Recording Of Electrical Activity Research Articles

Electrophysiological Evidence for A Number-Action Mapping in Infancy.

In the last decades, a growing body of literature has focused on the link between number and action. Many studies conducted on adult participants have provided evidence for a bidirectional influence between numerosity processing and grasping or reaching actions. However, it is not yet clear whether this link is functional in early infancy. Here, we used the event-related potential (ERP) technique to record electrical activity of the brain in response to number-hand pairings. We implemented a cueing paradigm where 3- to 4-month-old infants observed images showing either congruency (e.g., a large numerosity primed by a large hand opening) or incongruency (e.g., a large numerosity primed by a small hand opening). Infants' brain activity was modulated by the congruency of the pairings: amplitudes recorded over frontal and parietal-occipital scalp positions differed for congruent versus incongruent pairings. These findings suggest that the association between number and hand action processing is already functional early in life.

A Multifunctional Hybrid Graphene and Microfluidic Platform to Interface Topological Neuron Networks

AbstractThe nervous system is as complex as difficult to probe. Innovative tools reducing the network complexity and being able to interrogate neurons are crucial to better understand its function and organization. In this study, solution‐gated graphene field effect transistors (GFETs) are combined with multi‐compartment microfluidic platform for multimodal and long‐lasting recording of neuron electrical activity. The fluidic microchannels, somatic and synaptic chambers enable to define the neuron network topology, while the graphene devices provide localized, highly sensitive, and optically transparent sensing sites. Immunofluorescence staining assesses for the healthy state and outgrowth of neurons within the microfluidic circuit, while calcium imaging demonstrates the maturation and spontaneous activity of the designed network. The efficient cell‐sensor alignment obtained by the microfluidic circuit enables to reach the highest reported signal‐to‐noise ratio for single‐units detection with GFETs, revealing additional information that can remain hidden from recordings when using conventional microelectrode arrays. Thus, the combination of graphene sensors and microfluidic circuits leverages the advantages of two state‐of‐the‐art technologies for highly efficient sensing of model neural networks. Being fully transparent and therefore compatible with optogenetic tools and high‐resolution microscopy, this novel platform can provide a versatile lab‐on‐chip for diagnosis and treatment of tomorrow.

Heart Response to Harmonic Music Interval Stimuli Via Deep Learning Structures

The effect of music on the heart is reflected in variables such as heart rate and electrocardiographic (ECG) signals. ECG is a record of heart electrical activity and is a useful tool in diagnosing various cardiopathies. Artificial intelligence techniques have recently been implemented to analyze ECG and RR-interval data and are used thus in the present study to examine the influence on the heart of harmonic musical intervals and colored noise. Harmonic intervals were chosen because of their emotional response, while noise has been linked to positive responses such as improved sleep quality. A deep learning system was implemented, employing the ResNet-18 and GoogLeNet pre-trained networks to discriminate 31 different classes of ECG and RR-interval responses to the sound stimuli. Following an exploratory approach, deep learning was selected as an alternative to traditional analysis with the expectation that it could be incorporated into future music perception research. Classification revealed the ability of the implemented system to demonstrate heart response to the stimuli. ECG signals performed best, with 97% accuracy and Matthew’s coefficient of 0.97, while RR-interval achieved a 93% accuracy and Matthews coefficient of 0.93, suggesting that the considered stimuli of harmonic musical intervals and noise produced different responses in the heart. Moreover, the Matthews coefficient values above 0.7 and close to 1 imply a correlation between the two types of stimuli and the heart response, as measured by ECG and RR-interval signals.

Simultaneous recording of electrical and metabolic activity of cardiac cells in vitro using an organic charge modulated field effect transistor array.

In vitro electrogenic cells monitoring is an important objective in several scientific and technological fields, such as electrophysiology, pharmacology and brain machine interfaces, and can represent an interesting opportunity in other translational medicine applications. One of the key aspects of cellular cultures is the complexity of their behavior, due to the different kinds of bio-related signals, both chemical and electrical, that characterize these systems. In order to fully understand and exploit this extraordinary complexity, specific devices and tools are needed. However, at the moment this important scientific field is characterized by the lack of easy-to-use, low-cost devices for the sensing of multiple cellular parameters. To the aim of providing a simple and integrated approach for the study of in vitro electrogenic cultures, we present here a new solution for the monitoring of both the electrical and the metabolic cellular activity. In particular, we show here how a particular device called Micro Organic Charge Modulated Array (MOA) can be conveniently engineered and then used to simultaneously record the complete cell activity using the same device architecture. The system has been tested using primary cardiac rat myocytes and allowed to detect the metabolic and electrical variations thar occur upon the administration of different drugs. This first example could lay the basis for the development of a new generation of multi-sensing tools that can help to efficiently probe the multifaceted in vitro environment.

