scholarly journals Recording site placement on planar silicon-based probes affects signal quality in acute neuronal recordings

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Richárd Fiáth ◽  
Domokos Meszéna ◽  
Zoltán Somogyvári ◽  
Mihály Boda ◽  
Péter Barthó ◽  
...  
Keyword(s):  
Single Unit ◽  
Brain Activity ◽  
Amplitude Distribution ◽  
High Amplitude ◽  
Neural Implants ◽  
Recording Site ◽  
Significant Difference ◽  
Planar Silicon ◽  
Silicon Based ◽  
Unit Yield

AbstractMultisite, silicon-based probes are widely used tools to record the electrical activity of neuronal populations. Several physical features of these devices are designed to improve their recording performance. Here, our goal was to investigate whether the position of recording sites on the silicon shank might affect the quality of the recorded neural signal in acute experiments. Neural recordings obtained with five different types of high-density, single-shank, planar silicon probes from anesthetized rats were analyzed. Wideband data were filtered to extract spiking activity, then the amplitude distribution of samples and quantitative properties of the recorded brain activity (single unit yield, spike amplitude and isolation distance) were compared between sites located at different positions of the silicon shank, focusing particularly on edge and center sites. Edge sites outperformed center sites: for all five probe types there was a significant difference in the signal power computed from the amplitude distributions, and edge sites recorded significantly more large amplitude samples both in the positive and negative range. Although the single unit yield was similar between site positions, the difference in spike amplitudes was noticeable in the range corresponding to high-amplitude spikes. Furthermore, the advantage of edge sites slightly decreased with decreasing shank width. Our results might aid the design of novel neural implants in enhancing their recording performance by identifying more efficient recording site placements.

scholarly journals Recording site placement on planar silicon-based probes affects neural signal quality: edge sites enhance acute recording performance

2020 ◽  
Author(s):  
Richárd Fiáth ◽  
Domokos Meszéna ◽  
Mihály Boda ◽  
Péter Barthó ◽  
Patrick Ruther ◽  
...  
Keyword(s):  
Single Unit ◽  
Shielding Effect ◽  
Signal Quality ◽  
Neural Implants ◽  
Recording Site ◽  
Neural Signal ◽  
Planar Silicon ◽  
Silicon Based ◽  
Unit Yield ◽  
Spiking Activity

AbstractObjectiveMultisite, silicon-based probes are widely used tools to record the electrical activity of neuronal populations. Several physical features of these devices (e.g. shank thickness, tip geometry) are designed to improve their recording performance. Here, our goal was to investigate whether the position of recording sites on the silicon shank might affect the quality of the recorded neural signal in acute experiments.ApproachNeural recordings obtained with five different types of high-density, single-shank, planar silicon probes from anesthetized rats were analyzed. Wideband data were filtered (500 - 5000 Hz) to extract spiking activity, then various quantitative properties (e.g. amplitude distribution of the filtered potential, single unit yield) of the recorded cortical and thalamic activity were compared between sites located at different positions of the silicon shank, focusing particularly on edge and center sites.Main resultsEdge sites outperformed center sites: mean values of the examined properties of the spiking activity were in most cases higher for edge sites (~94%, 33/35) and a large fraction of these differences were also statistically significant (~45%, 15/33) with effect sizes ranging from small to large. Although the single unit yield was similar between site positions, the difference in signal quality was remarkable in the range corresponding to high-amplitude spikes. Furthermore, the advantage of edge sites slightly decreased for probes having a narrower shank.SignificanceThe better signal quality on edge sites might be the result of the reduced shielding effect of the silicon shank providing a larger field of view for edge sites to detect spikes, or the less tissue damage caused near the edges of the shank. Our results might aid the design of novel neural implants in enhancing their recording performance by identifying more efficient recording site placements.

Spatio-temporal Pattern of EEG in Young Brain Respiration-training Children

2001 ◽  
Vol 29 (01) ◽  
pp. 23-35 ◽  
Author(s):  
Hyung Rae Kim ◽  
Soo Yong Kim ◽  
Dai Jin Kim ◽  
Young Youn Kim ◽  
Sang Kyu Park ◽  
...  
Keyword(s):  
Short Term Memory ◽  
Brain Activity ◽  
Occipital Cortex ◽  
Temporal Analysis ◽  
High Amplitude ◽  
Control Group ◽  
Significant Difference ◽  
Spatio Temporal ◽  
Mental Integration ◽  
The Brain

