scholarly journals Faster than the brain’s speed of light: Retinocortical interactions differ in high frequency activity when processing darks and lights

2017 ◽  
Author(s):  
Britta U. Westner ◽  
Sarang S. Dalal
Keyword(s):  
Neural Activity ◽  
Visual Processing ◽  
High Frequency ◽  
Speed Of Light ◽  
Oscillatory Potential ◽  
Light Onset ◽  
Retinal Activity ◽  
Narrow Bandwidth ◽  
Cortical Responses ◽  
High Frequency Activity

AbstractVisual processing of dark visual stimuli has been hypothesized to occur faster relative to bright stimuli. We investigated the timing, processing, and propagation of neural activity in response to darks and lights, operationalized as light offset and onset, in the human visual system by recording electroretinography (ERG) simultaneously with magnetoencephalography (MEG) in humans. We discovered that dark onset resulted in 75–95 Hz retinal activity that we call the dark retinal oscillatory potential, occurring with the same latency as the analogous but more broadband (55–195 Hz) oscillatory potential at light onset. Both retinal oscillations coupled with subsequent cortical activity of corresponding bandwidths, but cortical responses for darks indeed occurred earlier than for lights. Darks therefore propagate from retina to cortex more quickly than lights, potentially resulting from a thalamic advantage. Furthermore, we found that this propagation is effectuated by high frequency retinocortical coupling of narrow bandwidth for darks but wide bandwidth for lights.

Modulating motor function after stroke: Differential effects of high-frequency rTMS on movement kinematics and neural activity in subcortical and cortical MCA stroke

2008 ◽  
Vol 39 (01) ◽  
Author(s):  
M Ameli ◽  
C Grefkes ◽  
F Kemper ◽  
L Wang ◽  
M Dafotakis ◽  
...  
Keyword(s):  
Motor Function ◽  
Neural Activity ◽  
High Frequency ◽  
Movement Kinematics ◽  
Differential Effects

scholarly journals Novel approach to modeling high-frequency activity data to assess therapeutic effects of analgesics in chronic pain conditions

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Zekun Xu ◽  
Eric Laber ◽  
Ana-Maria Staicu ◽  
B. Duncan X. Lascelles
Keyword(s):  
High Frequency ◽  
Activity Patterns ◽  
Treatment Strategies ◽  
Therapeutic Effects ◽  
Activity Levels ◽  
Activity Data ◽  
Novel Approach ◽  
High Frequency Activity ◽  
Using Data ◽  
Chronic Pain Conditions

AbstractOsteoarthritis (OA) is a chronic condition often associated with pain, affecting approximately fourteen percent of the population, and increasing in prevalence. A globally aging population have made treating OA-associated pain as well as maintaining mobility and activity a public health priority. OA affects all mammals, and the use of spontaneous animal models is one promising approach for improving translational pain research and the development of effective treatment strategies. Accelerometers are a common tool for collecting high-frequency activity data on animals to study the effects of treatment on pain related activity patterns. There has recently been increasing interest in their use to understand treatment effects in human pain conditions. However, activity patterns vary widely across subjects; furthermore, the effects of treatment may manifest in higher or lower activity counts or in subtler ways like changes in the frequency of certain types of activities. We use a zero inflated Poisson hidden semi-Markov model to characterize activity patterns and subsequently derive estimators of the treatment effect in terms of changes in activity levels or frequency of activity type. We demonstrate the application of our model, and its advance over traditional analysis methods, using data from a naturally occurring feline OA-associated pain model.

Alpha and broadband high‐frequency activity track task dynamics and predict performance in controlled decision‐making

2021 ◽  
Author(s):  
Saskia Haegens ◽  
Yagna J. Pathak ◽  
Elliot H. Smith ◽  
Charles B. Mikell ◽  
Garrett P. Banks ◽  
...  
Keyword(s):  
Decision Making ◽  
High Frequency ◽  
High Frequency Activity

The “Mosaic Stage” in Amodal Completion as Characterized by Magnetoencephalography Responses

2006 ◽  
Vol 18 (8) ◽  
pp. 1394-1405 ◽  
Author(s):  
Gijs Plomp ◽  
Lichan Liu ◽  
Cees van Leeuwen ◽  
Andreas A. Ioannides
Keyword(s):  
Neural Activity ◽  
Visual Processing ◽  
Early Stage ◽  
Amodal Completion ◽  
Peak Latency ◽  
Per Se

We investigated the process of amodal completion in a same-different experiment in which test pairs were preceded by sequences of two figures. The first of these could be congruent to a global or local completion of an occluded part in the second figure, or a mosaic interpretation of it. We recorded and analyzed the magnetoencephalogram for the second figures. Compared to control conditions, in which unrelated primes were shown, occlusion and mosaic primes reduced the peak latency and amplitude of neural activity evoked by the occlusion patterns. Compared to occlusion primes, mosaic ones reduced the latency but increased the amplitude of evoked neural activity. Processes relating to a mosaic interpretation of the occlusion pattern, therefore, can dominate in an early stage of visual processing. The results did not provide evidence for the presence of a functional “mosaic stage” in completion per se, but characterize the mosaic interpretation as a qualitatively special one that can rapidly emerge in visual processing when context favors it.