Inferring monosynaptic connections from paired dendritic spine Ca2+ imaging and large-scale recording of extracellular spiking

Objective: Techniques to identify monosynaptic connections between neurons have been vital for neuroscience research, facilitating important advancements concerning network topology, synaptic plasticity, and synaptic integration, among others. Approach: Here, we introduce a novel approach to identify and monitor monosynaptic connections using high-resolution dendritic spine Ca2+ imaging combined with simultaneous large-scale recording of extracellular electrical activity by means of high-density microelectrode arrays. Main results: We introduce an easily adoptable analysis pipeline that associates the imaged spine with its presynaptic unit and test it on in vitro recordings. The method is further validated and optimized by simulating synaptically-evoked spine Ca2+ transients based on measured spike trains in order to obtain simulated ground-truth connections. Significance: The proposed approach offers unique advantages as (a) it can be used to identify monosynaptic connections with an accurate localization of the synapse within the dendritic tree, (b) it provides precise information of presynaptic spiking, and (c) postsynaptic spine Ca2+ signals and, finally, (d) the non-invasive nature of the proposed method allows for long-term measurements. The analysis toolkit together with the rich data sets that were acquired are made publicly available for further exploration by the research community.

α1-adrenergic receptors accompanied by GATA4 expression are related to proarrhythmic conduction and automaticity in rat interatrial septum.

The development of interatrial septum (IAS) is a complicated process, which continues during postnatal life. The hypertrophic signals in developing heart are mediated among others by α-adrenergic pathways. These facts suggest the presence of specific electrophysiological features in developing IAS. This study was aimed to investigate the electrical activity in the tissue preparations of IAS from rat heart in normal conditions and under stimulation of adrenoreceptors. Intracellular recording of electrical activity revealed less negative level of resting membrane potential in IAS if compared to myocardium of left atrium. In normal conditions, non-paced IAS preparations were quiescent, but noradrenaline (10-5M) and phenylephrine (10-5M) induced spontaneous action potentials, which could be abolished by α1-blocker prazosin (10-5M), but not β1-blocker atenolol (10-5M). Optical mapping showed drastic phenylephrine-induced slowing of conduction in adult rat IAS. The α1-dependent ectopic automaticity of IAS myocardium might be explained by immunohistochemical data indicating the presence of transcription factor GATA4 and abundant α1A-adrenoreceptors in myocytes from adult rat IAS. An elevated sensitivity to adrenergic stimulation due to involvement of α1-adrenergic pathways may underlie increased proarrhythmic potential of adult IAS at least in rats.

Multichannel Wireless Neurosensing System for battery-free monitoring of neuronal activity

Electrical activity recordings are critical for evaluating and understanding brain function. We present a novel wireless, implantable, and battery-free device, namely the Wireless Neurosensing System (WiNS), and for the first time, we evaluate multichannel recording capabilities in vivo. For a preliminary evaluation, we performed a benchtop experiment with emulated sinusoidal signals of varying amplitude and frequency, representative of neuronal activity. We later performed and analyzed electrocortical recordings in rats of evoked somatosensory activity in response to three paradigms: hind/fore limb and whisker stimulation. Wired recordings were used for comparison and validation of WiNS. We found that through the channel multiplexing element of WiNS, it is possible to perform multichannel recordings with a maximum sampling rate of ∼10 kHz for a total of eight channels. This sampling rate is appropriate for monitoring the full range of neuronal signals of interest, from low-frequency population recordings of electrocorticography and local field potentials to high-frequency individual neuronal spike recordings. These in vivo experiments demonstrated that the evoked neuronal activity recorded with WiNS is comparable to that recorded with a wired system under identical circumstances. Analysis of critical parameters for interpreting the somatosensory evoked activity showed no statistically significant difference between the parameters obtained by a wired system versus those obtained using WiNS. Therefore, WiNS can match the performance of more invasive recording systems. WiNS is a groundbreaking technology with potential applications throughout neuroscience as it offers a simple alternative to address the pitfalls of battery-powered neuronal implants.

