Multimodal intraoperative monitoring (MIOM) during cervical spine surgical procedures in 246 patients

PubMed Central

Sutter, Martin A.; Grob, Dieter; Jeszenszky, Dezsö; Porchet, François; Dvorak, Jiri

2007-01-01

A prospective study of 246 patients who received multimodal intraoperative monitoring during cervical spine surgery between March 2000 and December 2005. To determine the sensitivity and specificity of MIOM techniques used to monitor spinal cord and nerve root function during cervical spine surgery. It is appreciated that complication rate of cervical spine surgery is low, however, there is a significant risk of neurological injury. The combination of monitoring of ascending and descending pathways may provide more sensitive and specific results giving immediate feedback information and/or alert regarding any neurological changes during the operation to the surgeon. Intraoperative somatosensory spinal and cerebral evoked potentials combined with continuous EMG and motor-evoked potentials of the spinal cord and muscles were evaluated and compared with postoperative clinical neurological changes. A total of 246 consecutive patients with cervical pathologies, majority spinal stenosis due to degenerative changes of cervical spine were monitored by means of MIOM during the surgical procedure. About 232 patients presented true negative while 2 patients false negative responses. About ten patients presented true positive responses where neurological deficit after the operation was predicted and two patients presented false positive findings. The sensitivity of MIOM applied during cervical spine procedure (anterior and/or posterior) was 83.3% and specificity of 99.2%. MIOM is an effective method of monitoring the spinal cord functional integrity during cervical spine surgery and can help to reduce the risk of neurological deficit by alerting the surgeon when monitoring changes are observed. PMID:17610090

Intraoperative Neurophysiological Monitoring in Spine Surgery: A Significant Tool for Neuronal Protection and Functional Restoration.

PubMed

Scibilia, Antonino; Raffa, Giovanni; Rizzo, Vincenzo; Quartarone, Angelo; Visocchi, Massimiliano; Germanò, Antonino; Tomasello, Francesco

2017-01-01

Although there is recent evidence for the role of intraoperative neurophysiological monitoring (IONM) in spine surgery, there are no uniform opinions on the optimal combination of the different tools. At our institution, multimodal IONM (mIONM) approach in spine surgery involves the evaluation of somatosensory evoked potentials (SEPs) and motor evoked potentials (MEPs) with electrical transcranial stimulation, including the use of a multipulse technique with multiple myomeric registration of responses from limbs, and a single-pulse technique with D-wave registration through epi- and intradural recording, and free running and evoked electromyography (frEMG and eEMG) with bilateral recording from segmental target muscles. We analyzed the impact of the mIONM on the preservation of neuronal structures and on functional restoration in a prospective series of patients who underwent spine surgery. We observed an improvement of neurological status in 50 % of the patients. The D-wave registration was the most useful intraoperative tool, especially when MEP and SEP responses were absent or poorly recordable. Our preliminary data confirm that mIONM plays a fundamental role in the identification and functional preservation of the spinal cord and nerve roots. It is highly sensitive and specific for detecting and avoiding neurological injury during spine surgery and represents a helpful tool for achieving optimal postoperative functional outcome.

[Neuroeffector connections of multimodal neurons in the African snail (Achatina fulica)].

PubMed

Bugaĭ, V V; Zhuravlev, V L; Safonova, T A

2004-02-01

Using a new method of animal preparation, the efferent connections of giant paired neurons on the dorsal surface of visceral and right parietal ganglia of snail, Achatina fulica, were examined. It was found that spikes in giant neurons d-VLN and d-RPLN evoke postjunctional potentials in different points of the snail body and viscerae (in the heart, in pericardium, in lung cavity and kidney walls, in mantle and body wall muscles, in tentacle retractors and in cephalic artery). The preliminary analysis of synaptic latency and facilitation suggests a direct connections between giant neurons and investigated efferents.

Exploring brainstem function in multiple sclerosis by combining brainstem reflexes, evoked potentials, clinical and MRI investigations.

PubMed

Magnano, Immacolata; Pes, Giovanni Mario; Pilurzi, Giovanna; Cabboi, Maria Paola; Ginatempo, Francesca; Giaconi, Elena; Tolu, Eusebio; Achene, Antonio; Salis, Antonio; Rothwell, John C; Conti, Maurizio; Deriu, Franca

2014-11-01

To investigate vestibulo-masseteric (VMR), acoustic-masseteric (AMR), vestibulo-collic (VCR) and trigemino-collic (TCR) reflexes in patients with multiple sclerosis (MS); to relate abnormalities of brainstem reflexes (BSRs) to multimodal evoked potentials (EPs), clinical and Magnetic Resonance Imaging (MRI) findings. Click-evoked VMR, AMR and VCR were recorded from active masseter and sternocleidomastoid muscles, respectively; TCR was recorded from active sternocleidomastoid muscles, following electrical stimulation of the infraorbital nerve. EPs and MRI were performed with standard techniques. Frequencies of abnormal BSRs were: VMR 62.1%, AMR 55.1%, VCR 25.9%, TCR 58.6%. Brainstem dysfunction was identified by these tests, combined into a four-reflex battery, in 86.9% of cases, by EPs in 82.7%, MRI in 71.7% and clinical examination in 37.7% of cases. The sensitivity of paired BSRs/EPs (93.3%) was significantly higher than combined MRI/clinical testing (70%) in patients with disease duration ⩽6.4years. BSR alterations significantly correlated with clinical, EP and MRI findings. The four-BSR battery effectively increases the performance of standard EPs in early detection of brainstem impairment, otherwise undetected by clinical examination and neuroimaging. Multiple BSR assessment usefully supplements conventional testing and monitoring of brainstem function in MS, especially in newly diagnosed patients. Copyright © 2014 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.

Correlation between electrical and hemodynamic responses during visual stimulation with graded contrasts

NASA Astrophysics Data System (ADS)

Si, Juanning; Zhang, Xin; Li, Yuejun; Zhang, Yujin; Zuo, Nianming; Jiang, Tianzi

2016-09-01

Brain functional activity involves complex cellular, metabolic, and vascular chain reactions, making it difficult to comprehend. Electroencephalography (EEG) and functional near infrared spectroscopy (fNIRS) have been combined into a multimodal neuroimaging method that captures both electrophysiological and hemodynamic information to explore the spatiotemporal characteristics of brain activity. Because of the significance of visually evoked functional activity in clinical applications, numerous studies have explored the amplitude of the visual evoked potential (VEP) to clarify its relationship with the hemodynamic response. However, relatively few studies have investigated the influence of latency, which has been frequently used to diagnose visual diseases, on the hemodynamic response. Moreover, because the latency and the amplitude of VEPs have different roles in coding visual information, investigating the relationship between latency and the hemodynamic response should be helpful. In this study, checkerboard reversal tasks with graded contrasts were used to evoke visual functional activity. Both EEG and fNIRS were employed to investigate the relationship between neuronal electrophysiological activities and the hemodynamic responses. The VEP amplitudes were linearly correlated with the hemodynamic response, but the VEP latency showed a negative linear correlation with the hemodynamic response.

Explicit Encoding of Multimodal Percepts by Single Neurons in the Human Brain

PubMed Central

Quiroga, Rodrigo Quian; Kraskov, Alexander; Koch, Christof; Fried, Itzhak

2010-01-01

Summary Different pictures of Marilyn Monroe can evoke the same percept, even if greatly modified as in Andy Warhol’s famous portraits. But how does the brain recognize highly variable pictures as the same percept? Various studies have provided insights into how visual information is processed along the “ventral pathway,” via both single-cell recordings in monkeys [1, 2] and functional imaging in humans [3, 4]. Interestingly, in humans, the same “concept” of Marilyn Monroe can be evoked with other stimulus modalities, for instance by hearing or reading her name. Brain imaging studies have identified cortical areas selective to voices [5, 6] and visual word forms [7, 8]. However, how visual, text, and sound information can elicit a unique percept is still largely unknown. By using presentations of pictures and of spoken and written names, we show that (1) single neurons in the human medial temporal lobe (MTL) respond selectively to representations of the same individual across different sensory modalities; (2) the degree of multimodal invariance increases along the hierarchical structure within the MTL; and (3) such neuronal representations can be generated within less than a day or two. These results demonstrate that single neurons can encode percepts in an explicit, selective, and invariant manner, even if evoked by different sensory modalities. PMID:19631538

Giant multimodal heart motoneurons of Achatina fulica: a new cardioregulatory input in pulmonates.

PubMed

Zhuravlev, V; Bugaj, V; Kodirov, S; Safonova, T; Staruschenko, A

2001-08-01

The regulation of the heartbeat by the two largest neurons, d-VLN and d-RPLN, on the dorsal surface of visceral and right parietal ganglia of Giant African snail, Achatina fulica, was examined. Using the new method of animal preparation, for the first time, discrete biphasic inhibitory-excitatory junction potentials (I-EJPs) in the heart and several muscles of the visceral sac were recorded. The duration of hyperpolarizing phase (H-phase) of biphasic I-EJPs was 269+/-5.6 ms (n=5), which is 2-3 times less than that of the cholinergic inhibitory JPs (682+/-68.5 ms, n=5). The H-phase of I-EJPs was not altered by the application of atropine, picrotoxine, succinylcholinchloride, D-tubocurarine and tetraethylammonium or substitution of Cl(-) ions. Even the low-frequency neuronal discharges (1-2 imp/s) evoked significant facilitation and potentiation of the H-phase. Between the multimodal neurons d-VLN/d-RPLN and mantle or visceral organs there is evidence of direct synaptic connections. These neurons were found to have no axonal branches in the intestinal nerve as once suspected but reach the heart through several other nerves. New giant heart motoneurons do not interact with previously identified cardioregulatory neurons.

Early functional MRI activation predicts motor outcome after ischemic stroke: a longitudinal, multimodal study.

PubMed

Du, Juan; Yang, Fang; Zhang, Zhiqiang; Hu, Jingze; Xu, Qiang; Hu, Jianping; Zeng, Fanyong; Lu, Guangming; Liu, Xinfeng

2018-05-15

An accurate prediction of long term outcome after stroke is urgently required to provide early individualized neurorehabilitation. This study aimed to examine the added value of early neuroimaging measures and identify the best approaches for predicting motor outcome after stroke. This prospective study involved 34 first-ever ischemic stroke patients (time since stroke: 1-14 days) with upper limb impairment. All patients underwent baseline multimodal assessments that included clinical (age, motor impairment), neurophysiological (motor-evoked potentials, MEP) and neuroimaging (diffusion tensor imaging and motor task-based fMRI) measures, and also underwent reassessment 3 months after stroke. Bivariate analysis and multivariate linear regression models were used to predict the motor scores (Fugl-Meyer assessment, FMA) at 3 months post-stroke. With bivariate analysis, better motor outcome significantly correlated with (1) less initial motor impairment and disability, (2) less corticospinal tract injury, (3) the initial presence of MEPs, (4) stronger baseline motor fMRI activations. In multivariate analysis, incorporating neuroimaging data improved the predictive accuracy relative to only clinical and neurophysiological assessments. Baseline fMRI activation in SMA was an independent predictor of motor outcome after stroke. A multimodal model incorporating fMRI and clinical measures best predicted the motor outcome following stroke. fMRI measures obtained early after stroke provided independent prediction of long-term motor outcome.

Adding pregabalin to a multimodal analgesic regimen does not reduce pain scores following cosmetic surgery: a randomized trial.

PubMed

Chaparro, Luis Enrique; Clarke, Hance; Valdes, Paola A; Mira, Mauricio; Duque, Lorena; Mitsakakis, Nicholas

2012-12-01

Multimodal analgesia increases the chance of successful discharge and pain control after surgery, and pregabalin is being promoted as an effective analgesic, based on placebo-controlled studies. We investigated whether adding pregabalin improved pain control and reduced opioid requests when it was added to a multimodal analgesic regimen for cosmetic surgery. One hundred and ten women who underwent same-day cosmetic surgery were randomized to receive oral pregabalin, 75 mg q12 h for five consecutive days starting the night before surgery, or identical placebos. Participants, outcomes assessors, and the statistician were blinded. The primary outcome was postoperative numerical movement-evoked pain scores at 2, 24, 48, 72, and 96 h after surgery. The secondary outcomes included pain scores at rest; incidence of moderate to severe pain; and analgesic and antiemetic requirements; as well as the incidence of nausea, vomiting, and somnolence. Based on 99 patients who completed the study, we found no difference between the groups in the primary outcome; 72 h after surgery, movement-evoked median pain scores were <4/10 in both groups. We found no differences in opioid requirements (p = 0.95) or anti-inflammatory requirements (p = 0.45), and no difference in opioid-related adverse events. Perioperative pregabalin 75 mg twice a day does not increase benefit when it is added to an already multimodal analgesic regimen for patients undergoing cosmetic surgery. Several factors could explain our findings, including the possibility of publication bias in the current literature.

Intraoperative neurophysiological monitoring of the cortico-spinal tract in image-guided mini-invasive neurosurgery.

PubMed

Cordella, Roberto; Acerbi, Francesco; Broggi, Morgan; Vailati, Davide; Nazzi, Vittoria; Schiariti, Marco; Tringali, Giovanni; Ferroli, Paolo; Franzini, Angelo; Broggi, Giovanni

2013-06-01

To evaluate the role of intraoperative neurophysiological monitoring in image-guided mini-invasive neurosurgery. Twenty-one patients were operated under general anaesthesia with the aid of multimodal intraoperative neurophysiological monitoring to remove supratentorials tumors closely related to the cortico-spinal tract. Pre-operative assessment included fMRI scans and tractography that were uploaded into the intraoperative neuro-navigation system. Monitoring consisted in simultaneously recording EEG, electrocorticography, transcranial and direct motor evoked potentials (tMEP and dMEP), somatosensory evoked potentials and subcortical stimulation during the whole procedures. The recording of all the electrophysiological signals was possible in all procedures. SSEP guided the positioning of the strip electrode over the motor cortex (N20 phase inversion) that was used to evoke dMEP and monitor the lower limb motor responses; subcortical stimulation to unveil the spatial relationship between the tumors and motor fibers. Four patients had transient worsening of the symptoms, but only two had a long-term worsening, although not severe, of the pre-op clinical status. Intraoperative neurophysiology has a great value in mini-invasive neurosurgery, especially because the motor cortex is not exposed, consequently it cannot be directly mapped. This report describes a valuable scheme making use of as many electrophysiological signals as possible to constantly monitor the motor functions. A useful method to monitor motor functions in mini-invasive neurosurgery was described. Copyright © 2012 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.

Contemporary approach to neurologic prognostication of coma after cardiac arrest.

PubMed

Ben-Hamouda, Nawfel; Taccone, Fabio S; Rossetti, Andrea O; Oddo, Mauro

2014-11-01

Coma after cardiac arrest (CA) is an important cause of admission to the ICU. Prognosis of post-CA coma has significantly improved over the past decade, particularly because of aggressive postresuscitation care and the use of therapeutic targeted temperature management (TTM). TTM and sedatives used to maintain controlled cooling might delay neurologic reflexes and reduce the accuracy of clinical examination. In the early ICU phase, patients' good recovery may often be indistinguishable (based on neurologic examination alone) from patients who eventually will have a poor prognosis. Prognostication of post-CA coma, therefore, has evolved toward a multimodal approach that combines neurologic examination with EEG and evoked potentials. Blood biomarkers (eg, neuron-specific enolase [NSE] and soluble 100-β protein) are useful complements for coma prognostication; however, results vary among commercial laboratory assays, and applying one single cutoff level (eg, > 33 μg/L for NSE) for poor prognostication is not recommended. Neuroimaging, mainly diffusion MRI, is emerging as a promising tool for prognostication, but its precise role needs further study before it can be widely used. This multimodal approach might reduce false-positive rates of poor prognosis, thereby providing optimal prognostication of comatose CA survivors. The aim of this review is to summarize studies and the principal tools presently available for outcome prediction and to describe a practical approach to the multimodal prognostication of coma after CA, with a particular focus on neuromonitoring tools. We also propose an algorithm for the optimal use of such multimodal tools during the early ICU phase of post-CA coma.

Neurovascular and neuroimaging effects of the hallucinogenic serotonin receptor agonist psilocin in the rat brain

PubMed Central

Spain, Aisling; Howarth, Clare; Khrapitchev, Alexandre A.; Sharp, Trevor; Sibson, Nicola R.; Martin, Chris

2015-01-01

The development of pharmacological magnetic resonance imaging (phMRI) has presented the opportunity for investigation of the neurophysiological effects of drugs in vivo. Psilocin, a hallucinogen metabolised from psilocybin, was recently reported to evoke brain region-specific, phMRI signal changes in humans. The present study investigated the effects of psilocin in a rat model using phMRI and then probed the relationship between neuronal and haemodynamic responses using a multimodal measurement preparation. Psilocin (2 mg/kg or 0.03 mg/kg i.v.) or vehicle was administered to rats (N = 6/group) during either phMRI scanning or concurrent imaging of cortical blood flow and recording of local field potentials. Compared to vehicle controls psilocin (2 mg/kg) evoked phMRI signal increases in a number of regions including olfactory and limbic areas and elements of the visual system. PhMRI signal decreases were seen in other regions including somatosensory and motor cortices. Investigation of neurovascular coupling revealed that whilst neuronal responses (local field potentials) to sensory stimuli were decreased in amplitude by psilocin administration, concurrently measured haemodynamic responses (cerebral blood flow) were enhanced. The present findings show that psilocin evoked region-specific changes in phMRI signals in the rat, confirming recent human data. However, the results also suggest that the haemodynamic signal changes underlying phMRI responses reflect changes in both neuronal activity and neurovascular coupling. This highlights the importance of understanding the neurovascular effects of pharmacological manipulations for interpreting haemodynamic neuroimaging data. PMID:26192543

The extraction of motion-onset VEP BCI features based on deep learning and compressed sensing.

PubMed

Ma, Teng; Li, Hui; Yang, Hao; Lv, Xulin; Li, Peiyang; Liu, Tiejun; Yao, Dezhong; Xu, Peng

2017-01-01

Motion-onset visual evoked potentials (mVEP) can provide a softer stimulus with reduced fatigue, and it has potential applications for brain computer interface(BCI)systems. However, the mVEP waveform is seriously masked in the strong background EEG activities, and an effective approach is needed to extract the corresponding mVEP features to perform task recognition for BCI control. In the current study, we combine deep learning with compressed sensing to mine discriminative mVEP information to improve the mVEP BCI performance. The deep learning and compressed sensing approach can generate the multi-modality features which can effectively improve the BCI performance with approximately 3.5% accuracy incensement over all 11 subjects and is more effective for those subjects with relatively poor performance when using the conventional features. Compared with the conventional amplitude-based mVEP feature extraction approach, the deep learning and compressed sensing approach has a higher classification accuracy and is more effective for subjects with relatively poor performance. According to the results, the deep learning and compressed sensing approach is more effective for extracting the mVEP feature to construct the corresponding BCI system, and the proposed feature extraction framework is easy to extend to other types of BCIs, such as motor imagery (MI), steady-state visual evoked potential (SSVEP)and P300. Copyright © 2016 Elsevier B.V. All rights reserved.

Behavioral and Functional Assays for Investigating Mechanisms of Noxious Cold Detection and Multimodal Sensory Processing in Drosophila Larvae

PubMed Central

Patel, Atit A.; Cox, Daniel N.

2017-01-01

To investigate cellular, molecular and behavioral mechanisms of noxious cold detection, we developed cold plate behavioral assays and quantitative means for evaluating the predominant noxious cold-evoked contraction behavior. To characterize neural activity in response to noxious cold, we implemented a GCaMP6-based calcium imaging assay enabling in vivo studies of intracellular calcium dynamics in intact Drosophila larvae. We identified Drosophila class III multidendritic (md) sensory neurons as multimodal sensors of innocuous mechanical and noxious cold stimuli and to dissect the mechanistic bases of multimodal sensory processing we developed two independent functional assays. First, we developed an optogenetic dose response assay to assess whether levels of neural activation contributes to the multimodal aspects of cold sensitive sensory neurons. Second, we utilized CaMPARI, a photo-switchable calcium integrator that stably converts fluorescence from green to red in presence of high intracellular calcium and photo-converting light, to assess in vivo functional differences in neural activation levels between innocuous mechanical and noxious cold stimuli. These novel assays enable investigations of behavioral and functional roles of peripheral sensory neurons and multimodal sensory processing in Drosophila larvae. PMID:28835907

Application of a multicompartment dynamical model to multimodal optical imaging for investigating individual cerebrovascular properties

NASA Astrophysics Data System (ADS)

Desjardins, Michèle; Gagnon, Louis; Gauthier, Claudine; Hoge, Rick D.; Dehaes, Mathieu; Desjardins-Crépeau, Laurence; Bherer, Louis; Lesage, Frédéric

2009-02-01

Biophysical models of hemodynamics provide a tool for quantitative multimodal brain imaging by allowing a deeper understanding of the interplay between neural activity and blood oxygenation, volume and flow responses to stimuli. Multicompartment dynamical models that describe the dynamics and interactions of the vascular and metabolic components of evoked hemodynamic responses have been developed in the literature. In this work, multimodal data using near-infrared spectroscopy (NIRS) and diffuse correlation flowmetry (DCF) is used to estimate total baseline hemoglobin concentration (HBT0) in 7 adult subjects. A validation of the model estimate and investigation of the partial volume effect is done by comparing with time-resolved spectroscopy (TRS) measures of absolute HBT0. Simultaneous NIRS and DCF measurements during hypercapnia are then performed, but are found to be hardly reproducible. The results raise questions about the feasibility of an all-optical model-based estimation of individual vascular properties.

Concurrent OCT imaging of stimulus evoked retinal neural activation and hemodynamic responses

NASA Astrophysics Data System (ADS)

Son, Taeyoon; Wang, Benquan; Lu, Yiming; Chen, Yanjun; Cao, Dingcai; Yao, Xincheng

2017-02-01

It is well established that major retinal diseases involve distortions of the retinal neural physiology and blood vascular structures. However, the details of distortions in retinal neurovascular coupling associated with major eye diseases are not well understood. In this study, a multi-modal optical coherence tomography (OCT) imaging system was developed to enable concurrent imaging of retinal neural activity and vascular hemodynamics. Flicker light stimulation was applied to mouse retinas to evoke retinal neural responses and hemodynamic changes. The OCT images were acquired continuously during the pre-stimulation, light-stimulation, and post-stimulation phases. Stimulus-evoked intrinsic optical signals (IOSs) and hemodynamic changes were observed over time in blood-free and blood regions, respectively. Rapid IOSs change occurred almost immediately after stimulation. Both positive and negative signals were observed in adjacent retinal areas. The hemodynamic changes showed time delays after stimulation. The signal magnitudes induced by light stimulation were observed in blood regions and did not show significant changes in blood-free regions. These differences may arise from different mechanisms in blood vessels and neural tissues in response to light stimulation. These characteristics agreed well with our previous observations in mouse retinas. Further development of the multimodal OCT may provide a new imaging method for studying how retinal structures and metabolic and neural functions are affected by age-related macular degeneration (AMD), glaucoma, diabetic retinopathy (DR), and other diseases, which promises novel noninvasive biomarkers for early disease detection and reliable treatment evaluations of eye diseases.

Proximal and distal esophageal sensitivity is decreased in patients with Barrett’s esophagus

PubMed Central

Krarup, Anne L; Olesen, Søren S; Funch-Jensen, Peter; Gregersen, Hans; Drewes, Asbjørn M

2011-01-01

AIM: To investigate sensations to multimodal pain stimulation in the metaplastic and normal parts of the esophagus in patients with Barrett’s esophagus (BE). METHODS: Fifteen patients with BE and 15 age-matched healthy volunteers were subjected to mechanical, thermal and electrical pain stimuli of the esophagus. Both the metaplastic part and the normal part (4 and 14 cm, respectively, above the esophago-gastric junction) were examined. At sensory thresholds the stimulation intensity, referred pain areas, and evoked brain potentials were recorded. RESULTS: Patients were hyposensitive to heat stimulation both in the metaplastic part [median stimulation time to reach the pain detection threshold: 15 (12-34) s vs 14 (6-23) s in controls; F = 4.5, P = 0.04] and the normal part of the esophagus [median 17 (6-32) s vs 13 (8-20) s in controls; F = 6.2, P = 0.02]. Furthermore, patients were hyposensitive in the metaplastic part of the esophagus to mechanical distension [median volume at moderate pain: 50 (20-50) mL vs 33 (13-50) mL in controls; F = 5.7, P = 0.02]. No indication of central nervous system abnormalities was present, as responses were comparable between groups to electrical pain stimuli in the metaplastic part [median current evoking moderate pain: 13 (6-26) mA vs 12 (9-24) mA in controls; F = 0.1, P = 0.7], and in the normal part of the esophagus [median current evoking moderate pain: 9 (6-16) mA, vs 11 (5-11) mA in controls; F = 3.4, P = 0.07]. Furthermore, no differences were seen for the referred pain areas (P-values all > 0.3) or latencies and amplitudes for the evoked brain potentials (P-values all > 0.1). CONCLUSION: Patients with BE are hyposensitive both in the metaplastic and normal part of esophagus likely as a result of abnormalities affecting peripheral nerve pathways. PMID:21274382

Transesophageal versus transcranial motor evoked potentials to monitor spinal cord ischemia.

PubMed

Tsuda, Kazumasa; Shiiya, Norihiko; Takahashi, Daisuke; Ohkura, Kazuhiro; Yamashita, Katsushi; Kando, Yumi; Arai, Yoshifumi

2016-02-01

We have previously reported that transesophageal motor evoked potential is feasible and more stable than transcranial motor evoked potential. This study aimed to investigate the efficacy of transesophageal motor evoked potential to monitor spinal cord ischemia. Transesophageal and transcranial motor evoked potentials were recorded in 13 anesthetized dogs at the bilateral forelimbs, anal sphincters, and hindlimbs. Spinal cord ischemia was induced by aortic balloon occlusion at the 8th to 10th thoracic vertebra level. In the 12 animals with motor evoked potential disappearance, occlusion was maintained for 10 minutes (n = 6) or 40 minutes (n = 6) after motor evoked potential disappearance. Neurologic function was evaluated by Tarlov score at 24 and 48 hours postoperatively. Time to disappearance of bilateral motor evoked potentials was quicker in transesophageal motor evoked potentials than in transcranial motor evoked potentials at anal sphincters (6.9 ± 3.1 minutes vs 8.3 ± 3.4 minutes, P = .02) and hindlimbs (5.7 ± 1.9 minutes vs 7.1 ± 2.7 minutes, P = .008). Hindlimb function was normal in all dogs in the 10-minute occlusion group, and motor evoked potentials recovery (>75% on both sides) after reperfusion was quicker in transesophageal motor evoked potentials than transcranial motor evoked potentials at hindlimbs (14.8 ± 5.6 minutes vs 24.7 ± 8.2 minutes, P = .001). At anal sphincters, transesophageal motor evoked potentials always reappeared (>25%), but transcranial motor evoked potentials did not in 3 of 6 dogs. In the 40-minute occlusion group, hindlimb motor evoked potentials did not reappear in 4 dogs with paraplegia. Among the 2 remaining dogs, 1 with paraparesis (Tarlov 3) showed delayed recovery (>75%) of hindlimb motor evoked potentials without reappearance of anal sphincter motor evoked potentials. In another dog with spastic paraplegia, transesophageal motor evoked potentials from the hindlimbs remained less than 20%, whereas transcranial motor evoked potentials showed recovery (>75%). Transesophageal motor evoked potentials may be superior to transcranial motor evoked potentials in terms of quicker response to spinal cord ischemia and better prognostic value. Copyright © 2016 The American Association for Thoracic Surgery. Published by Elsevier Inc. All rights reserved.

Multimodal pain stimulation of the gastrointestinal tract

PubMed Central

Drewes, Asbjørn Mohr; Gregersen, Hans

2006-01-01

Understanding and characterization of pain and other sensory symptoms are among the most important issues in the diagnosis and assessment of patient with gastrointestinal disorders. Methods to evoke and assess experimental pain have recently developed into a new area with the possibility for multimodal stimulation (e.g., electrical, mechanical, thermal and chemical stimulation) of different nerves and pain pathways in the human gut. Such methods mimic to a high degree the pain experienced in the clinic. Multimodal pain methods have increased our basic understanding of different peripheral receptors in the gut in health and disease. Together with advanced muscle analysis, the methods have increased our understanding of receptors sensitive to mechanical, chemical and temperature stimuli in diseases, such as systemic sclerosis and diabetes. The methods can also be used to unravel central pain mechanisms, such as those involved in allodynia, hyperalgesia and referred pain. Abnormalities in central pain mechanisms are often seen in patients with chronic gut pain and hence methods relying on multimodal pain stimulation may help to understand the symptoms in these patients. Sex differences have been observed in several diseases of the gut, and differences in central pain processing between males and females have been hypothesized using multimodal pain stimulations. Finally, multimodal methods have recently been used to gain more insight into the effect of drugs against pain in the GI tract. Hence, the multimodal methods undoubtedly represents a major step forward in the future characterization and treatment of patients with various diseases of the gut. PMID:16688791

Evoking Emotions and Unpacking Layered Histories through Young Children's Illustrations of Racial Bus Segregation

ERIC Educational Resources Information Center

Kuby, Candace R.

2013-01-01

Drawing on theories of multi-modality and critical visual literacy, this article focuses on images that five-and six year-olds painted in a class-made book, Voice on the Bus, about racial segregation. The article discusses how children used illustrations to convey their understandings of Rosa Parks' bus arrest in Alabama. A post-structural view…

Cortical neurons and networks are dormant but fully responsive during isoelectric brain state.

PubMed

Altwegg-Boussac, Tristan; Schramm, Adrien E; Ballestero, Jimena; Grosselin, Fanny; Chavez, Mario; Lecas, Sarah; Baulac, Michel; Naccache, Lionel; Demeret, Sophie; Navarro, Vincent; Mahon, Séverine; Charpier, Stéphane

2017-09-01

A continuous isoelectric electroencephalogram reflects an interruption of endogenously-generated activity in cortical networks and systematically results in a complete dissolution of conscious processes. This electro-cerebral inactivity occurs during various brain disorders, including hypothermia, drug intoxication, long-lasting anoxia and brain trauma. It can also be induced in a therapeutic context, following the administration of high doses of barbiturate-derived compounds, to interrupt a hyper-refractory status epilepticus. Although altered sensory responses can be occasionally observed on an isoelectric electroencephalogram, the electrical membrane properties and synaptic responses of individual neurons during this cerebral state remain largely unknown. The aim of the present study was to characterize the intracellular correlates of a barbiturate-induced isoelectric electroencephalogram and to analyse the sensory-evoked synaptic responses that can emerge from a brain deprived of spontaneous electrical activity. We first examined the sensory responsiveness from patients suffering from intractable status epilepticus and treated by administration of thiopental. Multimodal sensory responses could be evoked on the flat electroencephalogram, including visually-evoked potentials that were significantly amplified and delayed, with a high trial-to-trial reproducibility compared to awake healthy subjects. Using an analogous pharmacological procedure to induce prolonged electro-cerebral inactivity in the rat, we could describe its cortical and subcortical intracellular counterparts. Neocortical, hippocampal and thalamo-cortical neurons were all silent during the isoelectric state and displayed a flat membrane potential significantly hyperpolarized compared with spontaneously active control states. Nonetheless, all recorded neurons could fire action potentials in response to intracellularly injected depolarizing current pulses and their specific intrinsic electrophysiological features were preserved. Manipulations of the membrane potential and intracellular injection of chloride in neocortical neurons failed to reveal an augmented synaptic inhibition during the isoelectric condition. Consistent with the sensory responses recorded from comatose patients, large and highly reproducible somatosensory-evoked potentials could be generated on the inactive electrocorticogram in rats. Intracellular recordings revealed that the underlying neocortical pyramidal cells responded to sensory stimuli by complex synaptic potentials able to trigger action potentials. As in patients, sensory responses in the isoelectric state were delayed compared to control responses and exhibited an elevated reliability during repeated stimuli. Our findings demonstrate that during prolonged isoelectric brain state neurons and synaptic networks are dormant rather than excessively inhibited, conserving their intrinsic properties and their ability to integrate and propagate environmental stimuli. © The Author (2017). Published by Oxford University Press on behalf of the Guarantors of Brain. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Effects of pharmacological agents on subcortical resistance shifts

NASA Technical Reports Server (NTRS)

Klivington, K. A.

1975-01-01

Microliter quantities of tetrodotoxin, tetraethylammonium chloride, and picrotoxin injected into the inferior colliculus and superior olive of unanesthetized cats differentially affect the amplitude and waveform of click-evoked potentials and evoked resistance shifts. Tetrodotoxin simultaneously reduces the negative phase of the evoked potential and eliminates the evoked resistance shift. Tetraethylammonium enhances the negative evoked potential component, presumably of postsynaptic origin, without significantly altering evoked resistance shift amplitude. Picrotoxin also enhances the negative evoked potential wave but increases evoked resistance shift amplitude. These findings implicate events associated with postsynaptic membrane depolarization in the production of the evoked resistance shift.

Direct estimation of evoked hemoglobin changes by multimodality fusion imaging

PubMed Central

Huppert, Theodore J.; Diamond, Solomon G.; Boas, David A.

2009-01-01

In the last two decades, both diffuse optical tomography (DOT) and blood oxygen level dependent (BOLD)-based functional magnetic resonance imaging (fMRI) methods have been developed as noninvasive tools for imaging evoked cerebral hemodynamic changes in studies of brain activity. Although these two technologies measure functional contrast from similar physiological sources, i.e., changes in hemoglobin levels, these two modalities are based on distinct physical and biophysical principles leading to both limitations and strengths to each method. In this work, we describe a unified linear model to combine the complimentary spatial, temporal, and spectroscopic resolutions of concurrently measured optical tomography and fMRI signals. Using numerical simulations, we demonstrate that concurrent optical and BOLD measurements can be used to create cross-calibrated estimates of absolute micromolar deoxyhemoglobin changes. We apply this new analysis tool to experimental data acquired simultaneously with both DOT and BOLD imaging during a motor task, demonstrate the ability to more robustly estimate hemoglobin changes in comparison to DOT alone, and show how this approach can provide cross-calibrated estimates of hemoglobin changes. Using this multimodal method, we estimate the calibration of the 3 tesla BOLD signal to be −0.55% ± 0.40% signal change per micromolar change of deoxyhemoglobin. PMID:19021411

Monitoring multiple sclerosis by multimodal evoked potentials: Numerically versus ordinally scaled scoring systems.

PubMed

Schlaeger, Regina; Hardmeier, Martin; D'Souza, Marcus; Grize, Leticia; Schindler, Christian; Kappos, Ludwig; Fuhr, Peter

2016-03-01

To compare the ability of different evoked potential scores (EPS) to monitor and predict the disease course in multiple sclerosis (MS). Seventy-two patients with MS or clinically isolated syndrome were investigated by visual, motor, and somatosensory EP and expanded disability status scale (EDSS) at baseline (T0) and months 6, 12, 24, 36 (T4). EP results were rated according to ordinal (o), semi-quantitative (sq), and quantitative (q) EPS. Spearman rank correlation and multivariable linear regression were used to investigate the associations between EPS and clinical disability. All EPS correlated with EDSS cross-sectionally (0.72⩽rho⩽0.87, all p<0.001) and longitudinally (0.39⩽rho⩽0.47, all p⩽0.004). EPS(T0) and EDSS(T0) together explained 85-86% of EDSS(T4) variance. A posteriori power calculation showed that the sample sizes needed to detect significant changes over 6 months in q-EPS, sq-EPS and o-EPS with 90% certainty would be 50, 129 and 222, respectively. q-EPS change(T1-T0) correlated with EDSS change(T4-T0) (rho=0.56, p<0.001), while sq-EPS and o-EPS changes(T1-T0) did not. All three EPS allow disease course monitoring in MS. However, the quantitative EPS detects clinically relevant short-term changes with a smaller sample size than semi-quantitative or ordinal EPS. These results underscore the potential of EPS to characterize MS disease evolution. Copyright © 2016. Published by Elsevier Ireland Ltd.

Do evoked potentials contribute to the functional follow-up and clinical prognosis of multiple sclerosis?

PubMed

Giffroy, Xavier; Maes, Nathalie; Albert, Adelin; Maquet, Pierre; Crielaard, Jean-Michel; Dive, Dominique

2017-03-01

The clinical variability and complexity of multiple sclerosis (MS) challenges the individual clinical course prognostication. This study aimed to find out whether multimodal evoked potentials (EP) correlate with the motor components of multiple sclerosis functional composite (MSFCm) and predict clinically relevant motor functional deterioration. One hundred MS patients were assessed at baseline (T 0 ) and about 7.5 years later (T 1 ), with visual, somatosensory and motor EP and rated on the Expanded Disability Status Scale (EDSS) and the MSFCm, including the 9 Hole Peg Test and the Timed 25 Foot Walk (T25FW). The Spearman correlation coefficient (r S ) was used to evaluate the cross-sectional and longitudinal relationship between EP Z scores and clinical findings. The predictive value of baseline electrophysiological data for clinical worsening (EDSS, 9-HPT, T25FW, MSFCm) during follow-up was assessed by logistic regression analysis. Unlike longitudinal correlations, cross-sectional correlations between EP Z scores and clinical outcomes were all significant and ranged between 0.22 and 0.67 (p < 0.05). The global EP Z score was systematically predictive of EDSS and MSFCm worsening over time (all p < 0.05). EP latency was a better predictor than amplitude, although weaker than latency and amplitude aggregation in the global EP Z score. The study demonstrates that EP numerical scores can be used for motor function monitoring and outcome prediction in patients with MS.

A joint sparse representation-based method for double-trial evoked potentials estimation.

PubMed

Yu, Nannan; Liu, Haikuan; Wang, Xiaoyan; Lu, Hanbing

2013-12-01

In this paper, we present a novel approach to solving an evoked potentials estimating problem. Generally, the evoked potentials in two consecutive trials obtained by repeated identical stimuli of the nerves are extremely similar. In order to trace evoked potentials, we propose a joint sparse representation-based double-trial evoked potentials estimation method, taking full advantage of this similarity. The estimation process is performed in three stages: first, according to the similarity of evoked potentials and the randomness of a spontaneous electroencephalogram, the two consecutive observations of evoked potentials are considered as superpositions of the common component and the unique components; second, making use of their characteristics, the two sparse dictionaries are constructed; and finally, we apply the joint sparse representation method in order to extract the common component of double-trial observations, instead of the evoked potential in each trial. A series of experiments carried out on simulated and human test responses confirmed the superior performance of our method. © 2013 Elsevier Ltd. Published by Elsevier Ltd. All rights reserved.

