1-A-D-24. Source-level analysis of brain oscillatory activity using hilbert transformation

The default mode network (DMN) is the most prominent intrinsic connectivity network, serving as a key architecture of the brain's functional organization. Conversely, dysregulation of the DMN is characteristic of major neuropsychiatric disorders. However, the field still lacks mechanistic insights into the regulation of the DMN and effective interventions for DMN dysregulation. The current study approached this problem by manipulating neural synchrony, particularly, alpha (8-12 Hz) oscillations, a dominant intrinsic oscillatory activity that has been increasingly associated with the DMN in both function and physiology. Using high-definition (HD) alpha-frequency transcranial alternating current stimulation (α-tACS) to stimulate the cortical source of alpha oscillations, in combination with simultaneous EEG-fMRI, we demonstrated that α-tACS (vs. sham control) not only augmented EEG alpha oscillations but also strengthened fMRI and (source-level) alpha connectivity within the core of the DMN. Importantly, increase in alpha oscillations mediated the DMN connectivity enhancement. These findings thus identify a mechanistic link between alpha oscillations and DMN functioning. That transcranial alpha modulation can upregulate the DMN further highlights an effective non-invasive intervention to normalize DMN functioning in various disorders.

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Occipital neural dynamics in cannabis and alcohol use: independent effects of addiction

Scientific Reports ◽

10.1038/s41598-021-01493-y ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Brandon J. Lew ◽

Anabel Salimian ◽

Tony W. Wilson

Keyword(s):

Gamma Activity ◽

Oscillatory Activity ◽

Addictive Disorders ◽

Visual Spatial ◽

Comparison Groups ◽

Alpha Response ◽

Source Level ◽

Independent Effects ◽

Post Hoc ◽

Main Effects

AbstractAlcohol and cannabis use disorder (AUD/CUD) are two of the most common addictive disorders. While studies are beginning to understand the neural changes related to acute and chronic use, few studies have examined the independent effects of AUD and CUD on neural oscillatory activity. We examined 45 adults who reported current use of both cannabis and alcohol. Participants underwent the SCID-V to determine whether they met criteria for AUD and/or CUD. Participants also completed a visual-spatial processing task while undergoing magnetoencephalography (MEG). ANCOVA with a 2 × 2 design was then used to identify the main effects of AUD and CUD on source-level oscillatory activity. Of the 45 adults, 17 met criteria for AUD, and 26 met criteria for CUD. All participants, including comparison groups, reported use of both cannabis and alcohol. Statistical analyses showed a main effect of AUD, such that participants with AUD displayed a blunted occipital alpha (8–16 Hz) response. Post-hoc testing showed this decreased alpha response was related to increased AUD symptoms, above and beyond amount of use. No effects of AUD or CUD were identified in visual theta or gamma activity. In conclusion, AUD was associated with reduced alpha responses and scaled with increasing severity, independent of CUD. These findings indicate that alpha oscillatory activity may play an integral part in networks affected by alcohol addiction.

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Session details: Source-level analysis

ACM SIGPLAN Notices ◽

10.1145/3263118 ◽

2007 ◽

Vol 42 (7) ◽

Author(s):

J. Regehr

Keyword(s):

Source Level ◽

Level Analysis

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Transcranial stimulation of alpha oscillations up-regulates the default mode network

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.2110868119 ◽

2021 ◽

Vol 119 (1) ◽

pp. e2110868119

Author(s):

Kevin J. Clancy ◽

Jeremy A. Andrzejewski ◽

Yuqi You ◽

Jens T. Rosenberg ◽

Mingzhou Ding ◽

...

Keyword(s):

Default Mode Network ◽

Functional Organization ◽

Oscillatory Activity ◽

High Definition ◽

Alpha Oscillations ◽

Default Mode ◽

Effective Interventions ◽

Transcranial Alternating Current Stimulation ◽

Source Level ◽

Eeg Alpha

The default mode network (DMN) is the most-prominent intrinsic connectivity network, serving as a key architecture of the brain’s functional organization. Conversely, dysregulated DMN is characteristic of major neuropsychiatric disorders. However, the field still lacks mechanistic insights into the regulation of the DMN and effective interventions for DMN dysregulation. The current study approached this problem by manipulating neural synchrony, particularly alpha (8 to 12 Hz) oscillations, a dominant intrinsic oscillatory activity that has been increasingly associated with the DMN in both function and physiology. Using high-definition alpha-frequency transcranial alternating current stimulation (α-tACS) to stimulate the cortical source of alpha oscillations, in combination with simultaneous electroencephalography and functional MRI (EEG-fMRI), we demonstrated that α-tACS (versus Sham control) not only augmented EEG alpha oscillations but also strengthened fMRI and (source-level) alpha connectivity within the core of the DMN. Importantly, increase in alpha oscillations mediated the DMN connectivity enhancement. These findings thus identify a mechanistic link between alpha oscillations and DMN functioning. That transcranial alpha modulation can up-regulate the DMN further highlights an effective noninvasive intervention to normalize DMN functioning in various disorders.