High-definition electro-anatomical mapping of Koch’s Triangle including AV node potentials recordings in consecutive AVNRT patients

Abstract Funding Acknowledgements Type of funding sources: None. Background Activation mapping of Koch’s Triangle, even when coupled with high density mapping, is incomplete without recordings of AV nodal electrical activity. Purpose To identify, through a highly specific methodology and high-density electro-anatomical mapping (HDM), the slow AVN potential (AVNP) and the precise activation modality of Koch’s Triangle in SR in atrio-ventricular nodal reentrant tachycardia (AVNRT) patients. Method The 3D KT geometry was created from the Orion mapping and the Rhythmia Mapping System. KT was divided into 8 distinct regions moving from an antero-septal to postero-septal areas and bounded by tricuspid annulus (TA) anteriorly and tendon of Todaro posteriorly. AV nodal potential activity was recorded by non-standard bipolar electrogram filtering at 0.50–300 Hz. The AVNP was defined as a slow frequency potential between atrial and ventricular EGM similar to that reported by Scherlag and Jackman, and it was confirmed by high frequency atrial pacing. The AVNP was annotated at the end of electrogram when it was followed in the same recording by a sharp potential; otherwise it was annotated at the center. Data are reported as mean±SD. Results Twenty successful SP ablation cases of typical AVNRT from 7 centers were included. RA acquired points during SR were 2512±1400 (123±67 acquired inside the KT, KT area of 41±64 mm2). The time of a complete RA mapping was 19.2±8 min. The AVNP was detected in all cases (n=20, 100%). At the mid-region of the KT, AVNP was identified in 20 (100%) cases; at postero-septal regions bounded anteriorly by the TA and posteriorly by the lateral wall toward the crista terminalis AVN was present in 17 (85%) cases; at mid-postero-septal regions AVN was detected in 15 (75%) cases. In all patients, the first activation in the KT was recorded in the antero-septal region at the expected site of the fast pathway; then the wavefront spread in two directions: anteriorly toward the His-bundle and posteriorly toward the base of KT colliding with the wavefront coming from the opposite direction through the slow pathway. In all patients, abolition of the SP and acute procedural success was achieved in the first procedure with 5.4±3 RF ablations. In 30 out 35 (86%) ablation sites, ablations were done at sites with concurrent detectable AVNP. No complications occurred. Conclusions High-density mapping using a non-standard bipolar electrograms filtering at 0.50–300 Hz showed multiple electrograms in SR including low frequency potential that may represent the electrical activity of compact node and inferior extensions.

A Subdural Bioelectronic Implant to Record Electrical Activity from the Spinal Cord in Freely Moving Rats

Bioelectronic devices have found use at the interface with neural tissue to investigate and treat nervous system disorders. Here, the development and characterization of a very thin flexible bioelectronic implant inserted along the thoracic spinal cord in rats directly in contact with and conformable to the dorsal surface of the spinal cord are presented. There is no negative impact on hind‐limb functionality nor any change in the volume or shape of the spinal cord. The bioelectronic implant is maintained in rats for a period of 12 weeks. The first subdural recordings of spinal cord activity in freely moving animals are presented; rats are plugged in via a recording cable and allowed to freely behave and move around on a raised platform. Recordings contained multiple distinct voltage waveforms spatially localize to individual electrodes. This device has great potential to monitor electrical signaling in the spinal cord after an injury and in the future, this implant will facilitate the identification of biomarkers in spinal cord injury and recovery, while enabling the delivery of localized electroceutical and chemical treatments.

Classification of EEG signals: An interpretable approach using functional data analysis

Electroencephalography (EEG) is a noninvasive method to record electrical activity of the brain. The EEG data is continuous flow of voltages, in this paper, we consider them as functional data, and propose a three-stage algorithm based on functional data analysis, with the advantage of interpretability. Specifically, the time and frequency information are extracted by wavelet transform in the first stage. Then, functional testing is utilized to select EEG channels and frequencies that show significant differences for different human behaviors. In the third stage, we propose to use penalized multiple functional logistic regression to interpretably classify human behaviors. With simulation and a scalp EEG data as validation set, we show that the proposed three-stage algorithm provides an interpretable classification of the scalp EEG signals.