A simple model for the generation of the vestibular evoked myogenic potential (VEMP).

PubMed

Wit, Hero P; Kingma, Charlotte M

2006-06-01

To describe the mechanism by which the vestibular evoked myogenic potential is generated. Vestibular evoked myogenic potential generation is modeled by adding a large number of muscle motor unit action potentials. These action potentials occur randomly in time along a 100 ms long time axis. But because between approximately 15 and 20 ms after a loud short sound stimulus (almost) no action potentials are generated during VEMP measurements in human subjects, no action potentials are present in the model during this time. The evoked potential is the result of the lack of amplitude cancellation in the averaged surface electromyogram at the edges of this 5 ms long time interval. The relatively simple model describes generation and some properties of the vestibular evoked myogenic potential very well. It is shown that, in contrast with other evoked potentials (BAEPs, VERs), the vestibular evoked myogenic potential is the result of an interruption of activity and not that of summed synchronized neural action potentials.

Effect profile of paracetamol, Δ9-THC and promethazine using an evoked pain test battery in healthy subjects.

PubMed

van Amerongen, G; Siebenga, P; de Kam, M L; Hay, J L; Groeneveld, G J

2018-04-10

A battery of evoked pain tasks (PainCart) was developed to investigate the pharmacodynamic properties of novel analgesics in early-phase clinical research. As part of its clinical validation, compounds with different pharmacological mechanisms of actions are investigated. The aim was to investigate the analgesic effects of classic and nonclassic analgesics compared to a sedating negative control in a randomized placebo-controlled crossover study in 24 healthy volunteers using the PainCart. The PainCart consisted of pain tasks eliciting electrical, pressure, heat, cold and inflammatory pain. Subjective scales for cognitive functioning and psychotomimetic effects were included. Subjects were administered each of the following oral treatments: paracetamol (1000 mg), Δ9-THC (10 mg), promethazine (50 mg) or matching placebo. Pharmacodynamic measurements were performed at baseline and repeated up to 10 h postdose. Paracetamol did not show a significant reduction in pain sensation or subjective cognitive functioning compared to placebo. Promethazine induced a statistically significant reduction in PTT for cold pressor and pressure stimulation. Furthermore, reduced subjective alertness was observed. Δ9-THC showed a statistically significant decrease in PTT for electrical and pressure stimulation. Δ9-THC also demonstrated subjective effects, including changes in alertness and calmness, as well as feeling high and psychotomimetic effects. This study found a decreased pain tolerance due to Δ9-THC and promethazine, or lack thereof, using an evoked pain task battery. Pain thresholds following paracetamol administration remained unchanged, which may be due to insufficient statistical power. We showed that pain thresholds determined using this pain test battery are not driven by sedation. The multimodal battery of evoked pain tasks utilized in this study may play an important role in early-phase clinical drug development. This battery of pain tasks is not sensitive to the effects of sedation alone, and thus suitable to investigate the analgesic potential of novel analgesic compounds. © 2018 European Pain Federation - EFIC®.

Electroretinography and Visual Evoked Potentials in Childhood Brain Tumor Survivors.

PubMed

Pietilä, Sari; Lenko, Hanna L; Oja, Sakari; Koivisto, Anna-Maija; Pietilä, Timo; Mäkipernaa, Anne

2016-07-01

This population-based cross-sectional study evaluates the clinical value of electroretinography and visual evoked potentials in childhood brain tumor survivors. A flash electroretinography and a checkerboard reversal pattern visual evoked potential (or alternatively a flash visual evoked potential) were done for 51 survivors (age 3.8-28.7 years) after a mean follow-up time of 7.6 (1.5-15.1) years. Abnormal electroretinography was obtained in 1 case, bilaterally delayed abnormal visual evoked potentials in 22/51 (43%) cases. Nine of 25 patients with infratentorial tumor location, and altogether 12 out of 31 (39%) patients who did not have tumors involving the visual pathways, had abnormal visual evoked potentials. Abnormal electroretinographies are rarely observed, but abnormal visual evoked potentials are common even without evident anatomic lesions in the visual pathway. Bilateral changes suggest a general and possibly multifactorial toxic/adverse effect on the visual pathway. Electroretinography and visual evoked potential may have clinical and scientific value while evaluating long-term effects of childhood brain tumors and tumor treatment. © The Author(s) 2016.

Loss of lower limb motor evoked potentials and spinal cord injury during the initial exposure in scoliosis surgery.

PubMed

Legatt, Alan D; Fried, Stephen J; Amaral, Terry D; Sarwahi, Vishal; Moguilevitch, Marina

2014-04-01

To report a case of motor evoked potential changes and spinal cord injury during the initial dissection in scoliosis surgery. Motor evoked potentials to transcranial electrical stimulation were recorded from multiple muscles. Somatosensory evoked potentials to limb nerve stimulation were recorded from the scalp. Clear motor evoked potentials were initially present in all monitored muscles. The patient was then pharmacologically paralyzed for the initial dissection. More than usual bleeding was encountered during that dissection, prompting transfusion. As the neuromuscular blockade subsided, motor evoked potentials persisted in the hand muscles but disappeared and remained absent in all monitored leg muscles. The spine had not been instrumented. A wake-up test demonstrated paraplegia; the surgery was aborted. There were no adverse somatosensory evoked potential changes. MRI showed an anterior spinal cord infarct. Copious soft tissue bleeding during the initial dissection might have lowered pressures in critical segmental arteries enough to cause spinal cord infarction through a steal phenomenon. The lack of somatosensory evoked potential changes reflected sparing of the dorsal columns. When neuromuscular blockade is used during the initial soft tissue dissection, motor evoked potentials should be assessed after this, but before spinal instrumentation, to determine whether there had been any spinal cord compromise during the initial dissection.

Evaluation of Pain Assessment Techniques and Analgesia Efficacy in a Female Guinea Pig (Cavia porcellus) Model of Surgical Pain

PubMed Central

Oliver, Vanessa L; Athavale, Stephanie; Simon, Katherine E; Kendall, Lon V; Nemzek, Jean A; Lofgren, Jennifer L

2017-01-01

Guinea pigs (Cavia porcellus) are a frequently used species in research, often involving potentially painful procedures. Therefore, evidence-based recommendations regarding analgesia are critically needed to optimize their wellbeing. Our laboratory examined the efficacy of carprofen and extended-release (ER) buprenorphine, alone and as a multimodal combination, for relieving postsurgical pain in guinea pigs. Animals were assessed by using evoked (mechanical hypersensitivity), nonevoked (video ethogram, cageside ethogram, time-to-consumption test), and clinical (weight loss) measurements for 96 h during baseline, anesthesia–analgesia, and hysterectomy conditions. In addition, ER buprenorphine was evaluated pharmacologically. Guinea pigs treated with a single analgesic showed increased mechanical sensitivity for at least 96 h and indices of pain according to the video ethogram for as long as 8 h, compared with levels recorded during anesthesia–analgesia. In contrast, animals given both analgesics demonstrated increased mechanical sensitivity and behavioral evidence of pain for only 2 h after surgery compared with anesthesia–analgesia. The cageside ethogram and time-to-consumption tests failed to identify differences between conditions or treatment groups, highlighting the difficulty of identifying pain in guinea pigs without remote observation. Guinea pigs treated with multimodal analgesia or ER buprenorphine lost at least 10% of their baseline weights, whereas weight loss in carprofen animals was significantly lower (3%). Plasma levels for ER buprenorphine exceeded 0.9 ng/mL from 8 to 96 h after injection. Of the 3 analgesia regimens evaluated, multimodal analgesia provided the most effective pain control in guinea pigs. However the weight loss in the ER buprenorphine–treated animals may need to be considered during analgesia selection. PMID:28724492

A Brief Review of the Pharmacology of Amitriptyline and Clinical Outcomes in Treating Fibromyalgia

PubMed Central

Lawson, Kim

2017-01-01

Fibromyalgia is a complex chronic condition characterized by pain, physical fatigue, sleep disorder and cognitive impairment. Evidence-based guidelines recommend antidepressants as treatments of fibromyalgia where tricyclics are often considered to have the greatest efficacy, with amitriptyline often being a first-line treatment. Amitriptyline evokes a preferential reduction in pain and fatigue of fibromyalgia, and in the Fibromyalgia Impact Questionnaire (FIQ) score, which is a quality of life assessment. The multimodal profile of the mechanisms of action of amitriptyline include monoamine reuptake inhibition, receptor modulation and ion channel modulation. Several of the actions of amitriptyline on multiple nociceptive and sensory processes at central and peripheral locations have the potential to act cumulatively to suppress the characteristic symptoms of fibromyalgia. Greater understanding of the role of these mechanisms of action of amitriptyline could provide further clues to the pathophysiology of fibromyalgia and to a preferable pharmacological profile for future drug development. PMID:28536367

Vestibular evoked potentials (VsEPs) of cortical origin produced by impulsive acceleration applied at the nasion.

PubMed

Todd, Neil P M; McLean, Aisha; Paillard, Aurore; Kluk, Karolina; Colebatch, James G

2014-12-01

We report the results of a study to record vestibular evoked potentials (VsEPs) of cortical origin produced by impulsive acceleration (IA). In a sample of 12 healthy participants, evoked potentials recorded by 70 channel electroencephalography were obtained by IA stimulation at the nasion and compared with evoked potentials from the same stimulus applied to the forefingers. The nasion stimulation gave rise to a series of positive and negative deflections in the latency range of 26-72 ms, which were dependent on the polarity of the applied IA. In contrast, evoked potentials from the fingers were characterised by a single N50/P50 deflection at about 50 ms and were polarity invariant. Source analysis confirmed that the finger evoked potentials were somatosensory in origin, i.e. were somatosensory evoked potentials, and suggested that the nasion evoked potentials plausibly included vestibular midline and frontal sources, as well as contributions from the eyes, and thus were likely VsEPs. These results show considerable promise as a new method for assessment of the central vestibular system by means of VsEPs produced by IA applied to the head.

Skin denervation does not alter cortical potentials to surface concentric electrode stimulation: A comparison with laser evoked potentials and contact heat evoked potentials.

PubMed

La Cesa, S; Di Stefano, G; Leone, C; Pepe, A; Galosi, E; Alu, F; Fasolino, A; Cruccu, G; Valeriani, M; Truini, A

2018-01-01

In the neurophysiological assessment of patients with neuropathic pain, laser evoked potentials (LEPs), contact heat evoked potentials (CHEPs) and the evoked potentials by the intraepidermal electrical stimulation via concentric needle electrode are widely agreed as nociceptive specific responses; conversely, the nociceptive specificity of evoked potentials by surface concentric electrode (SE-PREPs) is still debated. In this neurophysiological study we aimed at verifying the nociceptive specificity of SE-PREPs. We recorded LEPs, CHEPs and SE-PREPs in eleven healthy participants, before and after epidermal denervation produced by prolonged capsaicin application. We also used skin biopsy to verify the capsaicin-induced nociceptive nerve fibre loss in the epidermis. We found that whereas LEPs and CHEPs were suppressed after capsaicin-induced epidermal denervation, the surface concentric electrode stimulation of the same denervated skin area yielded unchanged SE-PREPs. The suppression of LEPs and CHEPs after nociceptive nerve fibre loss in the epidermis indicates that these techniques are selectively mediated by nociceptive system. Conversely, the lack of SE-PREP changes suggests that SE-PREPs do not provide selective information on nociceptive system function. Capsaicin-induced epidermal denervation abolishes laser evoked potentials (LEPs) and contact heat evoked potentials (CHEPs), but leaves unaffected pain-related evoked potentials by surface concentric electrode (SE-PREPs). These findings suggest that unlike LEPs and CHEPs, SE-PREPs are not selectively mediated by nociceptive system. © 2017 European Pain Federation - EFIC®.

Early Prognostication Markers in Cardiac Arrest Patients Treated with Hypothermia

PubMed Central

Karapetkova, Maria; Koenig, Matthew A.; Jia, Xiaofeng

2015-01-01

Background and purpose Established prognostication markers, such as clinical findings, electroencephalography (EEG), and biochemical markers, used by clinicians to predict neurologic outcome after cardiac arrest (CA) are altered under therapeutic hypothermia (TH) conditions and their validity remains uncertain. Methods MEDLINE and EMBASE were searched for evidence on the current standards for neurologic outcome prediction for out-of-hospital CA patients treated with TH and the validity of a wide range of prognostication markers. Relevant studies that suggested one or several established biomarkers, and multimodal approaches for prognostication were included and reviewed. Results While the prognostic accuracy of various tests has been questioned after TH, pupillary light reflexes and somatosensory evoked potentials (SSEP) are still strongly associated with negative outcome for early prognostication. Increasingly, EEG background activity has also been identified as a valid predictor for outcome after 72 hours after CA and a preferred prognostic method in clinical settings. Neuroimaging techniques, such as MRI and CT, can identify functional and structural brain injury, but are not readily available at the patient’s bedside because of limited availability and high costs. Conclusions A multimodal algorithm composed of neurological examination, EEG-based quantitative testing, and SSEP, in conjunction with newer MRI sequences, if available, holds promise for accurate prognostication in CA patients treated with TH. In order to avoid premature withdrawal of care, prognostication should be performed later than 72 hours after CA. PMID:26228521

Exploring the Mechanisms of Exercise-Induced Hypoalgesia Using Somatosensory and Laser Evoked Potentials.

PubMed

Jones, Matthew D; Taylor, Janet L; Booth, John; Barry, Benjamin K

2016-01-01

Exercise-induced hypoalgesia is well described, but the underlying mechanisms are unclear. The aim of this study was to examine the effect of exercise on somatosensory evoked potentials, laser evoked potentials, pressure pain thresholds and heat pain thresholds. These were recorded before and after 3-min of isometric elbow flexion exercise at 40% of the participant's maximal voluntary force, or an equivalent period of rest. Exercise-induced hypoalgesia was confirmed in two experiments (Experiment 1-SEPs; Experiment 2-LEPs) by increased pressure pain thresholds at biceps brachii (24.3 and 20.6% increase in Experiment 1 and 2, respectively; both d > 0.84 and p < 0.001) and first dorsal interosseous (18.8 and 21.5% increase in Experiment 1 and 2, respectively; both d > 0.57 and p < 0.001). In contrast, heat pain thresholds were not significantly different after exercise (forearm: 10.8% increase, d = 0.35, p = 0.10; hand: 3.6% increase, d = 0.06, p = 0.74). Contrasting effects of exercise on the amplitude of laser evoked potentials (14.6% decrease, d = -0.42, p = 0.004) and somatosensory evoked potentials (10.9% increase, d = -0.02, p = 1) were also observed, while an equivalent period of rest showed similar habituation (laser evoked potential: 7.3% decrease, d = -0.25, p = 0.14; somatosensory evoked potential: 20.7% decrease, d = -0.32, p = 0.006). The differential response of pressure pain thresholds and heat pain thresholds to exercise is consistent with relative insensitivity of thermal nociception to the acute hypoalgesic effects of exercise. Conflicting effects of exercise on somatosensory evoked potentials and laser evoked potentials were observed. This may reflect non-nociceptive contributions to the somatosensory evoked potential, but could also indicate that peripheral nociceptors contribute to exercise-induced hypoalgesia.

Longitudinal Structural and Functional Brain Network Alterations in a Mouse Model of Neuropathic Pain.

PubMed

Bilbao, Ainhoa; Falfán-Melgoza, Claudia; Leixner, Sarah; Becker, Robert; Singaravelu, Sathish Kumar; Sack, Markus; Sartorius, Alexander; Spanagel, Rainer; Weber-Fahr, Wolfgang

2018-04-22

Neuropathic pain affects multiple brain functions, including motivational processing. However, little is known about the structural and functional brain changes involved in the transition from an acute to a chronic pain state. Here we combined behavioral phenotyping of pain thresholds with multimodal neuroimaging to longitudinally monitor changes in brain metabolism, structure and connectivity using the spared nerve injury (SNI) mouse model of chronic neuropathic pain. We investigated stimulus-evoked pain responses prior to SNI surgery, and one and twelve weeks following surgery. A progressive development and potentiation of stimulus-evoked pain responses (cold and mechanical allodynia) were detected during the course of pain chronification. Voxel-based morphometry demonstrated striking decreases in volume following pain induction in all brain sites assessed - an effect that reversed over time. Similarly, all global and local network changes that occurred following pain induction disappeared over time, with two notable exceptions: the nucleus accumbens, which played a more dominant role in the global network in a chronic pain state and the prefrontal cortex and hippocampus, which showed lower connectivity. These changes in connectivity were accompanied by enhanced glutamate levels in the hippocampus, but not in the prefrontal cortex. We suggest that hippocampal hyperexcitability may contribute to alterations in synaptic plasticity within the nucleus accumbens, and to pain chronification. Copyright © 2018 The Authors. Published by Elsevier Ltd.. All rights reserved.

Whole-brain diffusion tensor imaging in correlation to visual-evoked potentials in multiple sclerosis: a tract-based spatial statistics analysis.

PubMed

Lobsien, D; Ettrich, B; Sotiriou, K; Classen, J; Then Bergh, F; Hoffmann, K-T

2014-01-01

Functional correlates of microstructural damage of the brain affected by MS are incompletely understood. The purpose of this study was to evaluate correlations of visual-evoked potentials with microstructural brain changes as determined by DTI in patients with demyelinating central nervous disease. Sixty-one patients with clinically isolated syndrome or MS were prospectively recruited. The mean P100 visual-evoked potential latencies of the right and left eyes of each patient were calculated and used for the analysis. For DTI acquisition, a single-shot echo-planar imaging pulse sequence with 80 diffusion directions was performed at 3T. Fractional anisotropy, radial diffusivity, and axial diffusivity were calculated and correlated with mean P100 visual-evoked potentials by tract-based spatial statistics. Significant negative correlations between mean P100 visual-evoked potentials and fractional anisotropy and significant positive correlations between mean P100 visual-evoked potentials and radial diffusivity were found widespread over the whole brain. The highest significance was found in the optic radiation, frontoparietal white matter, and corpus callosum. Significant positive correlations between mean P100 visual-evoked potentials and axial diffusivity were less widespread, notably sparing the optic radiation. Microstructural changes of the whole brain correlated significantly with mean P100 visual-evoked potentials. The distribution of the correlations showed clear differences among axial diffusivity, fractional anisotropy, and radial diffusivity, notably in the optic radiation. This finding suggests a stronger correlation of mean P100 visual-evoked potentials to demyelination than to axonal damage. © 2014 by American Journal of Neuroradiology.

Electrophysiological studies of the nervous system

NASA Technical Reports Server (NTRS)

Galambos, R.

1972-01-01

The electrophysiology of the nervous system is studied using cats and human subjects. Data cover effects of chlorolose on evoked potential, the evoked resistance shift that accompanies evoked potentials, and the relationship of eye movements to potentials aroused by visual stimulation.

Bedside functional brain imaging in critically-ill children using high-density EEG source modeling and multi-modal sensory stimulation.

PubMed

Eytan, Danny; Pang, Elizabeth W; Doesburg, Sam M; Nenadovic, Vera; Gavrilovic, Bojan; Laussen, Peter; Guerguerian, Anne-Marie

2016-01-01

Acute brain injury is a common cause of death and critical illness in children and young adults. Fundamental management focuses on early characterization of the extent of injury and optimizing recovery by preventing secondary damage during the days following the primary injury. Currently, bedside technology for measuring neurological function is mainly limited to using electroencephalography (EEG) for detection of seizures and encephalopathic features, and evoked potentials. We present a proof of concept study in patients with acute brain injury in the intensive care setting, featuring a bedside functional imaging set-up designed to map cortical brain activation patterns by combining high density EEG recordings, multi-modal sensory stimulation (auditory, visual, and somatosensory), and EEG source modeling. Use of source-modeling allows for examination of spatiotemporal activation patterns at the cortical region level as opposed to the traditional scalp potential maps. The application of this system in both healthy and brain-injured participants is demonstrated with modality-specific source-reconstructed cortical activation patterns. By combining stimulation obtained with different modalities, most of the cortical surface can be monitored for changes in functional activation without having to physically transport the subject to an imaging suite. The results in patients in an intensive care setting with anatomically well-defined brain lesions suggest a topographic association between their injuries and activation patterns. Moreover, we report the reproducible application of a protocol examining a higher-level cortical processing with an auditory oddball paradigm involving presentation of the patient's own name. This study reports the first successful application of a bedside functional brain mapping tool in the intensive care setting. This application has the potential to provide clinicians with an additional dimension of information to manage critically-ill children and adults, and potentially patients not suited for magnetic resonance imaging technologies.

A Perturbation Based Decomposition of Compound-Evoked Potentials for Characterization of Nerve Fiber Size Distributions.

PubMed

Szlavik, Robert B

2016-02-01

The characterization of peripheral nerve fiber distributions, in terms of diameter or velocity, is of clinical significance because information associated with these distributions can be utilized in the differential diagnosis of peripheral neuropathies. Electro-diagnostic techniques can be applied to the investigation of peripheral neuropathies and can yield valuable diagnostic information while being minimally invasive. Nerve conduction velocity studies are single parameter tests that yield no detailed information regarding the characteristics of the population of nerve fibers that contribute to the compound-evoked potential. Decomposition of the compound-evoked potential, such that the velocity or diameter distribution of the contributing nerve fibers may be determined, is necessary if information regarding the population of contributing nerve fibers is to be ascertained from the electro-diagnostic study. In this work, a perturbation-based decomposition of compound-evoked potentials is proposed that facilitates determination of the fiber diameter distribution associated with the compound-evoked potential. The decomposition is based on representing the single fiber-evoked potential, associated with each diameter class, as being perturbed by contributions, of varying degree, from all the other diameter class single fiber-evoked potentials. The resultant estimator of the contributing nerve fiber diameter distribution is valid for relatively large separations in diameter classes. It is also useful in situations where the separation between diameter classes is small and the concomitant single fiber-evoked potentials are not orthogonal.

Auditory- and visual-evoked potentials in Mexican infants are not affected by maternal supplementation with 400 mg/d docosahexaenoic acid in the second half of pregnancy.

PubMed

Stein, Aryeh D; Wang, Meng; Rivera, Juan A; Martorell, Reynaldo; Ramakrishnan, Usha

2012-08-01

The evidence relating prenatal supplementation with DHA to offspring neurological development is limited. We investigated the effect of prenatal DHA supplementation on infant brainstem auditory-evoked responses and visual- evoked potentials in a double-blind, randomized controlled trial in Cuernavaca, Mexico. Pregnant women were supplemented daily with 400 mg DHA or placebo from gestation wk 18-22 through delivery. DHA and placebo groups did not differ in maternal characteristics at randomization or infant characteristics at birth. Brainstem auditory-evoked responses were measured at 1 and 3 mo in 749 and 664 infants, respectively, and visual-evoked potentials were measured at 3 and 6 mo in 679 and 817 infants, respectively. Left-right brainstem auditory-evoked potentials were moderately correlated (range, 0.26-0.43; all P < 0.001) and left-right visual-evoked potentials were strongly correlated (range, 0.79-0.94; all P < 0.001) within any assessment. Correlations across visits were modest to moderate (range, 0.09-0.38; all P < 0.01). The offspring of DHA-supplemented women did not differ from those of control women with respect to any outcome measure (all comparisons P > 0.10). We conclude that DHA supplementation during pregnancy did not influence brainstem auditory-evoked responses at 1 and 3 mo or visual-evoked potentials at 3 and 6 mo.

ROLE OF NMDA, NICOTINIC, AND GABA RECEPTORS IN THE STEADY STATE VISUAL EVOKED POTENTIAL IN RATS.

EPA Science Inventory

This manuscript characterizes the receptor pathways involved in pattern-evoked potential generation in rats

" NMDA and nicotinic acetylcholine receptors appear to be involved in the generation of the steady-state pattern evoked response in vivo.

" The pattern evok...

Exploring the Mechanisms of Exercise-Induced Hypoalgesia Using Somatosensory and Laser Evoked Potentials

PubMed Central

Jones, Matthew D.; Taylor, Janet L.; Booth, John; Barry, Benjamin K.

2016-01-01

Exercise-induced hypoalgesia is well described, but the underlying mechanisms are unclear. The aim of this study was to examine the effect of exercise on somatosensory evoked potentials, laser evoked potentials, pressure pain thresholds and heat pain thresholds. These were recorded before and after 3-min of isometric elbow flexion exercise at 40% of the participant's maximal voluntary force, or an equivalent period of rest. Exercise-induced hypoalgesia was confirmed in two experiments (Experiment 1–SEPs; Experiment 2–LEPs) by increased pressure pain thresholds at biceps brachii (24.3 and 20.6% increase in Experiment 1 and 2, respectively; both d > 0.84 and p < 0.001) and first dorsal interosseous (18.8 and 21.5% increase in Experiment 1 and 2, respectively; both d > 0.57 and p < 0.001). In contrast, heat pain thresholds were not significantly different after exercise (forearm: 10.8% increase, d = 0.35, p = 0.10; hand: 3.6% increase, d = 0.06, p = 0.74). Contrasting effects of exercise on the amplitude of laser evoked potentials (14.6% decrease, d = −0.42, p = 0.004) and somatosensory evoked potentials (10.9% increase, d = −0.02, p = 1) were also observed, while an equivalent period of rest showed similar habituation (laser evoked potential: 7.3% decrease, d = −0.25, p = 0.14; somatosensory evoked potential: 20.7% decrease, d = −0.32, p = 0.006). The differential response of pressure pain thresholds and heat pain thresholds to exercise is consistent with relative insensitivity of thermal nociception to the acute hypoalgesic effects of exercise. Conflicting effects of exercise on somatosensory evoked potentials and laser evoked potentials were observed. This may reflect non-nociceptive contributions to the somatosensory evoked potential, but could also indicate that peripheral nociceptors contribute to exercise-induced hypoalgesia. PMID:27965587

Properties of visual evoked potentials to onset of movement on a television screen.

PubMed

Kubová, Z; Kuba, M; Hubacek, J; Vít, F

1990-08-01

In 80 subjects the dependence of movement-onset visual evoked potentials on some measures of stimulation was examined, and these responses were compared with pattern-reversal visual evoked potentials to verify the effectiveness of pattern movement application for visual evoked potential acquisition. Horizontally moving vertical gratings were generated on a television screen. The typical movement-onset reactions were characterized by one marked negative peak only, with a peak time between 140 and 200 ms. In all subjects the sufficient stimulus duration for acquisition of movement-onset-related visual evoked potentials was 100 ms; in some cases it was only 20 ms. Higher velocity (5.6 degree/s) produced higher amplitudes of movement-onset visual evoked potentials than did the lower velocity (2.8 degrees/s). In 80% of subjects, the more distinct reactions were found in the leads from lateral occipital areas (in 60% from the right hemisphere), with no correlation to handedness of subjects. Unlike pattern-reversal visual evoked potentials, the movement-onset responses tended to be larger to extramacular stimulation (annular target of 5 degrees-9 degrees) than to macular stimulation (circular target of 5 degrees diameter).

[A Case of Left Vertebral Artery Aneurysm Showing Evoked Potentials on Bilateral Electrode by the Left Vagus Nerve Stimulation to Electromyographic Tracheal Tube].

PubMed

Kadoya, Tatsuo; Uehara, Hirofumi; Yamamoto, Toshinori; Shiraishi, Munehiro; Kinoshita, Yuki; Joyashiki, Takeshi; Enokida, Kengo

2016-02-01

Previously, we reported a case of brainstem cavernous hemangioma showing false positive responses to electromyographic tracheal tube (EMG tube). We concluded that the cause was spontaneous respiration accompanied by vocal cord movement. We report a case of left vertebral artery aneurysm showing evoked potentials on bilateral electrodes by the left vagus nerve stimulation to EMG tube. An 82-year-old woman underwent clipping of a left unruptured vertebral artery-posterior inferior cerebellar artery aneurysm. General anesthesia was induced with remifentanil, propofol and suxamethonium, and was maintained with oxygen, air, remifentanil and propofol. We monitored somatosensory evoked potentials, motor evoked potentials, and electromyogram of the vocal cord. When the manipulation reached brainstem and the instrument touched the left vagus nerve, evoked potentials appeared on bilateral electrodes. EMG tube is equipped with two electrodes on both sides. We concluded that the left vagus nerve stimulation generated evoked potentials of the left laryngeal muscles, and they were simultaneously detected as potential difference between two electrodes on both sides. EMG tube is used to identify the vagus nerve. However, it is necessary to bear in mind that each vagus nerve stimulation inevitably generates evoked potentials on bilateral electrodes.

Combined evoked potentials in co-occuring attention deficit hyperactivity disorder and epilepsy.

PubMed

Major, Zoltán Zsigmond

2011-07-30

Evoked potentials, both stimulus related and event related, show disturbances in attention deficit-hyperactivity disorder and epilepsies, too. This study was designed to evaluate if these potentials are characteristically influenced by the presence of the two diseases, individually, and in the case of co-occurrence. Forty children were included, and four groups were formed, control group, ADHD group, epilepsy group and a group with the comorbidity of epilepsy and ADHD. Epilepsy patients were under proper antiepileptic treatment; ADHD patients were free of specific therapy. Brainstem auditory evoked potentials, visual evoked potentials and auditory P300 evaluation were performed. The latency of the P100 and N135 visual evoked potential components was significantly extended by the presence of epilepsy. If ADHD was concomitantly present, this effect was attenuated. Brainstem auditory evoked potential components were prolonged in the presence of the comorbidity, considering the waves elicited in the brainstem. P300 latencies were prolonged by the presence of co-occurring ADHD and epilepsy. Feedback parameters showed overall reduction of the tested cognitive performances in the ADHD group. Disturbances produced by the presence of ADHD-epilepsy comorbidity reveal hypothetically a linked physiopathological path for both diseases, and offers an approach with possible diagnostic importance, combined evoked potential recordings.

Monitoring somatosensory evoked potentials in spinal cord ischemia-reperfusion injury

PubMed Central

Ji, Yiming; Meng, Bin; Yuan, Chenxi; Yang, Huilin; Zou, Jun

2013-01-01

It remains unclear whether spinal cord ischemia-reperfusion injury caused by ischemia and other non-mechanical factors can be monitored by somatosensory evoked potentials. Therefore, we monitored spinal cord ischemia-reperfusion injury in rabbits using somatosensory evoked potential detection technology. The results showed that the somatosensory evoked potential latency was significantly prolonged and the amplitude significantly reduced until it disappeared during the period of spinal cord ischemia. After reperfusion for 30–180 minutes, the amplitude and latency began to gradually recover; at 360 minutes of reperfusion, the latency showed no significant difference compared with the pre-ischemic value, while the somatosensory evoked potential amplitude in-creased, and severe hindlimb motor dysfunctions were detected. Experimental findings suggest that changes in somatosensory evoked potential latency can reflect the degree of spinal cord ischemic injury, while the amplitude variations are indicators of the late spinal cord reperfusion injury, which provide evidence for the assessment of limb motor function and avoid iatrogenic spinal cord injury. PMID:25206629

Early prediction of coma recovery after cardiac arrest with blinded pupillometry.

PubMed

Solari, Daria; Rossetti, Andrea O; Carteron, Laurent; Miroz, John-Paul; Novy, Jan; Eckert, Philippe; Oddo, Mauro

2017-06-01

Prognostication studies on comatose cardiac arrest (CA) patients are limited by lack of blinding, potentially causing overestimation of outcome predictors and self-fulfilling prophecy. Using a blinded approach, we analyzed the value of quantitative automated pupillometry to predict neurological recovery after CA. We examined a prospective cohort of 103 comatose adult patients who were unconscious 48 hours after CA and underwent repeated measurements of quantitative pupillary light reflex (PLR) using the Neurolight-Algiscan device. Clinical examination, electroencephalography (EEG), somatosensory evoked potentials (SSEP), and serum neuron-specific enolase were performed in parallel, as part of standard multimodal assessment. Automated pupillometry results were blinded to clinicians involved in patient care. Cerebral Performance Categories (CPC) at 1 year was the outcome endpoint. Survivors (n = 50 patients; 32 CPC 1, 16 CPC 2, 2 CPC 3) had higher quantitative PLR (median = 20 [range = 13-41] vs 11 [0-55] %, p < 0.0001) and constriction velocity (1.46 [0.85-4.63] vs 0.94 [0.16-4.97] mm/s, p < 0.0001) than nonsurvivors. At 48 hours, a quantitative PLR < 13% had 100% specificity and positive predictive value to predict poor recovery (0% false-positive rate), and provided equal performance to that of EEG and SSEP. Reduced quantitative PLR correlated with higher serum neuron-specific enolase (Spearman r = -0.52, p < 0.0001). Reduced quantitative PLR correlates with postanoxic brain injury and, when compared to standard multimodal assessment, is highly accurate in predicting long-term prognosis after CA. This is the first prognostication study to show the value of automated pupillometry using a blinded approach to minimize self-fulfilling prophecy. Ann Neurol 2017;81:804-810. © 2017 American Neurological Association.

[Mirror therapy for inflammatory rheumatic pain: Potentials and limitations].

PubMed

Bekrater-Bodmann, R

2015-11-01

Mirror therapy reduces chronic pain and might also be suitable for the treatment of inflammatory rheumatic pain. On the basis of the relevant literature this article a) characterizes the universal alterations in body perception and body representation in chronic pain, b) describes the potential mechanisms underlying mirror therapy and c) discusses the chances of success of mirror therapy for the treatment of inflammatory rheumatic pain. Literature search on the effectiveness and mechanisms of mirror therapy and derived procedures for the potential treatment of pain in inflammatory rheumatic disorders. There is evidence that mirror therapy can alleviate chronic pain experiences by correcting the accompanying distorted body perception as well as body representation by multimodal sensory stimulation. As there is probably a similar distortion in persons with chronic pain related to inflammatory rheumatic disorders, mirror therapy might also have positive effects in this field; however, the accompanying characteristics of these disorders, such as motor impairment and motor-evoked pain, may complicate the implementation of this kind of treatment. Mirror therapy represents an intervention with few side effects and might have positive effects on the experience of chronic pain in patients with inflammatory rheumatic disorders. Further clinical research is required in order to evaluate the potential of mirror therapy and associated interventional methods for the treatment of inflammatory rheumatic pain.

Auditory- and Visual-Evoked Potentials in Mexican Infants Are Not Affected by Maternal Supplementation with 400 mg/d Docosahexaenoic Acid in the Second Half of Pregnancy1234

PubMed Central

Stein, Aryeh D.; Wang, Meng; Rivera, Juan A.; Martorell, Reynaldo; Ramakrishnan, Usha

2012-01-01

The evidence relating prenatal supplementation with DHA to offspring neurological development is limited. We investigated the effect of prenatal DHA supplementation on infant brainstem auditory-evoked responses and visual- evoked potentials in a double-blind, randomized controlled trial in Cuernavaca, Mexico. Pregnant women were supplemented daily with 400 mg DHA or placebo from gestation wk 18–22 through delivery. DHA and placebo groups did not differ in maternal characteristics at randomization or infant characteristics at birth. Brainstem auditory-evoked responses were measured at 1 and 3 mo in 749 and 664 infants, respectively, and visual-evoked potentials were measured at 3 and 6 mo in 679 and 817 infants, respectively. Left-right brainstem auditory-evoked potentials were moderately correlated (range, 0.26–0.43; all P < 0.001) and left-right visual-evoked potentials were strongly correlated (range, 0.79–0.94; all P < 0.001) within any assessment. Correlations across visits were modest to moderate (range, 0.09–0.38; all P < 0.01). The offspring of DHA-supplemented women did not differ from those of control women with respect to any outcome measure (all comparisons P > 0.10). We conclude that DHA supplementation during pregnancy did not influence brainstem auditory-evoked responses at 1 and 3 mo or visual-evoked potentials at 3 and 6 mo. PMID:22739364

Evoked potentials in multiple sclerosis.

PubMed

Kraft, George H

2013-11-01

Before the development of magnetic resonance imaging (MRI), evoked potentials (EPs)-visual evoked potentials, somatosensory evoked potentials, and brain stem auditory evoked responses-were commonly used to determine a second site of disease in patients being evaluated for possible multiple sclerosis (MS). The identification of an area of the central nervous system showing abnormal conduction was used to supplement the abnormal signs identified on the physical examination-thus identifying the "multiple" in MS. This article is a brief overview of additional ways in which central nervous system (CNS) physiology-as measured by EPs-can still contribute value in the management of MS in the era of MRIs. Copyright © 2013 Elsevier Inc. All rights reserved.

Combined ocular and cervical vestibular evoked myogenic potential in individuals with vestibular hyporeflexia and in patients with Ménière's disease.

PubMed

Silva, Tatiana Rocha; de Resende, Luciana Macedo; Santos, Marco Aurélio Rocha

The vestibular evoked myogenic potential is a potential of mean latency that measures the muscle response to auditory stimulation. This potential can be generated from the contraction of the sternocleidomastoid muscle and also from the contraction of extraocular muscles in response to high-intensity sounds. This study presents a combined or simultaneous technique of cervical and ocular vestibular evoked myogenic potential in individuals with changes in the vestibular system, for use in otoneurologic diagnosis. To characterize the records and analyze the results of combined cervical and ocular VEMP in individuals with vestibular hyporeflexia and in those with Ménière's disease. The study included 120 subjects: 30 subjects with vestibular hyporeflexia, 30 with Ménière's disease, and 60 individuals with normal hearing. Data collection was performed by simultaneously recording the cervical and ocular vestibular evoked myogenic potential. There were differences between the study groups (individuals with vestibular hyporeflexia and individuals with Ménière's disease) and the control group for most of wave parameters in combined cervical and ocular vestibular evoked myogenic potential. For cervical vestibular evoked myogenic potential, it was observed that the prolongation of latency of the P13 and N23 waves was the most frequent finding in the group with vestibular hyporeflexia and in the group with Ménière's disease. For ocular vestibular evoked myogenic potential, prolonged latency of N10 and P15 waves was the most frequent finding in the study groups. Combined cervical and ocular vestibular evoked myogenic potential presented relevant results for individuals with vestibular hyporeflexia and for those with Ménière's disease. There were differences between the study groups and the control group for most of the wave parameters in combined cervical and ocular vestibular evoked myogenic potential. Copyright © 2016 Associação Brasileira de Otorrinolaringologia e Cirurgia Cérvico-Facial. Published by Elsevier Editora Ltda. All rights reserved.

