Investigating and Modulating Physiological and Pathological Brain Oscillations: The Role of Oscillatory Activity in Neural Plasticity

Neurophysiological studies in humans employing magneto- (MEG) and electro- (EEG) encephalography increasingly suggest that oscillatory rhythmic activity of the brain may be a core mechanism for binding sensory information across space, time, and object features to generate a unified perceptual representation. To distinguish whether oscillatory activity is causally related to binding processes or whether, on the contrary, it is a mere epiphenomenon, one possibility is to employ neuromodulatory techniques such as transcranial alternating current stimulation (tACS). tACS has seen a rising interest due to its ability to modulate brain oscillations in a frequency-dependent manner. In the present review, we critically summarize current tACS evidence for a causal role of oscillatory activity in spatial, temporal, and feature binding in the context of visual perception. For temporal binding, the emerging picture supports a causal link with the power and the frequency of occipital alpha rhythms (8–12 Hz); however, there is no consistent evidence on the causal role of the phase of occipital tACS. For feature binding, the only study available showed a modulation by occipital alpha tACS. The majority of studies that successfully modulated oscillatory activity and behavioral performance in spatial binding targeted parietal areas, with the main rhythms causally linked being the theta (~7 Hz) and beta (~18 Hz) frequency bands. On the other hand, spatio-temporal binding has been directly modulated by parieto-occipital gamma (~40–60 Hz) and alpha (10 Hz) tACS, suggesting a potential role of cross-frequency coupling when binding across space and time. Nonetheless, negative or partial results have also been observed, suggesting methodological limitations that should be addressed in future research. Overall, the emerging picture seems to support a causal role of brain oscillations in binding processes and, consequently, a certain degree of plasticity for shaping binding mechanisms in visual perception, which, if proved to have long lasting effects, can find applications in different clinical populations.

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EEG correlates of cognitive functions and neuropsychiatric disorders: A review of oscillatory activity and neural synchrony abnormalities

Current Psychiatry Research and Reviews ◽

10.2174/2666082216999201209130117 ◽

2020 ◽

Vol 16 ◽

Author(s):

Meysam Amidfar ◽

Yong-Ku Kim

Keyword(s):

Psychiatric Disorders ◽

Cognitive Functions ◽

Spectral Power ◽

Large Body ◽

Oscillatory Activity ◽

Brain Oscillations ◽

Emotional Symptoms ◽

Obsessive Compulsive ◽

Neuropsychiatric Diseases ◽

Obsessive Compulsive Disorders

Background: A large body of evidence suggested that disruption of neural rhythms and synchronization of brain oscillations are correlated with variety of cognitive and perceptual processes. Cognitive deficits are common features of psychiatric disorders that complicate treatment of the motivational, affective and emotional symptoms. Objective: Electrophysiological correlates of cognitive functions will contribute to understanding of neural circuits controlling cognition, the causes of their perturbation in psychiatric disorders and developing novel targets for treatment of cognitive impairments. Methods: This review includes description of brain oscillations in Alzheimer’s disease, bipolar disorder, attentiondeficit/hyperactivity disorder, major depression, obsessive compulsive disorders, anxiety disorders, schizophrenia and autism. Results: The review clearly shows that the reviewed neuropsychiatric diseases are associated with fundamental changes in both spectral power and coherence of EEG oscillations. Conclusion: In this article we examined nature of brain oscillations, association of brain rhythms with cognitive functions and relationship between EEG oscillations and neuropsychiatric diseases. Accordingly, EEG oscillations can most likely be used as biomarkers in psychiatric disorders.

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Memory: Looking back and looking forward

Brain and Neuroscience Advances ◽

10.1177/2398212818794830 ◽

2018 ◽

Vol 2 ◽

pp. 239821281879483 ◽

Cited By ~ 5

Author(s):

John P. Aggleton ◽

Richard G. M. Morris

Keyword(s):

Neural Plasticity ◽

Imaging Studies ◽

Activation Patterns ◽

Memory Research ◽

Neuronal Ensembles ◽

Disadvantaged Populations ◽

Episodic Memories ◽

Source Of Information ◽

Looking Back

This review brings together past and present achievements in memory research, ranging from molecular to psychological discoveries. Despite some false starts, major advances include our growing understanding of learning-related neural plasticity and the characterisation of different classes of memory. One striking example is the ability to reactivate targeted neuronal ensembles so that an animal will seemingly re-experience a particular memory, with the further potential to modify such memories. Meanwhile, human functional imaging studies can distinguish individual episodic memories based on voxel activation patterns. While the hippocampus continues to provide a rich source of information, future progress requires broadening our research to involve other sites. Related challenges include the need to understand better the role of glial–neuron interactions and to look beyond the synapse as the sole site of experience-dependent plasticity. Unmet goals include translating our neuroscientific knowledge in order to optimise learning and memory, especially among disadvantaged populations.