Isolating the Neural Substrates of Visually Guided Attention Orienting in Humans.

The neural processes that enable healthy humans to orient attention to sudden visual events are poorly understood because they are tightly intertwined with purely sensory processes. Here we isolated visually guided orienting activity from sensory activity using event-related potentials (ERPs). By recording ERPs to a lateral stimulus and comparing waveforms obtained under conditions of attention and inattention, we identified an early positive deflection over the ipsilateral visual cortex that was associated with the covert orienting of visual attention to the stimulus. Across five experiments with male and female adult participants, this ipsilateral visual orienting activity (VOA) could be distinguished from purely sensory-evoked activity and from other top-down spatial attention effects. The VOA was linked with behavioral measures of orienting, being significantly larger when the stimulus was detected rapidly than when it was detected more slowly, and its presence was independent of saccadic eye movements toward the targets. The VOA appears to be a specific neural index of the visually guided orienting of attention to a stimulus that appears abruptly in an otherwise uncluttered visual field.SIGNIFICANCE STATEMENT The study of visual attention orienting has been an important impetus for the field of cognitive neuroscience. Seminal reaction-time studies demonstrated that a suddenly appearing visual stimulus attracts attention involuntarily, but the neural processes associated with visually guided attention orienting have been difficult to isolate because they are intertwined with sensory processes that trigger the orienting. Here, we disentangled orienting activity from sensory activity using scalp recordings of event-related electrical activity in the human brain. A specific neural index of visually guided attention orienting was identified. Surprisingly, whereas peripheral sensory stimulation is processed initially and predominantly by the contralateral visual cortex, this electrophysiological index of visual orienting was recorded over the cerebral hemisphere that was ipsilateral to the attention-capturing stimulus.

Synchronized Intracranial Electrical Activity and Gait Recording in Parkinson’s Disease Patients With Freezing of Gait

BackgroundThis study aimed to describe a synchronized intracranial electroencephalogram (EEG) recording and motion capture system, which was designed to explore the neural dynamics during walking of Parkinson’s disease (PD) patients with freezing of gait (FOG). Preliminary analysis was performed to test the reliability of this system.MethodsA total of 8 patients were enrolled in the study. All patients underwent bilateral STN-DBS surgery and were implanted with a right subdural electrode covering premotor and motor area. Synchronized electrophysiological and gait data were collected using the Nihon Kohden EEG amplifier and Codamotion system when subjects performed the Timed Up and Go (TUG) test. To verify the reliability of the acquisition system and data quality, we calculated and compared the FOG index between freezing and non-freezing periods during walking. For electrophysiological data, we first manually reviewed the scaled (five levels) quality during waking. Spectra comprising broadband electrocorticography (ECoG) and local field potential (LFP) were also compared between the FOG and non-FOG states. Lastly, connectivity analysis using coherence between cortical and STN electrodes were conducted. In addition, we also use machine learning approaches to classified FOG and non-FOG.ResultsA total of 8 patients completed 41 walking tests, 30 of which had frozen episodes, and 21 of the 30 raw data were level 1 or 2 in quality (70%). The mean ± SD walking time for the TUG test was 85.94 ± 47.68 s (range: 38 to 190.14 s); the mean ± SD freezing duration was 12.25 ± 7.35 s (range: 1.71 to 27.50 s). The FOG index significantly increased during the manually labeled FOG period (P < 0.05). The beta power of STN LFP in the FOG period was significantly higher than that in the non-FOG period (P < 0.05), while the band power of ECoG did not exhibit a significant difference between walking states. The coherence between the ECoG and STN LFP was significantly greater in high beta and gamma bands during the FOG period compared with the shuffled surrogates (P < 0.05). Lastly, STN-LFP band power features showed above-chance performance (p < 0.01, permutation test) in identifying FOG epochs.ConclusionIn this study, we established and verified the synchronized ECoG/LFP and gait recording system in PD patients with FOG. Further neural substrates underlying FOG could be explored using the current system.