Brainstem auditory and somatosensory evoked potentials in relation to clinical and neuroimaging findings in Chiari type 1 malformation.

PubMed

Moncho, Dulce; Poca, Maria-Antonia; Minoves, Teresa; Ferré, Alejandro; Rahnama, Kimia; Sahuquillo, Juan

2015-04-01

The aim of this study was to describe the abnormalities found in the recordings of evoked potentials (EPs), in particular those of brainstem auditory evoked potentials and somatosensory evoked potentials, in a homogeneous series of patients with Chiari type 1 malformation (CM-1) and study their relationship with clinical symptoms and malformation severity. CM-1 is characterized by cerebellar tonsils that descend below the foramen magnum and may be associated with EP alterations. However, only a small number of authors have described these tests in CM-1, and the patient groups studied to date have been small and heterogeneous. The clinical findings, neuroimages, and EP findings were retrospectively studied in a cohort of 50 patients with CM-1. Seventy percent of patients had EP abnormalities (brainstem auditory evoked potential: 52%, posterior tibial nerve somatosensory evoked potential: 42%, and median nerve somatosensory evoked potential: 34%). The most frequent alteration was an increased central conduction time. Morphometric measurements differed between the normal and pathological groups, although no statistical significance was found when comparing these groups. A high percentage of patients with CM-1 show EP alterations regardless of their clinical or radiological findings, thus highlighting the necessity of performing these tests, especially in patients with few or no symptoms.

Multimodal image analysis of the retina in Hunter syndrome (mucopolysaccharidosis type II): Case report.

PubMed

Salvucci, Isadora Darriba Macedo; Finzi, Simone; Oyamada, Maria Kiyoko; Kim, Chong Ae; Pimentel, Sérgio Luis Gianotti

2018-01-01

We report a case of retinal and posterior ocular findings in a 33-year-old man diagnosed with Hunter syndrome (Mucopolysaccharidosis type II) in a multimodal imaging way. Our patient was complaining of blurred night vision for the past 3 years. He had not received any systemic treatment for Hunter syndrome. Vision acuity was 20/20 in both eyes and corneas were clear. Fundus examination revealed bilateral crowded and hyperemic optic nerve heads (elevated in the ocular ultrasound) and areas of subretinal hypopigmentation. There was hyperautofluorescence at the central fovea and perifovea, and a diffuse bilateral choroidal fluorescence in angiography. Macular SD-OCT showed a thinning of the external retina at the perifovea in both eyes. Visual field testing showed a bilateral ring scotoma. The full field ERG was subnormal, with a negative response in the scotopic phase. Visual Evoked Potencial test and cranial MRI were normal. Our multimodal analysis reported here attempted to contribute to the knowledge of the natural history of GAG deposition in the eye, focusing on the retina and retinal pigment epithelium. Defining this natural history is essential for a proper comparison with Hunter patients receiving systemic treatment, thus determining if it can or cannot improve retinal function in humans with this disorder.

Cortical Integration of Audio-Visual Information

PubMed Central

Vander Wyk, Brent C.; Ramsay, Gordon J.; Hudac, Caitlin M.; Jones, Warren; Lin, David; Klin, Ami; Lee, Su Mei; Pelphrey, Kevin A.

2013-01-01

We investigated the neural basis of audio-visual processing in speech and non-speech stimuli. Physically identical auditory stimuli (speech and sinusoidal tones) and visual stimuli (animated circles and ellipses) were used in this fMRI experiment. Relative to unimodal stimuli, each of the multimodal conjunctions showed increased activation in largely non-overlapping areas. The conjunction of Ellipse and Speech, which most resembles naturalistic audiovisual speech, showed higher activation in the right inferior frontal gyrus, fusiform gyri, left posterior superior temporal sulcus, and lateral occipital cortex. The conjunction of Circle and Tone, an arbitrary audio-visual pairing with no speech association, activated middle temporal gyri and lateral occipital cortex. The conjunction of Circle and Speech showed activation in lateral occipital cortex, and the conjunction of Ellipse and Tone did not show increased activation relative to unimodal stimuli. Further analysis revealed that middle temporal regions, although identified as multimodal only in the Circle-Tone condition, were more strongly active to Ellipse-Speech or Circle-Speech, but regions that were identified as multimodal for Ellipse-Speech were always strongest for Ellipse-Speech. Our results suggest that combinations of auditory and visual stimuli may together be processed by different cortical networks, depending on the extent to which speech or non-speech percepts are evoked. PMID:20709442

Assessment and Development of Oculomotor Flying Skills by the Application of the Channel Theory of Vision.

DTIC Science & Technology

1983-11-04

visual acuity in amblyopia , using steady-state visual evoked potentials. In J. E. Desmedt (Ed.), Visual evoked potentials in man: new developments... amblyopia by the evoked potential method. Ophthalmologica, 1977s 175, 159-164. 61. Regan, D. & Spekreijse, H. Auditory-visual interactions and the

Postoperative neurological deficits may occur despite unchanged intraoperative somatosensory evoked potentials.

PubMed

Lesser, R P; Raudzens, P; Lüders, H; Nuwer, M R; Goldie, W D; Morris, H H; Dinner, D S; Klem, G; Hahn, J F; Shetter, A G

1986-01-01

We describe 6 patients who demonstrated postoperative neurological deficits despite unchanged somatosensory evoked potentials during intraoperative monitoring. Although there is both experimental and clinical evidence that somatosensory evoked potentials are sensitive to some types of intraoperative mishap, the technique should be employed with an awareness of its possible limitations.

Brainstem Auditory Evoked Potential in HIV-Positive Adults.

PubMed

Matas, Carla Gentile; Samelli, Alessandra Giannella; Angrisani, Rosanna Giaffredo; Magliaro, Fernanda Cristina Leite; Segurado, Aluísio C

2015-10-20

To characterize the findings of brainstem auditory evoked potential in HIV-positive individuals exposed and not exposed to antiretroviral treatment. This research was a cross-sectional, observational, and descriptive study. Forty-five HIV-positive individuals (18 not exposed and 27 exposed to the antiretroviral treatment - research groups I and II, respectively - and 30 control group individuals) were assessed through brainstem auditory evoked potential. There were no significant between-group differences regarding wave latencies. A higher percentage of altered brainstem auditory evoked potential was observed in the HIV-positive groups when compared to the control group. The most common alteration was in the low brainstem. HIV-positive individuals have a higher percentage of altered brainstem auditory evoked potential that suggests central auditory pathway impairment when compared to HIV-negative individuals. There was no significant difference between individuals exposed and not exposed to antiretroviral treatment.

Cortico-cortical evoked potentials for sites of early versus late seizure spread in stereoelectroencephalography.

PubMed

Lega, Bradley; Dionisio, Sasha; Flanigan, Patrick; Bingaman, William; Najm, Imad; Nair, Dileep; Gonzalez-Martinez, Jorge

2015-09-01

Cortico-cortical evoked potentials offer the possibility of understanding connectivity within seizure networks to improve diagnosis and more accurately identify candidates for seizure surgery. We sought to determine if cortico-cortical evoked potentials and post-stimulation oscillatory changes differ for sites of EARLY versus LATE ictal spread. 37 patients undergoing stereoelectroencephalography were tested using a cortico-cortical evoked potential paradigm. All electrodes were classified according to the speed of ictal spread. EARLY spread sites were matched to a LATE spread site equidistant from the onset zone. Root-mean-square was used to quantify evoked responses and post-stimulation gamma band power and coherence were extracted and compared. Sites of EARLY spread exhibited significantly greater evoked responses after stimulation across all patients (t(36)=2.973, p=0.004). Stimulation elicited enhanced gamma band activity at EARLY spread sites (t(36)=2.61, p=0.03, FDR corrected); this gamma band oscillation was highly coherent with the onset zone. Cortico-cortical evoked potentials and post-stimulation changes in gamma band activity differ between sites of EARLY versus LATE ictal spread. The oscillatory changes can help visualize connectivity within the seizure network. Copyright © 2015 Elsevier B.V. All rights reserved.

Gravity influences top-down signals in visual processing.

PubMed

Cheron, Guy; Leroy, Axelle; Palmero-Soler, Ernesto; De Saedeleer, Caty; Bengoetxea, Ana; Cebolla, Ana-Maria; Vidal, Manuel; Dan, Bernard; Berthoz, Alain; McIntyre, Joseph

2014-01-01

Visual perception is not only based on incoming visual signals but also on information about a multimodal reference frame that incorporates vestibulo-proprioceptive input and motor signals. In addition, top-down modulation of visual processing has previously been demonstrated during cognitive operations including selective attention and working memory tasks. In the absence of a stable gravitational reference, the updating of salient stimuli becomes crucial for successful visuo-spatial behavior by humans in weightlessness. Here we found that visually-evoked potentials triggered by the image of a tunnel just prior to an impending 3D movement in a virtual navigation task were altered in weightlessness aboard the International Space Station, while those evoked by a classical 2D-checkerboard were not. Specifically, the analysis of event-related spectral perturbations and inter-trial phase coherency of these EEG signals recorded in the frontal and occipital areas showed that phase-locking of theta-alpha oscillations was suppressed in weightlessness, but only for the 3D tunnel image. Moreover, analysis of the phase of the coherency demonstrated the existence on Earth of a directional flux in the EEG signals from the frontal to the occipital areas mediating a top-down modulation during the presentation of the image of the 3D tunnel. In weightlessness, this fronto-occipital, top-down control was transformed into a diverging flux from the central areas toward the frontal and occipital areas. These results demonstrate that gravity-related sensory inputs modulate primary visual areas depending on the affordances of the visual scene.

Acute Stress Alters Auditory Selective Attention in Humans Independent of HPA: A Study of Evoked Potentials

PubMed Central

Elling, Ludger; Steinberg, Christian; Bröckelmann, Ann-Kathrin; Dobel, Christan; Bölte, Jens; Junghofer, Markus

2011-01-01

Background Acute stress is a stereotypical, but multimodal response to a present or imminent challenge overcharging an organism. Among the different branches of this multimodal response, the consequences of glucocorticoid secretion have been extensively investigated, mostly in connection with long-term memory (LTM). However, stress responses comprise other endocrine signaling and altered neuronal activity wholly independent of pituitary regulation. To date, knowledge of the impact of such “paracorticoidal” stress responses on higher cognitive functions is scarce. We investigated the impact of an ecological stressor on the ability to direct selective attention using event-related potentials in humans. Based on research in rodents, we assumed that a stress-induced imbalance of catecholaminergic transmission would impair this ability. Methodology/Principal Findings The stressor consisted of a single cold pressor test. Auditory negative difference (Nd) and mismatch negativity (MMN) were recorded in a tonal dichotic listening task. A time series of such tasks confirmed an increased distractibility occuring 4–7 minutes after onset of the stressor as reflected by an attenuated Nd. Salivary cortisol began to rise 8–11 minutes after onset when no further modulations in the event-related potentials (ERP) occurred, thus precluding a causal relationship. This effect may be attributed to a stress-induced activation of mesofrontal dopaminergic projections. It may also be attributed to an activation of noradrenergic projections. Known characteristics of the modulation of ERP by different stress-related ligands were used for further disambiguation of causality. The conjuncture of an attenuated Nd and an increased MMN might be interpreted as indicating a dopaminergic influence. The selective effect on the late portion of the Nd provides another tentative clue for this. Conclusions/Significance Prior studies have deliberately tracked the adrenocortical influence on cognition, as it has proven most influential with respect to LTM. However, current cortisol-optimized study designs would have failed to detect the present findings regarding attention. PMID:21483666

Cervical sympathetic block prolongs the latency and reduces the amplitude of trigeminal somatosensory evoked potentials on the contralateral side.

PubMed

Kawaguchi, Jun; Matsuura, Nobuyuki; Kasahara, Masataka; Ichinohe, Tatsuya

2015-02-01

The purpose of this study was to investigate the latency and amplitude of trigeminal somatosensory evoked potentials to clarify how nerve function on the contralateral side is affected after cervical sympathetic block (CSB). Subjects comprised 16 volunteers. For CSB, the tip of a needle was contacted with the transverse process of the sixth cervical vertebra on the right side, and lidocaine was injected. Trigeminal somatosensory evoked potentials were recorded bilaterally from C5/C6 scalp positions. Pupil diameters were also measured. Electrical stimulations were applied to the left-side lower lip, and trigeminal somatosensory evoked potentials waveforms derived from both sides of the scalp were recorded. Then, electrical stimulations were applied to the right-side of the lower lip, and recording was again performed. Recordings were performed at 5, 15, and 30 minutes after CSB. On the CSB side, pupil diameter decreased at 5 and 15 minutes after CSB. Trigeminal somatosensory evoked potentials at contralateral stimulation showed a prolongation of the latency in both P20 and N25 components on bilateral recording sites 5 and 15 minutes after CSB. Trigeminal somatosensory evoked potentials' amplitude at contralateral stimulation was smaller than at ipsilateral stimulation 5 minutes after CSB. Cervical sympathetic block prolongs the latency and reduces the amplitude of trigeminal somatosensory evoked potentials on the contralateral side.

Click- and chirp-evoked human compound action potentials

PubMed Central

Chertoff, Mark; Lichtenhan, Jeffery; Willis, Marie

2010-01-01

In the experiments reported here, the amplitude and the latency of human compound action potentials (CAPs) evoked from a chirp stimulus are compared to those evoked from a traditional click stimulus. The chirp stimulus was created with a frequency sweep to compensate for basilar membrane traveling wave delay using the O-Chirp equations from Fobel and Dau [(2004). J. Acoust. Soc. Am. 116, 2213–2222] derived from otoacoustic emission data. Human cochlear traveling wave delay estimates were obtained from derived compound band action potentials provided by Eggermont [(1979). J. Acoust. Soc. Am. 65, 463–470]. CAPs were recorded from an electrode placed on the tympanic membrane (TM), and the acoustic signals were monitored with a probe tube microphone attached to the TM electrode. Results showed that the amplitude and latency of chirp-evoked N1 of the CAP differed from click-evoked CAPs in several regards. For the chirp-evoked CAP, the N1 amplitude was significantly larger than the click-evoked N1s. The latency-intensity function was significantly shallower for chirp-evoked CAPs as compared to click-evoked CAPs. This suggests that auditory nerve fibers respond with more unison to a chirp stimulus than to a click stimulus. PMID:21117748

Awake vs. anesthetized: layer-specific sensory processing in visual cortex and functional connectivity between cortical areas

PubMed Central

Sellers, Kristin K.; Bennett, Davis V.; Hutt, Axel; Williams, James H.

2015-01-01

During general anesthesia, global brain activity and behavioral state are profoundly altered. Yet it remains mostly unknown how anesthetics alter sensory processing across cortical layers and modulate functional cortico-cortical connectivity. To address this gap in knowledge of the micro- and mesoscale effects of anesthetics on sensory processing in the cortical microcircuit, we recorded multiunit activity and local field potential in awake and anesthetized ferrets (Mustela putoris furo) during sensory stimulation. To understand how anesthetics alter sensory processing in a primary sensory area and the representation of sensory input in higher-order association areas, we studied the local sensory responses and long-range functional connectivity of primary visual cortex (V1) and prefrontal cortex (PFC). Isoflurane combined with xylazine provided general anesthesia for all anesthetized recordings. We found that anesthetics altered the duration of sensory-evoked responses, disrupted the response dynamics across cortical layers, suppressed both multimodal interactions in V1 and sensory responses in PFC, and reduced functional cortico-cortical connectivity between V1 and PFC. Together, the present findings demonstrate altered sensory responses and impaired functional network connectivity during anesthesia at the level of multiunit activity and local field potential across cortical layers. PMID:25833839

A Multimodal Imaging- and Stimulation-based Method of Evaluating Connectivity-related Brain Excitability in Patients with Epilepsy

PubMed Central

Shafi, Mouhsin M.; Whitfield-Gabrieli, Susan; Chu, Catherine J.; Pascual-Leone, Alvaro; Chang, Bernard S.

2017-01-01

Resting-state functional connectivity MRI (rs-fcMRI) is a technique that identifies connectivity between different brain regions based on correlations over time in the blood-oxygenation level dependent signal. rs-fcMRI has been applied extensively to identify abnormalities in brain connectivity in different neurologic and psychiatric diseases. However, the relationship among rs-fcMRI connectivity abnormalities, brain electrophysiology and disease state is unknown, in part because the causal significance of alterations in functional connectivity in disease pathophysiology has not been established. Transcranial Magnetic Stimulation (TMS) is a technique that uses electromagnetic induction to noninvasively produce focal changes in cortical activity. When combined with electroencephalography (EEG), TMS can be used to assess the brain's response to external perturbations. Here we provide a protocol for combining rs-fcMRI, TMS and EEG to assess the physiologic significance of alterations in functional connectivity in patients with neuropsychiatric disease. We provide representative results from a previously published study in which rs-fcMRI was used to identify regions with abnormal connectivity in patients with epilepsy due to a malformation of cortical development, periventricular nodular heterotopia (PNH). Stimulation in patients with epilepsy resulted in abnormal TMS-evoked EEG activity relative to stimulation of the same sites in matched healthy control patients, with an abnormal increase in the late component of the TMS-evoked potential, consistent with cortical hyperexcitability. This abnormality was specific to regions with abnormal resting-state functional connectivity. Electrical source analysis in a subject with previously recorded seizures demonstrated that the origin of the abnormal TMS-evoked activity co-localized with the seizure-onset zone, suggesting the presence of an epileptogenic circuit. These results demonstrate how rs-fcMRI, TMS and EEG can be utilized together to identify and understand the physiological significance of abnormal brain connectivity in human diseases. PMID:27911366

[The algorithms and development for the extraction of evoked potentials].

PubMed

Niu, Jie; Qiu, Tianshuang

2004-06-01

The extraction of evoked potentials is a main subject in the area of brain signal processing. In recent years, the single-trial extraction of evoked potentials has been focused on by many studies. In this paper, the approaches based on the wavelet transform, the neural network, the high order acumulants and the independent component analysis are briefly reviewed.

Human cerebral potentials evoked by moving dynamic random dot stereograms.

PubMed

Herpers, M J; Caberg, H B; Mol, J M

1981-07-01

In 11 normal healthy human subjects an evoked potential was elicited by moving dynamic random dot stereograms. The random dots were generated by a minicomputer. An average of each of 8 EEG channels of the subjects tested was made. The maximum of the cerebral evoked potentials thus found was localized in the central and parietal region. No response earlier than 130--150 msec after the stimulus could be proved. The influence of fixation, the number of dots provided, an interocular interstimulus interval in the presentation of the dots, and lense accommodation movements on the evoked stereoptic potentials was investigated and discussed. An interocular interstimulus interval (left eye leading) in the presentation of the dots caused an increase in latency of the response much longer than the imposed interstimulus interval itself. It was shown that no accommodation was needed to perceive the depth impression, and to evoke the cerebral response with random dot stereograms. There are indications of an asymmetry between the two hemispheres in the handling of depth perception after 250 msec. The potential distribution of the evoked potentials strongly suggests that they are not generated in the occipital region.

[Application of evoked potentials monitoring in total thoracoabdominal aorta aneurysm repair].

PubMed

Duan, Y Y; Zheng, J; Pan, X D; Zhu, J M; Liu, Y M; Ge, Y P; Cheng, L J; Sun, L Z

2016-04-05

To evaluate the application value of evoked potentials (EP) monitoring in patients undergoing aorta-iliac bypass for total thoracoabdominal aorta aneurysm repair (tTAAAR). A prospective study, with a total of 31 patients undergoing tTAAAR and intraoperative EP monitoring from June 2014 to April 2015 was carried out. The results of intraoperative evoked potentials, clinical outcomes and follow-up data of patients were collected for further evaluation. The EP wave disappeared [motor evoked potentials for (55.6±18.1) min, somatosensory evoked potentials for (50.3±18.7) min] after proximal descending aorta being clamped, and gradually recovered after the segment arteries of spine cord were reconstructed. The EP wave was restored to normal level at the end of operation in all the cases. The somatosensory evoked potentials remained unchanged in 2 cases (false negative). One case died after operation. No spinal cord injury occurred. The median follow-up after operation was 10 months (5-14 months). There was no delayed neurological deficit. EP provided an on-line monitoring of the condition of spinal cord function, which become an intraoperative protocol to avoid the irreversible injury of spinal cord.

Objective correlate of subjective pain perception by contact heat-evoked potentials.

PubMed

Granovsky, Yelena; Granot, Michal; Nir, Rony-Reuven; Yarnitsky, David

2008-01-01

The method of pain-evoked potentials has gained considerable acceptance over the last 3 decades regarding its objectivity, repeatability, and quantifiability. The present study explored whether the relationship between pain-evoked potentials and pain psychophysics obtained by contact heat stimuli is similar to those observed for the conventionally used laser stimulation. Evoked potentials (EPs) were recorded in response to contact heat stimuli at different body sites in 24 healthy volunteers. Stimuli at various temperatures were applied to the forearm (43 degrees C, 46 degrees C, 49 degrees C, and 52 degrees C) and leg (46 degrees C and 49 degrees C). The amplitudes of both components (N2 and P2) were strongly associated with the intensity of the applied stimuli and with subjective pain perception. Yet, regression analysis revealed pain perception and not stimulus intensity as the major contributing factor. A significant correlation was found between the forearm and the leg for both psychophysics and EPs amplitude. Contact heat can generate readily distinguishable evoked potentials on the scalp, consistent between upper and lower limbs. Although these potentials bear positive correlation with both stimulus intensity and pain magnitude, the latter is the main contributor to the evoked brain response.

Contact Heat Evoked Potentials (CHEPs) in Patients with Mild-Moderate Alzheimer's Disease and Matched Control--A Pilot Study.

PubMed

Jensen-Dahm, Christina; Madsen, Caspar Skau; Waldemar, Gunhild; Ballegaard, Martin; Hejl, Anne-Mette; Johnsen, Birger; Jensen, Troels Staehelin

2016-04-01

Clinical studies have found that patients with Alzheimer's disease report pain of less intensity and with a lower affective response, which has been thought to be due to altered pain processing. The authors wished to examine the cerebral processing of non-painful and painful stimuli using somatosensory evoked potentials and contact heat evoked potentials in patients with Alzheimer's disease and in healthy elderly controls. Case-control study Twenty outpatients with mild-moderate Alzheimer's disease and in 17 age- and gender-matched healthy controls were included Contact heat evoked potentials and somatosensory evoked potentials were recorded in all subjects. Furthermore, warmth detection threshold and heat pain threshold were assessed. Patients and controls also rated quality and intensity of the stimuli. The authors found no difference on contact heat evoked potential amplitude (P = 0.59) or latency of N2 or P2 wave (P = 0.62 and P = 0.75, respectively) between patients and controls. In addition, there was no difference in regard to pain intensity scores or pain quality. The patients and controls had similar warmth detection threshold and heat pain threshold. Somatosensory evoked potentials, amplitude, and latency were within normal range and similar for the two groups. The findings suggest that the processing of non-painful and painful stimuli is preserved in patients with mild to moderate Alzheimer's disease. © 2015 American Academy of Pain Medicine. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Sunlight irradiance and habituation of visual evoked potentials in migraine: The environment makes its mark.

PubMed

Lisicki, Marco; D'Ostilio, Kevin; Erpicum, Michel; Schoenen, Jean; Magis, Delphine

2017-01-01

Background Migraine is a complex multifactorial disease that arises from the interaction between a genetic predisposition and an enabling environment. Habituation is considered as a fundamental adaptive behaviour of the nervous system that is often impaired in migraine populations. Given that migraineurs are hypersensitive to light, and that light deprivation is able to induce functional changes in the visual cortex recognizable through visual evoked potentials habituation testing, we hypothesized that regional sunlight irradiance levels could influence the results of visual evoked potentials habituation studies performed in different locations worldwide. Methods We searched the literature for visual evoked potentials habituation studies comparing healthy volunteers and episodic migraine patients and correlated their results with levels of local solar radiation. Results After reviewing the literature, 26 studies involving 1291 participants matched our inclusion criteria. Deficient visual evoked potentials habituation in episodic migraine patients was reported in 19 studies. Mean yearly sunlight irradiance was significantly higher in locations of studies reporting deficient habituation. Correlation analyses suggested that visual evoked potentials habituation decreases with increasing sunlight irradiance in migraine without aura patients. Conclusion Results from this hypothesis generating analysis suggest that variations in sunlight irradiance may induce adaptive modifications in visual processing systems that could be reflected in visual evoked potentials habituation, and thus partially account for the difference in results between studies performed in geographically distant centers. Other causal factors such as genetic differences could also play a role, and therefore well-designed prospective trials are warranted.

Spinal NMDA-receptor dependent amplification of nociceptive transmission to rat primary somatosensory cortex (SI).

PubMed

Kalliomäki, Jarkko; Granmo, Marcus; Schouenborg, Jens

2003-07-01

The role of NMDA mechanisms in spinal pathways mediating acute nociceptive input to the somatosensory cortex is not clear. In this study, the effect of NMDA-antagonists on nociceptive C fibre transmission to the primary somatosensory cortex (SI) was investigated. Cortical field potentials evoked by CO(2)-laser stimulation of the skin were recorded in the halothane/nitrous oxide anaesthetized rat. The SI nociceptive evoked potential (EP) amplitudes were dependent on the frequency of noxious heat stimulation. The amplitudes of SI potentials evoked by CO(2)-laser pulses (duration 15-20 ms, stimulation energy 21-28 mJ/mm(2)) delivered at a frequency of 0.1 Hz were approximately 40% of the amplitudes of potentials evoked by 1.0 Hz stimulation. After intrathecal lumbar application of either of the NMDA-antagonists CPP or MK-801, the amplitudes of nociceptive SI potentials, evoked by 1.0 Hz stimulation of the contralateral hindpaw, were reduced to approximately 40% of controls. By contrast, field potentials evoked by 0.1 Hz stimulation of the hindpaw were unaffected by MK-801. SI potentials evoked by 1.0 Hz stimulation of the contralateral forepaw did not change after lumbar application of CPP or MK-801, indicating that the depression of hindpaw EPs was due to a segmental effect in the spinal cord. It is concluded that spinal NMDA-receptor mechanisms amplify the acute transmission of nociceptive C fiber input to SI in a frequency-dependent way.

The Relationship of Visual Evoked Potential Asymmetries to the Performance of Sonar Operators

DTIC Science & Technology

1981-08-11

also been related to EP variability. Schizophrenic adults and patients with Korsakoff’s Syndrome have shown higher evoked potential variability than...average evoked response in Korsakoff patients. J. Psychiatry Res. 6: 253-260, 1969. Santoro, T. and D. Fender. Rules for the perception of

The pivotal role of multimodality reporter sensors in drug discovery: from cell based assays to real time molecular imaging.

PubMed

Ray, Pritha

2011-04-01

Development and marketing of new drugs require stringent validation that are expensive and time consuming. Non-invasive multimodality molecular imaging using reporter genes holds great potential to expedite these processes at reduced cost. New generations of smarter molecular imaging strategies such as Split reporter, Bioluminescence resonance energy transfer, Multimodality fusion reporter technologies will further assist to streamline and shorten the drug discovery and developmental process. This review illustrates the importance and potential of molecular imaging using multimodality reporter genes in drug development at preclinical phases.

The association between later cortical potentials and later phases of postural reactions evoked by perturbations to upright stance.

PubMed

Quant, Sylvia; Maki, Brian E; McIlroy, William E

2005-06-24

Previous studies have suggested that early cortical potentials (e.g. N1) that are evoked by perturbations to upright stance are associated with sensory processing of the initial perturbation and that later potentials may represent cognitive processing of this perturbation. However, it has also been suggested that later cortical potentials could reflect sensory and motor processing of later phases of the postural reaction. The current study set out to provide additional insight into the association between perturbation-evoked cortical potentials and postural reactions evoked by whole-body perturbations. By altering the deceleration onset of the perturbation, which altered the timing of later postural responses, we determined whether changes in later postural responses were associated with changes in later potentials. Based on previous work, we hypothesized that later potentials would not be associated with changes in later postural responses. During stance, seven healthy young adults were instructed to maintain their balance following two types of perturbations: (1) acceleration phase immediately followed by a deceleration phase (TASK 1), and (2) acceleration phase followed by a delayed deceleration phase (TASK 2). In spite of profound task differences in later postural responses, results revealed no significant differences in later potentials. This work provides additional support for the idea that latter elements of perturbation-evoked cortical responses are likely independent of evoked motor reactions required to maintain stability.

Addition of a Sagittal Cervical Posture Corrective Orthotic Device to a Multimodal Rehabilitation Program Improves Short- and Long-Term Outcomes in Patients With Discogenic Cervical Radiculopathy.

PubMed

Moustafa, Ibrahim M; Diab, Aliaa A; Taha, Shimaa; Harrison, Deed E

2016-12-01

To investigate the immediate and 1-year effects of a multimodal program, with cervical lordosis and anterior head translation (AHT) rehabilitation, on the intensity of pain, disability, and peripheral and central nervous system function in patients with discogenic cervical radiculopathy (CR). A randomized controlled trial with 1-year and 10-week follow-up. University research laboratory. Patients (N=60; 27 men) with chronic discogenic CR, a defined hypolordotic cervical spine, and AHT posture were randomly assigned to a control group (n=30; mean age, 43.9±6.2y) or an intervention group (n=30; mean age, 41.5±3.7y). Both groups received the multimodal program; in addition, the intervention group received the Denneroll cervical traction device. AHT distance, cervical lordosis, arm pain intensity, neck pain intensity, and disability (Neck Disability Index [NDI]), dermatomal somatosensory evoked potentials (DSSEPs), and central somatosensory conduction time (N13-N20). Measures were assessed at 3 time intervals: baseline, 10 weeks, and 1-year follow-up. After 10 weeks of treatment, between-group analysis showed equal improvement in arm pain intensity (P=.40), neck pain intensity (P=.60), and latency of DSSEPs (P=.60) in both intervention and control groups. However, also at 10 weeks, there were significant differences between groups, favoring the intervention group for cervical lordosis (P<.0005), AHT distance (P<.0005), amplitude of DSSEPs (P<.0005), N13 to N20 conduction time (P<.0005), and NDI (P<.0005). Although at 1-year follow-up, between-group analysis identified a regression back to baseline values for the control group. Thus, all variables were significantly different, favoring the intervention group at 1-year follow-up: cervical lordosis (P<.0005), AHT distance (P<.0005), latency and amplitude of DSSEPs (P<.0005), N13 to N20 conduction time (P<.0005), intensity of neck and arm pain, and NDI (P<.0005). The addition of the Denneroll cervical orthotic device to a multimodal program positively affected discogenic CR outcomes at long-term follow-up. We speculate that improved cervical lordosis and reduced AHT contributed to our findings. Copyright © 2016 American Congress of Rehabilitation Medicine. Published by Elsevier Inc. All rights reserved.

Auditory evoked potentials in two short-finned pilot whales (Globicephala macrorhynchus).

PubMed

Schlundt, Carolyn E; Dear, Randall L; Houser, Dorian S; Bowles, Ann E; Reidarson, Tom; Finneran, James J

2011-02-01

The hearing sensitivities of two short-finned pilot whales (Globicephala macrorhynchus) were investigated by measuring auditory evoked potentials generated in response to clicks and sinusoidal amplitude modulated (SAM) tones. The first whale tested, an adult female, was a long-time resident at SeaWorld San Diego with a known health history. Click-evoked responses in this animal were similar to those measured in other echolocating odontocetes. Auditory thresholds were comparable to dolphins of similar age determined with similar evoked potential methods. The region of best sensitivity was near 40 kHz and the upper limit of functional hearing was between 80 and 100 kHz. The second whale tested, a juvenile male, was recently stranded and deemed non-releasable. Click-evoked potentials were not detected in this animal and testing with SAM tones suggested severe hearing loss above 10 kHz.

Use of the Stockwell Transform in the Detection of P300 Evoked Potentials with Low-Cost Brain Sensors.

PubMed

Pérez-Vidal, Alan F; Garcia-Beltran, Carlos D; Martínez-Sibaja, Albino; Posada-Gómez, Rubén

2018-05-09

The evoked potential is a neuronal activity that originates when a stimulus is presented. To achieve its detection, various techniques of brain signal processing can be used. One of the most studied evoked potentials is the P300 brain wave, which usually appears between 300 and 500 ms after the stimulus. Currently, the detection of P300 evoked potentials is of great importance due to its unique properties that allow the development of applications such as spellers, lie detectors, and diagnosis of psychiatric disorders. The present study was developed to demonstrate the usefulness of the Stockwell transform in the process of identifying P300 evoked potentials using a low-cost electroencephalography (EEG) device with only two brain sensors. The acquisition of signals was carried out using the Emotiv EPOC ® device—a wireless EEG headset. In the feature extraction, the Stockwell transform was used to obtain time-frequency information. The algorithms of linear discriminant analysis and a support vector machine were used in the classification process. The experiments were carried out with 10 participants; men with an average age of 25.3 years in good health. In general, a good performance (75⁻92%) was obtained in identifying P300 evoked potentials.

Visual and brainstem auditory evoked potentials in infants with severe vitamin B12 deficiency.

PubMed

Demir, Nihat; Koç, Ahmet; Abuhandan, Mahmut; Calik, Mustafa; Işcan, Akin

2015-01-01

Vitamin B12 plays an important role in the development of mental, motor, cognitive, and social functions via its role in DNA synthesis and nerve myelination. Its deficiency in infants might cause neuromotor retardation as well as megaloblastic anemia. The objective of this study was to investigate the effects of infantile vitamin B12 deficiency on evoked brain potentials and determine whether improvement could be obtained with vitamin B12 replacement at appropriate dosages. Thirty patients with vitamin B12 deficiency and 30 age-matched healthy controls were included in the study. Hematological parameters, visual evoked potentials, and brainstem auditory evoked potentials tests were performed prior to treatment, 1 week after treatment, and 3 months after treatment. Visual evoked potentials (VEPs) and brainstem auditory evoked potentials (BAEPs) were found to be prolonged in 16 (53.3%) and 15 (50%) patients, respectively. Statistically significant improvements in VEP and BAEP examinations were determined 3 months after treatment. Three months after treatment, VEP and BAEP examinations returned to normal in 81.3% and 53.3% of subjects with prolonged VEPs and BAEPs, respectively. These results demonstrate that vitamin B12 deficiency in infants causes significant impairment in the auditory and visual functioning tests of the brain, such as VEP and BAEP.

Middle Latency Auditory Evoked Potential (MLAEP) in Workers with and without Tinnitus who are Exposed to Occupational Noise.

PubMed

dos Santos Filha, Valdete Alves Valentins; Samelli, Alessandra Giannella; Matas, Carla Gentile

2015-09-11

Tinnitus is an important occupational health concern, but few studies have focused on the central auditory pathways of workers with a history of occupational noise exposure. Thus, we analyzed the central auditory pathways of workers with a history of occupational noise exposure who had normal hearing threshold, and compared middle latency auditory evoked potential in those with and without noise-induced tinnitus. Sixty individuals (30 with and 30 without tinnitus) underwent the following procedures: anamnesis, immittance measures, pure-tone air conduction thresholds at all frequencies between 0.25-8 kHz, and middle latency auditory evoked potentials. Quantitative analysis of latencies and amplitudes of middle latency auditory evoked potential showed no significant differences between the groups with and without tinnitus. In the qualitative analysis, we found that both groups showed increased middle latency auditory evoked potential latencies. The study group had more alterations of the "both" type regarding the Na-Pa amplitude, while the control group had more "electrode effect" alterations, but these alterations were not significantly different when compared to controls. Individuals with normal hearing with or without tinnitus who are exposed to occupational noise have altered middle latency auditory evoked potential, suggesting impairment of the auditory pathways in cortical and subcortical regions. Although differences did not reach significance, individuals with tinnitus seemed to have more abnormalities in components of the middle latency auditory evoked potential when compared to individuals without tinnitus, suggesting alterations in the generation and transmission of neuroelectrical impulses along the auditory pathway.

Refractory episodic vertigo: role of intratympanic gentamicin and vestibular evoked myogenic potentials.

PubMed

Celis-Aguilar, Erika; Hinojosa-González, Ramon; Vales-Hidalgo, Olivia; Coutinho-Toledo, Heloisa

Even today, the treatment of intractable vertigo remains a challenge. Vestibular ablation with intratympanic gentamicin stands as a good alternative in the management of refractory vertigo patients. To control intractable vertigo through complete saccular and horizontal canal vestibular ablation with intratympanic gentamicin treatment. Patients with refractory episodic vertigo were included. The inclusion criteria were: unilateral ear disease, moderate to profound sensorineural hearing loss, and failure to other treatments. Included patients underwent 0.5-0.8mL of gentamicin intratympanic application at a 30mg/mL concentration. Vestibular ablation was confirmed by the absence of response on cervical vestibular evoked myogenic potentials and no response on caloric tests. Audiometry, electronystagmography with iced water, and vestibular evoked myogenic potentials were performed in all patients. Ten patients were included; nine patients with Meniere's disease and one patient with (late onset) delayed hydrops. Nine patients showed an absent response on vestibular evoked myogenic potentials and no response on caloric tests. The only patient with low amplitude on cervical vestibular evoked myogenic potentials had vertigo recurrence. Vertigo control was achieved in 90% of the patients. One patient developed hearing loss >30dB. Cervical vestibular evoked myogenic potentials confirmed vestibular ablation in patients treated with intratympanic gentamicin. High-grade vertigo control was due to complete saccular and horizontal canal ablation (no response to iced water in electronystagmography and no response on cervical vestibular evoked myogenic potentials). Copyright © 2016 Associação Brasileira de Otorrinolaringologia e Cirurgia Cérvico-Facial. Published by Elsevier Editora Ltda. All rights reserved.