We have evaluated the effect of 'Brain Respiration training on brain activity' using Karhunen-Loeve (KL) decomposition as a method for spatio-temporal analysis of the electroencepha logram (EEG). BR training is a form of breath-work to optimize the function of the brain by concentrating Qi energy in the brain. Recently, BR-training has been reported to improve emotional maturity (i.e., EQ), short-term memory and intuition (Yoo et al., 1998). EEG data were taken during BR-training from 12 young BR-trainees (average age: 9.4 years) who had trained fro 4 to 14 months, and during relaxation from age matched non-trained children. Spatio-temporal analysis showed a significant difference of EEG dynamics in right prefrontal, right inferior frontal, posterior temporal, parietal and occipital areas between BR-trainees and the control group. Amplitude of eigenvector components of BR-trainees in the areas of frontal, temporal and occipital cortex was larger than that of non-trained children (values were smaller in parietal cortex), with remarkably high amplitude alpha coherence all over the scalp. These results suggest that BR-taining possibly activates brain function through changes in the activity of the frontal association area where higher mental integration and creative activities are mediated.

scholarly journals Increased signal diversity/complexity of spontaneous EEG, but not evoked EEG responses, in ketamine-induced psychedelic state in humans

2019 ◽  
Author(s):  
Nadine Farnes ◽  
Bjørn E. Juel ◽  
André S. Nilsen ◽  
Luis G. Romundstad ◽  
Johan F. Storm
Keyword(s):  
Brain Activity ◽  
Altered States Of Consciousness ◽  
Altered States ◽  
Eeg Signal ◽  
Eyes Closed ◽  
Electrical Brain Activity ◽  
States Of Consciousness ◽  
Significant Difference ◽  
Eyes Open ◽  
Signal Diversity

AbstractObjectiveHow and to what extent electrical brain activity is affected in pharmacologically altered states of consciousness, where it is mainly the phenomenological content rather than the level of consciousness that is altered, is not well understood. An example is the moderately psychedelic state caused by low doses of ketamine. Therefore, we investigated whether and how measures of evoked and spontaneous electroencephalographic (EEG) signal diversity are altered by sub-anaesthetic levels of ketamine compared to normal wakefulness, and how these measures relate to subjective assessments of consciousness.MethodsHigh-density electroencephalography (EEG, 62 channels) was used to record spontaneous brain activity and responses evoked by transcranial magnetic stimulation (TMS) in 10 healthy volunteers before and after administration of sub-anaesthetic doses of ketamine in an open-label within-subject design. Evoked signal diversity was assessed using the perturbational complexity index (PCI), calculated from the global EEG responses to local TMS perturbations. Signal diversity of spontaneous EEG, with eyes open and eyes closed, was assessed by Lempel Ziv complexity (LZc), amplitude coalition entropy (ACE), and synchrony coalition entropy (SCE).ResultsAlthough no significant difference was found in the index of TMS-evoked complexity (PCI) between the sub-anaesthetic ketamine condition and normal wakefulness, all the three measures of spontaneous EEG signal diversity showed significantly increased values in the sub-anaesthetic ketamine condition. This increase in signal diversity also correlated with subjective assessment of altered states of consciousness. Moreover, spontaneous signal diversity was significantly higher when participants had eyes open compared to eyes closed, both during normal wakefulness and during influence of sub-anaesthetic ketamine doses.ConclusionThe results suggest that PCI and spontaneous signal diversity may be complementary and potentially measure different aspects of consciousness. Thus, our results seem compatible with PCI being indicative of the brain’s ability to sustain consciousness, as indicated by previous research, while it is possible that spontaneous EEG signal diversity may be indicative of the complexity of conscious content. The observed sensitivity of the latter measures to visual input seems to support such an interpretation. Thus, sub-anaesthetic ketamine may increase the complexity of both the conscious content (experience) and the brain activity underlying it, while the level, degree, or general capacity of consciousness remains largely unaffected.

Planar silicon-based light polarizers

2004 ◽  
Vol 29 (2) ◽  
pp. 195 ◽  
Author(s):  
J. Diener ◽  
N. Künzner ◽  
E. Gross ◽  
D. Kovalev ◽  
M. Fujii
Keyword(s):  
Planar Silicon ◽  
Silicon Based

The Effect of Crystal Dependence on Brain Activity Related to the Perception of Pleasure Using fMRI

2021 ◽  
Vol 8 (3) ◽  
Author(s):  
Ali Yoonessi ◽  
Seyed Amir Hossein Batouli ◽  
Iman Ahmadnezhad ◽  
Hamid Soltanian-zadeh
Keyword(s):  
Case Control Study ◽  
Brain Activity ◽  
Economic Status ◽  
Smoking History ◽  
Control Group ◽  
Human Society ◽  
Significant Difference ◽  
History Of ◽  
The Brain ◽  
Control Study

