urethan-anesthetized rats across spontaneously expressed theta and SO states. We show that synaptic excitability was significantly enhanced in all pathways during the SO as compared with theta with the exception of the medial perforant path to the dentate gyrus, which showed greater excitability during theta. Furthermore, within each ongoing rhythm, there was a phase-dependent modulation of synaptic excitability. This occurred across all sites and similarly favored the falling phase (positive to negative) of both theta and the SO. Differential effects on the input, processing, and output circuitries of the hippocampus across mutually exclusive coordinated oscillatory patterns expressed during different states may be relevant for the staging of memory processes in the medial temporal lobe.

Rhythmic Activity and Individual Variability in Recognition Memory: Theta Oscillations Correlate with Performance whereas Alpha Oscillations Correlate with ERPs

2017 ◽  
Vol 29 (1) ◽  
pp. 183-202 ◽  
Author(s):  
Yvonne Y. Chen ◽  
Jeremy B. Caplan
Keyword(s):  
Individual Differences ◽  
Recognition Memory ◽  
Memory Task ◽  
Rhythmic Activity ◽  
Individual Variability ◽  
Theta Oscillations ◽  
Alpha Oscillations ◽  
Alpha Oscillation ◽  
Familiarity And Recollection ◽  
Visual Inattention

During study trials of a recognition memory task, alpha (∼10 Hz) oscillations decrease, and concurrently, theta (4–8 Hz) oscillations increase when later memory is successful versus unsuccessful (subsequent memory effect). Likewise, at test, reduced alpha and increased theta activity are associated with successful memory (retrieval success effect). Here we take an individual-differences approach to test three hypotheses about theta and alpha oscillations in verbal, old/new recognition, measuring the difference in oscillations between hit trials and miss trials. First, we test the hypothesis that theta and alpha oscillations have a moderately mutually exclusive relationship; but no support for this hypothesis was found. Second, we test the hypothesis that theta oscillations explain not only memory effects within participants, but also individual differences. Supporting this prediction, durations of theta (but not alpha) oscillations at study and at test correlated significantly with d′ across participants. Third, we test the hypothesis that theta and alpha oscillations reflect familiarity and recollection processes by comparing oscillation measures to ERPs that are implicated in familiarity and recollection. The alpha-oscillation effects correlated with some ERP measures, but inversely, suggesting that the actions of alpha oscillations on memory processes are distinct from the roles of familiarity- and recollection-linked ERP signals. The theta-oscillation measures, despite differentiating hits from misses, did not correlate with any ERP measure; thus, theta oscillations may reflect elaborative processes not tapped by recollection-related ERPs. Our findings are consistent with alpha oscillations reflecting visual inattention, which can modulate memory, and with theta oscillations supporting recognition memory in ways that complement the most commonly studied ERPs.

EEG Event-Related Desynchronization and Event-Related Synchronization

2017 ◽  
Author(s):  
Gert Pfurtscheller ◽  
Fernando Lopes da Silva
Keyword(s):  
Resting State ◽  
Rhythmic Activity ◽  
Oscillatory Activity ◽  
Motor Tasks ◽  
Stroke Patients ◽  
Phase Coupling ◽  
Pressure Oscillations ◽  
Frequency Bands ◽  
Event Related Desynchronization ◽  
Evoked Response Potentials

Event-related desynchronization (ERD) reflects a decrease of oscillatory activity related to internally or externally paced events. The increase of rhythmic activity is called event-related synchronization (ERS). They represent dynamical states of thalamocortical networks associated with cortical information-processing changes. This chapter discusses differences between ERD/ERS and evoked response potentials and methodologies for quantifying ERD/ERS and selecting frequency bands. It covers the interpretation of ERD/ERS in the alpha and beta bands and theta ERS and alpha ERD in behavioral tasks. ERD/ERS in scalp and subdural recordings, in various frequency bands, is discussed. Also presented is the modulation of alpha and beta rhythms by 0.1-Hz oscillations in the resting state and phase-coupling of the latter with slow changes of prefrontal hemodynamic signals (HbO2), blood pressure oscillations, and heart rate interval variations in the resting state and in relation to behavioral motor tasks. Potential uses of ERD-based strategies in stroke patients are discussed.