Multimodal assessment of hemispheric lateralization for language and its relevance for behavior.

PubMed

Piervincenzi, C; Petrilli, A; Marini, A; Caulo, M; Committeri, G; Sestieri, C

2016-11-15

Although different MRI-based techniques have been proposed to assess the hemispheric lateralization for language (HLL), the agreement across methods, and its relationship with language abilities, are still a matter of debate. In the present study we obtained measures of HLL using both task-evoked activity during the execution of three different protocols and task-free methods of functional [resting state functional connectivity (rs-FC)] and anatomical [diffusion tensor imaging (DTI) tractography] connectivity. Regional analyses focusing on the perisylvian language network were conducted to assess the consistency of HLL across techniques. In addition, following a multimodal approach, we identified macro-factors of lateralization and examined their relationship with language performance. Our findings indicate the existence of a negative relationship between the structural asymmetry of the direct segment of the arcuate fasciculus (AF) and the inter-hemispheric rs-FC of key nodes of the perisylvian network. Instead, despite all the language tasks exhibited a leftward pattern of asymmetry, measures of HLL derived from task-evoked activity did not show a direct relationship with those obtained with the two task-free methods. Furthermore, a robust brain-behavioral relationship was observed only with a specific macro-factor that combined HLL measures derived from all MRI techniques. In particular, general language performance was positively related to more symmetrical structural organization, stronger inter-hemispheric communication at rest but more lateralized activation of Wernicke's territory during production tasks. Our findings, while not supporting the existence of a direct relationship between indices of hemispheric lateralization for language derived from different MRI techniques, indicate that general language performance can be indexed using combined MRI measures. The same approach might prove successful for likewise complex human behaviours. Copyright © 2016 Elsevier Inc. All rights reserved.

Evoked potentials in immobilized cats to a combination of clicks with painful electrocutaneous stimuli

NASA Technical Reports Server (NTRS)

Gilinskiy, M. A.; Korsakov, I. A.

1979-01-01

Averaged evoked potentials in the auditory, somatosensory, and motor cortical zones, as well as in the mesencephalic reticular formation were recorded in acute experiments on nonanesthetized, immobilized cats. Omission of the painful stimulus after a number of pairings resulted in the appearance of a delayed evoked potential, often resembling the late phases of the response to the painful stimulus. The characteristics of this response are discussed in comparison with conditioned changes of the sensory potential amplitudes.

Chirp-modulated visual evoked potential as a generalization of steady state visual evoked potential

NASA Astrophysics Data System (ADS)

Tu, Tao; Xin, Yi; Gao, Xiaorong; Gao, Shangkai

2012-02-01

Visual evoked potentials (VEPs) are of great concern in cognitive and clinical neuroscience as well as in the recent research field of brain-computer interfaces (BCIs). In this study, a chirp-modulated stimulation was employed to serve as a novel type of visual stimulus. Based on our empirical study, the chirp stimuli visual evoked potential (Chirp-VEP) preserved frequency features of the chirp stimulus analogous to the steady state evoked potential (SSVEP), and therefore it can be regarded as a generalization of SSVEP. Specifically, we first investigated the characteristics of the Chirp-VEP in the time-frequency domain and the fractional domain via fractional Fourier transform. We also proposed a group delay technique to derive the apparent latency from Chirp-VEP. Results on EEG data showed that our approach outperformed the traditional SSVEP-based method in efficiency and ease of apparent latency estimation. For the recruited six subjects, the average apparent latencies ranged from 100 to 130 ms. Finally, we implemented a BCI system with six targets to validate the feasibility of Chirp-VEP as a potential candidate in the field of BCIs.

Vestibular receptors contribute to cortical auditory evoked potentials.

PubMed

Todd, Neil P M; Paillard, Aurore C; Kluk, Karolina; Whittle, Elizabeth; Colebatch, James G

2014-03-01

Acoustic sensitivity of the vestibular apparatus is well-established, but the contribution of vestibular receptors to the late auditory evoked potentials of cortical origin is unknown. Evoked potentials from 500 Hz tone pips were recorded using 70 channel EEG at several intensities below and above the vestibular acoustic threshold, as determined by vestibular evoked myogenic potentials (VEMPs). In healthy subjects both auditory mid- and long-latency auditory evoked potentials (AEPs), consisting of Na, Pa, N1 and P2 waves, were observed in the sub-threshold conditions. However, in passing through the vestibular threshold, systematic changes were observed in the morphology of the potentials and in the intensity dependence of their amplitude and latency. These changes were absent in a patient without functioning vestibular receptors. In particular, for the healthy subjects there was a fronto-central negativity, which appeared at about 42 ms, referred to as an N42, prior to the AEP N1. Source analysis of both the N42 and N1 indicated involvement of cingulate cortex, as well as bilateral superior temporal cortex. Our findings are best explained by vestibular receptors contributing to what were hitherto considered as purely auditory evoked potentials and in addition tentatively identify a new component that appears to be primarily of vestibular origin. Copyright © 2013 The Authors. Published by Elsevier B.V. All rights reserved.

NLP-12 engages different UNC-13 proteins to potentiate tonic and evoked release.

PubMed

Hu, Zhitao; Vashlishan-Murray, Amy B; Kaplan, Joshua M

2015-01-21

A neuropeptide (NLP-12) and its receptor (CKR-2) potentiate tonic and evoked ACh release at Caenorhabditis elegans neuromuscular junctions. Increased evoked release is mediated by a presynaptic pathway (egl-30 Gαq and egl-8 PLCβ) that produces DAG, and by DAG binding to short and long UNC-13 proteins. Potentiation of tonic ACh release persists in mutants deficient for egl-30 Gαq and egl-8 PLCβ and requires DAG binding to UNC-13L (but not UNC-13S). Thus, NLP-12 adjusts tonic and evoked release by distinct mechanisms. Copyright © 2015 the authors 0270-6474/15/351038-05$15.00/0.

Generalized alternating stimulation: a novel method to reduce stimulus artifact in electrically evoked compound action potentials.

PubMed

Alvarez, Isaac; de la Torre, Angel; Sainz, Manuel; Roldan, Cristina; Schoesser, Hansjoerg; Spitzer, Philipp

2007-09-15

Stimulus artifact is one of the main limitations when considering electrically evoked compound action potential for clinical applications. Alternating stimulation (average of recordings obtained with anodic-cathodic and cathodic-anodic bipolar stimulation pulses) is an effective method to reduce stimulus artifact when evoked potentials are recorded. In this paper we extend the concept of alternating stimulation by combining anodic-cathodic and cathodic-anodic recordings with a weight in general different to 0.5. We also provide an automatic method to obtain an estimation of the optimal weights. Comparison with conventional alternating, triphasic stimulation and masker-probe paradigm shows that the generalized alternating method improves the quality of electrically evoked compound action potential responses.

Development of visual evoked potentials in neonates. A study using light emitting diode goggles.

PubMed Central

Chin, K C; Taylor, M J; Menzies, R; Whyte, H

1985-01-01

We used a signal averager with light emitting diode goggles as the photostimulator to study the development of the visual evoked potentials in 40 normal neonates of between 23 and 42 weeks' gestation. All except two infants of less than 24 weeks' gestation had replicable visual evoked potentials. A negative peak of latency (mean (SD), 308 (21) msec) was present in all infants, but the development of the primary positive peak depended on maturity. Only infants of 37 weeks or more had a consistent positive peak of latency (mean (SD), 220 (22) msec). The practical simplicity and reliability of this technique has distinct advantages over previous conventional recording systems. Neonatal visual evoked potentials are shown to change with maturity. PMID:4091582

Sensory and semantic activations evoked by action attributes of manipulable objects: Evidence from ERPs

PubMed Central

Lee, Chia-lin; Huang, Hsu-Wen; Federmeier, Kara D.; Buxbaum, Laurel J.

2018-01-01

“Two route” theories of object-related action processing posit different temporal activation profiles of grasp-to-move actions (rapidly evoked based on object structure) versus skilled use actions (more slowly activated based on semantic knowledge). We capitalized on the exquisite temporal resolution and multidimensionality of Event-Related Potentials (ERPs) to directly test this hypothesis. Participants viewed manipulable objects (e.g., calculator) preceded by objects sharing either “grasp”, “use”, or no action attributes (e.g., bar of soap, keyboard, earring, respectively), as well as by action-unrelated but taxonomically-related objects (e.g., abacus); participants judged whether the two objects were related. The results showed more positive responses to “grasp-to-move” primed objects than “skilled use” primed objects or unprimed objects starting in the P1 (0–150 ms) time window and continuing onto the subsequent N1 and P2 components (150–300 ms), suggesting that only “grasp-to-move”, but not “skilled use”, actions may facilitate visual attention to object attributes. Furthermore, reliably reduced N400s (300–500 ms), an index of semantic processing, were observed to taxonomically primed and “skilled use” primed objects relative to unprimed objects, suggesting that “skilled use” action attributes are a component of distributed, multimodal semantic representations of objects. Together, our findings provide evidence supporting two-route theories by demonstrating that “grasp-to-move” and “skilled use” actions impact different aspects of object processing and highlight the relationship of “skilled use” information to other aspects of semantic memory. PMID:29183777

Effect of intrathecal baclofen on evoked pain perception: an evoked potentials and quantitative thermal testing study.

PubMed

Kumru, H; Kofler, M; Flores, M C; Portell, E; Robles, V; Leon, N; Vidal, J

2013-08-01

Somatic antinociceptive effects of baclofen have been demonstrated in animal models. We hypothesized that if enhanced thermal or pain sensitivity is produced by loss of gamma-aminobutyric acid (GABA)-ergic tone in the central nervous system, spinal administration of GABA agonists might be predicted to be effective in thermal and/or pain perception changes and pain-related evoked potentials in candidates for intrathecal baclofen (ITB) treatment. Eleven patients with severe spinal cord injury (SCI) who suffered from severe spasticity were evaluated during a 50-μg ITB bolus test. Warm and heat pain thresholds, evoked heat pain perception, and contact heat-evoked potentials (CHEPs) were determined above SCI level from the right and left sides. Nine age- and gender-matched healthy volunteers undergoing repeat testing without any placebo injection served as control group. In patients, heat pain perception threshold increased, and evoked pain perception and amplitude of CHEPs decreased significantly after ITB bolus application in comparison with baseline (p < 0.005), with no change in warm perception threshold. In controls, no significant changes were observed in repeat testing over time. Our findings indicate that ITB modulates heat pain perception threshold, evoked heat pain perception and heat pain-related evoked potentials without inducing warm perception threshold changes in SCI patients. This phenomenon should be taken into account in the clinical evaluation and management of pain in patients receiving baclofen. © 2012 European Federation of International Association for the Study of Pain Chapters.

Pain-related somatosensory evoked potentials and functional brain magnetic resonance in the evaluation of neurologic recovery after cardiac arrest: a case study of three patients.

PubMed

Zanatta, Paolo; Messerotti Benvenuti, Simone; Baldanzi, Fabrizio; Bendini, Matteo; Saccavini, Marsilio; Tamari, Wadih; Palomba, Daniela; Bosco, Enrico

2012-03-31

This case series investigates whether painful electrical stimulation increases the early prognostic value of both somatosensory-evoked potentials and functional magnetic resonance imaging in comatose patients after cardiac arrest. Three single cases with hypoxic-ischemic encephalopathy were considered. A neurophysiological evaluation with an electroencephalogram and somatosensory-evoked potentials during increased electrical stimulation in both median nerves was performed within five days of cardiac arrest. Each patient also underwent a functional magnetic resonance imaging evaluation with the same neurophysiological protocol one month after cardiac arrest. One patient, who completely recovered, showed a middle latency component at a high intensity of stimulation and the activation of all brain areas involved in cerebral pain processing. One patient in a minimally conscious state only showed the cortical somatosensory response and the activation of the primary somatosensory cortex. The last patient, who was in a vegetative state, did not show primary somatosensory evoked potentials; only the activation of subcortical brain areas occurred. These preliminary findings suggest that the pain-related somatosensory evoked potentials performed to increase the prognosis of comatose patients after cardiac arrest are associated with regional brain activity showed by functional magnetic resonance imaging during median nerves electrical stimulation. More importantly, this cases report also suggests that somatosensory evoked potentials and functional magnetic resonance imaging during painful electrical stimulation may be sensitive and complementary methods to predict the neurological outcome in the acute phase of coma. Thus, pain-related somatosensory-evoked potentials may be a reliable and a cost-effective tool for planning the early diagnostic evaluation of comatose patients.

Characterization of Motor and Somatosensory Evoked Potentials in the Yucatan Micropig Using Transcranial and Epidural Stimulation.

PubMed

Benavides, Francisco D; Santamaria, Andrea J; Bodoukhin, Nikita; Guada, Luis G; Solano, Juan P; Guest, James D

2017-09-15

Yucatan micropigs have brain and spinal cord dimensions similar to humans and are useful for certain spinal cord injury (SCI) translational studies. Micropigs are readily trained in behavioral tasks, allowing consistent testing of locomotor loss and recovery. However, there has been little description of their motor and sensory pathway neurophysiology. We established methods to assess motor and sensory cortical evoked potentials in the anesthetized, uninjured state. We also evaluated epidurally evoked motor and sensory stimuli from the T6 and T9 levels, spanning the intended contusion injury epicenter. Response detection frequency, mean latency and amplitude values, and variability of evoked potentials were determined. Somatosensory evoked potentials were reliable and best detected during stimulation of peripheral nerve and epidural stimulation by referencing the lateral cortex to midline Fz. The most reliable hindlimb motor evoked potential (MEP) occurred in tibialis anterior. We found MEPs in forelimb muscles in response to thoracic epidural stimulation likely generated from propriospinal pathways. Cranially stimulated MEPs were easier to evoke in the upper limbs than in the hindlimbs. Autopsy studies revealed substantial variations in cortical morphology between animals. This electrophysiological study establishes that neurophysiological measures can be reliably obtained in micropigs in a time frame compatible with other experimental procedures, such as SCI and transplantation. It underscores the need to better understand the motor control pathways, including the corticospinal tract, to determine which therapeutics are suitable for testing in the pig model.

Amphiregulin and PTEN evoke a multimodal mechanism of acquired resistance to PI3K inhibition

PubMed Central

Edgar, Kyle A.; Crocker, Lisa; Cheng, Eric; Wagle, Marie-Claire; Wongchenko, Matthew; Yan, Yibing; Wilson, Timothy R.; Dompe, Nicholas; Neve, Richard M.; Belvin, Marcia; Sampath, Deepak; Friedman, Lori S.; Wallin, Jeffrey J.

2014-01-01

Phosphoinositide-3 kinase (PI3K) signaling pathway alterations occur broadly in cancer and PI3K is a promising therapeutic target. Here, we investigated acquired resistance to GDC-0941, a PI3K inhibitor in clinical trials. Colorectal cancer (CRC) cells made to be resistant to GDC-0941 were discovered to secrete amphiregulin, which resulted in increased EGFR/MAPK signaling. Moreover, prolonged PI3K pathway inhibition in cultured cells over a period of months led to a secondary loss of PTEN in 40% of the CRC lines with acquired resistance to PI3K inhibition. In the absence of PI3K inhibitor, these PTEN-null PI3K inhibitor-resistant clones had elevated PI3K pathway signaling and decreased sensitivity to MAPK pathway inhibitors. Importantly, PTEN loss was not able to induce resistance to PI3K inhibitors in the absence of amphiregulin, indicating a multimodal mechanism of acquired resistance. The combination of PI3K and MAPK pathway inhibitors overcame acquired resistance in vitro and in vivo. PMID:25053989

Amphiregulin and PTEN evoke a multimodal mechanism of acquired resistance to PI3K inhibition.

PubMed

Edgar, Kyle A; Crocker, Lisa; Cheng, Eric; Wagle, Marie-Claire; Wongchenko, Matthew; Yan, Yibing; Wilson, Timothy R; Dompe, Nicholas; Neve, Richard M; Belvin, Marcia; Sampath, Deepak; Friedman, Lori S; Wallin, Jeffrey J

2014-03-01

Phosphoinositide-3 kinase (PI3K) signaling pathway alterations occur broadly in cancer and PI3K is a promising therapeutic target. Here, we investigated acquired resistance to GDC-0941, a PI3K inhibitor in clinical trials. Colorectal cancer (CRC) cells made to be resistant to GDC-0941 were discovered to secrete amphiregulin, which resulted in increased EGFR/MAPK signaling. Moreover, prolonged PI3K pathway inhibition in cultured cells over a period of months led to a secondary loss of PTEN in 40% of the CRC lines with acquired resistance to PI3K inhibition. In the absence of PI3K inhibitor, these PTEN-null PI3K inhibitor-resistant clones had elevated PI3K pathway signaling and decreased sensitivity to MAPK pathway inhibitors. Importantly, PTEN loss was not able to induce resistance to PI3K inhibitors in the absence of amphiregulin, indicating a multimodal mechanism of acquired resistance. The combination of PI3K and MAPK pathway inhibitors overcame acquired resistance in vitro and in vivo.

The Nature and Process of Development in Averaged Visually Evoked Potentials: Discussion on Pattern Structure.

ERIC Educational Resources Information Center

Izawa, Shuji; Mizutani, Tohru

This paper examines the development of visually evoked EEG patterns in retarded and normal subjects. The paper focuses on the averaged visually evoked potentials (AVEP) in the central and occipital regions of the brain in eyes closed and eyes open conditions. Wave pattern, amplitude, and latency are examined. The first section of the paper reviews…

Phantom somatosensory evoked potentials following selective intraneural electrical stimulation in two amputees.

PubMed

Granata, Giuseppe; Di Iorio, Riccardo; Romanello, Roberto; Iodice, Francesco; Raspopovic, Stanisa; Petrini, Francesco; Strauss, Ivo; Valle, Giacomo; Stieglitz, Thomas; Čvančara, Paul; Andreu, David; Divoux, Jean-Louis; Guiraud, David; Wauters, Loic; Hiairrassary, Arthur; Jensen, Winnie; Micera, Silvestro; Rossini, Paolo Maria

2018-06-01

The aim of the paper is to objectively demonstrate that amputees implanted with intraneural interfaces are truly able to feel a sensation in the phantom hand by recording "phantom" somatosensory evoked potentials from the corresponding brain areas. We implanted four transverse intrafascicular multichannel electrodes, available with percutaneous connections to a multichannel electrical stimulator, in the median and ulnar nerves of two left trans-radial amputees. Two channels of the implants that were able to elicit sensations during intraneural nerve stimulation were chosen, in both patients, for recording somatosensory evoked potentials. We recorded reproducible evoked responses by stimulating the median and the ulnar nerves in both cases. Latencies were in accordance with the arrival of somatosensory information to the primary somatosensory cortex. Our results provide evidence that sensations generated by intraneural stimulation are truly perceived by amputees and located in the phantom hand. Moreover, our results strongly suggest that sensations perceived in different parts of the phantom hand result in different evoked responses. Somatosensory evoked potentials obtained by selective intraneural electrical stimulation in amputee patients are a useful tool to provide an objective demonstration of somatosensory feedback in new generation bidirectional prostheses. Copyright © 2018. Published by Elsevier B.V.

Effects of single cycle binaural beat duration on auditory evoked potentials.

PubMed

Mihajloski, Todor; Bohorquez, Jorge; Özdamar, Özcan

2014-01-01

Binaural beat (BB) illusions are experienced as continuous central pulsations when two sounds with slightly different frequencies are delivered to each ear. It has been shown that steady-state auditory evoked potentials (AEPs) to BBs can be captured and investigated. The authors recently developed a new method of evoking transient AEPs to binaural beats using frequency modulated stimuli. This methodology was able to create single BBs in predetermined intervals with varying carrier frequencies. This study examines the effects of the BB duration and the frequency modulating component of the stimulus on the binaural beats and their evoked potentials. Normal hearing subjects were tested with a set of four durations (25, 50, 100, and 200 ms) with two stimulation configurations, binaural dichotic (binaural beats) and diotic (frequency modulation). The results obtained from the study showed that out of the given durations, the 100 ms beat, was capable of evoking the largest amplitude responses. The frequency modulation effect showed a decrease in peak amplitudes with increasing beat duration until their complete disappearance at 200 ms. Even though, at 200 ms, the frequency modulation effects were not present, the binaural beats were still perceived and captured as evoked potentials.

How to assess prognosis after cardiac arrest and therapeutic hypothermia.

PubMed

Taccone, Fabio; Cronberg, Tobias; Friberg, Hans; Greer, David; Horn, Janneke; Oddo, Mauro; Scolletta, Sabino; Vincent, Jean-Louis

2014-01-14

The prognosis of patients who are admitted in a comatose state following successful resuscitation after cardiac arrest remains uncertain. Although the introduction of therapeutic hypothermia (TH) and improvements in post-resuscitation care have significantly increased the number of patients who are discharged home with minimal brain damage, short-term assessment of neurological outcome remains a challenge. The need for early and accurate prognostic predictors is crucial, especially since sedation and TH may alter the neurological examination and delay the recovery of motor response for several days. The development of additional tools, including electrophysiological examinations (electroencephalography and somatosensory evoked potentials), neuroimaging and chemical biomarkers, may help to evaluate the extent of brain injury in these patients. Given the extensive literature existing on this topic and the confounding effects of TH on the strength of these tools in outcome prognostication after cardiac arrest, the aim of this narrative review is to provide a practical approach to post-anoxic brain injury when TH is used. We also discuss when and how these tools could be combined with the neurological examination in a multimodal approach to improve outcome prediction in this population.

Cortical functional correlates of responsiveness to short-lasting preventive intervention with ketogenic diet in migraine: a multimodal evoked potentials study.

PubMed

Di Lorenzo, Cherubino; Coppola, Gianluca; Bracaglia, Martina; Di Lenola, Davide; Evangelista, Maurizio; Sirianni, Giulio; Rossi, Paolo; Di Lorenzo, Giorgio; Serrao, Mariano; Parisi, Vincenzo; Pierelli, Francesco

2016-01-01

Here, we aim to identify cortical electrofunctional correlates of responsiveness to short-lasting preventiveintervention with ketogenic diet (KD) in migraine. Eighteen interictal migraineurs underwent visual (VEPs) and median nerve somatosensory (SSEPs) evokedpotentials before and after 1 month of KD during ketogenesis. We measured VEPs N1-P1 and SSEPs N20-P25 amplitudes respectively in six and in two sequential blocks of 100 sweeps as well as habituation as theslope of the linear regression between block 1 to 6 for VEPs or between 1 to 2 for SSEPs. After 1-month of KD, a significant reduction in the mean attack frequency and duration was observed (all P< 0.001). The KD did not change the 1st SSEP and VEP block of responses, but significantly inducednormalization of the interictally reduced VEPs and SSEPs (all p < 0.01) habituation during the subsequentblocks. KD could restore normal EPs habituation curves during stimulus repetition without significantly changing theearly amplitude responses. Thus, we hypothesize that KD acts on habituation regulating the balancebetween excitation and inhibition at the cortical level.

Diagnostic accuracy of evoked potentials for functional impairment after contusive spinal cord injury in adult rats.

PubMed

Thirumala, Parthasarathy; Zhou, James; Krishnan, Rohan; Manem, Nihita; Umredkar, Shreya; Hamilton, D K; Balzer, Jeffrey R; Oudega, Martin

2016-03-01

Iatrogenic spinal cord injury (SCI) is a cause of potentially debilitating post-operative neurologic complications. Currently, intra-operative neurophysiological monitoring (IONM) via somatosensory evoked potentials and motor-evoked potentials is used to detect and prevent impending SCI. However, no empirically validated interventions exist to halt the progression of iatrogenic SCI once it is detected. This is in part due to the lack of a suitable translational model that mimics the circumstances surrounding iatrogenic SCI detected via IONM. Here, we evaluate a model of simulated contusive iatrogenic SCI detected via IONM in adult female Sprague-Dawley rats. We show that transient losses of somatosensory evoked potentials responses are 88.24% sensitive (95% confidence interval [CI] 63.53-98.20) and 80% specific (95% CI 51.91-95.43) for significant functional impairment following simulated iatrogenic SCI. Similarly, we show that transient losses in motor-evoked potentials responses are 70.83% sensitive (95% CI 48.91-87.33) and 100% specific (95% CI 62.91-100.00) for significant functional impairment following simulated iatrogenic SCI. These results indicate that our model is a suitable replica of the circumstances surrounding clinical iatrogenic SCI. Copyright © 2015 Elsevier Ltd. All rights reserved.

Unknown Pseudocholinesterase Deficiency in a Patient Undergoing TIVA with Planned Motor Evoked Potential Monitoring: A Case Report.

PubMed

Binkley, Candace

2016-06-01

Pseudocholinesterase abnormalities are a genetic cause of aberrant metabolism of the depolarizing muscle relaxant succinylcholine. This article examines a case where succinylcholine was chosen to facilitate intubation due to its ultra short duration and the request of the surgeon to monitor motor evoked potentials. Following succinylcholine administration the neurophysiologist was unable to obtain motor evoked potentials. This case study highlights the intraoperative and postoperative management of an elderly patient with an unknown pseudocholinesterase deficiency.

Human auditory evoked potentials in the assessment of brain function during major cardiovascular surgery.

PubMed

Rodriguez, Rosendo A

2004-06-01

Focal neurologic and intellectual deficits or memory problems are relatively frequent after cardiac surgery. These complications have been associated with cerebral hypoperfusion, embolization, and inflammation that occur during or after surgery. Auditory evoked potentials, a neurophysiologic technique that evaluates the function of neural structures from the auditory nerve to the cortex, provide useful information about the functional status of the brain during major cardiovascular procedures. Skepticism regarding the presence of artifacts or difficulty in their interpretation has outweighed considerations of its potential utility and noninvasiveness. This paper reviews the evidence of their potential applications in several aspects of the management of cardiac surgery patients. The sensitivity of auditory evoked potentials to the effects of changes in brain temperature makes them useful for monitoring cerebral hypothermia and rewarming during cardiopulmonary bypass. The close relationship between evoked potential waveforms and specific anatomic structures facilitates the assessment of the functional integrity of the central nervous system in cardiac surgery patients. This feature may also be relevant in the management of critical patients under sedation and coma or in the evaluation of their prognosis during critical care. Their objectivity, reproducibility, and relative insensitivity to learning effects make auditory evoked potentials attractive for the cognitive assessment of cardiac surgery patients. From a clinical perspective, auditory evoked potentials represent an additional window for the study of underlying cerebral processes in healthy and diseased patients. From a research standpoint, this technology offers opportunities for a better understanding of the particular cerebral deficits associated with patients who are undergoing major cardiovascular procedures.

Basilar artery hypoplasia associated with changes of brainstem potential, transcranial Doppler and perfusion-weighted imaging.

PubMed

Zhang, Dao Pei; Yin, Suo; Zhang, Shu Ling; Zhang, Jie Wen; Ma, Qian Kun; Lu, Gui Feng

2017-07-01

The aim of this study was to observe brainstem hemodynamic alterations associated with basilar artery hypoplasia (BAH). Nine hundred and fifty-two consecutive patients received emergency multimodal computed tomography; magnetic resonance imaging and magnetic resonance angiogram during the period of January 2011 to December 2014 were included. The vascular risk factors, brainstem auditory evoked potential (BAEP), blink reflex (BR), transcranial Doppler (TCD) and dynamic susceptibility contrast-enhanced perfusion-weighted imaging were completed. There was significant difference in the abnormal rates of TCD and BAEP between BAH and non-BAH patients. A positive correlation between basilar artery diameter and systolic velocity among BAH patients was suggested. V-wave value was used to predict posterior circulation infarction (PCI) with the sensitivity of 0.933 and specificity of 0.50 with the cutoff value of 5.97 s. Abnormal BR rate was also significantly different in BAH and non-BAH patients. The latency of R2 was used to predict PCI with the sensitivity of 0.933 and specificity of 0.50 with the cutoff value of 46.4 ms. The incidence of hypoperfusion was higher in BAH than non-BAH group and it was significant difference. BAH is closely associated with hemodynamic alterations within the pons, which might contribute to vascular vertigo due to regional hypoperfusion.

A new method for registration of kinesthetic evoked potentials for studies of proprioceptive sensitivity in normal subjects and patients with organic lesions in the brain.

PubMed

Gordeev, S A; Voronin, S G

2015-01-01

The proprioceptive sensitivity of healthy volunteers and convalescents after acute cerebrovascular episodes was studied by a new neurophysiological method for registration of kinesthetic evoked potentials emerging in response to passive 50(o) bending of the hand in the wrist joint with the angular acceleration of 350 rad/sec(2). Kinesthetic evoked potentials were recorded above the somatosensory cortex projection areas in the hemispheres contra- and ipsilateral to the stimulated limb. The patients exhibited significantly longer latencies and lesser amplitudes of the early components of response in the involved hemisphere in comparison with normal subjects. The method for registration of the kinesthetic evoked potentials allows a more detailed study of the mechanisms of kinesthetic sensitivity in health and in organic involvement of the brain.

Vertex evoked potentials in a rating-scale detection task: Relation to signal probability

NASA Technical Reports Server (NTRS)

Squires, K. C.; Squires, N. K.; Hillyard, S. A.

1974-01-01

Vertex evoked potentials were recorded from human subjects performing in an auditory detection task with rating scale responses. Three values of a priori probability of signal presentation were tested. The amplitudes of the N1 and P3 components of the vertex potential associated with correct detections of the signal were found to be systematically related to the strictness of the response criterion and independent of variations in a priori signal probability. No similar evoked potential components were found associated with signal absent judgements (misses and correct rejections) regardless of the confidence level of the judgement or signal probability. These results strongly support the contention that the form of the vertex evoked response is closely correlated with the subject's psychophysical decision regarding the presence or absence of a threshold level signal.

Intraoperative neurophysiological monitoring during endoscopic endonasal surgery for pediatric skull base tumors.

PubMed

Elangovan, Cheran; Singh, Supriya Palwinder; Gardner, Paul; Snyderman, Carl; Tyler-Kabara, Elizabeth C; Habeych, Miguel; Crammond, Donald; Balzer, Jeffrey; Thirumala, Parthasarathy D

2016-02-01

OBJECT The aim of this study was to evaluate the value of intraoperative neurophysiological monitoring (IONM) using electromyography (EMG), brainstem auditory evoked potentials (BAEPs), and somatosensory evoked potentials (SSEPs) to predict and/or prevent postoperative neurological deficits in pediatric patients undergoing endoscopic endonasal surgery (EES) for skull base tumors. METHODS All consecutive pediatric patients with skull base tumors who underwent EES with at least 1 modality of IONM (BAEP, SSEP, and/or EMG) at our institution between 1999 and 2013 were retrospectively reviewed. Staged procedures and repeat procedures were identified and analyzed separately. To evaluate the diagnostic accuracy of significant free-run EMG activity, the prevalence of cranial nerve (CN) deficits and the sensitivity, specificity, and positive and negative predictive values were calculated. RESULTS A total of 129 patients underwent 159 procedures; 6 patients had a total of 9 CN deficits. The incidences of CN deficits based on the total number of nerves monitored in the groups with and without significant free-run EMG activity were 9% and 1.5%, respectively. The incidences of CN deficits in the groups with 1 staged and more than 1 staged EES were 1.5% and 29%, respectively. The sensitivity, specificity, and negative predictive values (with 95% confidence intervals) of significant EMG to detect CN deficits in repeat procedures were 0.55 (0.22-0.84), 0.86 (0.79-0.9), and 0.97 (0.92-0.99), respectively. Two patients had significant changes in their BAEPs that were reversible with an increase in mean arterial pressure. CONCLUSIONS IONM can be applied effectively and reliably during EES in children. EMG monitoring is specific for detecting CN deficits and can be an effective guide for dissecting these procedures. Triggered EMG should be elicited intraoperatively to check the integrity of the CNs during and after tumor resection. Given the anatomical complexity of pediatric EES and the unique challenges encountered, multimodal IONM can be a valuable adjunct to these procedures.

Contemporary Multi-Modal Historical Representations and the Teaching of Disciplinary Understandings in History

ERIC Educational Resources Information Center

Donnelly, Debra J.

2018-01-01

Traditional privileging of the printed text has been considerably eroded by rapid technological advancement and in Australia, as elsewhere, many History teaching programs feature an array of multi-modal historical representations. Research suggests that engagement with the visual and multi-modal constructs has the potential to enrich the pedagogy…

Effects of core body temperature on changes in spinal somatosensory-evoked potential in acute spinal cord compression injury: an experimental study in the rat.

PubMed

Jou, I M

2000-08-01

Acute spinal cord injury was induced by a clip compression model in rats to approximate spinal cord injury encountered in spinal surgery. Spinal somatosensory-evoked potential neuromonitoring was used to study the electrophysiologic change. To compare and correlate changes in evoked potential after acute compression at different core temperatures with postoperative neurologic function and histologic change, to evaluate current intraoperative neuromonitoring warning criteria for neural damage, and to confirm the protective effect of hypothermia in acute spinal cord compression injury by electrophysiologic, histologic, and clinical observation. With the increase in aggressive correction of spinal deformities, and the invasiveness of surgical instruments, the incidence of neurologic complication appears to have increased despite the availability of sensitive intraoperative neuromonitoring techniques designed to alert surgeons to impending neural damage. Many reasons have been given for the frequent failures of neuromonitoring, but the influence of temperature-a very important and frequently encountered factor-on evoked potential has not been well documented. Specifically, decrease in amplitude and elongation of latency seem not to have been sufficiently taken into account when intraoperative neuromonitoring levels were interpreted and when acceptable intraoperative warning criteria were determined. Experimental acute spinal cord injury was induced in rats by clip compression for two different intervals and at three different core temperatures. Spinal somatosensory-evoked potential, elicited by stimulating the median nerve and recorded from the cervical interspinous C2-C3, was monitored immediately before and after compression, and at 15-minute intervals for 1 hour. Spinal somatosensory-evoked potential change is almost parallel to temperature-based amplitude reduction and latency elongation. Significant neurologic damage induced by acute compression of the cervical spinal cord produced a degree of effect on the amplitude of spinal somatosensory-evoked potential in normothermic conditions that differed from the effect in moderately hypothermic conditions. Using the same electromonitoring criteria,moderately hypothermic groups showed a significantly higher false-negative rate statistically (35%) than normothermic groups (10%). Systemic cooling may protect against the detrimental effects of aggressive spinal surgical procedures. There is still not enough published information available to establish statistically and ethically acceptable intraoperative neuromonitoring warning and intervention criteria conclusively. Therefore, an urgent need exists for further investigation. Although a reduction of more than 50% in evoked potential still seems acceptable as an indicator of impending neural function loss, maintenance of more than 50% of baseline evoked potential is no guarantee of normal postoperative neural function, especially at lower than normal temperatures.

[The modified method registration of kinesthetic evoked potentials and its application for research of proprioceptive sensitivity disorders at spondylogenic cervical myelopathy].

PubMed

Gordeev, S A; Voronin, S G

2016-01-01

To analyze the efficacy of modified (passive radiocarpal articulation flexion/extension) and «standard» (passive radiocarpal articulation flexion) methods of kinesthetic evoked potentials for proprioceptive sensitivity assessment in healthy subjects and patients with spondylotic cervical myelopathy. The study included 14 healthy subjects (4 women and 10 men, mean age 54.1±10.5 years) and 8 patients (2 women and 6 men, mean age 55.8±10.9 years) with spondylotic cervical myelopathy. Muscle-joint sensation was examined during the clinical study. A modified method of kinesthetic evoked potentials was developed. This method differed from the "standard" one by the organization of a cycle including several passive movements,where each new movement differed from the preceding one by the direction. The modified method of kinesthetic evoked potentials ensures more reliable kinesthetic sensitivity assessment due to movement variability. Asignificant increaseof the latent periods of the early components of the response was found in patients compared to healthy subjects. The modified method of kinesthetic evoked potentials can be used for objective diagnosis of proprioceptive sensitivity disorders in patients with spondylotic cervical myelopathy.

Feasibility and performance evaluation of generating and recording visual evoked potentials using ambulatory Bluetooth based system.

PubMed

Ellingson, Roger M; Oken, Barry

2010-01-01

Report contains the design overview and key performance measurements demonstrating the feasibility of generating and recording ambulatory visual stimulus evoked potentials using the previously reported custom Complementary and Alternative Medicine physiologic data collection and monitoring system, CAMAS. The methods used to generate visual stimuli on a PDA device and the design of an optical coupling device to convert the display to an electrical waveform which is recorded by the CAMAS base unit are presented. The optical sensor signal, synchronized to the visual stimulus emulates the brain's synchronized EEG signal input to CAMAS normally reviewed for the evoked potential response. Most importantly, the PDA also sends a marker message over the wireless Bluetooth connection to the CAMAS base unit synchronized to the visual stimulus which is the critical averaging reference component to obtain VEP results. Results show the variance in the latency of the wireless marker messaging link is consistent enough to support the generation and recording of visual evoked potentials. The averaged sensor waveforms at multiple CPU speeds are presented and demonstrate suitability of the Bluetooth interface for portable ambulatory visual evoked potential implementation on our CAMAS platform.

Visual evoked potential in RCS rats with Okayama University-type retinal prosthesis (OUReP™) implantation.

PubMed

Alamusi; Matsuo, Toshihiko; Hosoya, Osamu; Uchida, Tetsuya

2017-06-01

Photoelectric dye-coupled polyethylene film, designated Okayama University type-retinal prosthesis or OUReP™, generates light-evoked surface electric potentials and stimulates neurons. The dye-coupled films or plain films were implanted subretinally in both eyes of 10 Royal College of Surgeons rats with hereditary retinal dystrophy at the age of 6 weeks. Visual evoked potentials in response to monocular flashing light stimuli were recorded from cranially-fixed electrodes, 4 weeks and 8 weeks after the implantation. After the recording, subretinal film implantation was confirmed histologically in 7 eyes with dye-coupled films and 7 eyes with plain films. The recordings from these 7 eyes in each group were used for statistical analysis. The amplitudes of visual evoked potentials in the consecutive time points from 125 to 250 ms after flash were significantly larger in the 7 eyes with dye-coupled film implantation, compared to the 7 eyes with plain film implantation at 8 weeks after the implantation (P < 0.05, repeated-measure ANOVA). The photoelectric dye-coupled polyethylene film, as retinal prosthesis, gave rise to visual evoked potential in response to flashing light.