Visual cortex plasticity in cochlear implant users revealed in a visual motion detection task

ObjectiveThe aim of this study was to investigate brain reorganization following cochlear implantation using electroencephalography, an implant-compatible technique to record electrical brain activity. MethodsWe investigated cortical plasticity in cochlear implant (CI) users using visual evoked potentials in response to visual motion changes. We estimated visual and auditory neural sources in CI users (n = 20) and normal hearing (NH) matched control participants (n = 22). ResultsResults showed intra-modal plasticity in the visual cortex of CI users, revealed by higher P1 and visual mismatch negativity amplitude, and greater contribution of the visual cortex during visual motion changes compared to NH controls. ConclusionsOur results suggest more efficient processing of visual information in CI users that may reflect enhanced multimodal compensatory strategies during speech processing. SignificanceThis study showcases an objective, implant-compatible method that could be used in a clinical setting to measure and longitudinally track cortical plastic changes, enabling a better understanding of the link between individual patterns of cortical plasticity and CI outcomes.

EEG readings in dogs depending on their living condition and training. Preliminary study

The basic method for imaging functional states of the brain involves recordings of electrical activity, i.e., electroencephalograpy (EEG). The majority of studies of EEG recordings in animals have been performed with the use of pharmacological agents that restrict animals’ mobility. Assessment of electrical brain activity can provide assessments of behavior, including social and utility-related behavior, under a number of welfare conditions. Our studies were conducted on 2 female dogs - one trained and one untrained dog. The recordings of the EEG signal were made at full consciousness and with the animalsin an unrestrained, static position. EEG readings were recorded during a voice-command and under complete-silence. Analysis of the EEG signal frequency in the case of the untrained dog showed maximum amplitude at 17 Hz (beta 1-beta 2 range), which suggested increased brain activity in response to voice commands. Response of trained female to the sound stimulus was manifested by the dominant components in the beta 3 range (20 Hz-28 Hz) and there were no periods of dominant alpha rhythm in that measurement. The dog was calm but waited for the commands attentively and actively. However, in the untrained dog during periods of relaxation and rest associated with the presence of a guardian, frequencies close to the alpha rhythm were noted (8 Hz-14 Hz).

Ellagic acid and allopurinol decrease H2O2 concentrations, epileptiform activity and astrogliosis after status epilepticus in the hippocampus of adult rats.

Status epilepticus (SE) can result in an overproduction of hydrogen peroxide (H2O2), which contributes to oxidative stress and brain injury during different phases of epileptogenesis and seizures. The purpose of this study was to evaluate the effects of ellagic acid and allopurinol administered after SE on H2O2 concentrations, electrical activity and GFAP immunoreactivity in the hippocampus of rats evaluated on Day 18 after SE. H2O2 levels were measured using an online technique with high temporal resolution and simultaneous electrical activity recording. For this purpose, the lateral ventricles of male Wistar rats (200-250g) were injected with pilocarpine (2.4mg/2µl) to induce SE. After SE, rats were injected with ellagic acid (50mg/kg i.p., and two additional doses at 24 and 48h) or allopurinol (50mg/kg i.p., single dose). Administration of ellagic acid or allopurinol after SE significantly reduced the H2O2 concentrations and decreased the presence of epileptiform activity and GFAP immunoreactivity in the hippocampus 18days after SE. In conclusion, the administration of antioxidants potentially reduces oxidative stress, which indicates the possible attenuation of the neurobiological consequences after SE.

Coherent theta oscillations in the cerebellum and supplementary motor area mediate visuomotor adaptation

The cerebellum and its interaction with cortical areas play a key role in our ability to flexibly adapt a motor program in response to sensory input. Current knowledge about specific neural mechanisms underlying the process of visuomotor adaptation is however lacking. Using a novel placement of EEG electrodes to record electric activity from the cerebellum, we studied local cerebellar activity, as well as its coupling with neocortical activity to obtain direct neurophysiological markers of visuomotor adaptation in humans. We found increased theta (4–8 Hz) power in “cerebellar” as well as cortical electrodes, when subjects first encountered a visual manipulation. Theta power decreased as subjects adapted to the perturbation, and rebounded when the manipulation was suddenly removed. This effect was observed in two distinct locations: a cerebellar cluster and a central cluster, which were localized in left cerebellar crus I (lCB) and right supplementary motor area (rSMA) using linear constrained minimum variance beamforming. Importantly, we found that better adaptation was associated with increased theta power in left cerebellar electrodes and a right sensorimotor cortex electrode. Finally, increased rSMA -> lCB connectivity was significantly decreased with adaptation. These results demonstrate that: (1) cerebellar theta power is markedly modulated over the course of visuomotor adaptation and (2) theta oscillations could serve as a key mechanism for communication within a cortico-cerebellar loop.