Context-Dependent Modulation of Early Visual Cortical Responses to Numerical and Nonnumerical Magnitudes

2021 ◽  
pp. 1-12
Author(s):  
Joonkoo Park ◽  
Sonia Godbole ◽  
Marty G. Woldorff ◽  
Elizabeth M. Brannon
Keyword(s):  
Visual Processing ◽  
Context Dependency ◽  
Numerical Magnitude ◽  
Continuous Variables ◽  
Processing Stream ◽  
Cortical Responses ◽  
Early Visual Cortex ◽  
Context Dependent ◽  
Visual Cortical ◽  
The Brain

Abstract Whether and how the brain encodes discrete numerical magnitude differently from continuous nonnumerical magnitude is hotly debated. In a previous set of studies, we orthogonally varied numerical (numerosity) and nonnumerical (size and spacing) dimensions of dot arrays and demonstrated a strong modulation of early visual evoked potentials (VEPs) by numerosity and not by nonnumerical dimensions. Although very little is known about the brain's response to systematic changes in continuous dimensions of a dot array, some authors intuit that the visual processing stream must be more sensitive to continuous magnitude information than to numerosity. To address this possibility, we measured VEPs of participants viewing dot arrays that changed exclusively in one nonnumerical magnitude dimension at a time (size or spacing) while holding numerosity constant and compared this to a condition where numerosity was changed while holding size and spacing constant. We found reliable but small neural sensitivity to exclusive changes in size and spacing; however, changing numerosity elicited a much more robust modulation of the VEPs. Together with previous work, these findings suggest that sensitivity to magnitude dimensions in early visual cortex is context dependent: The brain is moderately sensitive to changes in size and spacing when numerosity is held constant, but sensitivity to these continuous variables diminishes to a negligible level when numerosity is allowed to vary at the same time. Neurophysiological explanations for the encoding and context dependency of numerical and nonnumerical magnitudes are proposed within the framework of neuronal normalization.

scholarly journals Neurostimulation stabilizes spiking neural networks by disrupting seizure-like oscillatory transitions

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Scott Rich ◽  
Axel Hutt ◽  
Frances K. Skinner ◽  
Taufik A. Valiante ◽  
Jérémie Lefebvre
Keyword(s):  
Neural Activity ◽  
High Frequency ◽  
Network Dynamics ◽  
Mean Field ◽  
High Frequency Stimulation ◽  
Seizure Onset ◽  
Oscillatory Dynamics ◽  
Seizure State ◽  
Frequency Stimulation ◽  
Mathematical Analyses

Abstract An improved understanding of the mechanisms underlying neuromodulatory approaches to mitigate seizure onset is needed to identify clinical targets for the treatment of epilepsy. Using a Wilson–Cowan-motivated network of inhibitory and excitatory populations, we examined the role played by intrinsic and extrinsic stimuli on the network’s predisposition to sudden transitions into oscillatory dynamics, similar to the transition to the seizure state. Our joint computational and mathematical analyses revealed that such stimuli, be they noisy or periodic in nature, exert a stabilizing influence on network responses, disrupting the development of such oscillations. Based on a combination of numerical simulations and mean-field analyses, our results suggest that high variance and/or high frequency stimulation waveforms can prevent multi-stability, a mathematical harbinger of sudden changes in network dynamics. By tuning the neurons’ responses to input, stimuli stabilize network dynamics away from these transitions. Furthermore, our research shows that such stabilization of neural activity occurs through a selective recruitment of inhibitory cells, providing a theoretical undergird for the known key role these cells play in both the healthy and diseased brain. Taken together, these findings provide new vistas on neuromodulatory approaches to stabilize neural microcircuit activity.

scholarly journals Olfaction Modulates Early Neural Responses to Matching Visual Objects

2015 ◽  
Vol 27 (4) ◽  
pp. 832-841 ◽  
Author(s):  
Amanda K. Robinson ◽  
Judith Reinhard ◽  
Jason B. Mattingley
Keyword(s):  
Neural Activity ◽  
Visual Processing ◽  
Sensory Information ◽  
Neural Correlates ◽  
Neural Responses ◽  
Visual Objects ◽  
Cortical Areas ◽  
Early Visual Processing ◽  
Considerable Research ◽  
Matter Concentration

Sensory information is initially registered within anatomically and functionally segregated brain networks but is also integrated across modalities in higher cortical areas. Although considerable research has focused on uncovering the neural correlates of multisensory integration for the modalities of vision, audition, and touch, much less attention has been devoted to understanding interactions between vision and olfaction in humans. In this study, we asked how odors affect neural activity evoked by images of familiar visual objects associated with characteristic smells. We employed scalp-recorded EEG to measure visual ERPs evoked by briefly presented pictures of familiar objects, such as an orange, mint leaves, or a rose. During presentation of each visual stimulus, participants inhaled either a matching odor, a nonmatching odor, or plain air. The N1 component of the visual ERP was significantly enhanced for matching odors in women, but not in men. This is consistent with evidence that women are superior in detecting, discriminating, and identifying odors and that they have a higher gray matter concentration in olfactory areas of the OFC. We conclude that early visual processing is influenced by olfactory cues because of associations between odors and the objects that emit them, and that these associations are stronger in women than in men.

scholarly journals High-frequency activity in experimental and clinical epileptic foci

2011 ◽  
Vol 97 (3) ◽  
pp. 300-307 ◽  
Author(s):  
Premysl Jiruska ◽  
Anatol Bragin
Keyword(s):  
High Frequency ◽  
High Frequency Activity

scholarly journals Encoding of Multiple Reward-Related Computations in Transient and Sustained High-Frequency Activity in Human OFC

2018 ◽  
Vol 28 (18) ◽  
pp. 2889-2899.e3 ◽  
Author(s):  
Ignacio Saez ◽  
Jack Lin ◽  
Arjen Stolk ◽  
Edward Chang ◽  
Josef Parvizi ◽  
...  
Keyword(s):  
High Frequency ◽  
High Frequency Activity
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