Local classifiers for evoked potentials recorded from behaving rats.

PubMed

Jakuczun, Wit; Kublik, Ewa; Wójcik, Daniel K; Wróbel, Andrzej

2005-01-01

Dynamic states of the brain determine the way information is processed in local neural networks. We have applied classical conditioning paradigm in order to study whether habituated and aroused states can be differentiated in single barrel column of rat's somatosensory cortex by means of analysis of field potentials evoked by stimulation of a single vibrissa. A new method using local classifiers is presented which allows for reliable and meaningful classification of single evoked potentials which might be consequently attributed to different functional states of the cortical column.

Absence of both auditory evoked potentials and auditory percepts dependent on timing cues.

PubMed

Starr, A; McPherson, D; Patterson, J; Don, M; Luxford, W; Shannon, R; Sininger, Y; Tonakawa, L; Waring, M

1991-06-01

An 11-yr-old girl had an absence of sensory components of auditory evoked potentials (brainstem, middle and long-latency) to click and tone burst stimuli that she could clearly hear. Psychoacoustic tests revealed a marked impairment of those auditory perceptions dependent on temporal cues, that is, lateralization of binaural clicks, change of binaural masked threshold with changes in signal phase, binaural beats, detection of paired monaural clicks, monaural detection of a silent gap in a sound, and monaural threshold elevation for short duration tones. In contrast, auditory functions reflecting intensity or frequency discriminations (difference limens) were only minimally impaired. Pure tone audiometry showed a moderate (50 dB) bilateral hearing loss with a disproportionate severe loss of word intelligibility. Those auditory evoked potentials that were preserved included (1) cochlear microphonics reflecting hair cell activity; (2) cortical sustained potentials reflecting processing of slowly changing signals; and (3) long-latency cognitive components (P300, processing negativity) reflecting endogenous auditory cognitive processes. Both the evoked potential and perceptual deficits are attributed to changes in temporal encoding of acoustic signals perhaps occurring at the synapse between hair cell and eighth nerve dendrites. The results from this patient are discussed in relation to previously published cases with absent auditory evoked potentials and preserved hearing.

Intraoperative Functional Mapping and Monitoring during Glioma Surgery

PubMed Central

SAITO, Taiichi; MURAGAKI, Yoshihiro; MARUYAMA, Takashi; TAMURA, Manabu; NITTA, Masayuki; OKADA, Yoshikazu

2015-01-01

Glioma surgery represents a significant advance with respect to improving resection rates using new surgical techniques, including intraoperative functional mapping, monitoring, and imaging. Functional mapping under awake craniotomy can be used to detect individual eloquent tissues of speech and/or motor functions in order to prevent unexpected deficits and promote extensive resection. In addition, monitoring the patient’s neurological findings during resection is also very useful for maximizing the removal rate and minimizing deficits by alarming that the touched area is close to eloquent regions and fibers. Assessing several types of evoked potentials, including motor evoked potentials (MEPs), sensory evoked potentials (SEPs) and visual evoked potentials (VEPs), is also helpful for performing surgical monitoring in patients under general anesthesia (GA). We herein review the utility of intraoperative mapping and monitoring the assessment of neurological findings, with a particular focus on speech and the motor function, in patients undergoing glioma surgery. PMID:25744346

Transcranial electric motor evoked potential monitoring during spine surgery: is it safe?

PubMed

Schwartz, Daniel M; Sestokas, Anthony K; Dormans, John P; Vaccaro, Alexander R; Hilibrand, Alan S; Flynn, John M; Li, P Mark; Shah, Suken A; Welch, William; Drummond, Denis S; Albert, Todd J

2011-06-01

Retrospective review. To report on the safety of repetitive transcranial electric stimulation (RTES) for eliciting motor-evoked potentials during spine surgery. Theoretical concerns over the safety of RTES have hindered broader acceptance of transcranial electric motor-evoked potentials (tceMEP), despite successful implementation of spinal cord monitoring with tceMEPs in many large spine centers, as well as their apparent superiority over mixed-nerve somatosensory-evoked potentials (SSEP) for detection of spinal cord injury. The records of 18,862 consecutive patients who met inclusion criteria and underwent spine surgery with tceMEP monitoring were reviewed for RTES-related complications. This large retrospective review identified only 26 (0.14%) cases with RTES-related complications; all but one of these were tongue lacerations, most of which were self-limiting. The results demonstrate that RTES is a highly safe modality for monitoring spinal cord motor tract function intraoperatively.

Innovative neurophysiological methods in itch research: long-latency evoked potentials after electrical and thermal stimulation in patients with atopic dermatitis.

PubMed

Yudina, Marina M; Toropina, Galina G; Lvov, Andrey; Gieler, Uwe

2011-10-01

The aim of this study was to examine the findings of innovative neurophysiological methods of itch research. Short-latency and pain-related somatosensory-evoked potentials after electrical stimulation, as well as long-latency evoked potentials after thermal stimulation were studied in 38 patients with atopic dermatitis (AD) and 26 healthy volunteers. Quantitative Sensory Testing of thermal perception was performed in 22 patients with AD from the main AD group and in 15 healthy volunteers. Brain hyperactivity to electrical stimuli, delayed thermal-evoked potentials and elevated thermal thresholds were revealed in patients with AD compared with healthy controls. The data indicate small nerve fibre dysfunction in patients with AD, which may contribute to the pathogenesis of AD and chronic itch. The study demonstrates objective approaches to assess the function of small nerve fibres in patients with chronic itch.

Meaning Making through Multiple Modalities in a Biology Classroom: A Multimodal Semiotics Discourse Analysis

ERIC Educational Resources Information Center

Jaipal, Kamini

2010-01-01

The teaching of science is a complex process, involving the use of multiple modalities. This paper illustrates the potential of a multimodal semiotics discourse analysis framework to illuminate meaning-making possibilities during the teaching of a science concept. A multimodal semiotics analytical framework is developed and used to (1) analyze the…

Surgical monitoring with auditory evoked potentials.

PubMed

Lüders, H

1988-07-01

This comprehensive review of surgical monitoring with auditory evoked potentials (AEPs) includes a detailed discussion of techniques used for recording brainstem auditory evoked potentials, direct eight-nerve potentials, and electrocochleograms. The normal waveform of these different potentials is discussed, and the typical patterns of abnormalities seen with different insults to the peripheral or central auditory pathways are presented. The mechanisms most probably responsible for changes in AEPs during surgical procedures are analyzed. A critical analysis is made of what represents a significant change in AEPs. Also considered is the predictive value of intrasurgical changes of AEPs. Finally, attempts are made to determine whether AEPs monitoring can assist the surgeon in the prevention of postsurgical complications.

Micro-field evoked potentials recorded from the porcine sub-dural cortical surface utilizing a microelectrode array.

PubMed

Kitzmiller, Joseph P; Hansford, Derek J; Fortin, Linda D; Obrietan, Karl H; Bergdall, Valerie K; Beversdorf, David Q

2007-05-15

A sub-dural surface microelectrode array designed to detect micro-field evoked potentials has been developed. The device is comprised of an array of 350-microm square gold contacts, with bidirectional spacing of 150 microm, contained within a polyimide Kapton material. Cytotoxicity testing suggests that the device is suitable for use with animal and human patients. Implementation of the device in animal studies revealed that reliable evoked potentials could be acquired. Further work will be needed to determine how these micro-field potentials, which demonstrate selectivity for one eye, relate to the distribution of the ocular dominance columns of the occipital cortex.

Micro-Field Evoked Potentials Recorded from the Porcine Sub-Dural Cortical Surface Utilizing a Microelectrode Array

PubMed Central

Kitzmiller, Joseph P.; Hansford, Derek J.; Fortin, Linda D.; Obrietan, Karl H.; Bergdall, Valerie K.

2007-01-01

A sub-dural surface microelectrode array designed to detect microfield evoked potentials has been developed. The device is comprised of an array of 350-micron square gold contacts, with bi-directional spacing of 150 microns, contained within a polyimide Kapton material. Cytotoxicity testing suggests that the device is suitable for use with animal and human patients. Implementation of the device in animal studies revealed that reliable evoked potentials could be acquired. Further work will be needed to determine how these microfield potentials, which demonstrate selectivity for one eye, relate to the distribution of the ocular dominance columns of the occipital cortex. PMID:17298849

Interside Latency Differences in Brainstem Auditory and Somatosensory Evoked Potentials. Defining Upper Limits to Determine Asymmetry.

PubMed

Moncho, Dulce; Poca, Maria A; Minoves, Teresa; Ferré, Alejandro; Sahuquillo, Juan

2015-10-01

Limits of the interside differences are invaluable when interpreting asymmetry in brainstem auditory evoked potentials and somatosensory evoked potentials (SEP) recordings. The aim of this study was to analyze the normal upper limits of interside latency differences of brainstem auditory evoked potentials and SEP from the posterior tibial nerve and median nerve to determine asymmetry. The authors performed a prospective study in 56 healthy subjects aged 15 to 64 years with no neurological or hearing disorders. They analyzed (1) the latencies of I, III, and V waves and I-III, III-V, and I-V intervals and the amplitude ratios V/I and IV/I for brainstem auditory evoked potentials bilaterally; (2) the latencies of N8, N22, N28, and P37 waves and the interval N22-P37 and the amplitude P37 for posterior tibial nerve SEP bilaterally; and (3) the latencies and amplitudes of N9, N13, and N20 waves and N9-N13 and N13-N20 intervals for median nerve SEP bilaterally. The interside differences for these parameters were calculated and analyzed. The authors obtained an upper limit for the interside latency differences from brainstem auditory evoked potentials that was significantly lower than the previously published data. However, the upper limits of interside latency differences for SEP were similar to those previously reported. The findings of this study should be considered when laboratories analyze asymmetry using the normative data published by another center, however temporarily, in organizing new laboratories.

Deep brain stimulation of the ventral hippocampus restores deficits in processing of auditory evoked potentials in a rodent developmental disruption model of schizophrenia.

PubMed

Ewing, Samuel G; Grace, Anthony A

2013-02-01

Existing antipsychotic drugs are most effective at treating the positive symptoms of schizophrenia but their relative efficacy is low and they are associated with considerable side effects. In this study deep brain stimulation of the ventral hippocampus was performed in a rodent model of schizophrenia (MAM-E17) in an attempt to alleviate one set of neurophysiological alterations observed in this disorder. Bipolar stimulating electrodes were fabricated and implanted, bilaterally, into the ventral hippocampus of rats. High frequency stimulation was delivered bilaterally via a custom-made stimulation device and both spectral analysis (power and coherence) of resting state local field potentials and amplitude of auditory evoked potential components during a standard inhibitory gating paradigm were examined. MAM rats exhibited alterations in specific components of the auditory evoked potential in the infralimbic cortex, the core of the nucleus accumbens, mediodorsal thalamic nucleus, and ventral hippocampus in the left hemisphere only. DBS was effective in reversing these evoked deficits in the infralimbic cortex and the mediodorsal thalamic nucleus of MAM-treated rats to levels similar to those observed in control animals. In contrast stimulation did not alter evoked potentials in control rats. No deficits or stimulation-induced alterations were observed in the prelimbic and orbitofrontal cortices, the shell of the nucleus accumbens or ventral tegmental area. These data indicate a normalization of deficits in generating auditory evoked potentials induced by a developmental disruption by acute high frequency, electrical stimulation of the ventral hippocampus. Copyright © 2012 Elsevier B.V. All rights reserved.

Deep brain stimulation of the ventral hippocampus restores deficits in processing of auditory evoked potentials in a rodent developmental disruption model of schizophrenia

PubMed Central

Ewing, Samuel G.; Grace, Anthony A.

2012-01-01

Existing antipsychotic drugs are most effective at treating the positive symptoms of schizophrenia, but their relative efficacy is low and they are associated with considerable side effects. In this study deep brain stimulation of the ventral hippocampus was performed in a rodent model of schizophrenia (MAM-E17) in an attempt to alleviate one set of neurophysiological alterations observed in this disorder. Bipolar stimulating electrodes were fabricated and implanted, bilaterally, into the ventral hippocampus of rats. High frequency stimulation was delivered bilaterally via a custom-made stimulation device and both spectral analysis (power and coherence) of resting state local field potentials and amplitude of auditory evoked potential components during a standard inhibitory gating paradigm were examined. MAM rats exhibited alterations in specific components of the auditory evoked potential in the infralimbic cortex, the core of the nucleus accumbens, mediodorsal thalamic nucleus, and ventral hippocampus in the left hemisphere only. DBS was effective in reversing these evoked deficits in the infralimbic cortex and the mediodorsal thalamic nucleus of MAM-treated rats to levels similar to those observed in control animals. In contrast stimulation did not alter evoked potentials in control rats. No deficits or stimulation-induced alterations were observed in the prelimbic and orbitofrontal cortices, the shell of the nucleus accumbens or ventral tegmental area. These data indicate a normalization of deficits in generating auditory evoked potentials induced by a developmental disruption by acute high frequency, electrical stimulation of the ventral hippocampus. PMID:23269227

Evoked potentials are useful for diagnosis of neuromyelitis optica spectrum disorder.

PubMed

Ohnari, Keiko; Okada, Kazumasa; Takahashi, Toshiyuki; Mafune, Kosuke; Adachi, Hiroaki

2016-05-15

Neuromyelitis optica spectrum disorder (NMOSD) has been differentiated from relapsing-remitting multiple sclerosis (RRMS) by clinical, laboratory, and pathological findings, including the presence of the anti-aquaporin 4 antibody. Measurement of evoked potentials (EPs) is often used for the diagnosis of RRMS, although the possibility of applying EPs to the diagnosis of NMOSD has not been investigated in detail. Eighteen patients with NMOSD and 28 patients with RRMS were included in this study. The patients' neurological symptoms and signs were examined and their EPs were recorded. Characteristic findings were absence of visual evoked potentials and absence of motor evoked potentials in the lower extremities in patients with NMOSD, and a delay in these potentials in patients with RRMS. Most patients with NMOSD did not present abnormal subclinical EPs, whereas many patients with RRMS did. None of the patients with NMOSD showed abnormalities in auditory brainstem responses. NMOSD can be differentiated from RRMS by EP data obtained in the early stages of these diseases. Copyright © 2016 Elsevier B.V. All rights reserved.

SOMATOSENSORY EVOKED POTENTIALS

EPA Science Inventory

Somatosensory evoked potentials (SEPs) have been used by neuroscientists for many years. The versatility of the method is attested to be the differing purposes to which it has been applied. Initially, SEPs were used to uncover basic principles of sensory processing. A casual glan...

A comparison of auditory evoked potentials to acoustic beats and to binaural beats.

PubMed

Pratt, Hillel; Starr, Arnold; Michalewski, Henry J; Dimitrijevic, Andrew; Bleich, Naomi; Mittelman, Nomi

2010-04-01

The purpose of this study was to compare cortical brain responses evoked by amplitude modulated acoustic beats of 3 and 6 Hz in tones of 250 and 1000 Hz with those evoked by their binaural beats counterparts in unmodulated tones to indicate whether the cortical processes involved differ. Event-related potentials (ERPs) were recorded to 3- and 6-Hz acoustic and binaural beats in 2000 ms duration 250 and 1000 Hz tones presented with approximately 1 s intervals. Latency, amplitude and source current density estimates of ERP components to beats-evoked oscillations were determined and compared across beat types, beat frequencies and base (carrier) frequencies. All stimuli evoked tone-onset components followed by oscillations corresponding to the beat frequency, and a subsequent tone-offset complex. Beats-evoked oscillations were higher in amplitude in response to acoustic than to binaural beats, to 250 than to 1000 Hz base frequency and to 3 Hz than to 6 Hz beat frequency. Sources of the beats-evoked oscillations across all stimulus conditions located mostly to left temporal lobe areas. Differences between estimated sources of potentials to acoustic and binaural beats were not significant. The perceptions of binaural beats involve cortical activity that is not different than acoustic beats in distribution and in the effects of beat- and base frequency, indicating similar cortical processing. Copyright 2010 Elsevier B.V. All rights reserved.

Interactions of cervico-ocular and vestibulo-ocular fast-phase signals in the control of eye position in rabbits.

PubMed Central

Barmack, N H; Errico, P; Ferraresi, A; Pettorossi, V E

1989-01-01

1. Eye movements in unanaesthetized rabbits were studied during horizontal neck-proprioceptive stimulation (movement of the body with respect to the fixed head), when this stimulation was given alone and when it was given simultaneously with vestibular stimulation (rotation of the head-body). The effect of neck-proprioceptive stimulation on modifying the anticompensatory fast-phase eye movements (AFPs) evoked by vestibular stimulation was studied with a 'conditioning-test' protocol; the 'conditioning' stimulus was a neck-proprioceptive signal evoked by a step-like change in body position with respect to the head and the 'test' stimulus was a vestibular signal evoked by a step rotation of the head-body. 2. The influence of eye position and direction of slow eye movements on the occurrence of compensatory fast-phase eye movements (CFPs) evoked by neck-proprioceptive stimulation was also examined. 3. The anticompensatory fast phase (AFP) evoked by vestibular stimulation was attenuated by a preceding neck-proprioceptive stimulus which when delivered alone evoked compensatory slow-phase eye movements (CSP) in the same direction as the CSP evoked by vestibular stimulation. Conversely, the vestibularly evoked AFP was potentiated by a neck-proprioceptive stimulus which evoked CSPs opposite to that of vestibularly evoked CSPs. 4. Eccentric initial eye positions increased the probability of occurrence of midline-directed compensatory fast-phase eye movements (CFPs) evoked by appropriate neck-proprioceptive stimulation. 5. The gain of the horizontal cervico-ocular reflex (GHCOR) was measured from the combined changes in eye position resulting from AFPs and CSPs. GHCOR was potentiated during simultaneous vestibular stimulation. This enhancement of GHCOR occurred at neck-proprioceptive stimulus frequencies which, in the absence of conjoint vestibular stimulation, do not evoke CSPs. PMID:2795479

Influence of rotating shift work on visual reaction time and visual evoked potential.

PubMed

R V, Hemamalini; N, Krishnamurthy; A, Saravanan

2014-10-01

The present day life style is changing the circadian rhythm of the body especially in rotating night shift workers. The impact of this prolongs their reaction time. Night shift also interferes with the circadian variation of pupil size which may affect the visual evoked potential. To compare the visual reaction time, visual evoked potential (VEP) in rotating night shift workers & day workers and also to correlate the changes in visual reaction time with visual evoked potential. Forty healthy male security guards & staff (25 - 35 y) who did rotating night shifts at least for six months & 40 d workers (25 - 35 y) who did not do night shift in last two years were involved in the study. Visual reaction time and the latency & amplitude of VEP were recorded. Kolmogorov- Smirnov test for normalcy showed the latencies & amplitude of VEP to be normally distributed. Student's unpaired t test showed significant difference (p<0.05) in the visual time and in the latencies of VEP between night shift & day workers. There was no significant difference in the amplitude of VEP. Night shift workers who are prone to circadian rhythm alteration will have prolonged visual reaction time & visual evoked potential abnormalities. Implementation of Bright Light Therapy would be beneficial to the night shift worker.

Evaluation of afferent pain pathways in adrenomyeloneuropathic patients.

PubMed

Yagüe, Sara; Veciana, Misericordia; Casasnovas, Carlos; Ruiz, Montserrat; Pedro, Jordi; Valls-Solé, Josep; Pujol, Aurora

2018-03-01

Patients with adrenomyeloneuropathy may have dysfunctions of visual, auditory, motor and somatosensory pathways. We thought on examining the nociceptive pathways by means of laser evoked potentials (LEPs), to obtain additional information on the pathophysiology of this condition. In 13 adrenomyeloneuropathic patients we examined LEPs to leg, arm and face stimulation. Normative data were obtained from 10 healthy subjects examined in the same experimental conditions. We also examined brainstem auditory evoked potentials (BAEPs), pattern reversal full-field visual evoked potentials (VEPs), motor evoked potentials (MEPs) and somatosensory evoked potentials (SEPs). Upper and lower limb MEPs and SEPs, as well as BAEPs, were abnormal in all patients, while VEPs were abnormal in 3 of them (23.1%). LEPs revealed abnormalities to stimulation of the face in 4 patients (30.7%), the forearm in 4 patients (30.7%) and the leg in 10 patients (76.9%). The pathologic process of adrenomyeloneuropathy is characterized by a preferential involvement of auditory, motor and somatosensory tracts and less severely of the visual and nociceptive pathways. This non-inflammatory distal axonopathy preferably damages large myelinated spinal tracts but there is also partial involvement of small myelinated fibres. LEPs studies can provide relevant information about afferent pain pathways involvement in adrenomyeloneuropathic patients. Copyright © 2017 International Federation of Clinical Neurophysiology. Published by Elsevier B.V. All rights reserved.

Electropysiologic evaluation of the visual pathway in patients with multiple sclerosis.

PubMed

Rodriguez-Mena, Diego; Almarcegui, Carmen; Dolz, Isabel; Herrero, Raquel; Bambo, Maria P; Fernandez, Javier; Pablo, Luis E; Garcia-Martin, Elena

2013-08-01

To evaluate the ability of visual evoked potentials and pattern electroretinograms (PERG) to detect subclinical axonal damage in patients during the early diagnostic stage of multiple sclerosis (MS). The authors also compared the ability of optical coherence tomography (OCT), PERG, and visual evoked potentials to detect axonal loss in MS patients and correlated the functional and structural properties of the retinal nerve fiber layer. Two hundred twenty-eight eyes of 114 subjects (57 MS patients and 57 age- and sex-matched healthy controls) were included. The visual pathway was evaluated based on functional and structural assessments. All patients underwent a complete ophthalmic examination that included assessment of visual acuity, ocular motility, intraocular pressure, visual field, papillary morphology, OCT, visual evoked potentials, and PERG. Visual evoked potentials (P100 latency and amplitude), PERG (N95 amplitude and N95/P50 ratio), and OCT parameters differed significantly between MS patients and healthy subjects. Moderate significant correlations were found between visual evoked potentials or PERG parameters and OCT measurements. Axonal damage in ganglion cells of the visual pathway can be detected based on structural measures provided by OCT in MS patients and by the N95 component and N95/P50 index of PERG, thus providing good correlation between function and structure.

Premature infants display increased noxious-evoked neuronal activity in the brain compared to healthy age-matched term-born infants.

PubMed

Slater, Rebeccah; Fabrizi, Lorenzo; Worley, Alan; Meek, Judith; Boyd, Stewart; Fitzgerald, Maria

2010-08-15

This study demonstrates that infants who are born prematurely and who have experienced at least 40days of intensive or special care have increased brain neuronal responses to noxious stimuli compared to healthy newborns at the same postmenstrual age. We have measured evoked potentials generated by noxious clinically-essential heel lances in infants born at term (8 infants; born 37-40weeks) and in infants born prematurely (7 infants; born 24-32weeks) who had reached the same postmenstrual age (mean age at time of heel lance 39.2+/-1.2weeks). These noxious-evoked potentials are clearly distinguishable from shorter latency potentials evoked by non-noxious tactile sensory stimulation. While the shorter latency touch potentials are not dependent on the age of the infant at birth, the noxious-evoked potentials are significantly larger in prematurely-born infants. This enhancement is not associated with specific brain lesions but reflects a functional change in pain processing in the brain that is likely to underlie previously reported changes in pain sensitivity in older ex-preterm children. Our ability to quantify and measure experience-dependent changes in infant cortical pain processing will allow us to develop a more rational approach to pain management in neonatal intensive care. Copyright (c) 2010 Elsevier Inc. All rights reserved.

Somatosensory attention identifies both overt and covert awareness in disorders of consciousness.

PubMed

Gibson, Raechelle M; Chennu, Srivas; Fernández-Espejo, Davinia; Naci, Lorina; Owen, Adrian M; Cruse, Damian

2016-09-01

Some patients diagnosed with disorders of consciousness retain sensory and cognitive abilities beyond those apparent from their overt behavior. Characterizing these covert abilities is crucial for diagnosis, prognosis, and medical ethics. This multimodal study investigates the relationship between electroencephalographic evidence for perceptual/cognitive preservation and both overt and covert markers of awareness. Fourteen patients with severe brain injuries were evaluated with an electroencephalographic vibrotactile attention task designed to identify a hierarchy of residual somatosensory and cognitive abilities: (1) somatosensory steady-state evoked responses, (2) bottom-up attention orienting (P3a event-related potential), and (3) top-down attention (P3b event-related potential). Each patient was also assessed with a clinical behavioral scale and 2 functional magnetic resonance imaging assessments of covert command following. Six patients produced only sensory responses, with no evidence of cognitive event-related potentials. A further 8 patients demonstrated reliable bottom-up attention-orienting responses (P3a). No patient showed evidence of top-down attention (P3b). Only those patients who followed commands, whether overtly with behavior or covertly with functional neuroimaging, also demonstrated event-related potential evidence of attentional orienting. Somatosensory attention-orienting event-related potentials differentiated patients who could follow commands from those who could not. Crucially, this differentiation was irrespective of whether command following was evident through overt external behavior, or through covert functional neuroimaging methods. Bedside electroencephalographic methods may corroborate more expensive and challenging methods such as functional neuroimaging, and thereby assist in the accurate diagnosis of awareness. Ann Neurol 2016;80:412-423. © 2016 American Neurological Association.

Recording and assessment of evoked potentials with electrode arrays.

PubMed

Miljković, N; Malešević, N; Kojić, V; Bijelić, G; Keller, T; Popović, D B

2015-09-01

In order to optimize procedure for the assessment of evoked potentials and to provide visualization of the flow of action potentials along the motor systems, we introduced array electrodes for stimulation and recording and developed software for the analysis of the recordings. The system uses a stimulator connected to an electrode array for the generation of evoked potentials, an electrode array connected to the amplifier, A/D converter and computer for the recording of evoked potentials, and a dedicated software application. The method has been tested for the assessment of the H-reflex on the triceps surae muscle in six healthy humans. The electrode array with 16 pads was positioned over the posterior aspect of the thigh, while the recording electrode array with 16 pads was positioned over the triceps surae muscle. The stimulator activated all the pads of the stimulation electrode array asynchronously, while the signals were recorded continuously at all the recording sites. The results are topography maps (spatial distribution of evoked potentials) and matrices (spatial visualization of nerve excitability). The software allows the automatic selection of the lowest stimulation intensity to achieve maximal H-reflex amplitude and selection of the recording/stimulation pads according to predefined criteria. The analysis of results shows that the method provides rich information compared with the conventional recording of the H-reflex with regard the spatial distribution.

Anxiety affects the amplitudes of red and green color-elicited flash visual evoked potentials in humans.

PubMed

Hosono, Yuki; Kitaoka, Kazuyoshi; Urushihara, Ryo; Séi, Hiroyoshi; Kinouchi, Yohsuke

2014-01-01

It has been reported that negative emotional changes and conditions affect the visual faculties of humans at the neural level. On the other hand, the effects of emotion on color perception in particular, which are based on evoked potentials, are unknown. In the present study, we investigated whether different anxiety levels affect the color information processing for each of 3 wavelengths by using flash visual evoked potentials (FVEPs) and State-Trait Anxiety Inventory. In results, significant positive correlations were observed between FVEP amplitudes and state or trait anxiety scores in the long (sensed as red) and middle (sensed as green) wavelengths. On the other hand, short-wavelength-evoked FVEPs were not correlated with anxiety level. Our results suggest that negative emotional conditions may affect color sense processing in humans.

Supramodal representation of emotions.

PubMed

Klasen, Martin; Kenworthy, Charles A; Mathiak, Krystyna A; Kircher, Tilo T J; Mathiak, Klaus

2011-09-21

Supramodal representation of emotion and its neural substrates have recently attracted attention as a marker of social cognition. However, the question whether perceptual integration of facial and vocal emotions takes place in primary sensory areas, multimodal cortices, or in affective structures remains unanswered yet. Using novel computer-generated stimuli, we combined emotional faces and voices in congruent and incongruent ways and assessed functional brain data (fMRI) during an emotional classification task. Both congruent and incongruent audiovisual stimuli evoked larger responses in thalamus and superior temporal regions compared with unimodal conditions. Congruent emotions were characterized by activation in amygdala, insula, ventral posterior cingulate (vPCC), temporo-occipital, and auditory cortices; incongruent emotions activated a frontoparietal network and bilateral caudate nucleus, indicating a greater processing load in working memory and emotion-encoding areas. The vPCC alone exhibited differential reactions to congruency and incongruency for all emotion categories and can thus be considered a central structure for supramodal representation of complex emotional information. Moreover, the left amygdala reflected supramodal representation of happy stimuli. These findings document that emotional information does not merge at the perceptual audiovisual integration level in unimodal or multimodal areas, but in vPCC and amygdala.

High frequency bone conduction auditory evoked potentials in the guinea pig: Assessing cochlear injury after ossicular chain manipulation.

PubMed

Bergin, M J; Bird, P A; Vlajkovic, S M; Thorne, P R

2015-12-01

Permanent high frequency (>4 kHz) sensorineural hearing loss following middle ear surgery occurs in up to 25% of patients. The aetiology of this loss is poorly understood and may involve transmission of supra-physiological forces down the ossicular chain to the cochlea. Investigating the mechanisms of this injury using animal models is challenging, as evaluating cochlear function with evoked potentials is confounded when ossicular manipulation disrupts the normal air conduction (AC) pathway. Bone conduction (BC) using clinical bone vibrators in small animals is limited by poor transducer output at high frequencies sensitive to trauma. The objectives of the present study were firstly to evaluate a novel high frequency bone conduction transducer with evoked auditory potentials in a guinea pig model, and secondly to use this model to investigate the impact of middle ear surgical manipulation on cochlear function. We modified a magnetostrictive device as a high frequency BC transducer and evaluated its performance by comparison with a calibrated AC transducer at frequencies up to 32 kHz using the auditory brainstem response (ABR), compound action potential (CAP) and summating potential (SP). To mimic a middle ear traumatising stimulus, a rotating bur was brought in to contact with the incudomalleal complex and the effect on evoked cochlear potentials was observed. BC-evoked potentials followed the same input-output function pattern as AC potentials for all ABR frequencies. Deterioration in CAP and SP thresholds was observed after ossicular manipulation. It is possible to use high frequency BC to evoke responses from the injury sensitive basal region of the cochlea and so not rely on AC with the potential confounder of conductive hearing loss. Ongoing research explores how these findings evolve over time, and ways in which injury may be reduced and the cochlea protected during middle ear surgery. Copyright © 2015 Elsevier B.V. All rights reserved.

The effects of neck flexion on cerebral potentials evoked by visual, auditory and somatosensory stimuli and focal brain blood flow in related sensory cortices

PubMed Central

2012-01-01

Background A flexed neck posture leads to non-specific activation of the brain. Sensory evoked cerebral potentials and focal brain blood flow have been used to evaluate the activation of the sensory cortex. We investigated the effects of a flexed neck posture on the cerebral potentials evoked by visual, auditory and somatosensory stimuli and focal brain blood flow in the related sensory cortices. Methods Twelve healthy young adults received right visual hemi-field, binaural auditory and left median nerve stimuli while sitting with the neck in a resting and flexed (20° flexion) position. Sensory evoked potentials were recorded from the right occipital region, Cz in accordance with the international 10–20 system, and 2 cm posterior from C4, during visual, auditory and somatosensory stimulations. The oxidative-hemoglobin concentration was measured in the respective sensory cortex using near-infrared spectroscopy. Results Latencies of the late component of all sensory evoked potentials significantly shortened, and the amplitude of auditory evoked potentials increased when the neck was in a flexed position. Oxidative-hemoglobin concentrations in the left and right visual cortices were higher during visual stimulation in the flexed neck position. The left visual cortex is responsible for receiving the visual information. In addition, oxidative-hemoglobin concentrations in the bilateral auditory cortex during auditory stimulation, and in the right somatosensory cortex during somatosensory stimulation, were higher in the flexed neck position. Conclusions Visual, auditory and somatosensory pathways were activated by neck flexion. The sensory cortices were selectively activated, reflecting the modalities in sensory projection to the cerebral cortex and inter-hemispheric connections. PMID:23199306

Transcranial Motor-Evoked Potentials Are More Readily Acquired Than Somatosensory-Evoked Potentials in Children Younger Than 6 Years.

PubMed

McIntyre, Ian W; Francis, Lisa; McAuliffe, John J

2016-01-01

There is a general belief that somatosensory-evoked potentials (SSEPs) are more easily obtained than transcranial motor-evoked potentials (TcMEPs) in children younger than 6 years. We tested this assumption and the assumption that motor-evoked potentials are rarely obtained in children younger than 2 years. The records of all patients who were monitored during surgical procedures between April 1, 2010, and June 30, 2013, were reviewed and those who were younger than 72 months at the time of surgery were identified and analyzed for the rate of obtaining clinically useful SSEPs and motor-evoked potentials. Subgroup analysis was performed by age. A total of 146 patients were identified, 9 had SSEPs without TcMEPs monitored, 117 had both TcMEPs and SSEPs monitored, and the remainder had only electromyographic monitoring. All patients who were to have TcMEPs recorded received a total IV anesthetic. Among the 117 patients who had both SSEPs and TcMEPs monitored, clinically relevant TcMEPs were obtained more frequently than SSEPs (110/117 vs 89/117; χ = 14.82; P = 0.00012). There were significant differences between the rates of obtaining SSEPs and TcMEPs in the 0- to 23-month (P = 0.0038) and 24- to 47-month (P = 0.0056) age groups. Utilization of a double-train stimulation technique facilitated obtaining TcMEPs in the youngest patients. TcMEPs can be obtained more easily than SSEPs in patients younger than 72 months if a permissive anesthetic technique is used. The success rate for obtaining TcMEPs can be further enhanced by the use of a temporal facilitation (double-train) stimulation technique.

Utility of Brainstem Trigeminal Evoked Potentials in Patients With Primary Trigeminal Neuralgia Treated by Microvascular Decompression.

PubMed

Zhu, Jin; Zhang, Xin; Zhao, Hua; Tang, Yin-Da; Ying, Ting-Ting; Li, Shi-Ting

2017-09-01

To investigate the characteristics of brainstem trigeminal evoked potentials (BTEP) waveform in patients with and without trigeminal neuralgia (TN), and to discuss the utility of BTEP in patients with primary TN treated by microvascular decompression (MVD). A retrospective review of 43 patients who underwent BTEP between January 2016 and June 2016, including 33 patients with TN who underwent MVD and 10 patients without TN. Brainstem trigeminal evoked potentials characteristics of TN and non-TN were summarized, in particular to compare the BTEP changes between pre- and post-MVD, and to discover the relationship between BTEP changes and surgical outcome. Brainstem trigeminal evoked potentials can be recorded in patients without trigeminal neuralgia. Abnormal BTEP could be recorded when different branches were stimulated. After decompression, the original W2, W3 disappeared and then replaced by a large wave in most patients, or original wave poorly differentiated improved in some patients, showed as shorter latency and (or) amplitude increased. Brainstem trigeminal evoked potentials waveform of healthy side in patients with trigeminal neuralgia was similar to the waveform of patients without TN. In 3 patients, after decompression the W2, W3 peaks increased, and the latency, duration, IPLD did not change significantly. Until discharge, 87.9% (29/33) of the patients presented complete absence of pain without medication (BNI I) and 93.9% (31/33) had good pain control without medication (BNI I-II). Brainstem trigeminal evoked potentials can reflect the conduction function of the trigeminal nerve to evaluate the functional level of the trigeminal nerve conduction pathway. The improvement and restoration of BTEP waveforms are closely related to the postoperative curative effect.

Steady-state pattern electroretinogram and short-duration transient visual evoked potentials in glaucomatous and healthy eyes.

PubMed

Amarasekera, Dilru C; Resende, Arthur F; Waisbourd, Michael; Puri, Sanjeev; Moster, Marlene R; Hark, Lisa A; Katz, L Jay; Fudemberg, Scott J; Mantravadi, Anand V

2018-01-01

This study evaluates two rapid electrophysiological glaucoma diagnostic tests that may add a functional perspective to glaucoma diagnosis. This study aimed to determine the ability of two office-based electrophysiological diagnostic tests, steady-state pattern electroretinogram and short-duration transient visual evoked potentials, to discern between glaucomatous and healthy eyes. This is a cross-sectional study in a hospital setting. Forty-one patients with glaucoma and 41 healthy volunteers participated in the study. Steady-state pattern electroretinogram and short-duration transient visual evoked potential testing was conducted in glaucomatous and healthy eyes. A 64-bar-size stimulus with both a low-contrast and high-contrast setting was used to compare steady-state pattern electroretinogram parameters in both groups. A low-contrast and high-contrast checkerboard stimulus was used to measure short-duration transient visual evoked potential parameters in both groups. Steady-state pattern electroretinogram parameters compared were MagnitudeD, MagnitudeD/Magnitude ratio, and the signal-to-noise ratio. Short-duration transient visual evoked potential parameters compared were amplitude and latency. MagnitudeD was significantly lower in glaucoma patients when using a low-contrast (P = 0.001) and high-contrast (P < 0.001) 64-bar-size steady-state pattern electroretinogram stimulus. MagnitudeD/Magnitude ratio and SNR were significantly lower in the glaucoma group when using a high-contrast 64-bar-size stimulus (P < 0.001 and P = 0.010, respectively). Short-duration transient visual evoked potential amplitude and latency were not significantly different between the two groups. Steady-state pattern electroretinogram was effectively able to discern between glaucomatous and healthy eyes. Steady-state pattern electroretinogram may thus have a role as a clinically useful electrophysiological diagnostic tool. © 2017 Royal Australian and New Zealand College of Ophthalmologists.

Multifocal Visual Evoked Potential in Eyes With Temporal Hemianopia From Chiasmal Compression: Correlation With Standard Automated Perimetry and OCT Findings.