Fibroblast Growth Factor 1 Reduces Pulmonary Vein and Atrium Arrhythmogenesis via Modification of Oxidative Stress and Sodium/Calcium Homeostasis.

RationaleAtrial fibrillation is a critical health burden. Targeting calcium (Ca2+) dysregulation and oxidative stress are potential upstream therapeutic strategies. Fibroblast growth factor (FGF) 1 can modulate Ca2+ homeostasis and has antioxidant activity. The aim of this study was to investigate whether FGF1 has anti-arrhythmic potential through modulating Ca2+ homeostasis and antioxidant activity of pulmonary vein (PV) and left atrium (LA) myocytes.MethodsPatch clamp, western blotting, confocal microscopy, cellular and mitochondrial oxidative stress studies were performed in isolated rabbit PV and LA myocytes treated with or without FGF1 (1 and 10 ng/mL). Conventional microelectrodes were used to record electrical activity in isolated rabbit PV and LA tissue preparations with and without FGF1 (3 μg/kg, i.v.).ResultsFGF1-treated rabbits had a slower heart rate than that observed in controls. PV and LA tissues in FGF1-treated rabbits had slower beating rates and longer action potential duration than those observed in controls. Isoproterenol (1 μM)-treated PV and LA tissues in the FGF1-treated rabbits showed less changes in the increased beating rate and a lower incidence of tachypacing (20 Hz)-induced burst firing than those observed in controls. FGF1 (10 ng/mL)-treated PV and LA myocytes had less oxidative stress and Ca2+ transient than those observed in controls. Compared to controls, FGF1 (10 ng/mL) decreased INa−L in PV myocytes and lowered Ito, IKr−tail in LA myocytes. Protein kinase C (PKC)ε inhibition abolished the effects of FGF1 on the ionic currents of LA and PV myocytes.ConclusionFGF1 changes PV and LA electrophysiological characteristics possibly via modulating oxidative stress, Na+/Ca2+ homeostasis, and the PKCε pathway.

Recording Electrical Activity from the Brain of Behaving Octopus

Recording Electrical Activity from the Brain of Behaving Octopus

An efficient hybrid approach for the prediction of epilepsy using CNN with LSTM

Epileptic seizures are a severe neurological disorder with significant implications for public health. Epileptic seizure is one of the neurological disorders which affect either children in the age group of 10-20 years old or adults in the age group of 65-70 years old. It affects brain cells. Electroencephalogram (EEG) is the best tool for the recording of brain electrical activity. Epileptic seizures can be studied in four stages known as preictal, ictal, postictal, and interictal. This paper presents a literature review for the prediction of epilepsy using various machine learning-based approaches. This paper also presents the comparative analysis of various computational-based techniques used to predict epilepsy. This paper proposes a hybrid approach for the prediction of epilepsy using convolutional neural network and long-short-term memory. Here, the proposed model achieved an accuracy of 98%, precision of 98.21%, recall of 92.02%, F1-score of 95.01%, specificity of 99.56%, MCC of 93.84%, TPR of 92.02%, FPR of 0.44% and AUC is 100%. IT is also observed that the proposed model performed better in comparison to other approaches.

Chapter 18 - Brain oscillations and Parkinson disease

Brain oscillations have been associated with Parkinson's disease (PD) for a long time mainly due to the fundamental oscillatory nature of parkinsonian rest tremor. Over the years, this association has been extended to frequencies well above that of tremor, largely owing to the opportunities offered by deep brain stimulation (DBS) to record electrical activity directly from the patients' basal ganglia. This chapter reviews the results of research on brain oscillations in PD focusing on theta (4-7Hz), beta (13-35Hz), gamma (70-80Hz) and high-frequency oscillations (200-400Hz). For each of these oscillations, we describe localization and interaction with brain structures and between frequencies, changes due to dopamine intake, task-related modulation, and clinical relevance. The study of brain oscillations will also help to dissect the mechanisms of action of DBS. Overall, the chapter tentatively depicts PD in terms of "oscillopathy."