TMS entrainment of pre-stimulus oscillatory activity in tactile perception

2012 ◽  
Vol 25 (0) ◽  
pp. 152
Author(s):  
Manuela Ruzzoli ◽  
Salvador Soto-Faraco
Keyword(s):  
Parietal Cortex ◽  
Target Location ◽  
Repetitive Transcranial Magnetic Stimulation ◽  
Rhythmic Activity ◽  
Tactile Perception ◽  
Oscillatory Activity ◽  
Alpha Frequency ◽  
Specific Frequency ◽  
The Right ◽  
Beta Frequency

It is widely recognized that oscillatory activity plays an important functional role in neural systems. Decreases in alpha (∼10 Hz) EEG/MEG activity in the parietal cortex correlate with the deployment of spatial attention controlateral to target location in visual, auditory and tactile domains. Recently, repetitive Transcranial Magnetic Stimulation (rTMS) has been successfully applied to entrain a specific frequency at the parietal cortex (IPS) and the visual cortex. A short burst of 10 Hz rTMS impaired contralateral visual target detection and improved it ipsilaterally, compared to other control frequencies. This finding suggests a causal role of rhythmic activity in the alfa range in perception. The aim of the present study is to address whether entraining alpha frequency in the IPS plays a role in tactile orienting, indicating similarities between senses (vision and touch) in the communication between top-down (parietal) and primary sensory areas (V1 or S1). We applied rhythmic TMS at 10 and 20 Hz to the (right or left) IPS and S1, immediately before a masked vibrotactile target stimulus (present in 50% of the trials) to the left or right hand. Preliminary results lean towards the consequential effects of entraining alpha frequency into IPS for tactile detection such that it decreases tactile perception contralaterally and increases it ipsilaterally, compared to Beta frequency.

scholarly journals Cholinergic Regulation of the Posterior Medial Thalamic Nucleus

2006 ◽  
Vol 96 (5) ◽  
pp. 2265-2273 ◽  
Author(s):  
Radi Masri ◽  
Jason C. Trageser ◽  
Tatiana Bezdudnaya ◽  
Ying Li ◽  
Asaf Keller
Keyword(s):  
Brain Stem ◽  
Cholinergic System ◽  
Somatosensory System ◽  
Zona Incerta ◽  
State Dependent ◽  
Presynaptic Site ◽  
Behavioral States ◽  
Flow Of Information ◽  
The Brain

We previously showed that the GABAergic nucleus zona incerta (ZI) suppresses vibrissae-evoked responses in the posterior medial (POm) thalamus of the rodent somatosensory system. We proposed that this inhibitory incertothalamic pathway regulates POm responses during different behavioral states. Here we tested the hypothesis that this pathway is modulated by the ascending brain stem cholinergic system, which regulates sleep–wake cycles and states of vigilance. We demonstrate that cholinergic inputs facilitate POm responses to vibrissae stimulation. Activation of the cholinergic system by stimulation of brain stem cholinergic nuclei (laterodorsal tegmental and the pedunculopontine tegmental) or by tail pinch significantly increased the magnitude of POm responses to vibrissae stimulation. Microiontophoresis of the muscarinic receptor agonist carbachol enhanced POm responses to vibrissae stimulation. Application of carbachol to an in vitro slice preparation reduced the frequency but not the amplitude of miniature inhibitory postsynaptic currents, indicating a presynaptic site of action for carbachol. We conclude that the cholinergic system facilitates POm responses by suppressing GABAergic inputs from ZI. We propose the state-dependent gating hypothesis, which asserts that differing behavioral states, regulated by the brain stem cholinergic system, modulate the flow of information through POm.

scholarly journals Gamma activity accelerates during prefrontal development

2020 ◽  
Author(s):  
Sebastian H. Bitzenhofer ◽  
Jastyn A. Pöpplau ◽  
Ileana L. Hanganu-Opatz
Keyword(s):  
Prefrontal Cortex ◽  
Pyramidal Neurons ◽  
Temporal Dynamics ◽  
Rhythmic Activity ◽  
Gamma Oscillations ◽  
Gamma Activity ◽  
Oscillatory Activity ◽  
Gamma Frequency ◽  
Gamma Rhythms ◽  
Fast Oscillations

AbstractGamma oscillations are a prominent activity pattern in the cerebral cortex. While gamma rhythms have been extensively studied in the adult prefrontal cortex in the context of cognitive (dys)functions, little is known about their development. We addressed this issue by using extracellular recordings and optogenetic stimulations in mice across postnatal development. We show that fast rhythmic activity in the prefrontal cortex becomes prominent during the second postnatal week. While initially at about 15 Hz, fast oscillatory activity progressively accelerates with age and stabilizes within gamma frequency range (30-80 Hz) during the fourth postnatal week. Activation of layer 2/3 pyramidal neurons drives fast oscillations throughout development, yet the acceleration of their frequency follows similar temporal dynamics as the maturation of fast-spiking interneurons. These findings uncover the development of prefrontal gamma activity and provide a framework to examine the origin of abnormal gamma activity in neurodevelopmental disorders.

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