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The Role of Neural Plasticity in Tinnitus

Textbook of Tinnitus ◽

10.1007/978-1-60761-145-5_12 ◽

2011 ◽

pp. 99-102 ◽

Cited By ~ 3

Author(s):

Aage R. Møller

Keyword(s):

Neural Plasticity

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Hippocampal-prefrontal theta coupling develops as mice become proficient in associative odorant discrimination learning

10.1101/2021.09.28.462143 ◽

2021 ◽

Author(s):

Daniel Ramirez-Gordillo ◽

Andrew A. Parra ◽

K. Ulrich Bayer ◽

Diego Restrepo

Keyword(s):

Learning And Memory ◽

Discrimination Learning ◽

Gamma Oscillations ◽

Oscillatory Activity ◽

Dependent Protein Kinase ◽

Dependent Protein ◽

Theta Phase ◽

Phase Amplitude ◽

The Brain

Learning and memory requires coordinated activity between different regions of the brain. Here we studied the interaction between medial prefrontal cortex (mPFC) and hippocampal dorsal CA1 during associative odorant discrimination learning in the mouse. We found that as the animal learns to discriminate odorants in a go-no go task the coupling of high frequency neural oscillations to the phase of theta oscillations (phase-amplitude coupling or PAC) changes in a manner that results in divergence between rewarded and unrewarded odorant-elicited changes in the theta-phase referenced power (tPRP) for beta and gamma oscillations. In addition, in the proficient animal there was a decrease in the coordinated oscillatory activity between CA1 and mPFC in the presence of the unrewarded odorant. Furthermore, the changes in PAC resulted in a marked increase in the accuracy for decoding odorant identity from tPRP when the animal became proficient. Finally, we studied the role of Ca2+/calmodulin-dependent protein kinase II α (CaMKIIα), a protein involved in learning and memory, in oscillatory neural processing in this task. We find that the accuracy for decoding the odorant identity from tPRP decreases in CaMKIIα knockout mice and that this accuracy correlates with behavioral performance. These results implicate a role for PAC and CaMKIIα in olfactory go-no go associative learning in the hippocampal-prefrontal circuit.

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OSCILLATORY ACTIVITY | Seizures Beget Seizures in the Developing Brain: Central Role of GABA and High Frequency Oscillations

Encyclopedia of Basic Epilepsy Research ◽

10.1016/b978-012373961-2.00242-3 ◽

2009 ◽

pp. 1019-1023

Author(s):

Y. Ben-Ari ◽

I. Khalilov

Keyword(s):

High Frequency ◽

Developing Brain ◽

Oscillatory Activity ◽

High Frequency Oscillations

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Zinc-mediated Neurotransmission in Alzheimer's Disease: A Potential Role of the GPR39 in Dementia

Current Neuropharmacology ◽

10.2174/1570159x17666190704153807 ◽

2019 ◽

Vol 18 (1) ◽

pp. 2-13

Author(s):

Michal Rychlik ◽

Katarzyna Mlyniec

Keyword(s):

Alzheimer’S Disease ◽

Alzheimer's Disease ◽

Amyloid Beta ◽

Neural Plasticity ◽

Modern Society ◽

Neuroprotective Drugs ◽

Age Related ◽

Candidate Drug ◽

G Protein Coupled

: With more people reaching an advanced age in modern society, there is a growing need for strategies to slow down age-related neuropathology and loss of cognitive functions, which are a hallmark of Alzheimer's disease. Neuroprotective drugs and candidate drug compounds target one or more processes involved in the neurodegenerative cascade, such as excitotoxicity, oxidative stress, misfolded protein aggregation and/or ion dyshomeostasis. A growing body of research shows that a G-protein coupled zinc (Zn2+) receptor (GPR39) can modulate the abovementioned processes. : Zn2+itself has a diverse activity profile at the synapse, and by binding to numerous receptors, it plays an important role in neurotransmission. However, Zn2+ is also necessary for the formation of toxic oligomeric forms of amyloid beta, which underlie the pathology of Alzheimer’s disease. Furthermore, the binding of Zn2+ by amyloid beta causes a disruption of zincergic signaling, and recent studies point to GPR39 and its intracellular targets being affected by amyloid pathology. : In this review, we present neurobiological findings related to Zn2+ and GPR39, focusing on its signaling pathways, neural plasticity, interactions with other neurotransmission systems, as well as on the effects of pathophysiological changes observed in Alzheimer's disease on GPR39 function. : Direct targeting of the GPR39 might be a promising strategy for the pharmacotherapy of zincergic dyshomeostasis observed in Alzheimer’s disease. The information presented in this article will hopefully fuel further research into the role of GPR39 in neurodegeneration and help in identifying novel therapeutic targets for dementia.

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Perception of Rhythmic Speech Is Modulated by Focal Bilateral Transcranial Alternating Current Stimulation

Journal of Cognitive Neuroscience ◽

10.1162/jocn_a_01490 ◽

2020 ◽

Vol 32 (2) ◽

pp. 226-240 ◽

Cited By ~ 5

Author(s):

Benedikt Zoefel ◽

Isobella Allard ◽

Megha Anil ◽

Matthew H. Davis

Keyword(s):

Speech Perception ◽

Speech Processing ◽

Alternating Current ◽

Stream Segregation ◽

Causal Role ◽

Oscillatory Activity ◽

Transcranial Alternating Current Stimulation ◽

Neural Entrainment ◽

Actual Speech

Several recent studies have used transcranial alternating current stimulation (tACS) to demonstrate a causal role of neural oscillatory activity in speech processing. In particular, it has been shown that the ability to understand speech in a multi-speaker scenario or background noise depends on the timing of speech presentation relative to simultaneously applied tACS. However, it is possible that tACS did not change actual speech perception but rather auditory stream segregation. In this study, we tested whether the phase relation between tACS and the rhythm of degraded words, presented in silence, modulates word report accuracy. We found strong evidence for a tACS-induced modulation of speech perception, but only if the stimulation was applied bilaterally using ring electrodes (not for unilateral left hemisphere stimulation with square electrodes). These results were only obtained when data were analyzed using a statistical approach that was identified as optimal in a previous simulation study. The effect was driven by a phasic disruption of word report scores. Our results suggest a causal role of neural entrainment for speech perception and emphasize the importance of optimizing stimulation protocols and statistical approaches for brain stimulation research.

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