Background: Addiction is currently one of the problems of human society. Drug abuse is one of the most important issues in the field of addiction. Methamphetamine (crystal) is one of the drugs that has been abused in recent decades. Methods: In this case-control study, 10 individuals aged 20 to 40 years old with at least 2 years of experience of methamphetamine consumption without any history of drug use or other stimulants from clients and drug withdrawal centers in Tehran City, and 10 healthy volunteers were selected. Age, social status, and economic status of addicts were included in the fMRI apparatus, and 90 selected pleasurable, non-pleasurable, and neutral images (IAPS) were displayed by the projector through an event-related method. The playback time of each photo was 3 s, and after this process, the person outside the device, without the time limit selected the enjoyable and unpleasant images. Results: The results showed that there was no significant difference between the groups in terms of age, alcohol use, and smoking history (P < 0.05). There was no significant difference in terms of the age at first use between members of the methamphetamine-dependent group. Also, the methamphetamine-dependent group showed more brain activity in their pre-center and post-center gyrus than the normal (control) group. Conclusions: According to the results obtained in this study, in general, it can be concluded that there are some areas in the brain of addicts that are activated when watching pleasant photos, while these areas are not active in the brains of normal people.

scholarly journals Massively parallel microwire arrays integrated with CMOS chips for neural recording

2020 ◽  
Vol 6 (12) ◽  
pp. eaay2789 ◽  
Author(s):  
Abdulmalik Obaid ◽  
Mina-Elraheb Hanna ◽  
Yu-Wei Wu ◽  
Mihaly Kollo ◽  
Romeo Racz ◽  
...  
Keyword(s):  
Large Scale ◽  
Modular Design ◽  
Three Dimensional ◽  
Field Potential ◽  
Neural Interface ◽  
Neural Communication ◽  
New Strategy ◽  
Planar Silicon ◽  
Interface Devices ◽  
Silicon Based

Multi-channel electrical recordings of neural activity in the brain is an increasingly powerful method revealing new aspects of neural communication, computation, and prosthetics. However, while planar silicon-based CMOS devices in conventional electronics scale rapidly, neural interface devices have not kept pace. Here, we present a new strategy to interface silicon-based chips with three-dimensional microwire arrays, providing the link between rapidly-developing electronics and high density neural interfaces. The system consists of a bundle of microwires mated to large-scale microelectrode arrays, such as camera chips. This system has excellent recording performance, demonstrated via single unit and local-field potential recordings in isolated retina and in the motor cortex or striatum of awake moving mice. The modular design enables a variety of microwire types and sizes to be integrated with different types of pixel arrays, connecting the rapid progress of commercial multiplexing, digitisation and data acquisition hardware together with a three-dimensional neural interface.

Seismic detection of overpressuring and fracturing: An example from the Qaidam Basin, People’s Republic of China

Geophysics ◽  
1993 ◽  
Vol 58 (10) ◽  
pp. 1532-1543 ◽  
Author(s):  
Robert J. Paul
Keyword(s):  
Oil And Gas ◽  
Qaidam Basin ◽  
High Amplitude ◽  
Seismic Survey ◽  
Low Velocity ◽  
Velocity Anomaly ◽  
Deep Well ◽  
Significant Difference ◽  
Seismic Amplitudes ◽  
Definition Of

Shallow hydrocarbon reserves were discovered in 1959 in the Nan Yi Shan structure located near the western corner of the Qaidam Basin. The first successful deep well encountered an overpressured zone at 3000 m that resulted in a well blowout. To improve the structural definition of the field and delineate the overpressured layer a 3-D seismic survey was conducted. A region of anomalous seismic time sag associated with fracturing and small quantities of oil and gas was identified on the northwest plunging nose of the Nan Yi Shan anticline. The distribution of stacking (NMO) velocities in this region was regarded as abnormal; stacking velocities derived on the steeply dipping flanks adjacent to the sag anomaly were found to be slower than those on the shallower crest. Ray‐trace modeling of a buried low‐velocity anomaly provided a possible geometric solution to explain both the time variant nature of the sag and the unusual stacking velocity signature associated with it. A significant difference in seismic and sonic traveltimes was also observed for wells that penetrated the sag region and was attributed to localized fracturing. In a deeper interval, seismic amplitudes were used to identify gas‐saturated fracture porosity and to describe the spatial limits of overpressuring within a thin‐bed reservoir. Wells drilled through high‐amplitude anomalies encountered overpressuring, those drilled in a region of moderate seismic amplitude tested significant quantities of gas, and wells located outside the region of good coherent signal encountered poor or no hydrocarbon shows. These results demonstrate that with good quality seismic data and sufficient lateral and vertical resolution, thin fractured hydrocarbon‐bearing reservoirs can be delineated and overpressure zones identified.

scholarly journals Efficacy of ProTaper Retreatment System in Root Canals Obturated with Gutta-Percha Using Two Different Sealers and GuttaFlow