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Source-level analysis of brain activity in the process of learning and retrieving new information

10.1109/dcna53427.2021.9587008 ◽

2021 ◽

Author(s):

Vladimir Makarov ◽

Vadim Grubov ◽

Semen Kurkin ◽

Nikita Smirnov

Keyword(s):

Brain Activity ◽

New Information ◽

Source Level ◽

Level Analysis

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Monkey EEG links neuronal color and motion information across species and scales

10.1101/534990 ◽

2019 ◽

Author(s):

Florian Sandhaeger ◽

Constantin von Nicolai ◽

Earl K Miller ◽

Markus Siegel

Keyword(s):

Visual Processing ◽

Animal Studies ◽

Visual Stimulation ◽

Spatial Scales ◽

Color Information ◽

Motion Direction ◽

Non Invasive ◽

Source Level ◽

Random Dot Patterns ◽

Level Analysis

AbstractIt remains challenging to relate EEG and MEG to underlying circuit processes and comparable experiments on both spatial scales are rare. To close this gap between invasive and non-invasive electrophysiology we developed and recorded human-comparable EEG in macaque monkeys during visual stimulation with colored dynamic random dot patterns. Furthermore, we performed simultaneous microelectrode recordings from 6 areas of macaque cortex and human MEG. Motion direction and color information were accessible in all signal types. Tuning of the non-invasive signals was similar to V4 and IT, but not to dorsal and frontal areas. Thus, MEG and EEG were dominated by early visual and ventral stream sources. Source level analysis revealed corresponding information and latency gradients across the cortex. We show how information-based methods and monkey EEG can identify analogous properties of visual processing in signals spanning spatial scales from single units to MEG – a valuable framework for relating human and animal studies.

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Monkey EEG links neuronal color and motion information across species and scales

eLife ◽

10.7554/elife.45645 ◽

2019 ◽

Vol 8 ◽

Cited By ~ 5

Author(s):

Florian Sandhaeger ◽

Constantin von Nicolai ◽

Earl K Miller ◽

Markus Siegel

Keyword(s):

Visual Processing ◽

Animal Studies ◽

Visual Stimulation ◽

Spatial Scales ◽

Color Information ◽

Motion Direction ◽

Non Invasive ◽

Source Level ◽

Random Dot Patterns ◽

Level Analysis

It remains challenging to relate EEG and MEG to underlying circuit processes and comparable experiments on both spatial scales are rare. To close this gap between invasive and non-invasive electrophysiology we developed and recorded human-comparable EEG in macaque monkeys during visual stimulation with colored dynamic random dot patterns. Furthermore, we performed simultaneous microelectrode recordings from 6 areas of macaque cortex and human MEG. Motion direction and color information were accessible in all signals. Tuning of the non-invasive signals was similar to V4 and IT, but not to dorsal and frontal areas. Thus, MEG and EEG were dominated by early visual and ventral stream sources. Source level analysis revealed corresponding information and latency gradients across cortex. We show how information-based methods and monkey EEG can identify analogous properties of visual processing in signals spanning spatial scales from single units to MEG – a valuable framework for relating human and animal studies.

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Sensory and Cognitive Components of Auditory Processing in Individuals With Tinnitus

American Journal of Audiology ◽

10.1044/2019_aja-19-0011 ◽

2019 ◽

Vol 28 (4) ◽

pp. 834-842

Author(s):

Harini Vasudevan ◽

Hari Prakash Palaniswamy ◽

Ramaswamy Balakrishnan

Keyword(s):

Selective Attention ◽

Auditory Processing ◽

Function Analysis ◽

Event Related Potential ◽

Oscillatory Activity ◽

Default Mode ◽

Auditory Selective Attention ◽

Cognitive Components ◽

Mode Function ◽

Related Potentials

Purpose The main purpose of the study is to explore the auditory selective attention abilities (using event-related potentials) and the neuronal oscillatory activity in the default mode network sites (using electroencephalogram [EEG]) in individuals with tinnitus. Method Auditory selective attention was measured using P300, and the resting state EEG was assessed using the default mode function analysis. Ten individuals with continuous and bothersome tinnitus along with 10 age- and gender-matched control participants underwent event-related potential testing and 5 min of EEG recording (at wakeful rest). Results Individuals with tinnitus were observed to have larger N1 and P3 amplitudes along with prolonged P3 latency. The default mode function analysis revealed no significant oscillatory differences between the groups. Conclusion The current study shows changes in both the early sensory and late cognitive components of auditory processing. The change in the P3 component is suggestive of selective auditory attention deficit, and the sensory component (N1) suggests an altered bottom-up processing in individuals with tinnitus.

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