Wheels of Motion: Oscillatory Potentials in the Motor Cortex
Alexa Riehle, Eilon Vaadia in Motor Cortex in Voluntary Movements, 2004
The gamma band generally includes all frequencies over 30 Hz. Most of the work done on gamma oscillatory mechanisms is based in the hippocampus. But there are lots of neurons throughout the neocortex that can sustain high-frequency oscillations; all they need is sufficient depolarization.434 Szabadics et al. postulated at least two spatially segregated networks of inhibitory interneurons for high frequency synchronization, one directed at pyramidal cell dendrites, the other at pyramidal cell somata.91 They identified a population of cortical interneurons in layers 2 to 3 of rat somatosensory cortex with a dendritic target preference. These interneurons form a network, interacting via gap junctions and GABAergic synapses, that is capable of engaging coherent activity. The network can be activated by local pyramidal cells at beta and gamma frequencies.9l
The Gap between Intention and Action
Elizabeth B. Torres, Caroline Whyatt in Autism, 2017
Time-sensitive integration of cognitive, sensory, and motor information is achieved by binding action potentials that occur within the same “temporal binding window,” much like passengers entering a train car, or pedestrians entering segments of a revolving door. Singer (1999) first proposed that neuronal oscillations in the gamma frequency band between 30 and 90 cycles per second (Hz) could enable temporal binding. When groups of neurons are entrained in synchronized oscillations, their joint signal is amplified, and “noise” is reduced. High-frequency oscillations appear well suited to the rapid, time-sensitive integration of sensory inputs. Neuronal oscillations in the gamma frequency band have widespread evidence of importance in feature integration, selective attention, associative learning, lexical processing, and other forms of perception (Bhattacharya et al. 2002).
Augmenting Attention with Brain–Computer Interfaces
Chang S. Nam, Anton Nijholt, Fabien Lotte in Brain–Computer Interfaces Handbook, 2018
Analysis of oscillatory neural activity, for example, EEG rhythms sampled over different cortical areas, is a common method to extract neural features for endogenous BCIs. For example, EEG time-frequency analysis detects transient occurrences of neural oscillations, which in turn could be used to detect attentional shifts (Sanei & Chambers 2008). High-frequency oscillations (with a frequency greater than 30 Hz) indicate increased attention, as evident from EEG studies in humans (Kaiser & Lutzenberger 2005; Koelewijn et al. 2013; Musch et al. 2014) and intracranial recordings in monkeys (Fries et al. 2001).
Concussion history is negatively associated with visual-motor force complexity: evidence for persistent effects on visual-motor integration
Published in Brain Injury, 2018
Adam C. Raikes, Sydney Y. Schaefer, Breanna E. Studenka
Studenka and Raikes (2017) observed that individuals with multiple previous concussions had greater regularity than individuals with a single or no prior concussion during isometric visual-motor force tracking (27). This task relies on visual information for error detection and correction with limited proprioceptive input. It provides valuable information about visual information processing and integration with error detection and correction processes (28,29). However, single-scale regularity provides information about high-frequency oscillations (>16 Hertz (Hz) with data sampled at 100 Hz (30)), whereas the dominant frequencies in this task were observed below 12 Hz, and specifically below 4 Hz (27). Thus, single-scale regularity may fail to capture important information within the range of frequencies of interest.
The process of transferring negative impulses in capital markets – a wavelet analysis
Published in Journal of Applied Statistics, 2022
The proposed hypothesis assumes that the occurrence of contagion requires an impulse, as in the case of examining causality, hence it must be associated with the market’s lagged response. Covariance (the simultaneous response) is, on the other hand, a reflection of the financial markets’ interconnections. A successful verification of the proposed hypothesis would make it possible to depart from comparing correlations in the virtual tranquil and crisis periods and focus more attention on time lags. The other hypothesis to be verified assumes that limiting the scope of the analysis to high frequency oscillations only is an oversimplification. Responses to financial shocks may lose their intensity over a short period (up to four days), after which the markets regain their confidence relatively quickly. Delayed responses during financial crises may also be reflected by mid-term oscillations [4,5]. However, within short-term oscillations, corresponding to low scales, we can clearly see the very moment of contagion disclosure.
Focal cortical dysplasia: an update on diagnosis and treatment
Published in Expert Review of Neurotherapeutics, 2021
The relationship between HFOs and their pathological epileptogenic substrate is still matter of debate [76–78]. Jacobs and colleagues [76] found no relationship between HFO rates and distinct types of lesions (mesial temporal sclerosis, FCD, nodular heterotopia), thus suggesting that HFOs are nonspecific to a particular type of lesion, but rather reflect epileptogenicity per se. However, some evidence has emerged that certain brain lesions can generate HFOs more commonly than others. For instance, higher HFO rates were found in FCD and mesial temporal sclerosis compared to polymicrogyria and tuberous sclerosis [77]. In another study [78], high frequency oscillations rates were higher in FCD IIa and IIb than in FCD I. In these patients, HFO rates correlated with the overall seizure burden as measured over the last year rather than with the acute seizure burden during the long-term EEG recording, thus underscoring how HFOs could be used as a marker of the epileptogenic activity of the lesion.
Related Knowledge Centers
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