2011 ◽  
Vol 2011 ◽  
pp. 1-5 ◽  
Author(s):  
Jaya Siotia ◽  
Shashi Rashmi Acharya ◽  
Sunil Kumar Gupta
Keyword(s):  
Area Ratio ◽  
Variance Test ◽  
Root Canals ◽  
Gutta Percha ◽  
Significant Difference ◽  
Ah Plus ◽  
Group 3 ◽  
Group 2 ◽  
Silicon Based ◽  
Group 1

Objective. To compare the efficacy of ProTaper retreatment files in removing three different obturating materials.Study Design. Forty-five human, single-rooted premolars were divided into three experimental groups. Group 1 was obturated with gutta-percha and AH Plus sealer, Group 2 was obturated with gutta-percha and zinc oxide eugenol sealer, and Group 3 was obturated with GuttaFlow. Retreatment was done using the ProTaper universal rotary retreatment files. Root halves were visualized using magnifying loops at 3X magnification and optical stereomicroscope at 10X magnification. Images were analyzed using AutoCAD 2004 software to calculate area of the remaining debris in the canal. For statistical analysis were used variance test and ANOVA.Results. Total debris/canal area ratio between the three groups showed a statistically significant difference (P<0.001).Conclusion. ProTaper retreatment system did not produce completely clean canals in any of the groups. However, it had the best efficacy towards removing silicon based obturating material GuttaFlow.

scholarly journals The structured flow on the brain's resting state manifold

2022 ◽  
Author(s):  
Jan Fousek ◽  
Giovanni Rabuffo ◽  
Kashyap Gudibanda ◽  
Hiba Sheheitli ◽  
Viktor Jirsa ◽  
...  
Keyword(s):  
Resting State ◽  
Brain Activity ◽  
Activity Patterns ◽  
Predictive Coding ◽  
Network Connectivity ◽  
High Amplitude ◽  
Characteristic Functional ◽  
Spatio Temporal ◽  
Generative Mechanism ◽  
Task Conditions

Spontaneously fluctuating brain activity patterns emerge at rest and relate to brain functional networks involved in task conditions. Despite detailed descriptions of the spatio-temporal brain patterns, our understanding of their generative mechanism is still incomplete. Using a combination of computational modeling and dynamical systems analysis we provide a complete mechanistic description in terms of the constituent entities and the productive relation of their causal activities leading to the formation of a resting state manifold via the network connectivity. We demonstrate that the symmetry breaking by the connectivity creates a characteristic flow on the manifold, which produces the major empirical data features including spontaneous high amplitude co-activations, neuronal cascades, spectral cortical gradients, multistability and characteristic functional connectivity dynamics. The understanding of the brain's resting state manifold is fundamental for the construction of task-specific flows and manifolds used in theories of brain function such as predictive coding.

scholarly journals Effects of Congruency on Bereitschaftspotential While Performing a Bimanual Motor Task

2018 ◽  
Vol 9 (1) ◽  
pp. 63-79
Author(s):  
Meghan McGowan ◽  
Camille Hémond-Hill ◽  
Justine Nakazawa
Keyword(s):  
Reaction Time ◽  
Primary Motor Cortex ◽  
Brain Activity ◽  
Sensory Modality ◽  
Motor Task ◽  
Left Hand ◽  
Grand Average ◽  
Bimanual Task ◽  
Significant Difference ◽  
The Right

 The bereitschaftspotential (BP)—also known as the readiness potential—is a measure of brain activity that precedes voluntary movement by approximately one second in the supplementary motor area and the contralateral primary motor cortex. Motor task reaction time for bimanual task performance is affected by both the individual and the environment; however, it is unclear whether motor task reaction time (as measured via the BP) is significantly affected by congruency. A congruent motor task is an ipsilateral stimulus (e.g., a stimulus on the right is responded to by the right hand), and an incongruent task is a contralateral stimulus (e.g., a stimulus on the right is responded to by the left hand). Congruency is re-emerging as an important topic in motor learning as it may require different levels of cortical processing. The purpose of this study was to examine the effect of congruency on the BP. Participants were asked to complete the computer task, Keyboard Hero, where they pressed keys with both their left and right hands in response to discrete congruent and incongruent stimuli. A MUSE™  apparatus recorded brain activity 1000 ms prior to, and 1000 ms after each stimulus. Results from every participant for the incongruent and congruent trials were averaged and compared using a grand average waveform. Means of accuracy (how often participants pressed the key correctly) and BP for each condition were averaged and compared using a 95% Confidence Interval (CI). Across congruent and incongruent conditions, a non-significant difference (p > 0.05 ) was found in BP (p > 0.59 ), accuracy (p > 0.64 ), and BP within −200  ms to 200 ms (p > 0.31 ). BP and mean accuracy scores were not significantly different between congruent and incongruent conditions, which may be due to only minute differences in brain activity or due to the study’s design. Further research should analyze individual variations of the present study, such as stimulus location, differences in the responding limb, correctness of responses, and the sensory modality being tested

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