PubMed

Sousa, Rafael M; Oyamada, Maria K; Cunha, Leonardo P; Monteiro, Mário L R

2017-09-01

To verify whether multifocal visual evoked potential (mfVEP) can differentiate eyes with temporal hemianopia due to chiasmal compression from healthy controls. To assess the relationship between mfVEP, standard automated perimetry (SAP), and Fourier domain-optical coherence tomography (FD-OCT) macular and peripapillary retinal nerve fiber layer (RNFL) thickness measurements. Twenty-seven eyes with permanent temporal visual field (VF) defects from chiasmal compression on SAP and 43 eyes of healthy controls were submitted to mfVEP and FD-OCT scanning. Multifocal visual evoked potential was elicited using a stimulus pattern of 60 sectors and the responses were averaged for the four quadrants and two hemifields. Optical coherence tomography macular measurements were averaged in quadrants and halves, while peripapillary RNFL thickness was averaged in four sectors around the disc. Visual field loss was estimated in four quadrants and each half of the 24-2 strategy test points. Multifocal visual evoked potential measurements in the two groups were compared using generalized estimated equations, and the correlations between mfVEP, VF, and OCT findings were quantified. Multifocal visual evoked potential-measured temporal P1 and N2 amplitudes were significantly smaller in patients than in controls. No significant difference in amplitude was observed for nasal parameters. A significant correlation was found between mfVEP amplitudes and temporal VF loss, and between mfVEP amplitudes and the corresponding OCT-measured macular and RNFL thickness parameters. Multifocal visual evoked potential amplitude parameters were able to differentiate eyes with temporal hemianopia from controls and were significantly correlated with VF and OCT findings, suggesting mfVEP is a useful tool for the detection of visual abnormalities in patients with chiasmal compression.

Rhesus macaque model of chronic opiate dependence and neuro-AIDS: longitudinal assessment of auditory brainstem responses and visual evoked potentials

PubMed Central

Riazi, Mariam; Marcario, Joanne K; Samson, Frank K.; Kenjale, Himanshu; Adany, Istvan; Staggs, Vincent; Ledford, Emily; Marquis, Janet; Narayan, Opendra; Cheney, Paul D.

2013-01-01

Our work characterizes the effects of opiate (morphine) dependence on auditory brainstem and visual evoked responses in a rhesus macaque model of neuro-AIDS utilizing a chronic continuous drug delivery paradigm. The goal of this study was to clarify whether morphine is protective, or if it exacerbates simian immunodeficiency virus (SIV) related systemic and neurological disease. Our model employs a macrophage tropic CD4/CCR5 co-receptor virus, SIVmac239 (R71/E17), which crosses the blood brain barrier shortly after inoculation and closely mimics the natural disease course of human immunodeficiency virus (HIV) infection. The cohort was divided into 3 groups: morphine only, SIV only, and SIV + morphine. Evoked potential (EP) abnormalities in sub-clinically infected macaques were evident as early as eight weeks post-inoculation. Prolongations in EP latencies were observed in SIV-infected macaques across all modalities. Animals with the highest CSF viral loads and clinical disease showed more abnormalities than those with sub-clinical disease, confirming our previous work (Raymond et al, 1998, 1999, 2000). Although some differences were observed in auditory and visual evoked potentials in morphine treated compared to untreated SIV-infected animals, the effects were relatively small and not consistent across evoked potential type. However, morphine treated animals with subclinical disease had a clear tendency toward higher virus loads in peripheral and CNS tissues (Marcario et al., 2008) suggesting that if had been possible to follow all animals to end-stage disease, a clearer pattern of evoked potential abnormality might have emerged. PMID:19283490

Stimulus novelty, task relevance and the visual evoked potential in man

NASA Technical Reports Server (NTRS)

Courchesne, E.; Hillyard, S. A.; Galambos, R.

1975-01-01

The effect of task relevance on P3 (waveform of human evoked potential) waves and the methodologies used to deal with them are outlined. Visual evoked potentials (VEPs) were recorded from normal adult subjects performing in a visual discrimination task. Subjects counted the number of presentations of the numeral 4 which was interposed rarely and randomly within a sequence of tachistoscopically flashed background stimuli. Intrusive, task-irrelevant (not counted) stimuli were also interspersed rarely and randomly in the sequence of 2s; these stimuli were of two types: simples, which were easily recognizable, and novels, which were completely unrecognizable. It was found that the simples and the counted 4s evoked posteriorly distributed P3 waves while the irrelevant novels evoked large, frontally distributed P3 waves. These large, frontal P3 waves to novels were also found to be preceded by large N2 waves. These findings indicate that the P3 wave is not a unitary phenomenon but should be considered in terms of a family of waves, differing in their brain generators and in their psychological correlates.

Investigation of brachial plexus traction lesions by peripheral and spinal somatosensory evoked potentials.

PubMed Central

Jones, S J

1979-01-01

Peripheral, spinal and cortical somatosensory evoked potentials were recorded in 26 patients with unilateral traction injuries of the brachial plexus ganglia. Of 10 cases explored surgically the recordings correctly anticipated the major site of the lesion in eight. PMID:422958

Normalization of auditory evoked potential and visual evoked potential in patients with idiot savant.

PubMed

Chen, X; Zhang, M; Wang, J; Lou, F; Liang, J

1999-03-01

To investigate the variations of auditory evoked potentials (AEP) and visual evoked potentials (VEP) of patients with idiot savant (IS) syndrome. Both AEP and VEP were recorded from 7 patients with IS syndrome, 21 mentally retarded (MR) children without the syndrome and 21 normally age-matched controls, using a Dantec concerto SEEG-16 BEAM instrument. Both AEP and VEP of MR group showed significantly longer latencies (P1 and P2 latencies of AEP, P < 0.01; N1 and N2 latencies of VEP, P < 0.01/0.05), lower P2 amplitudes (P < 0.01) and higher P3 amplitudes (P < 0.01), as compared with normal controls. But none of above-mentioned changes was found with IS group. Almost all MR patients (90.1%) presented P4 component in both AEP and VEP, which was also in sharp contrast with its incidence in other 2 groups (IS: 14.3%; normal controls: 9.5%). Patients with idiot savant syndrome presented normalized AEP and VEP.

[Executive functioning and evoked potentials P300 pre- and post- treatment in attention deficit hyperactivity disorder].

PubMed

Roca, Patricia; Mulas, Fernando; Gandia, Rubén; Ortiz-Sánchez, Pedro; Abad, Luis

2013-02-22

Evoked potentials P300 and the analysis of executive functions have shown their utility in the monitoring of patients with symptoms of attention deficit hyperactivity disorder (ADHD). Neuropsychological profiles and evoked potentials P300 have been analysed for two groups of children with an ADHD treatment with atomoxetine and methylphenidate respectively. Correlations between P300 and the selected neuropsychological parameters are studied, and the differences between basal values and 1 year follow-up are analysed. Two groups were performed: a group of 22 children ADHD in the atomoxetine condition, and a group of 24 children ADHD in the methylphenidate condition. The results show a global improvement of all the parameters, in terms of executive function and P300 values in both, the atomoxetine and the methylphenidate group. Executive functions and evoked potentials P300 reflect an underlying processing and they are very useful in the clinical practice. This exploratory study shows the importance of designing personalized objective variables-based treatments.

Cortico-centric effects of general anesthetics on cerebrocortical evoked potentials.

PubMed

Voss, Logan J; Sleigh, James W

2015-12-01

Despite their ubiquitous use for rendering patients unconscious for surgery, our understanding of how general anesthetics cause hypnosis remains rudimentary at best. Recent years have seen increased interest in "top-down" cortico-centric theories of anesthetic action. The aim of this study was to explore this by investigating direct cortical effects of anesthetics on cerebrocortical evoked potentials in isolated mouse brain slices. Evoked potentials were elicited in cortical layer IV by electrical stimulation of the underlying white matter. The effects of three anesthetics (ketamine, etomidate, and isoflurane) on the amplitude, latency, and slope of short-latency evoked potentials were quantified. The N2/P3/N4 potentials–which represent the early cortical response–were enhanced by etomidate (increased P3-N4 slope, P <0.01), maintained by ketamine, and reduced by isoflurane (lower N2/P3 amplitude, P <0.01). These effects closely resemble those seen in vivo for the same drugs and point to a cortical mechanism independent of effects on subcortical structures such as the thalamus.

An indirect component in the evoked compound action potential of the vagal nerve.

PubMed

Ordelman, Simone C M A; Kornet, Lilian; Cornelussen, Richard; Buschman, Hendrik P J; Veltink, Peter H

2010-12-01

The vagal nerve plays a vital role in the regulation of the cardiovascular system. It not only regulates the heart but also sends sensory information from the heart back to the brain. We hypothesize that the evoked vagal nerve compound action potential contains components that are indirect via the brain stem or coming via the neural network on the heart. In an experimental study of 15 pigs, we identified four components in the evoked compound action potentials. The fourth component was found to be an indirect component, which came from the periphery. The latency of the indirect component increased when heart rate and contractility were decreased by burst stimulation (P = 0.01; n = 7). When heart rate and contractility were increased by dobutamine administration, the latency of the indirect component decreased (P = 0.01; n = 9). This showed that the latency of the indirect component of the evoked compound action potentials may relate to the state of the cardiovascular system.

Lack of habituation of evoked visual potentials in analytic information processing style: evidence in healthy subjects.

PubMed

Buonfiglio, Marzia; Toscano, M; Puledda, F; Avanzini, G; Di Clemente, L; Di Sabato, F; Di Piero, V

2015-03-01

Habituation is considered one of the most basic mechanisms of learning. Habituation deficit to several sensory stimulations has been defined as a trait of migraine brain and also observed in other disorders. On the other hand, analytic information processing style is characterized by the habit of continually evaluating stimuli and it has been associated with migraine. We investigated a possible correlation between lack of habituation of evoked visual potentials and analytic cognitive style in healthy subjects. According to Sternberg-Wagner self-assessment inventory, 15 healthy volunteers (HV) with high analytic score and 15 HV with high global score were recruited. Both groups underwent visual evoked potentials recordings after psychological evaluation. We observed significant lack of habituation in analytical individuals compared to global group. In conclusion, a reduced habituation of visual evoked potentials has been observed in analytic subjects. Our results suggest that further research should be undertaken regarding the relationship between analytic cognitive style and lack of habituation in both physiological and pathophysiological conditions.

Synchronized Astrocytic Ca2+ Responses in Neurovascular Coupling during Somatosensory Stimulation and for the Resting State.

PubMed

Gu, Xiaochun; Chen, Wei; Volkow, Nora D; Koretsky, Alan P; Du, Congwu; Pan, Yingtian

2018-06-26

The role of astrocytes in neurovascular coupling (NVC) is unclear. Here, we applied a multimodality imaging approach to concomitantly measure synchronized neuronal or astrocytic Ca 2+ and hemodynamic changes in the mouse somatosensory cortex at rest and during sensory electrical stimulation. Strikingly, we found that low-frequency stimulation (0.3-1 Hz), which consistently evokes fast neuronal Ca 2+ transients (6.0 ± 2.7 ms latency) that always precede vascular responses, does not always elicit astrocytic Ca 2+ transients (313 ± 65 ms latency). However, the magnitude of the hemodynamic response is increased when astrocytic transients occur, suggesting a facilitatory role of astrocytes in NVC. High-frequency stimulation (5-10 Hz) consistently evokes a large, delayed astrocytic Ca 2+ accumulation (3.48 ± 0.09 s latency) that is temporarily associated with vasoconstriction, suggesting a role for astrocytes in resetting NVC. At rest, neuronal, but not astrocytic, Ca 2+ fluctuations correlate with hemodynamic low-frequency oscillations. Taken together, these results support a role for astrocytes in modulating, but not triggering, NVC. Copyright © 2018 The Authors. Published by Elsevier Inc. All rights reserved.

Activation of Mechanosensitive Transient Receptor Potential/Piezo Channels in Odontoblasts Generates Action Potentials in Cocultured Isolectin B4-negative Medium-sized Trigeminal Ganglion Neurons.

PubMed

Sato, Masaki; Ogura, Kazuhiro; Kimura, Maki; Nishi, Koichi; Ando, Masayuki; Tazaki, Masakazu; Shibukawa, Yoshiyuki

2018-06-01

Various stimuli to the dentin surface elicit dentinal pain by inducing dentinal fluid movement causing cellular deformation in odontoblasts. Although odontoblasts detect deformation by the activation of mechanosensitive ionic channels, it is still unclear whether odontoblasts are capable of establishing neurotransmission with myelinated A delta (Aδ) neurons. Additionally, it is still unclear whether these neurons evoke action potentials by neurotransmitters from odontoblasts to mediate sensory transduction in dentin. Thus, we investigated evoked inward currents and evoked action potentials form trigeminal ganglion (TG) neurons after odontoblast mechanical stimulation. We used patch clamp recordings to identify electrophysiological properties and record evoked responses in TG neurons. We classified TG cells into small-sized and medium-sized neurons. In both types of neurons, we observed voltage-dependent inward currents. The currents from medium-sized neurons showed fast inactivation kinetics. When mechanical stimuli were applied to odontoblasts, evoked inward currents were recorded from medium-sized neurons. Antagonists for the ionotropic adenosine triphosphate receptor (P2X 3 ), transient receptor potential channel subfamilies, and Piezo1 channel significantly inhibited these inward currents. Mechanical stimulation to odontoblasts also generated action potentials in the isolectin B 4 -negative medium-sized neurons. Action potentials in these isolectin B 4 -negative medium-sized neurons showed a short duration. Overall, electrophysiological properties of neurons indicate that the TG neurons with recorded evoked responses after odontoblast mechanical stimulation were myelinated Aδ neurons. Odontoblasts established neurotransmission with myelinated Aδ neurons via P2X 3 receptor activation. The results also indicated that mechanosensitive TRP/Piezo1 channels were functionally expressed in odontoblasts. The activation of P2X 3 receptors induced an action potential in the Aδ neurons, underlying a sensory generation mechanism of dentinal pain. Copyright © 2018 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

Source analysis of short and long latency vestibular-evoked potentials (VsEPs) produced by left vs. right ear air-conducted 500 Hz tone pips.

PubMed

Todd, N P M; Paillard, A C; Kluk, K; Whittle, E; Colebatch, J G

2014-06-01

Todd et al. (2014) have recently demonstrated the presence of vestibular dependent changes both in the morphology and in the intensity dependence of auditory evoked potentials (AEPs) when passing through the vestibular threshold as determined by vestibular evoked myogenic potentials (VEMPs). In this paper we extend this work by comparing left vs. right ear stimulation and by conducting a source analysis of the resulting evoked potentials of short and long latency. Ten healthy, right-handed subjects were recruited and evoked potentials were recorded to both left- and right-ear sound stimulation, above and below vestibular threshold. Below VEMP threshold, typical AEPs were recorded, consisting of mid-latency (MLR) waves Na and Pa followed by long latency AEPs (LAEPs) N1 and P2. In the supra-threshold condition, the expected changes in morphology were observed, consisting of: (1) short-latency vestibular evoked potentials (VsEPs) which have no auditory correlate, i.e. the ocular VEMP (OVEMP) and inion response related potentials; (2) a later deflection, labelled N42/P52, followed by the LAEPs N1 and P2. Statistical analysis of the vestibular dependent responses indicated a contralateral effect for inion related short-latency responses and a left-ear/right-hemisphere advantage for the long-latency responses. Source analysis indicated that the short-latency effects may be mediated by a contralateral projection to left cerebellum, while the long-latency effects were mediated by a contralateral projection to right cingulate cortex. In addition we found evidence of a possible vestibular contribution to the auditory T-complex in radial temporal lobe sources. These last results raise the possibility that acoustic activation of the otolith organs could potentially contribute to auditory processing. Copyright © 2014 The Authors. Published by Elsevier B.V. All rights reserved.

Low-frequency rTMS inhibitory effects in the primary motor cortex: Insights from TMS-evoked potentials.

PubMed

Casula, Elias P; Tarantino, Vincenza; Basso, Demis; Arcara, Giorgio; Marino, Giuliana; Toffolo, Gianna Maria; Rothwell, John C; Bisiacchi, Patrizia S

2014-09-01

The neuromodulatory effects of repetitive transcranial magnetic stimulation (rTMS) have been mostly investigated by peripheral motor-evoked potentials (MEPs). New TMS-compatible EEG systems allow a direct investigation of the stimulation effects through the analysis of TMS-evoked potentials (TEPs). We investigated the effects of 1-Hz rTMS over the primary motor cortex (M1) of 15 healthy volunteers on TEP evoked by single pulse TMS over the same area. A second experiment in which rTMS was delivered over the primary visual cortex (V1) of 15 healthy volunteers was conducted to examine the spatial specificity of the effects. Single-pulse TMS evoked four main components: P30, N45, P60 and N100. M1-rTMS resulted in a significant decrease of MEP amplitude and in a significant increase of P60 and N100 amplitude. There was no effect after V1-rTMS. 1-Hz rTMS appears to increase the amount of inhibition following a TMS pulse, as demonstrated by the higher N100 and P60, which are thought to originate from GABAb-mediated inhibitory post-synaptic potentials. Our results confirm the reliability of the TMS-evoked N100 as a marker of cortical inhibition and provide insight into the neuromodulatory effects of 1-Hz rTMS. The present finding could be of relevance for therapeutic and diagnostic purposes. Copyright © 2014 Elsevier Inc. All rights reserved.

[Evoked potentials extraction based on cross-talk resistant adaptive noise cancellation].

PubMed

Zeng, Qingning; Li, Ling; Liu, Qinghua; Yao, Dezhong

2004-06-01

As Evoked Potentials are much lower in amplitude with respect to the on-going EEC, many trigger-related signals are needed for common averaging technique to enable the extraction of single-trail evoked potentials (EP). How to acquire EP through fewer evocations is an important research project. This paper proposes a cross-talk resistant adaptive noise cancellation method to extract EP. Together with the use of filtering technique and the common averaging technique, the present method needs much less evocations to acquire EP signals. According to the simulating experiment, it needs only several evocations or even only one evocation to get EP signals in good quality.

Effect of mechanical tactile noise on amplitude of visual evoked potentials: multisensory stochastic resonance.

PubMed

Méndez-Balbuena, Ignacio; Huidobro, Nayeli; Silva, Mayte; Flores, Amira; Trenado, Carlos; Quintanar, Luis; Arias-Carrión, Oscar; Kristeva, Rumyana; Manjarrez, Elias

2015-10-01

The present investigation documents the electrophysiological occurrence of multisensory stochastic resonance in the human visual pathway elicited by tactile noise. We define multisensory stochastic resonance of brain evoked potentials as the phenomenon in which an intermediate level of input noise of one sensory modality enhances the brain evoked response of another sensory modality. Here we examined this phenomenon in visual evoked potentials (VEPs) modulated by the addition of tactile noise. Specifically, we examined whether a particular level of mechanical Gaussian noise applied to the index finger can improve the amplitude of the VEP. We compared the amplitude of the positive P100 VEP component between zero noise (ZN), optimal noise (ON), and high mechanical noise (HN). The data disclosed an inverted U-like graph for all the subjects, thus demonstrating the occurrence of a multisensory stochastic resonance in the P100 VEP. Copyright © 2015 the American Physiological Society.

Disturbances of stem circumnutations evoked by wound-induced variation potentials in Helianthus annuus L.

PubMed

Stolarz, Maria; Dziubińska, Halina; Krupa, Maciej; Buda, Agnieszka; Trebacz, Kazimierz; Zawadzki, Tadeusz

2003-01-01

The relationship between evoked electrical activity and stem movements in three-week old sunflowers was demonstrated. Electrical potential changes (recorded by Ag/AgCl extracellular electrodes) and time-lapse images (from a top view camera) were recorded and analyzed. A heat stimulus applied to the tip of one of the second pair of leaves evoked a variation potential, transmitted basipetally along one side of the stem. After stimulation, disturbances of circumnutations occurred. They included: changes in the period, disorders in the elliptical shape, and, in some cases, reversion of direction (of movement). We suggest that asymmetrically propagated variation potential induces asymmetric stem shrinking and bending, which strongly disturbs circumnutations. Our results confirm the involvement of electrical potential changes in the mechanism of stem nutations.

WITHIN-SESSION CHANGES IN PEAK N160 AMPLITUDE OF FLASH EVOKED POTENTIALS IN RATS

EPA Science Inventory

The negative peak occurring approximately 160 msec after stimulation (peak N 160) flash evoked potentials (FEPS) of rats changes with repeated testing. abituation, sensitization, and arousal have all been invoked to explain these changes, but few studies have directly tested thes...

Emotion regulation and mania risk: Differential responses to implicit and explicit cues to regulate.

PubMed

Ajaya, Yatrika; Peckham, Andrew D; Johnson, Sheri L

2016-03-01

People prone to mania use emotion regulation (ER) strategies well when explicitly coached to do so in laboratory settings, but they find these strategies ineffective in daily life. We hypothesized that, compared with control participants, mania-prone people would show ER deficits when they received implicit, but not explicit, cues to use ER. Undergraduates (N = 66) completed the Hypomanic Personality Scale (HPS) and were randomly assigned to one of three experimental conditions: automatic ER (scrambled sentence primes), deliberate ER (verbal instructions), or control (no priming or instructions to use ER). Then, participants played a videogame designed to evoke anger. Emotion responses were measured with a multi-modal assessment of self-reported affect, psychophysiology, and facial expressions. Respiratory sinus arrhythmia (RSA) was used to index ER. The videogame effectively elicited subjective anger, angry facial expressions, and heart rate increases when keys malfunctioned. As hypothesized, persons who were more mania prone showed greater RSA increases in the deliberate ER condition than in the automatic or control conditions. One potential limitation is the use of an analog sample. Findings suggest that those at risk for mania require more explicit instruction to engage ER effectively. Copyright © 2015 Elsevier Ltd. All rights reserved.

Recovery of TES-MEPs during surgical decompression of the spine: a case series of eight patients.

PubMed

Visser, Jetze; Verra, Wiebe C; Kuijlen, Jos M; Horsting, Philip P; Journée, Henricus L

2014-12-01

This study aimed to illustrate the recovery of transcranial electrical stimulation motor evoked potentials during surgical decompression of the spinal cord in patients with impaired motor function preoperatively. Specific attention was paid to the duration of neurologic symptoms before surgery and the postoperative clinical recovery. A case series of eight patients was selected from a cohort of 74 patients that underwent spine surgery. The selected patients initially had low or absent transcranial electrical stimulation motor evoked potentials followed by a significant increase after surgical decompression of the spinal cord. A significant intraoperative increase in amplitude of motor evoked potentials was detected after decompression of the spinal cord or cauda equina in patients suffering from spinal canal stenosis (n = 2), extradural meningioma (n = 3), or a herniated nucleus polposus (n = 3). This was related to an enhanced neurologic outcome only if patients (n = 6) had a short onset (less than ½ year) of neurologic impairment before surgery. In patients with a short onset of neurologic impairment because of compression of the spinal cord or caudal fibers, an intraoperative recovery of transcranial electrical stimulation motor evoked potentials can indicate an improvement of motor function postoperatively. Therefore, transcranial electrical stimulation motor evoked potentials can be considered as a useful tool to the surgeon to monitor the quality of decompression of the spinal cord.

Normalization of sensorimotor integration by repetitive transcranial magnetic stimulation in cervical dystonia.

PubMed

Zittel, S; Helmich, R C; Demiralay, C; Münchau, A; Bäumer, T

2015-08-01

Previous studies indicated that sensorimotor integration and plasticity of the sensorimotor system are impaired in dystonia patients. We investigated motor evoked potential amplitudes and short latency afferent inhibition to examine corticospinal excitability and cortical sensorimotor integration, before and after inhibitory 1 Hz repetitive transcranial magnetic stimulation over primary sensory and primary motor cortex in patients with cervical dystonia (n = 12). Motor evoked potentials were recorded from the right first dorsal interosseous muscle after application of unconditioned transcranial magnetic test stimuli and after previous conditioning electrical stimulation of the right index finger at short interstimulus intervals of 25, 30 and 40 ms. Results were compared to a group of healthy age-matched controls. At baseline, motor evoked potential amplitudes did not differ between groups. Short latency afferent inhibition was reduced in cervical dystonia patients compared to healthy controls. Inhibitory 1 Hz sensory cortex repetitive transcranial magnetic stimulation but not motor cortex repetitive transcranial magnetic stimulation increased motor evoked potential amplitudes in cervical dystonia patients. Additionally, both 1 Hz repetitive transcranial magnetic stimulation over primary sensory and primary motor cortex normalized short latency afferent inhibition in these patients. In healthy subjects, sensory repetitive transcranial magnetic stimulation had no influence on motor evoked potential amplitudes and short latency afferent inhibition. Plasticity of sensorimotor circuits is altered in cervical dystonia patients.

Analysis of electrically evoked compound action potential of the auditory nerve in children with bilateral cochlear implants.

PubMed

Caldas, Fernanda Ferreira; Cardoso, Carolina Costa; Barreto, Monique Antunes de Souza Chelminski; Teixeira, Marina Santos; Hilgenberg, Anacléia Melo da Silva; Serra, Lucieny Silva Martins; Bahmad Junior, Fayez

2016-01-01

The cochlear implant device has the capacity to measure the electrically evoked compound action potential of the auditory nerve. The neural response telemetry is used in order to measure the electrically evoked compound action potential of the auditory nerve. To analyze the electrically evoked compound action potential, through the neural response telemetry, in children with bilateral cochlear implants. This is an analytical, prospective, longitudinal, historical cohort study. Six children, aged 1-4 years, with bilateral cochlear implant were assessed at five different intervals during their first year of cochlear implant use. There were significant differences in follow-up time (p=0.0082) and electrode position (p=0.0019) in the T-NRT measure. There was a significant difference in the interaction between time of follow-up and electrode position (p=0.0143) when measuring the N1-P1 wave amplitude between the three electrodes at each time of follow-up. The electrically evoked compound action potential measurement using neural response telemetry in children with bilateral cochlear implants during the first year of follow-up was effective in demonstrating the synchronized bilateral development of the peripheral auditory pathways in the studied population. Copyright © 2015 Associação Brasileira de Otorrinolaringologia e Cirurgia Cérvico-Facial. Published by Elsevier Editora Ltda. All rights reserved.

Oesophageal sensation assessed by electrical stimuli and brain evoked potentials--a new model for visceral nociception.

PubMed Central

Frøbert, O; Arendt-Nielsen, L; Bak, P; Funch-Jensen, P; Bagger, J P

1995-01-01

Sensory thresholds and brain evoked potentials were determined in 12 healthy volunteers using electrical stimulation of the oesophagus 28 and 38 cm from the nares. The peaks of the evoked potentials were designated N for negative deflections and P for positive. Continuous electrical stimulation (40 Hz) at the 38 cm position resembled heartburn (five of 12 subjects) while non-specific ('electrical') sensations were provoked at 28 cm (10 of 12). Thresholds of sensation and of pain were lower at the initial than the second determination, but did not differ with respect to stimulation site. The pain summation threshold to repeated stimuli (2 Hz, 5 stimuli) was determined for the first time in a viscus. This threshold was lower than the pain threshold to single stimuli at 38 cm (p < 0.02). Evoked potential latencies did not change significantly over a six month period while the N1/P2 amplitude was higher at the first measurement (p < 0.05). P1 and N1 latencies were significantly shorter 38 cm (medians 100 and 141 ms) than 28 cm from the nares (102 and 148 ms) (p = 0.04 and p = 0.008). Electrical stimulation of the oesophagus may serve as a human experimental model for visceral pain. Longer evoked potential latencies from the proximal compared with distal stimulations provide new information about the sensory pathways of the oesophagus. PMID:8549932

Ultrafast Narrow Band Modulation of VCSELs

NASA Technical Reports Server (NTRS)

Ning, Cun-Zheng; Biegel, Bryan A. (Technical Monitor)

2002-01-01

Multimode beating was greatly enhanced by taking output from part (e.g., half) of the output facet. Simpler sources of microwaves and millimeter waves of various frequencies were generated by varying the VCSEL diameter in a single multimode VCSEL our coupling of a few VCSELs. Breathing frequency in multi-mode operations affects modulation response and bandwidth. Optimizing RO frequency and mode beating frequency could potentially expand bandwidths suitable for wide band digital communications.

Effect of caffeine on vestibular evoked myogenic potential: a systematic review with meta-analysis.

PubMed

Souza, Maria Eduarda Di Cavalcanti Alves de; Costa, Klinger Vagner Teixeira da; Menezes, Pedro de Lemos

2017-12-24

Caffeine can be considered the most consumed drug by adults worldwide, and can be found in several foods, such as chocolate, coffee, tea, soda and others. Overall, caffeine in moderate doses, results in increased physical and intellectual productivity, increases the capacity of concentration and reduces the time of reaction to sensory stimuli. On the other hand, high doses can cause noticeable signs of mental confusion and error induction in intellectual tasks, anxiety, restlessness, muscle tremors, tachycardia, labyrinthine changes, and tinnitus. Considering that the vestibular evoked myogenic potential is a clinical test that evaluates the muscular response of high intensity auditory stimulation, the present systematic review aimed to analyze the effects of caffeine on vestibular evoked myogenic potential. This study consisted of the search of the following databases: MEDLINE, CENTRAL, ScienceDirect, Scopus, Web of Science, LILACS, SciELO and ClinicalTrials.gov. Additionally, the gray literature was also searched. The search strategy included terms related to intervention (caffeine or coffee consumption) and the primary outcome (vestibular evoked myogenic potential). Based on the 253 potentially relevant articles identified through the database search, only two full-text publications were retrieved for further evaluation, which were maintained for qualitative analysis. Analyzing the articles found, caffeine has no effect on vestibular evoked myogenic potential in normal individuals. Copyright © 2017 Associação Brasileira de Otorrinolaringologia e Cirurgia Cérvico-Facial. Published by Elsevier Editora Ltda. All rights reserved.

Waiting for the evidence: VEMP testing and the ability to differentiate utricular versus saccular function.

PubMed

Welgampola, Miriam S; Carey, John P

2010-08-01

The advent of cervical vestibular evoked myogenic potentials (CVEMPs) marked a milestone in clinical vestibular testing because they provided a simple means of assessing human otolith function. The availability of air-conducted (AC) sound and bone-conducted vibration (BCV) to evoke CVEMPs and development of a new technique of recording ocular vestibular-evoked myogenic potentials (OVEMPs) have increased the complexity of this simple test, yet extended its diagnostic capabilities. Here we highlight the evidence-based assumptions that guide interpretation of AC sound- and BCV-evoked VEMPs and the gaps in VEMP research thus far. Copyright (c) 2010 American Academy of Otolaryngology-Head and Neck Surgery Foundation. Published by Mosby, Inc. All rights reserved.

Effect of ischaemia on somatosensory evoked potentials in diabetic patients.

PubMed Central

López-Alburquerque, T; García Miguel, A; Ruiz Ezquerro, J J; de Portugal Alvarez, J

1987-01-01

The nerve action potential at the elbow and somatosensory evoked potentials (SEPs) at the scalp were recorded over 30 minutes of tourniquet-induced limb ischaemia in 10 diabetic patients and 10 controls. According to the SEP changes, an increased resistance to nerve ischaemia in diabetic patients was observed. The pathways involved in SEP conduction are discussed. PMID:3585354

Ghrelin potentiates cardiac reactivity to stress by modulating sympathetic control and beta-adrenergic response.

PubMed

Camargo-Silva, Gabriel; Turones, Larissa Córdova; da Cruz, Kellen Rosa; Gomes, Karina Pereira; Mendonça, Michelle Mendanha; Nunes, Allancer; de Jesus, Itamar Guedes; Colugnati, Diego Basile; Pansani, Aline Priscila; Pobbe, Roger Luis Henschel; Santos, Robson; Fontes, Marco Antônio Peliky; Guatimosim, Silvia; de Castro, Carlos Henrique; Ianzer, Danielle; Ferreira, Reginaldo Nassar; Xavier, Carlos Henrique

2018-03-01

Prior evidence indicates that ghrelin is involved in the integration of cardiovascular functions and behavioral responses. Ghrelin actions are mediated by the growth hormone secretagogue receptor subtype 1a (GHS-R1a), which is expressed in peripheral tissues and central areas involved in the control of cardiovascular responses to stress. In the present study, we assessed the role of ghrelin - GHS-R1a axis in the cardiovascular reactivity to acute emotional stress in rats. Ghrelin potentiated the tachycardia evoked by restraint and air jet stresses, which was reverted by GHS-R1a blockade. Evaluation of the autonomic balance revealed that the sympathetic branch modulates the ghrelin-evoked positive chronotropy. In isolated hearts, the perfusion with ghrelin potentiated the contractile responses caused by stimulation of the beta-adrenergic receptor, without altering the amplitude of the responses evoked by acetylcholine. Experiments in isolated cardiomyocytes revealed that ghrelin amplified the increases in calcium transient changes evoked by isoproterenol. Taken together, our results indicate that the Ghrelin-GHS-R1a axis potentiates the magnitude of stress-evoked tachycardia by modulating the autonomic nervous system and peripheral mechanisms, strongly relying on the activation of cardiac calcium transient and beta-adrenergic receptors. Copyright © 2018 Elsevier Inc. All rights reserved.

TRPM2 activation by cyclic ADP-ribose at body temperature is involved in insulin secretion

PubMed Central

Togashi, Kazuya; Hara, Yuji; Tominaga, Tomoko; Higashi, Tomohiro; Konishi, Yasunobu; Mori, Yasuo; Tominaga, Makoto

2006-01-01

There are eight thermosensitive TRP (transient receptor potential) channels in mammals, and there might be other TRP channels sensitive to temperature stimuli. Here, we demonstrate that TRPM2 can be activated by exposure to warm temperatures (>35°C) apparently via direct heat-evoked channel gating. β-NAD+- or ADP-ribose-evoked TRPM2 activity is robustly potentiated at elevated temperatures. We also show that, even though cyclic ADP-ribose (cADPR) does not activate TRPM2 at 25°C, co-application of heat and intracellular cADPR dramatically potentiates TRPM2 activity. Heat and cADPR evoke similar responses in rat insulinoma RIN-5F cells, which express TRPM2 endogenously. In pancreatic islets, TRPM2 is coexpressed with insulin, and mild heating of these cells evokes increases in both cytosolic Ca2+ and insulin release, which is KATP channel-independent and protein kinase A-mediated. Heat-evoked responses in both RIN-5F cells and pancreatic islets are significantly diminished by treatment with TRPM2-specific siRNA. These results identify TRPM2 as a potential molecular target for cADPR, and suggest that TRPM2 regulates Ca2+ entry into pancreatic β-cells at body temperature depending on the production of cADPR-related molecules, thereby regulating insulin secretion. PMID:16601673

Segmental somatosensory-evoked potentials as a diagnostic tool in chronic inflammatory demyelinating polyneuropathies, and other sensory neuropathies.

PubMed

Koutlidis, R M; Ayrignac, X; Pradat, P-F; Le Forestier, N; Léger, J-M; Salachas, F; Maisonobe, T; Fournier, E; Viala, K

2014-09-01

Somatosensory-evoked potentials with segmental recordings were performed with the aim of distinguishing chronic inflammatory demyelinating polyneuropathy from other sensory neuropathies. Four groups of 20 subjects each corresponded to patients with (1) possible sensory chronic inflammatory demyelinating polyneuropathy, (2) patients with sensory polyneuropathy of unknown origin, (3) patients with amyotrophic lateral sclerosis and (4) normal subjects. The patients selected for this study had preserved sensory potentials on electroneuromyogram and all waves were recordable in evoked potentials. Somatosensory-evoked potentials evaluations were carried out by stimulation of the posterior tibial nerve at the ankle, recording peripheral nerve potential in the popliteal fossa, radicular potential and spinal potential at the L4-L5 and T12 levels, and cortical at C'z, with determination of distal conduction time, proximal and radicular conduction time and central conduction time. In the group of chronic inflammatory demyelinating polyneuropathy, 80% of patients had abnormal conduction in the N8-N22 segment and 95% had abnormal N18-N22 conduction time. In the group of neuropathies, distal conduction was abnormal in most cases, whereas 60% of patients had no proximal abnormality. None of the patients in the group of amyotrophic lateral sclerosis had an abnormal N18-N22 conduction time. Somatosensory-evoked potentials with segmental recording can be used to distinguish between atypical sensory chronic inflammatory demyelinating polyneuropathy and other sensory neuropathies, at the early stage of the disease. Graphical representation of segmental conduction times provides a rapid and accurate visualization of the profile of each patient. Copyright © 2014 Elsevier Masson SAS. All rights reserved.

Correlation analysis of the long latency auditory evoked potential N2 and cognitive P3 with the level of lead poisoning in children

PubMed Central

Alvarenga, Kátia de Freitas; Alvarez Bernardez-Braga, Gabriela Rosito; Zucki, Fernanda; Duarte, Josilene Luciene; Lopes, Andrea Cintra; Feniman, Mariza Ribeiro

2013-01-01

Summary Introduction: The effects of lead on children's health have been widely studied. Aim: To analyze the correlation between the long latency auditory evoked potential N2 and cognitive P3 with the level of lead poisoning in Brazilian children. Methods: This retrospective study evaluated 20 children ranging in age from 7 to 14 years at the time of audiological and electrophysiological evaluations. We performed periodic surveys of the lead concentration in the blood and basic audiological evaluations. Furthermore, we studied the auditory evoked potential long latency N2 and cognitive P3 by analyzing the absolute latency of the N2 and P3 potentials and the P3 amplitude recorded at Cz. At the time of audiological and electrophysiological evaluations, the average concentration of lead in the blood was less than 10 ug/dL. Results: In conventional audiologic evaluations, all children had hearing thresholds below 20 dBHL for the frequencies tested and normal tympanometry findings; the auditory evoked potential long latency N2 and cognitive P3 were present in 95% of children. No significant correlations were found between the blood lead concentration and latency (p = 0.821) or amplitude (p = 0.411) of the P3 potential. However, the latency of the N2 potential increased with the concentration of lead in the blood, with a significant correlation (p = 0.030). Conclusion: Among Brazilian children with low lead exposure, a significant correlation was found between blood lead levels and the average latency of the auditory evoked potential long latency N2; however, a significant correlation was not observed for the amplitude and latency of the cognitive potential P3. PMID:25991992

Brainstem Auditory Evoked Potential Study in Children with Autistic Disorder.

ERIC Educational Resources Information Center

Wong, Virginia; Wong, Sik Nin

1991-01-01

Brainstem auditory evoked potentials were compared in 109 children with infantile autism, 38 with autistic condition, 19 with mental retardation, and 20 normal children. Children with infantile autism or autistic condition had significantly longer brainstem transmission time than normal children suggesting neurological damage as the basis of…

Intelligence and Complexity of the Averaged Evoked Potential: An Attentional Theory.

ERIC Educational Resources Information Center

Bates, Tim; And Others

1995-01-01

A study measuring average evoked potentials in 21 college students finds that intelligence test scores correlate significantly with the difference between string length in attended and nonattended conditions, a finding that suggests that previous inconsistencies in reporting string length-intelligence correlations may have resulted from confound…

Implementation of a microprocessor-based visual-evoked cortical potential recording and analysis system.

PubMed

Wilson, A; Fram, D; Sistar, J

1981-06-01

An Imsai 8080 microcomputer is being used to simultaneously generate a color graphics stimulus display and to record visual-evoked cortical potentials. A brief description of the hardware and software developed for this system is presented. Data storage and analysis techniques are also discussed.

Neural Dynamics Underlying Event-Related Potentials

NASA Technical Reports Server (NTRS)

Shah, Ankoor S.; Bressler, Steven L.; Knuth, Kevin H.; Ding, Ming-Zhou; Mehta, Ashesh D.; Ulbert, Istvan; Schroeder, Charles E.

2003-01-01

There are two opposing hypotheses about the brain mechanisms underlying sensory event-related potentials (ERPs). One holds that sensory ERPs are generated by phase resetting of ongoing electroencephalographic (EEG) activity, and the other that they result from signal averaging of stimulus-evoked neural responses. We tested several contrasting predictions of these hypotheses by direct intracortical analysis of neural activity in monkeys. Our findings clearly demonstrate evoked response contributions to the sensory ERP in the monkey, and they suggest the likelihood that a mixed (Evoked/Phase Resetting) model may account for the generation of scalp ERPs in humans.

Automated cortical auditory evoked potentials threshold estimation in neonates.

PubMed

Oliveira, Lilian Sanches; Didoné, Dayane Domeneghini; Durante, Alessandra Spada

2018-02-02

The evaluation of Cortical Auditory Evoked Potential has been the focus of scientific studies in infants. Some authors have reported that automated response detection is effective in exploring these potentials in infants, but few have reported their efficacy in the search for thresholds. To analyze the latency, amplitude and thresholds of Cortical Auditory Evoked Potential using an automatic response detection device in a neonatal population. This is a cross-sectional, observational study. Cortical Auditory Evoked Potentials were recorded in response to pure-tone stimuli of the frequencies 500, 1000, 2000 and 4000Hz presented in an intensity range between 0 and 80dB HL using a single channel recording. P1 was performed in an exclusively automated fashion, using Hotelling's T 2 statistical test. The latency and amplitude were obtained manually by three examiners. The study comprised 39 neonates up to 28 days old of both sexes with presence of otoacoustic emissions and no risk factors for hearing loss. With the protocol used, Cortical Auditory Evoked Potential responses were detected in all subjects at high intensity and thresholds. The mean thresholds were 24.8±10.4dB NA, 25±9.0dB NA, 28±7.8dB NA and 29.4±6.6dB HL for 500, 1000, 2000 and 4000Hz, respectively. Reliable responses were obtained in the assessment of cortical auditory potentials in the neonates assessed with a device for automatic response detection. Copyright © 2018 Associação Brasileira de Otorrinolaringologia e Cirurgia Cérvico-Facial. Published by Elsevier Editora Ltda. All rights reserved.

Electroencephalogram (EEG) and Magnetoencephalogram (MEG) as Tools for Evaluation of Cognitive Function

NASA Technical Reports Server (NTRS)

Fender, Derek H.; Hestenes, John D.

1985-01-01

We have developed computerized analysis and display techniques to help identify the origins of visually evoked scalped potentials (VESP). The potentials are recorded simultaneously from many electrodes (usually 40 to 48) spaced over the region of the scalp where appreciable evoked potentials are found in response to particular stimulus. Contour mapping algorithms are then used to display the time behavior of equipotential surfaces on the scalp during the VESP. We then use an optimization technique to select the parameters of arrays of current dipole sources within the model until the model equipotential field distribution closely fits the measured data. Computer graphics are then used to display, as a movie, the actual and model scalp potential fields and the parameters of the dipole generators within the model head during the course of VESP activity. We have devised reaction time tests that involve potentially separable stages of cognitive processing and utilize stimuli that produce measurable cognition-related features in the late component of the evoked potential. We have used these techniques to determine the loci in the brain where known cognition-related features in the evoked potential are generated and we have explored the extent to which each of these features can be related to the reaction time tasks. We have also examined the temporal-spatial aspects of their cerebral involvement. Our current work is planned to characterize the age-related changes in the processes performed by such sources. We also use a neuromagnetometer to measure the evoked magnetic fields in similar circumstances; we will discuss the relative merits of the two methodologies.

Increased discriminability of authenticity from multimodal laughter is driven by auditory information.

PubMed

Lavan, Nadine; McGettigan, Carolyn

2017-10-01

We present an investigation of the perception of authenticity in audiovisual laughter, in which we contrast spontaneous and volitional samples and examine the contributions of unimodal affective information to multimodal percepts. In a pilot study, we demonstrate that listeners perceive spontaneous laughs as more authentic than volitional ones, both in unimodal (audio-only, visual-only) and multimodal contexts (audiovisual). In the main experiment, we show that the discriminability of volitional and spontaneous laughter is enhanced for multimodal laughter. Analyses of relationships between affective ratings and the perception of authenticity show that, while both unimodal percepts significantly predict evaluations of audiovisual laughter, it is auditory affective cues that have the greater influence on multimodal percepts. We discuss differences and potential mismatches in emotion signalling through voices and faces, in the context of spontaneous and volitional behaviour, and highlight issues that should be addressed in future studies of dynamic multimodal emotion processing.

Prospectus on Multi-Modal Aspects of Human Factors in Transportation

DOT National Transportation Integrated Search

1991-02-01

This prospectus identifies and discusses a series of human factors : issues which are critical to transportation safety and productivity, and : examines the potential benefits that can accrue from taking a multi-modal : approach to human factors rese...

Multi-Modal Intelligent Traffic Signal Systems (MMITSS) impacts assessment.

DOT National Transportation Integrated Search

2015-08-01

The study evaluates the potential network-wide impacts of the Multi-Modal Intelligent Transportation Signal System (MMITSS) based on a field data analysis utilizing data collected from a MMITSS prototype and a simulation analysis. The Intelligent Tra...

Unisensory processing and multisensory integration in schizophrenia: A high-density electrical mapping study

PubMed Central

Stone, David B.; Urrea, Laura J.; Aine, Cheryl J.; Bustillo, Juan R.; Clark, Vincent P.; Stephen, Julia M.

2011-01-01

In real-world settings, information from multiple sensory modalities is combined to form a complete, behaviorally salient percept - a process known as multisensory integration. While deficits in auditory and visual processing are often observed in schizophrenia, little is known about how multisensory integration is affected by the disorder. The present study examined auditory, visual, and combined audio-visual processing in schizophrenia patients using high-density electrical mapping. An ecologically relevant task was used to compare unisensory and multisensory evoked potentials from schizophrenia patients to potentials from healthy normal volunteers. Analysis of unisensory responses revealed a large decrease in the N100 component of the auditory-evoked potential, as well as early differences in the visual-evoked components in the schizophrenia group. Differences in early evoked responses to multisensory stimuli were also detected. Multisensory facilitation was assessed by comparing the sum of auditory and visual evoked responses to the audio-visual evoked response. Schizophrenia patients showed a significantly greater absolute magnitude response to audio-visual stimuli than to summed unisensory stimuli when compared to healthy volunteers, indicating significantly greater multisensory facilitation in the patient group. Behavioral responses also indicated increased facilitation from multisensory stimuli. The results represent the first report of increased multisensory facilitation in schizophrenia and suggest that, although unisensory deficits are present, compensatory mechanisms may exist under certain conditions that permit improved multisensory integration in individuals afflicted with the disorder. PMID:21807011

The steady-state visual evoked potential in vision research: A review

PubMed Central

Norcia, Anthony M.; Appelbaum, L. Gregory; Ales, Justin M.; Cottereau, Benoit R.; Rossion, Bruno

2015-01-01

Periodic visual stimulation and analysis of the resulting steady-state visual evoked potentials were first introduced over 80 years ago as a means to study visual sensation and perception. From the first single-channel recording of responses to modulated light to the present use of sophisticated digital displays composed of complex visual stimuli and high-density recording arrays, steady-state methods have been applied in a broad range of scientific and applied settings.The purpose of this article is to describe the fundamental stimulation paradigms for steady-state visual evoked potentials and to illustrate these principles through research findings across a range of applications in vision science. PMID:26024451

Binaural Interaction in Specific Language Impairment: An Auditory Evoked Potential Study

ERIC Educational Resources Information Center

Clarke, Elaine M; Adams, Catherine

2007-01-01

The aim of the study was to examine whether auditory binaural interaction, defined as any difference between binaurally evoked responses and the sum of monaurally evoked responses, which is thought to index functions involved in the localization and detection of signals in background noise, is atypical in a group of children with specific language…

A Steady State Visually Evoked Potential Investigation of Memory and Ageing

ERIC Educational Resources Information Center

Macpherson, Helen; Pipingas, Andrew; Silberstein, Richard

2009-01-01

Old age is generally accompanied by a decline in memory performance. Specifically, neuroimaging and electrophysiological studies have revealed that there are age-related changes in the neural correlates of episodic and working memory. This study investigated age-associated changes in the steady state visually evoked potential (SSVEP) amplitude and…

Basic Hearing and Echolocation Mechanisms of Marine Mammals: Measured Auditory Evoked Potential and Behavioral Experiments FY 2007

DTIC Science & Technology

2007-01-01

Breese, M. (2007) Evoked-potential recovery during double click stimulation in a whale: A possibility of biosonar automatic gain control. Journal of...Yokohama Japan (published) Supin A.Ya, Nachtigall, P.E., and Breese, M. Source level to sensation level ratio of transmitted biosonar pulses in an

Short-Latency Median-Nerve Somatosensory-Evoked Potentials and Induced Gamma-Oscillations in Humans

ERIC Educational Resources Information Center

Fukuda, Miho; Nishida, Masaaki; Juhasz, Csaba; Muzik, Otto; Sood, Sandeep; Chugani, Harry T.; Asano, Eishi

2008-01-01

Recent studies have suggested that cortical gamma-oscillations are tightly linked with various forms of physiological activity. In the present study, the dynamic changes of intracranially recorded median-nerve somatosensory-evoked potentials (SEPs) and somatosensory-induced gamma-oscillations were animated on a three-dimensional MR image, and the…

INHIBITION OF BRAIN CHOLINESTERASE AND THE PHOTIC AFTER DISCHARGE OF FLASH EVOKED POTENTIALS PRODUCED BY CARBARYL IN LONG EVANS RATS.

EPA Science Inventory

Carbaryl is a widely used N-methyl carbamate pesticide that acts by inhibiting cholinesterases (ChE), which may lead to cholinergic toxicity. Flash evoked potentials (FEPs) are a neurophysiological response often used to detect central nervous system (CNS) changes following expos...

BRAIN CHOLINESTERASE INHIBITION PRODUCED BY PROPOXUR AND DEPRESSION OF THE PHOTIC AFTER DISCHARGE OF FLASH EVOKED POTENTIALS IN LONG EVANS RATS.

EPA Science Inventory

Propoxur is a widely used N-methyl carbamate pesticide that acts by inhibiting cholinesterases (ChE), which may lead to cholinergic toxicity. Flash evoked potentials (FEPs) are a neurophysiological response following stimulation of the visual system with flashes of light. They ar...

Temporal processing and long-latency auditory evoked potential in stutterers.

PubMed

Prestes, Raquel; de Andrade, Adriana Neves; Santos, Renata Beatriz Fernandes; Marangoni, Andrea Tortosa; Schiefer, Ana Maria; Gil, Daniela

Stuttering is a speech fluency disorder, and may be associated with neuroaudiological factors linked to central auditory processing, including changes in auditory processing skills and temporal resolution. To characterize the temporal processing and long-latency auditory evoked potential in stutterers and to compare them with non-stutterers. The study included 41 right-handed subjects, aged 18-46 years, divided into two groups: stutterers (n=20) and non-stutters (n=21), compared according to age, education, and sex. All subjects were submitted to the duration pattern tests, random gap detection test, and long-latency auditory evoked potential. Individuals who stutter showed poorer performance on Duration Pattern and Random Gap Detection tests when compared with fluent individuals. In the long-latency auditory evoked potential, there was a difference in the latency of N2 and P3 components; stutterers had higher latency values. Stutterers have poor performance in temporal processing and higher latency values for N2 and P3 components. Copyright © 2017 Associação Brasileira de Otorrinolaringologia e Cirurgia Cérvico-Facial. Published by Elsevier Editora Ltda. All rights reserved.

Brainstem auditory evoked potential wave V latency-intensity function in normal Dalmatian and Beagle puppies.

PubMed

Poncelet, L; Coppens, A; Deltenre, P

2000-01-01

This study investigated whether Dalmatian puppies with normal hearing bilaterally had the same click-evoked brainstem auditory potential characteristics as age-matched dogs of another breed. Short-latency brainstem auditory potentials evoked by condensation and rarefaction clicks were recorded in 23 1.5- to 2-month-old Dalmatian puppies with normal hearing bilaterally by a qualitative brainstem auditory evoked potential test and in 16 Beagle dogs of the same age. For each stimulus intensity, from 90 dB normal hearing level down to the wave V threshold, the sum of the potentials evoked by the 2 kinds of stimuli were added, giving an equivalent to the alternate click polarity stimulation. The slope of the L segment of the wave V latency-intensity curve was steeper in Dalmatian (-40 +/- 10 micros/dB) than in Beagles (-28 +/- 5 micros/dB, P < .001) puppies. The hearing threshold was lower in the Beagle puppies (P < .05). These results suggest that interbreed differences may exist at the level of cochlear function in this age class. The wave V latency and wave V-wave I latencies differences at high stimulus intensity were different between the groups of puppies (4.3 +/- 0.2 and 2.5 +/- 0.2 milliseconds, respectively, for Beagles; and 4.1 +/- 0.2 and 2.3 +/- 0.2 milliseconds for Dalmatians, P < .05). A different maturation speed of the neural pathways is one possible explanation of this observation.

Effects of propofol, sevoflurane, remifentanil, and (S)-ketamine in subanesthetic concentrations on visceral and somatosensory pain-evoked potentials.

PubMed

Untergehrer, Gisela; Jordan, Denis; Eyl, Sebastian; Schneider, Gerhard

2013-02-01

Although electroencephalographic parameters and auditory evoked potentials (AEP) reflect the hypnotic component of anesthesia, there is currently no specific and mechanism-based monitoring tool for anesthesia-induced blockade of nociceptive inputs. The aim of this study was to assess visceral pain-evoked potentials (VPEP) and contact heat-evoked potentials (CHEP) as electroencephalographic indicators of drug-induced changes of visceral and somatosensory pain. Additionally, AEP and electroencephalographic permutation entropy were used to evaluate sedative components of the applied drugs. In a study enrolling 60 volunteers, VPEP, CHEP (amplitude N2-P1), and AEP (latency Nb, amplitude Pa-Nb) were recorded without drug application and at two subanesthetic concentration levels of propofol, sevoflurane, remifentanil, or (s)-ketamine. Drug-induced changes of evoked potentials were analyzed. VPEP were generated by electric stimuli using bipolar electrodes positioned in the distal esophagus. For CHEP, heat pulses were given to the medial aspect of the right forearm using a CHEP stimulator. In addition to AEP, electroencephalographic permutation entropy was used to indicate level of sedation. With increasing concentrations of propofol, sevoflurane, remifentanil, and (s)-ketamine, VPEP and CHEP N2-P1 amplitudes decreased. AEP and electroencephalographic permutation entropy showed neither clinically relevant nor statistically significant suppression of cortical activity during drug application. Decreasing VPEP and CHEP amplitudes under subanesthetic concentrations of propofol, sevoflurane, remifentanil, and (s)-ketamine indicate suppressive drug effects. These effects seem to be specific for analgesia.

Practical Aspects of Access Network Indoor Extensions Using Multimode Glass and Plastic Optical Fibers

NASA Astrophysics Data System (ADS)

Keiser, Gerd; Liu, Hao-Yu; Lu, Shao-Hsi; Devi Pukhrambam, Puspa

2012-07-01

Low-cost multimode glass and plastic optical fibers are attractive for high-capacity indoor telecom networks. Many existing buildings already have glass multimode fibers installed for local area network applications. Future indoor applications will use combinations of glass multimode fibers with plastic optical fibers that have low losses in the 850-nm-1,310-nm range. This article examines real-world link losses when randomly interconnecting glass and plastic fiber segments having factory-installed connectors. Potential interconnection issues include large variations in connector losses among randomly selected fiber segments, asymmetric link losses in bidirectional links, and variations in bandwidths among different types of fibers.

Visual evoked potentials in patients after methanol poisoning.

PubMed

Urban, Pavel; Zakharov, Sergey; Diblík, Pavel; Pelclová, Daniela; Ridzoň, Petr

2016-01-01

We report the results of the visual evoked potentials (VEP) examination in patients after severe poisoning by methanol. The group of 47 patients (38 males and 9 females) was assembled out of persons who survived an outbreak of poisoning by the methanol adulterated alcohol beverages, which happened in the Czech Republic in 2012-2013. The visual evoked potentials examination was performed using monocular checkerboard pattern-reversal stimulation. Two criteria of abnormality were chosen: missing evoked response, and wave P1 latency > 117 ms. Non-parametric statistical methods (median, range, and the median test) were used to analyze factors influencing the VEP abnormality. The visual evoked potential was abnormal in 20 patients (43%), 5 of them had normal visual acuity on the Snellen chart. The VEP abnormality did not correlate significantly with initial serum concentrations of methanol, formic acid or lactate; however, it showed statistically significant inverse relation to the initial serum pH: the subgroup with the abnormal VEP had significantly lower median pH in comparison with the subgroup with the normal VEP (7.16 vs. 7.34, p = 0.04). The abnormality was not related to chronic alcohol abuse. The visual evoked potentials examination appeared sensitive enough to detected even subclinical impairment of the optic system. Metabolic acidosis is likely to be the key factor related to the development of visual damage induced by methanol. The examination performed with a delay of 1-9 months after the poisoning documented the situation relatively early after the event. It is considered as a baseline for the planned long-term follow-up of the patients, which will make it possible to assess the dynamics of the observed changes, their reversibility, and the occurrence of potential late sequelae. This work is available in Open Access model and licensed under a CC BY-NC 3.0 PL license.

Use of auditory evoked potentials for intra-operative awareness in anesthesia: a consciousness-based conceptual model.

PubMed

Dong, Xuebao; Suo, Puxia; Yuan, Xin; Yao, Xuefeng

2015-01-01

Auditory evoked potentials (AEPs) have been used as a measure of the depth of anesthesia during the intra-operative process. AEPs are classically divided, on the basis of their latency, into first, fast, middle, slow, and late components. The use of auditory evoked potential has been advocated for the assessment of Intra-operative awareness (IOA), but has not been considered seriously enough to universalize it. It is because we have not explored enough the impact of auditory perception and auditory processing on the IOA phenomena as well as on the subsequent psychological impact of IOA on the patient. More importantly, we have seldom tried to look at the phenomena of IOP from the perspective of consciousness itself. This perspective is especially important because many of IOA phenomena exist in the subconscious domain than they do in the conscious domain of explicit recall. Two important forms of these subconscious manifestations of IOA are the implicit recall phenomena and post-operative dreams related to the operation. Here, we present an integrated auditory consciousness-based model of IOA. We start with a brief description of auditory awareness and the factors affecting it. Further, we proceed to the evaluation of conscious and subconscious information processing by auditory modality and how they interact during and after intra-operative period. Further, we show that both conscious and subconscious auditory processing affect the IOA experience and both have serious psychological implications on the patient subsequently. These effects could be prevented by using auditory evoked potential during monitoring of anesthesia, especially the mid-latency auditory evoked potentials (MLAERs). To conclude our model with present hypothesis, we propose that the use of auditory evoked potential should be universal with general anesthesia use in order to prevent the occurrences of distressing outcomes resulting from both conscious and subconscious auditory processing during anesthesia.

Melatonin potentiates "inside-out" nano-thermotherapy in human breast cancer cells: a potential cancer target multimodality treatment based on melatonin-loaded nanocomposite particles.

PubMed

Xie, Wensheng; Gao, Qin; Wang, Dan; Wang, Wei; Yuan, Jie; Guo, Zhenhu; Yan, Hao; Wang, Xiumei; Sun, Xiaodan; Zhao, Lingyun

2017-01-01

With the wide recognition of oncostatic effect of melatonin, the current study proposes a potential breast cancer target multimodality treatment based on melatonin-loaded magnetic nanocomposite particles (Melatonin-MNPs). Melatonin-MNPs were fabricated by the single emulsion solvent extraction/evaporation method. Based on the facilitated transport of melatonin by the GLUT overexpressed on the cell membrane, such Melatonin-MNPs can be more favorably uptaken by MCF-7 cells compared with the melatonin-free nanocomposite particles, which indicates the cancer targeting ability of melatonin molecule. Inductive heating can be generated by exposure to the Melatonin-MNPs internalized within cancer cells under alternative magnetic field, so as to achieve the "inside-out" magnetic nano-thermotherapy. In addition to demonstrating the superior cytotoxic effect of such nano-thermotherapy over the conventional exogenous heating by metal bath, more importantly, the sustainable release of melatonin from the Melatonin-MNPs can be greatly promoted upon responsive to the magnetic heating. The multimodality treatment based on Melatonin-MNPs can lead to more significant decrease in cell viability than any single treatment, suggesting the potentiated effect of melatonin on the cytotoxic response to nano-thermotherapy. This study is the first to fabricate the precisely engineered melatonin-loaded multifunctional nanocomposite particles and demonstrate the potential in breast cancer target multimodality treatment.

Bisensory stimulation increases gamma-responses over multiple cortical regions.

PubMed

Sakowitz, O W; Quiroga, R Q; Schürmann, M; Başar, E

2001-04-01

In the framework of the discussion about gamma (approx. 40 Hz) oscillations as information carriers in the brain, we investigated the relationship between gamma responses in the EEG and intersensory association. Auditory evoked potentials (AEPs) and visual evoked potentials (VEPs) were compared with bisensory evoked potentials (BEPs; simultaneous auditory and visual stimulation) in 15 subjects. Gamma responses in AEPs, VEPs and BEPs were assessed by means of wavelet decomposition. Overall maximum gamma-components post-stimulus were highest in BEPs (P < 0.01). Bisensory evoked gamma-responses also showed significant central, parietal and occipital amplitude-increases (P < 0.001, P < 0.01, P < 0.05, respectively; prestimulus interval as baseline). These were of greater magnitude when compared with the unisensory responses. As a correlate of the marked gamma responses to bimodal stimulation we suggest a process of 'intersensory association', i.e. one of the steps between sensory transmission and perception. Our data may be interpreted as a further example of function-related gamma responses in the EEG.

Advanced driver assistance systems: Using multimodal redundant warnings to enhance road safety.

PubMed

Biondi, Francesco; Strayer, David L; Rossi, Riccardo; Gastaldi, Massimiliano; Mulatti, Claudio

2017-01-01

This study investigated whether multimodal redundant warnings presented by advanced assistance systems reduce brake response times. Warnings presented by assistance systems are designed to assist drivers by informing them that evasive driving maneuvers are needed in order to avoid a potential accident. If these warnings are poorly designed, they may distract drivers, slow their responses, and reduce road safety. In two experiments, participants drove a simulated vehicle equipped with a forward collision avoidance system. Auditory, vibrotactile, and multimodal warnings were presented when the time to collision was shorter than five seconds. The effects of these warnings were investigated with participants performing a concurrent cell phone conversation (Exp. 1) or driving in high-density traffic (Exp. 2). Braking times and subjective workload were measured. Multimodal redundant warnings elicited faster braking reaction times. These warnings were found to be effective even when talking on a cell phone (Exp. 1) or driving in dense traffic (Exp. 2). Multimodal warnings produced higher ratings of urgency, but ratings of frustration did not increase compared to other warnings. Findings obtained in these two experiments are important given that faster braking responses may reduce the potential for a collision. Copyright © 2016 Elsevier Ltd. All rights reserved.

Influence of detomidine and buprenorphine on motor-evoked potentials in horses.

PubMed

Nollet, H; Van Ham, L; Gasthuys, F; Dewulf, J; Vanderstraeten, G; Deprez, P

2003-04-26

Horses need to be sedated before they are investigated by transcranial magnetic stimulation because of the mild discomfort induced by the evoked muscle contraction and the noise of stimulation. This paper describes the influence of a combination of detomidine (10 microg/kg bodyweight) and a low dose of buprenorphine (2.4 microg/kg) on the onset latency and peak-to-peak amplitude of magnetic motor-evoked potentials in normal horses. There were no significant differences between measurements of these parameters made before the horses were sedated and measurements made 10 and 30 minutes after the drugs were administered.

[Evoked potentials N200/P300 disorders and clinical phenotype in Cuban families with paranoid schizophrenia: a family-based association study].

PubMed

Guerra López, Seidel; Martín Reyes, Migdyrai; Pedroso Rodríguez, María de Los Ángeles; Reyes Berazain, Adnelys; Mendoza Quiñones, Raúl; Bravo Collazo, Tania Martha; Días de Villarvilla, Thais; Machado Cano, María Julia; Bobés León, María Antonieta

2015-04-01

N200 and P300 event-related evoked potentials provide sensitive measurements of sensory and cognitive function and have been used to study information processing in patients with schizophrenia and their unaffected first-degree relatives. Reduced amplitude and increased latency of N200 and P300 potentials have been consistently reported in schizophrenia. Thus, event-related evoked potentials abnormalities are promising possible biological markers for genetic vulnerability to schizophrenia. To assess the association of changes in latency, amplitude and topographic distribution of potentials N200 and P300 of patients with paranoid schizophrenia and their healthy first-degree relatives, in families with schizophrenia multiplex. We measured latency and amplitude of the N200 and P300 component of evoked potentials using an auditory odd-ball paradigm in 25 schizophrenic patients (probands) from 60 families multiply affected with paranoid schizophrenia, 23 of their non-schizophrenic first-degree relatives and 25 unrelated healthy controls, through a study of family association. Schizophrenic patients and their relatives showed significant latency prolongation and amplitude reduction of the N200 and P300 waves compared to controls. Left-temporal as compared to right-temporal N200 and P300 were significantly smaller in schizophrenic patients and their non-schizophrenic first-degree relatives than in controls. Our results suggest that event-related evoked potentials abnormalities may serve as markers of genetic vulnerability in schizophrenia. Confirming results of other researchers, this present study suggests that latency prolongation and amplitude reduction of the N200 and P300 waves and an altered topography at temporal sites may be a trait “marker” of paranoid schizophrenia.

Auditory evoked potentials in children and adolescents with Down syndrome.

PubMed

Gregory, Letícia; Rosa, Rafael F M; Zen, Paulo R G; Sleifer, Pricila

2018-01-01

Down syndrome, or trisomy 21, is the most common genetic alteration in humans. The syndrome presents with several features, including hearing loss and changes in the central nervous system, which may affect language development in children and lead to school difficulties. The present study aimed to investigate group differences in the central auditory system by long-latency auditory evoked potentials and cognitive potential. An assessment of 23 children and adolescents with Down syndrome was performed, and a control group composed of 43 children and adolescents without genetic and/or neurological changes was used for comparison. All children underwent evaluation with pure tone and vocal audiometry, acoustic immitance measures, long-latency auditory evoked potentials, and cognitive potential. Longer latencies of the waves were found in the Down syndrome group than the control group, without significant differences in amplitude, suggesting that individuals with Down syndrome have difficulty in discrimination and auditory memory. It is, therefore, important to stimulate and monitor these children in order to enable adequate development and improve their life quality. We also emphasize the importance of the application of auditory evoked potentials in clinical practice, in order to contribute to the early diagnosis of hearing alterations and the development of more research in this area. © 2017 Wiley Periodicals, Inc.

Laryngeal and tracheal afferent nerve stimulation evokes swallowing in anaesthetized guinea pigs

PubMed Central

Tsujimura, Takanori; Udemgba, Chioma; Inoue, Makoto; Canning, Brendan J

2013-01-01

We describe swallowing reflexes evoked by laryngeal and tracheal vagal afferent nerve stimulation in anaesthetized guinea pigs. The swallowing reflexes evoked by laryngeal citric acid challenges were abolished by recurrent laryngeal nerve (RLN) transection and mimicked by electrical stimulation of the central cut ends of an RLN. By contrast, the number of swallows evoked by upper airway/pharyngeal distensions was not significantly reduced by RLN transection but they were virtually abolished by superior laryngeal nerve transection. Laryngeal citric acid-evoked swallowing was mimicked by laryngeal capsaicin challenges, implicating transient receptor potential vanilloid 1 (TRPV1)-expressing laryngeal afferent nerves arising from the jugular ganglia. The swallowing evoked by citric acid and capsaicin and evoked by electrical stimulation of either the tracheal or the laryngeal mucosa occurred at stimulation intensities that were typically subthreshold for evoking cough in these animals. Swallowing evoked by airway afferent nerve stimulation also desensitized at a much slower rate than cough. We speculate that swallowing is an essential component of airway protection from aspiration associated with laryngeal and tracheal afferent nerve activation. PMID:23858010

Analysis of the Averaged Visually Evoked Potentials in Normal Children. (RIEEC Research Bulletin 3.)

ERIC Educational Resources Information Center

Mizutani, Tohru; And Others

Evaluated were the properties and fine structures of averaged visually evoked potentials (AVEP) in 60 normal children between the ages of 2 and 9 years. Electroencephalographic recordings were taken while white diffuse flashes were used to deliver visual stimuli to the Ss. Three types of AVEP patterns were discerned, with no relationship observed…

Altered Automatic Face Processing in Individuals with High-Functioning Autism Spectrum Disorders: Evidence from Visual Evoked Potentials

ERIC Educational Resources Information Center

Fujita, Takako; Kamio, Yoko; Yamasaki, Takao; Yasumoto, Sawa; Hirose, Shinichi; Tobimatsu, Shozo

2013-01-01

Individuals with autism spectrum disorders (ASDs) have different automatic responses to faces than typically developing (TD) individuals. We recorded visual evoked potentials (VEPs) in 10 individuals with high-functioning ASD (HFASD) and 10 TD individuals. Visual stimuli consisted of upright and inverted faces (fearful and neutral) and objects…

Attentional Modulation of Visual-Evoked Potentials by Threat: Investigating the Effect of Evolutionary Relevance

ERIC Educational Resources Information Center

Brown, Christopher; El-Deredy, Wael; Blanchette, Isabelle

2010-01-01

In dot-probe tasks, threatening cues facilitate attention to targets and enhance the amplitude of the target P1 peak of the visual-evoked potential. While theories have suggested that evolutionarily relevant threats should obtain preferential neural processing, this has not been examined empirically. In this study we examined the effects of…

Emotional foundations of music as a non-pharmacological pain management tool in modern medicine.

PubMed

Bernatzky, Guenther; Presch, Michaela; Anderson, Mary; Panksepp, Jaak

2011-10-01

This paper reviews the use of music as an adjuvant to the control of pain, especially in medical procedures. Surgery causes stress and anxiety that exacerbates the experience of pain. Self-report of and physiological measures on post-surgical patients indicate that music therapy or music stimulation reduces the perception of pain, both alone and when part of a multimodal pain management program, and can reduce the need for pharmaceutical interventions. However, multimodal pain therapy, including non-pharmacological interventions after surgery, is still rare in medical practice. We summarize how music can enhance medical therapies and can be used as an adjuvant with other pain-management programs to increase the effectiveness of those therapies. As summarized, we currently know that musical pieces chosen by the patient are commonly, but not always, more effective than pieces chosen by another person. Further research should focus both on finding the specific indications and contra-indications of music therapy and on the biological and neurological pathways responsible for those findings (related evidence has implicated brain opioid and oxytocin mechanisms in affective changes evoked by music). In turn, these findings will allow medical investigators and practitioners to design guidelines and reliable, standardized applications for this promising method of pain management in modern medicine. Copyright © 2011 Elsevier Ltd. All rights reserved.

Effect of combined opioid receptor and α2-adrenoceptor blockade on anxiety and electrically evoked startle responses.

PubMed

Vo, Lechi; Drummond, Peter D

2017-06-01

The R3 component of the electrically evoked blink reflex may form part of a startle reaction. Acoustic startle responses are augmented by yohimbine, an α 2 -adrenoceptor antagonist that blocks α 2 -autoreceptors, and are potentiated by opioid receptor blockade. To investigate these influences on electrically evoked startle responses, 16 mg yohimbine, with (16 participants) or without 50 mg naltrexone (23 participants), was administered in separate double-blind placebo-controlled cross-over experiments. In each experiment, R3 (a probable component of the startle response) was examined before and after high-frequency electrical stimulation of the forearm, a procedure that initiates inhibitory pain controls. Anxiety and somatic symptoms were greater after yohimbine than placebo, and were potentiated by naltrexone. Pain ratings for the electrically evoked startle stimuli decreased after high-frequency electrical stimulation in the placebo session but remained stable after drug administration. Yohimbine with naltrexone, but not yohimbine alone, also blocked an inhibitory effect of high-frequency electrical stimulation on electrically evoked sharp sensations and R3. Together, the findings suggest that adding naltrexone to yohimbine potentiated anxiety and blocked inhibitory influences of high-frequency electrical stimulation on electrically evoked sensations and startle responses. Thus, opioid peptides could reduce activity in nociceptive and startle-reflex pathways, or inhibit crosstalk between these pathways. Failure of this inhibitory opioid influence might be important in chronically painful conditions that are aggravated by startle stimuli.

Unisensory processing and multisensory integration in schizophrenia: a high-density electrical mapping study.

PubMed

Stone, David B; Urrea, Laura J; Aine, Cheryl J; Bustillo, Juan R; Clark, Vincent P; Stephen, Julia M

2011-10-01

In real-world settings, information from multiple sensory modalities is combined to form a complete, behaviorally salient percept - a process known as multisensory integration. While deficits in auditory and visual processing are often observed in schizophrenia, little is known about how multisensory integration is affected by the disorder. The present study examined auditory, visual, and combined audio-visual processing in schizophrenia patients using high-density electrical mapping. An ecologically relevant task was used to compare unisensory and multisensory evoked potentials from schizophrenia patients to potentials from healthy normal volunteers. Analysis of unisensory responses revealed a large decrease in the N100 component of the auditory-evoked potential, as well as early differences in the visual-evoked components in the schizophrenia group. Differences in early evoked responses to multisensory stimuli were also detected. Multisensory facilitation was assessed by comparing the sum of auditory and visual evoked responses to the audio-visual evoked response. Schizophrenia patients showed a significantly greater absolute magnitude response to audio-visual stimuli than to summed unisensory stimuli when compared to healthy volunteers, indicating significantly greater multisensory facilitation in the patient group. Behavioral responses also indicated increased facilitation from multisensory stimuli. The results represent the first report of increased multisensory facilitation in schizophrenia and suggest that, although unisensory deficits are present, compensatory mechanisms may exist under certain conditions that permit improved multisensory integration in individuals afflicted with the disorder. Copyright © 2011 Elsevier Ltd. All rights reserved.

Preterm EEG: a multimodal neurophysiological protocol.

PubMed

Stjerna, Susanna; Voipio, Juha; Metsäranta, Marjo; Kaila, Kai; Vanhatalo, Sampsa

2012-02-18

Since its introduction in early 1950s, electroencephalography (EEG) has been widely used in the neonatal intensive care units (NICU) for assessment and monitoring of brain function in preterm and term babies. Most common indications are the diagnosis of epileptic seizures, assessment of brain maturity, and recovery from hypoxic-ischemic events. EEG recording techniques and the understanding of neonatal EEG signals have dramatically improved, but these advances have been slow to penetrate through the clinical traditions. The aim of this presentation is to bring theory and practice of advanced EEG recording available for neonatal units. In the theoretical part, we will present animations to illustrate how a preterm brain gives rise to spontaneous and evoked EEG activities, both of which are unique to this developmental phase, as well as crucial for a proper brain maturation. Recent animal work has shown that the structural brain development is clearly reflected in early EEG activity. Most important structures in this regard are the growing long range connections and the transient cortical structure, subplate. Sensory stimuli in a preterm baby will generate responses that are seen at a single trial level, and they have underpinnings in the subplate-cortex interaction. This brings neonatal EEG readily into a multimodal study, where EEG is not only recording cortical function, but it also tests subplate function via different sensory modalities. Finally, introduction of clinically suitable dense array EEG caps, as well as amplifiers capable of recording low frequencies, have disclosed multitude of brain activities that have as yet been overlooked. In the practical part of this video, we show how a multimodal, dense array EEG study is performed in neonatal intensive care unit from a preterm baby in the incubator. The video demonstrates preparation of the baby and incubator, application of the EEG cap, and performance of the sensory stimulations.

Cortical evoked potentials to an auditory illusion: binaural beats.

PubMed

Pratt, Hillel; Starr, Arnold; Michalewski, Henry J; Dimitrijevic, Andrew; Bleich, Naomi; Mittelman, Nomi

2009-08-01

To define brain activity corresponding to an auditory illusion of 3 and 6Hz binaural beats in 250Hz or 1000Hz base frequencies, and compare it to the sound onset response. Event-Related Potentials (ERPs) were recorded in response to unmodulated tones of 250 or 1000Hz to one ear and 3 or 6Hz higher to the other, creating an illusion of amplitude modulations (beats) of 3Hz and 6Hz, in base frequencies of 250Hz and 1000Hz. Tones were 2000ms in duration and presented with approximately 1s intervals. Latency, amplitude and source current density estimates of ERP components to tone onset and subsequent beats-evoked oscillations were determined and compared across beat frequencies with both base frequencies. All stimuli evoked tone-onset P(50), N(100) and P(200) components followed by oscillations corresponding to the beat frequency, and a subsequent tone-offset complex. Beats-evoked oscillations were higher in amplitude with the low base frequency and to the low beat frequency. Sources of the beats-evoked oscillations across all stimulus conditions located mostly to left lateral and inferior temporal lobe areas in all stimulus conditions. Onset-evoked components were not different across stimulus conditions; P(50) had significantly different sources than the beats-evoked oscillations; and N(100) and P(200) sources located to the same temporal lobe regions as beats-evoked oscillations, but were bilateral and also included frontal and parietal contributions. Neural activity with slightly different volley frequencies from left and right ear converges and interacts in the central auditory brainstem pathways to generate beats of neural activity to modulate activities in the left temporal lobe, giving rise to the illusion of binaural beats. Cortical potentials recorded to binaural beats are distinct from onset responses. Brain activity corresponding to an auditory illusion of low frequency beats can be recorded from the scalp.

Cortical Evoked Potentials to an Auditory Illusion: Binaural Beats

PubMed Central

Pratt, Hillel; Starr, Arnold; Michalewski, Henry J.; Dimitrijevic, Andrew; Bleich, Naomi; Mittelman, Nomi

2009-01-01

Objective: To define brain activity corresponding to an auditory illusion of 3 and 6 Hz binaural beats in 250 Hz or 1,000 Hz base frequencies, and compare it to the sound onset response. Methods: Event-Related Potentials (ERPs) were recorded in response to unmodulated tones of 250 or 1000 Hz to one ear and 3 or 6 Hz higher to the other, creating an illusion of amplitude modulations (beats) of 3 Hz and 6 Hz, in base frequencies of 250 Hz and 1000 Hz. Tones were 2,000 ms in duration and presented with approximately 1 s intervals. Latency, amplitude and source current density estimates of ERP components to tone onset and subsequent beats-evoked oscillations were determined and compared across beat frequencies with both base frequencies. Results: All stimuli evoked tone-onset P50, N100 and P200 components followed by oscillations corresponding to the beat frequency, and a subsequent tone-offset complex. Beats-evoked oscillations were higher in amplitude with the low base frequency and to the low beat frequency. Sources of the beats-evoked oscillations across all stimulus conditions located mostly to left lateral and inferior temporal lobe areas in all stimulus conditions. Onset-evoked components were not different across stimulus conditions; P50 had significantly different sources than the beats-evoked oscillations; and N100 and P200 sources located to the same temporal lobe regions as beats-evoked oscillations, but were bilateral and also included frontal and parietal contributions. Conclusions: Neural activity with slightly different volley frequencies from left and right ear converges and interacts in the central auditory brainstem pathways to generate beats of neural activity to modulate activities in the left temporal lobe, giving rise to the illusion of binaural beats. Cortical potentials recorded to binaural beats are distinct from onset responses. Significance: Brain activity corresponding to an auditory illusion of low frequency beats can be recorded from the scalp. PMID:19616993

Thermoreceptive innervation of human glabrous and hairy skin: a contact heat evoked potential analysis.

PubMed

Granovsky, Yelena; Matre, Dagfinn; Sokolik, Alexander; Lorenz, Jürgen; Casey, Kenneth L

2005-06-01

The human palm has a lower heat detection threshold and a higher heat pain threshold than hairy skin. Neurophysiological studies of monkeys suggest that glabrous skin has fewer low threshold heat nociceptors (AMH type 2) than hairy skin. Accordingly, we used a temperature-controlled contact heat evoked potential (CHEP) stimulator to excite selectively heat receptors with C fibers or Adelta-innervated AMH type 2 receptors in humans. On the dorsal hand, 51 degrees C stimulation produced painful pinprick sensations and 41 degrees C stimuli evoked warmth. On the glabrous thenar, 41 degrees C stimulation produced mild warmth and 51 degrees C evoked strong but painless heat sensations. We used CHEP responses to estimate the conduction velocities (CV) of peripheral fibers mediating these sensations. On hairy skin, 41 degrees C stimuli evoked an ultra-late potential (mean, SD; N wave latency: 455 (118) ms) mediated by C fibers (CV by regression analysis: 1.28 m/s, N=15) whereas 51 degrees C stimuli evoked a late potential (N latency: 267 (33) ms) mediated by Adelta afferents (CV by within-subject analysis: 12.9 m/s, N=6). In contrast, thenar responses to 41 and 51 degrees C were mediated by C fibers (average N wave latencies 485 (100) and 433 (73) ms, respectively; CVs 0.95-1.35 m/s by regression analysis, N=15; average CV=1.7 (0.41) m/s calculated from distal glabrous and proximal hairy skin stimulation, N=6). The exploratory range of the human and monkey palm is enhanced by the abundance of low threshold, C-innervated heat receptors and the paucity of low threshold AMH type 2 heat nociceptors.

Magnetic nanobubbles with potential for targeted drug delivery and trimodal imaging in breast cancer: an in vitro study.

PubMed

Song, Weixiang; Luo, Yindeng; Zhao, Yajing; Liu, Xinjie; Zhao, Jiannong; Luo, Jie; Zhang, Qunxia; Ran, Haitao; Wang, Zhigang; Guo, Dajing

2017-05-01

The aim of this study was to improve tumor-targeted therapy for breast cancer by designing magnetic nanobubbles with the potential for targeted drug delivery and multimodal imaging. Herceptin-decorated and ultrasmall superparamagnetic iron oxide (USPIO)/paclitaxel (PTX)-embedded nanobubbles (PTX-USPIO-HER-NBs) were manufactured by combining a modified double-emulsion evaporation process with carbodiimide technique. PTX-USPIO-HER-NBs were examined for characterization, specific cell-targeting ability and multimodal imaging. PTX-USPIO-HER-NBs exhibited excellent entrapment efficiency of Herceptin/PTX/USPIO and showed greater cytotoxic effects than other delivery platforms. Low-frequency ultrasound triggered accelerated PTX release. Moreover, the magnetic nanobubbles were able to enhance ultrasound, magnetic resonance and photoacoustics trimodal imaging. These results suggest that PTX-USPIO-HER-NBs have potential as a multimodal contrast agent and as a system for ultrasound-triggered drug release in breast cancer.

Estimating Single-Trial Responses in EEG

NASA Technical Reports Server (NTRS)

Shah, A. S.; Knuth, K. H.; Truccolo, W. A.; Mehta, A. D.; Fu, K. G.; Johnston, T. A.; Ding, M.; Bressler, S. L.; Schroeder, C. E.; Clancy, Daniel (Technical Monitor)

2002-01-01

Accurate characterization of single-trial field potential responses is critical from a number of perspectives. For example, it allows differentiation of an evoked response from ongoing EEG. We previously developed the multiple component Event Related Potential (mcERP) algorithm to improve resolution of the single-trial evoked response. The mcERP model states that multiple components, each specified by a stereotypic waveform varying in latency and amplitude from trial to trial, comprise the evoked response. Application of the mcERP algorithm to simulated data with three independent, synthetic components has shown that the model is capable of separating these components and estimating their variability. Application of the model to single trial, visual evoked potentials recorded simultaneously from all V1 laminae in an awake, fixating macaque yielded local and far-field components. Certain local components estimated by the model were distributed in both granular and supragranular laminae. This suggests a linear coupling between the responses of thalamo-recipient neuronal ensembles and subsequent responses of supragranular neuronal ensembles, as predicted by the feedforward anatomy of V1. Our results indicate that the mcERP algorithm provides a valid estimation of single-trial responses. This will enable analyses that depend on trial-to-trial variations and those that require separation of the evoked response from background EEG rhythms

Auditory fear conditioning modifies steady-state evoked potentials in the rat inferior colliculus.

PubMed

Lockmann, André Luiz Vieira; Mourão, Flávio Afonso Gonçalves; Moraes, Marcio Flávio Dutra

2017-08-01

The rat inferior colliculus (IC) is a major midbrain relay for ascending inputs from the auditory brain stem and has been suggested to play a key role in the processing of aversive sounds. Previous studies have demonstrated that auditory fear conditioning (AFC) potentiates transient responses to brief tones in the IC, but it remains unexplored whether AFC modifies responses to sustained periodic acoustic stimulation-a type of response called the steady-state evoked potential (SSEP). Here we used an amplitude-modulated tone-a 10-kHz tone with a sinusoidal amplitude modulation of 53.7 Hz-as the conditioning stimulus (CS) in an AFC protocol (5 CSs per day in 3 consecutive days) while recording local field potentials (LFPs) from the IC. In the preconditioning session ( day 1 ), the CS elicited prominent 53.7-Hz SSEPs. In the training session ( day 2 ), foot shocks occurred at the end of each CS (paired group) or randomized in the inter-CS interval (unpaired group). In the test session ( day 3 ), SSEPs markedly differed from preconditioning in the paired group: in the first two trials the phase to which the SSEP coupled to the CS amplitude envelope shifted ~90°; in the last two trials the SSEP power and the coherence of SSEP with the CS amplitude envelope increased. LFP power decreased in frequency bands other than 53.7 Hz. In the unpaired group, SSEPs did not change in the test compared with preconditioning. Our results show that AFC causes dissociated changes in the phase and power of SSEP in the IC. NEW & NOTEWORTHY Local field potential oscillations in the inferior colliculus follow the amplitude envelope of an amplitude-modulated tone, originating a neural response called the steady-state evoked potential. We show that auditory fear conditioning of an amplitude-modulated tone modifies two parameters of the steady-state evoked potentials in the inferior colliculus: first the phase to which the evoked oscillation couples to the amplitude-modulated tone shifts; subsequently, the evoked oscillation power increases along with its coherence with the amplitude-modulated tone. Copyright © 2017 the American Physiological Society.

Analysis of wave III of brain stem auditory evoked potential waveforms during microvascular decompression of cranial nerve VII for hemifacial spasm.

PubMed

Thirumala, Parthasarathy D; Krishnaiah, Balaji; Crammond, Donald J; Habeych, Miguel E; Balzer, Jeffrey R

2014-04-01

Intraoperative monitoring of brain stem auditory evoked potential during microvascular decompression (MVD) prevent hearing loss (HL). Previous studies have shown that changes in wave III (wIII) are an early and sensitive sign of auditory nerve injury. To evaluate the changes of amplitude and latency of wIII of brain stem auditory evoked potential during MVD and its association with postoperative HL. Hearing loss was classified by American Academy of Otolaryngology - Head and Neck Surgery (AAO-HNS) criteria, based on changes in pure tone audiometry and speech discrimination score. Retrospective analysis of wIII in patients who underwent intraoperative monitoring with brain stem auditory evoked potential during MVD was performed. A univariate logistic regression analysis was performed on independent variables amplitude of wIII and latency of wIII at change max and On-Skin, or a final recording at the time of skin closure. A further analysis for the same variables was performed adjusting for the loss of wave. The latency of wIII was not found to be significantly different between groups I and II. The amplitude of wIII was significantly decreased in the group with HL. Regression analysis did not find any increased odds of HL with changes in the amplitude of wIII. Changes in wave III did not increase the odds of HL in patients who underwent brain stem auditory evoked potential s during MVD. This information might be valuable to evaluate the value of wIII as an alarm criterion during MVD to prevent HL.

Neurophysiological correlates of abnormal somatosensory temporal discrimination in dystonia.

PubMed

Antelmi, Elena; Erro, Roberto; Rocchi, Lorenzo; Liguori, Rocco; Tinazzi, Michele; Di Stasio, Flavio; Berardelli, Alfredo; Rothwell, John C; Bhatia, Kailash P

2017-01-01

Somatosensory temporal discrimination threshold is often prolonged in patients with dystonia. Previous evidence suggested that this might be caused by impaired somatosensory processing in the time domain. Here, we tested if other markers of reduced inhibition in the somatosensory system might also contribute to abnormal somatosensory temporal discrimination in dystonia. Somatosensory temporal discrimination threshold was measured in 19 patients with isolated cervical dystonia and 19 age-matched healthy controls. We evaluated temporal somatosensory inhibition using paired-pulse somatosensory evoked potentials, spatial somatosensory inhibition by measuring the somatosensory evoked potentials interaction between simultaneous stimulation of the digital nerves in thumb and index finger, and Gamma-aminobutyric acid-ergic (GABAergic) sensory inhibition using the early and late components of high-frequency oscillations in digital nerves somatosensory evoked potentials. When compared with healthy controls, dystonic patients had longer somatosensory temporal discrimination thresholds, reduced suppression of cortical and subcortical paired-pulse somatosensory evoked potentials, less spatial inhibition of simultaneous somatosensory evoked potentials, and a smaller area of the early component of the high-frequency oscillations. A logistic regression analysis found that paired pulse suppression of the N20 component at an interstimulus interval of 5 milliseconds and the late component of the high-frequency oscillations were independently related to somatosensory temporal discrimination thresholds. "Dystonia group" was also a predictor of enhanced somatosensory temporal discrimination threshold, indicating a dystonia-specific effect that independently influences this threshold. Increased somatosensory temporal discrimination threshold in dystonia is related to reduced activity of inhibitory circuits within the primary somatosensory cortex. © 2016 International Parkinson and Movement Disorder Society. © 2016 International Parkinson and Movement Disorder Society.

Hearing Screening of High-Risk Newborns with Brainstem Auditory Evoked Potentials: A Follow-Up Study.

ERIC Educational Resources Information Center

Shannon, Dorothy A.; And Others

1984-01-01

The brainstem auditory evoked potential (BAEP) was evaluated as a hearing screening test in 168 high-risk newborns. The BAEP was found to be a sensitive procedure for the early identification of hearing-impaired newborns. However, the yield of significant hearing abnormalities was less than predicted in other studies using BAEP. (Author/CL)

Auditory Evoked Potentials and Hand Preference in 6-Month-Old Infants: Possible Gender-Related Differences in Cerebral Organization.

ERIC Educational Resources Information Center

Shucard, Janet L.; Shucard, David W.

1990-01-01

Verbal and musical stimuli were presented to infants in a study of the relations of evoked potential left-right amplitude asymmetries to gender and hand preference. There was a relation between asymmetry and hand preference, and for girls, between asymmetry and stimulus condition. Results suggest a gender difference in cerebral hemisphere…

DEPRESSION OF THE PHOTIC AFTER DISCHARGE OF FLASH EVOKED POTENTIALS BY PHYSOSTIGMINE, CARBARYL AND PROPOXUR AND THE RELATIONSHIP TO INHIBITION OF BRAIN CHOLINESTERASE

EPA Science Inventory

The effects of N-methyl carbamate pesticides on the photic after discharge (PhAD) of flash evoked potentials (FEPs) and the relationship between inhibition of brain cholinesterase (ChE) activity and the PhAD were evaluated. FEPs were recorded in Long Evans rats treated with physo...

The Effectiveness of FES-Evoked EMG Potentials to Assess Muscle Force and Fatigue in Individuals with Spinal Cord Injury

PubMed Central

Ibitoye, Morufu Olusola; Estigoni, Eduardo H.; Hamzaid, Nur Azah; Wahab, Ahmad Khairi Abdul; Davis, Glen M.

2014-01-01

The evoked electromyographic signal (eEMG) potential is the standard index used to monitor both electrical changes within the motor unit during muscular activity and the electrical patterns during evoked contraction. However, technical and physiological limitations often preclude the acquisition and analysis of the signal especially during functional electrical stimulation (FES)-evoked contractions. Hence, an accurate quantification of the relationship between the eEMG potential and FES-evoked muscle response remains elusive and continues to attract the attention of researchers due to its potential application in the fields of biomechanics, muscle physiology, and rehabilitation science. We conducted a systematic review to examine the effectiveness of eEMG potentials to assess muscle force and fatigue, particularly as a biofeedback descriptor of FES-evoked contractions in individuals with spinal cord injury. At the outset, 2867 citations were identified and, finally, fifty-nine trials met the inclusion criteria. Four hypotheses were proposed and evaluated to inform this review. The results showed that eEMG is effective at quantifying muscle force and fatigue during isometric contraction, but may not be effective during dynamic contractions including cycling and stepping. Positive correlation of up to r = 0.90 (p < 0.05) between the decline in the peak-to-peak amplitude of the eEMG and the decline in the force output during fatiguing isometric contractions has been reported. In the available prediction models, the performance index of the eEMG signal to estimate the generated muscle force ranged from 3.8% to 34% for 18 s to 70 s ahead of the actual muscle force generation. The strength and inherent limitations of the eEMG signal to assess muscle force and fatigue were evident from our findings with implications in clinical management of spinal cord injury (SCI) population. PMID:25025551

Large Amplitude Cortical Evoked Potentials in Nonepileptic Patients. Reviving an Old Neurophysiologic Tool to Help Detect CNS Pathology.

PubMed

Martín-Palomeque, Guillermo; Castro-Ortiz, Antonio; Pamplona-Valenzuela, Pilar; Saiz-Sepúlveda, Miguel Á; Cabañes-Martínez, Lidia; López, Jaime R

2017-01-01

Although large amplitude evoked potentials (EPs) are typically associated with progressive myoclonic epilepsy patients, giant EPs imply central nervous system (CNS) hyperexcitability and can be seen in various nonepileptic disorders. We performed a retrospective chart review including history, physical examination, imaging and diagnostic studies of nonepileptic patients with large amplitude somatosensory evoked potentials (SSEPs) and visual evoked potentials (VEPs) during 2007 to 2013. Large amplitude EPs were defined as follows: VEPs (N75-P100) >18 μV; and SSEPs (N20-P25) >6.4 μV. Recording montage for VEPs was Oz-Cz and SSEPs C3'/C4'-Fz. Fifty-two patients (33 females, 19 males; age range, 9-90 years) were identified. No CNS pathology was detected in 7 patients. All remaining patients were diagnosed with new CNS disorders including: vascular (37%); myelopathies (13%); demyelinating (11%); space occupying lesions (8.7%); syringomyelia (8.7%); hydrocephalus (6.5%); Vitamin B-12 deficiency (4.3%); multiple system atrophy (4.3%); and toxins (2.2%). This study supports the notion that large amplitude EP implies CNS hyperexcitability and CNS disease. These results confirm the utility of EP studies in patients with suspected CNS pathology.

Correlation of pattern reversal visual evoked potential parameters with the pattern standard deviation in primary open angle glaucoma.

PubMed

Kothari, Ruchi; Bokariya, Pradeep; Singh, Ramji; Singh, Smita; Narang, Purvasha

2014-01-01

To evaluate whether glaucomatous visual field defect particularly the pattern standard deviation (PSD) of Humphrey visual field could be associated with visual evoked potential (VEP) parameters of patients having primary open angle glaucoma (POAG). Visual field by Humphrey perimetry and simultaneous recordings of pattern reversal visual evoked potential (PRVEP) were assessed in 100 patients with POAG. The stimulus configuration for VEP recordings consisted of the transient pattern reversal method in which a black and white checker board pattern was generated (full field) and displayed on VEP monitor (colour 14″) by an electronic pattern regenerator inbuilt in an evoked potential recorder (RMS EMG EP MARK II). The results of our study indicate that there is a highly significant (P<0.001) negative correlation of P100 amplitude and a statistically significant (P<0.05) positive correlation of N70 latency, P100 latency and N155 latency with the PSD of Humphrey visual field in the subjects of POAG in various age groups as evaluated by Student's t-test. Prolongation of VEP latencies were mirrored by a corresponding increase of PSD values. Conversely, as PSD increases the magnitude of VEP excursions were found to be diminished.

Index finger somatosensory evoked potentials in blind Braille readers.

PubMed

Giriyappa, Dayananda; Subrahmanyam, Roopakala Mysore; Rangashetty, Srinivasa; Sharma, Rajeev

2009-01-01

Traditionally, vision has been considered the dominant modality in our multi-sensory perception of the surrounding world. Sensory input via non-visual tracts becomes of greater behavioural relevance in totally blind individuals to enable effective interaction with the world around them. These include audition and tactile perceptions, leading to an augmentation in these perceptions when compared with normal sighted individuals. The objective of the present work was to study the index finger somatosensory evoked potentials (SEPs) in totally blind and normal sighted individuals. SEPs were recorded in 15 Braille reading totally blind females and compared with 15 age-matched normal sighted females. Latency and amplitudes of somatosensory evoked potential waveforms (N9, N13, and N20) were measured. Amplitude of N20 SEP (a cortical somatosensory evoked potential) was significantly larger in the totally blind than in normal sighted individuals (p < 0.05). The amplitudes of N9 and N13 SEP and the latencies of all recorded SEPs showed no significant differences. Blindness has a profound effect on the Braille reading right index finger. Totally blind Braille readers have larger N20 amplitude, suggestive of greater somatosensory cortical representation of the Braille reading index finger.

Laser and somatosensory evoked potentials in amyotrophic lateral sclerosis.

PubMed

Isak, Baris; Tankisi, Hatice; Johnsen, Birger; Pugdahl, Kirsten; Finnerup, Nanna Brix; Fuglsang-Frederiksen, Anders

2016-10-01

Mild involvement of sensory nerves has been reported in previous studies in ALS patients. In this study, we assessed sensory pathways in ALS patients using laser evoked potentials (LEPs) and somatosensory evoked potentials (SSEPs). We recruited 18 ALS patients and 31 healthy subjects. Neodymium-doped yttrium aluminium perovskite (Nd:YAP)-laser was used to evoke LEPs in upper (UE) and lower (LE) extremities. N1 and N2P2 potentials were obtained from contralateral insular cortex (T3 or T4) and vertex (Cz), respectively. Median SSEPs were recorded from C3' or C4' and tibial SSEPs from Cz'. Compared to controls, ALS patients had longer N2 and P2 latencies, and smaller N2P2 amplitudes in both UE- and LE-LEPs (p<0.05), and longer latencies for median and tibial SSEPs (p<0.05). LEPs and SSEPs were abnormal in 72.2% and 56.6% patients, respectively. Cortical potentials showed that A-beta or A-delta sensory fibres, or both, were impaired in more than half of the ALS patients. The findings support that ALS is a multi-systemic disorder involving, although to a lesser degree, other systems than the motor. Copyright © 2016 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.

On hemispheric differences in evoked potentials to speech stimuli

NASA Technical Reports Server (NTRS)

Galambos, R.; Benson, P.; Smith, T. S.; Schulman-Galambos, C.; Osier, H.

1975-01-01

Confirmation is provided for the belief that evoked potentials may reflect differences in hemispheric functioning that are marginal at best. Subjects were right-handed and audiologically normal men and women, and responses were recorded using standard EEG techniques. Subjects were instructed to listen for the targets while laying in a darkened sound booth. Different stimuli, speech and tone signals, were used. Speech sounds were shown to evoke a response pattern that resembles that to tone or clicks. Analysis of variances on peak amplitude and latency measures showed no significant differences between hemispheres, however, a Wilcoxon test showed significant differences in hemispheres for certain target tasks.

Steady-state visual evoked potential (SSVEP)-based communication: impact of harmonic frequency components

NASA Astrophysics Data System (ADS)

Müller-Putz, Gernot R.; Scherer, Reinhold; Brauneis, Christian; Pfurtscheller, Gert

2005-12-01

Brain-computer interfaces (BCIs) can be realized on the basis of steady-state evoked potentials (SSEPs). These types of brain signals resulting from repetitive stimulation have the same fundamental frequency as the stimulation but also include higher harmonics. This study investigated how the classification accuracy of a 4-class BCI system can be improved by incorporating visually evoked harmonic oscillations. The current study revealed that the use of three SSVEP harmonics yielded a significantly higher classification accuracy than was the case for one or two harmonics. During feedback experiments, the five subjects investigated reached a classification accuracy between 42.5% and 94.4%.

Steady-state visual evoked potential (SSVEP)-based communication: impact of harmonic frequency components.

PubMed

Müller-Putz, Gernot R; Scherer, Reinhold; Brauneis, Christian; Pfurtscheller, Gert

2005-12-01

Brain-computer interfaces (BCIs) can be realized on the basis of steady-state evoked potentials (SSEPs). These types of brain signals resulting from repetitive stimulation have the same fundamental frequency as the stimulation but also include higher harmonics. This study investigated how the classification accuracy of a 4-class BCI system can be improved by incorporating visually evoked harmonic oscillations. The current study revealed that the use of three SSVEP harmonics yielded a significantly higher classification accuracy than was the case for one or two harmonics. During feedback experiments, the five subjects investigated reached a classification accuracy between 42.5% and 94.4%.

Multimodal Self-Authoring across Bi/Multilingual Educator and Student Learning Spaces

ERIC Educational Resources Information Center

Valdez, Verónica E.; Omerbašic, Delila

2015-01-01

Drawing on sociocultural perspectives, this article illustrates the potential for extending figured worlds through cultural artifacts. Using thematic and multimodal analysis, the authors first compare how spaces of authoring were produced in two professional development settings: Proyecto Bilingüe and Critical Education Studies. Following one…

"Imaginings": Reflections on Plurilingual Students' Creative Multimodal Works

ERIC Educational Resources Information Center

Stille, Saskia; Prasad, Gail

2015-01-01

The purpose of this article is to illustrate the potential contribution of a multimodal approach to English language teaching and learning in the educational context. Collaborating with English as a second language (ESL) and classroom teachers to explore ways to improve pedagogy in multilingual, multicultural schools, the authors discovered many…

Socioeconomic and travel demand forecasts for Virginia and potential policy responses : a report for VTrans2035 : Virginia's statewide multimodal transportation plan.

DOT National Transportation Integrated Search

2009-01-01

VTrans2035, Virginia's statewide multimodal transportation plan, requires 25-year forecasts of socioeconomic and travel activity. Between 2010 and 2035, daily vehicle miles traveled (DVMT) will increase between 35% and 45%, accompanied by increases i...

Mothers' multimodal information processing is modulated by multimodal interactions with their infants.

PubMed

Tanaka, Yukari; Fukushima, Hirokata; Okanoya, Kazuo; Myowa-Yamakoshi, Masako

2014-10-17

Social learning in infancy is known to be facilitated by multimodal (e.g., visual, tactile, and verbal) cues provided by caregivers. In parallel with infants' development, recent research has revealed that maternal neural activity is altered through interaction with infants, for instance, to be sensitive to infant-directed speech (IDS). The present study investigated the effect of mother- infant multimodal interaction on maternal neural activity. Event-related potentials (ERPs) of mothers were compared to non-mothers during perception of tactile-related words primed by tactile cues. Only mothers showed ERP modulation when tactile cues were incongruent with the subsequent words, and only when the words were delivered with IDS prosody. Furthermore, the frequency of mothers' use of those words was correlated with the magnitude of ERP differentiation between congruent and incongruent stimuli presentations. These results suggest that mother-infant daily interactions enhance multimodal integration of the maternal brain in parenting contexts.

Mothers' multimodal information processing is modulated by multimodal interactions with their infants

PubMed Central

Tanaka, Yukari; Fukushima, Hirokata; Okanoya, Kazuo; Myowa-Yamakoshi, Masako

2014-01-01

Social learning in infancy is known to be facilitated by multimodal (e.g., visual, tactile, and verbal) cues provided by caregivers. In parallel with infants' development, recent research has revealed that maternal neural activity is altered through interaction with infants, for instance, to be sensitive to infant-directed speech (IDS). The present study investigated the effect of mother- infant multimodal interaction on maternal neural activity. Event-related potentials (ERPs) of mothers were compared to non-mothers during perception of tactile-related words primed by tactile cues. Only mothers showed ERP modulation when tactile cues were incongruent with the subsequent words, and only when the words were delivered with IDS prosody. Furthermore, the frequency of mothers' use of those words was correlated with the magnitude of ERP differentiation between congruent and incongruent stimuli presentations. These results suggest that mother-infant daily interactions enhance multimodal integration of the maternal brain in parenting contexts. PMID:25322936

Saturation thresholds of evoked neural and hemodynamic responses in awake and asleep rats

NASA Astrophysics Data System (ADS)

Schei, Jennifer L.; Van Nortwick, Amy S.; Meighan, Peter C.; Rector, David M.

2011-03-01

Neural activation generates a hemodynamic response to the localized region replenishing nutrients to the area. Changes in vigilance state have been shown to alter the vascular response where the vascular response is muted during wake compared to quiet sleep. We tested the saturation thresholds of the neurovascular response in the auditory cortex during wake and sleep by chronically implanting rats with an EEG electrode, a light emitting diode (LED, 600 nm), and photodiode to simultaneously measure evoked response potentials (ERPs) and evoked hemodynamic responses. We stimulated the cortex with a single speaker click delivered at random intervals 2-13 s at varied stimulus intensities ranging from 45-80 dB. To further test the potential for activity related saturation, we sleep deprived animals for 2, 4, or 6 hours and recorded evoked responses during the first hour recovery period. With increasing stimulus intensity, integrated ERPs and evoked hemodynamic responses increased; however the hemodynamic response approached saturation limits at a lower stimulus intensity than the ERP. With longer periods of sleep deprivation, the integrated ERPs did not change but evoked hemodynamic responses decreased. There may be physical limits in cortical blood delivery and vascular compliance, and with extended periods of neural activity during wake, vessels may approach these limits.

Steady-State Somatosensory Evoked Potential for Brain-Computer Interface—Present and Future

PubMed Central

Ahn, Sangtae; Kim, Kiwoong; Jun, Sung Chan

2016-01-01

Brain-computer interface (BCI) performance has achieved continued improvement over recent decades, and sensorimotor rhythm-based BCIs that use motor function have been popular subjects of investigation. However, it remains problematic to introduce them to the public market because of their low reliability. As an alternative resolution to this issue, visual-based BCIs that use P300 or steady-state visually evoked potentials (SSVEPs) seem promising; however, the inherent visual fatigue that occurs with these BCIs may be unavoidable. For these reasons, steady-state somatosensory evoked potential (SSSEP) BCIs, which are based on tactile selective attention, have gained increasing attention recently. These may reduce the fatigue induced by visual attention and overcome the low reliability of motor activity. In this literature survey, recent findings on SSSEP and its methodological uses in BCI are reviewed. Further, existing limitations of SSSEP BCI and potential future directions for the technique are discussed. PMID:26834611

Automatic classification of visual evoked potentials based on wavelet decomposition

NASA Astrophysics Data System (ADS)

Stasiakiewicz, Paweł; Dobrowolski, Andrzej P.; Tomczykiewicz, Kazimierz

2017-04-01

Diagnosis of part of the visual system, that is responsible for conducting compound action potential, is generally based on visual evoked potentials generated as a result of stimulation of the eye by external light source. The condition of patient's visual path is assessed by set of parameters that describe the time domain characteristic extremes called waves. The decision process is compound therefore diagnosis significantly depends on experience of a doctor. The authors developed a procedure - based on wavelet decomposition and linear discriminant analysis - that ensures automatic classification of visual evoked potentials. The algorithm enables to assign individual case to normal or pathological class. The proposed classifier has a 96,4% sensitivity at 10,4% probability of false alarm in a group of 220 cases and area under curve ROC equals to 0,96 which, from the medical point of view, is a very good result.

Transfer function of multimode fiber links using an electric field propagation model: Application to Radio over Fibre Systems.

PubMed

Gasulla, I; Capmany, J

2006-10-02

We present a closed-form expression for the evaluation of the transfer function of a multimode fiber (MMF) link based on the electric field propagation model. After validating the result we investigate the potential for broadband transmission in regions far from baseband. We find that MMFs offer the potential for broadband ROF transmission in the microwave and millimetre wave regions in short and middle reach distances.

Median and ulnar muscle and sensory evoked potentials.

PubMed

Felsenthal, G

1978-08-01

The medical literature was reviewed to find suggested clinical applications of the study of the amplitude of evoked muscle action potentials (MAP) and sensory action potentials (SAP). In addition, the literature was reviewed to ascertain the normal amplitude and duration of the evoked MAP and SAP as well as the factors affecting the amplitude: age, sex, temperature, ischemia. The present study determined the normal amplitude and duration of the median and ulnar MAP and SAP in fifty normal subjects. The amplitude of evoked muscle or sensory action potentials depends on multiple factors. Increased skin resistance, capacitance, and impedance at the surface of the recording electrode diminishes the amplitude. Similarly, increased distance from the source of the action potential diminishes its amplitude. Increased interelectrode distance increases the amplitude of the bipolarly recorded sensory action potential until a certain interelectrode distance is exceeded and the diphasic response becomes tri- or tetraphasic. Artifact or poor technique may reduce the potential difference between the recording electrodes or obscure the late positive phase of the action potential and thus diminish the peak to peak amplitude measurement. Intraindividual comparison indicated a marked difference of amplitude in opposite hands. The range of the MAP of the abductor pollicis brevis in one hand was 40.0--100% of the response in the opposite hand. For the abductor digiti minimi, the MAP was 58.5--100% of the response of the opposite hand. The median and ulnar SAP was between 50--100% of the opposite SAP. Consequent to these findings the effect of hand dominance on the amplitude of median and ulnar evoked muscle and sensory action potentials was studied in 41 right handed volunteers. The amplitudes of the median muscle action potential (p less than 0.02) and the median and ulnar sensory action potentials (p less than 0.001) were significantly less in the dominant hand. There was no significant difference between the ulnar muscle action potentials or for the median and ulnar distal motor and sensory latencies in the right and left hands of this group of volunteers.

On the effects of multimodal information integration in multitasking.

PubMed

Stock, Ann-Kathrin; Gohil, Krutika; Huster, René J; Beste, Christian

2017-07-07

There have recently been considerable advances in our understanding of the neuronal mechanisms underlying multitasking, but the role of multimodal integration for this faculty has remained rather unclear. We examined this issue by comparing different modality combinations in a multitasking (stop-change) paradigm. In-depth neurophysiological analyses of event-related potentials (ERPs) were conducted to complement the obtained behavioral data. Specifically, we applied signal decomposition using second order blind identification (SOBI) to the multi-subject ERP data and source localization. We found that both general multimodal information integration and modality-specific aspects (potentially related to task difficulty) modulate behavioral performance and associated neurophysiological correlates. Simultaneous multimodal input generally increased early attentional processing of visual stimuli (i.e. P1 and N1 amplitudes) as well as measures of cognitive effort and conflict (i.e. central P3 amplitudes). Yet, tactile-visual input caused larger impairments in multitasking than audio-visual input. General aspects of multimodal information integration modulated the activity in the premotor cortex (BA 6) as well as different visual association areas concerned with the integration of visual information with input from other modalities (BA 19, BA 21, BA 37). On top of this, differences in the specific combination of modalities also affected performance and measures of conflict/effort originating in prefrontal regions (BA 6).

Neural signatures of economic parameters during decision-making: a functional MRI (FMRI), electroencephalography (EEG) and autonomic monitoring study.

PubMed

Minati, Ludovico; Grisoli, Marina; Franceschetti, Silvana; Epifani, Francesca; Granvillano, Alice; Medford, Nick; Harrison, Neil A; Piacentini, Sylvie; Critchley, Hugo D

2012-01-01

Adaptive behaviour requires an ability to obtain rewards by choosing between different risky options. Financial gambles can be used to study effective decision-making experimentally, and to distinguish processes involved in choice option evaluation from outcome feedback and other contextual factors. Here, we used a paradigm where participants evaluated 'mixed' gambles, each presenting a potential gain and a potential loss and an associated variable outcome probability. We recorded neural responses using autonomic monitoring, electroencephalography (EEG) and functional neuroimaging (fMRI), and used a univariate, parametric design to test for correlations with the eleven economic parameters that varied across gambles, including expected value (EV) and amount magnitude. Consistent with behavioural economic theory, participants were risk-averse. Gamble evaluation generated detectable autonomic responses, but only weak correlations with outcome uncertainty were found, suggesting that peripheral autonomic feedback does not play a major role in this task. Long-latency stimulus-evoked EEG potentials were sensitive to expected gain and expected value, while alpha-band power reflected expected loss and amount magnitude, suggesting parallel representations of distinct economic qualities in cortical activation and central arousal. Neural correlates of expected value representation were localized using fMRI to ventromedial prefrontal cortex, while the processing of other economic parameters was associated with distinct patterns across lateral prefrontal, cingulate, insula and occipital cortices including default-mode network and early visual areas. These multimodal data provide complementary evidence for distributed substrates of choice evaluation across multiple, predominantly cortical, brain systems wherein distinct regions are preferentially attuned to specific economic features. Our findings extend biologically-plausible models of risky decision-making while providing potential biomarkers of economic representations that can be applied to the study of deficits in motivational behaviour in neurological and psychiatric patients.

Objective quantification of the tinnitus decompensation by synchronization measures of auditory evoked single sweeps.

PubMed

Strauss, Daniel J; Delb, Wolfgang; D'Amelio, Roberto; Low, Yin Fen; Falkai, Peter

2008-02-01

Large-scale neural correlates of the tinnitus decompensation might be used for an objective evaluation of therapies and neurofeedback based therapeutic approaches. In this study, we try to identify large-scale neural correlates of the tinnitus decompensation using wavelet phase stability criteria of single sweep sequences of late auditory evoked potentials as synchronization stability measure. The extracted measure provided an objective quantification of the tinnitus decompensation and allowed for a reliable discrimination between a group of compensated and decompensated tinnitus patients. We provide an interpretation for our results by a neural model of top-down projections based on the Jastreboff tinnitus model combined with the adaptive resonance theory which has not been applied to model tinnitus so far. Using this model, our stability measure of evoked potentials can be linked to the focus of attention on the tinnitus signal. It is concluded that the wavelet phase stability of late auditory evoked potential single sweeps might be used as objective tinnitus decompensation measure and can be interpreted in the framework of the Jastreboff tinnitus model and adaptive resonance theory.

Multimodal Nonlinear Optical Microscopy

PubMed Central

Yue, Shuhua; Slipchenko, Mikhail N.; Cheng, Ji-Xin

2013-01-01

Because each nonlinear optical (NLO) imaging modality is sensitive to specific molecules or structures, multimodal NLO imaging capitalizes the potential of NLO microscopy for studies of complex biological tissues. The coupling of multiphoton fluorescence, second harmonic generation, and coherent anti-Stokes Raman scattering (CARS) has allowed investigation of a broad range of biological questions concerning lipid metabolism, cancer development, cardiovascular disease, and skin biology. Moreover, recent research shows the great potential of using CARS microscope as a platform to develop more advanced NLO modalities such as electronic-resonance-enhanced four-wave mixing, stimulated Raman scattering, and pump-probe microscopy. This article reviews the various approaches developed for realization of multimodal NLO imaging as well as developments of new NLO modalities on a CARS microscope. Applications to various aspects of biological and biomedical research are discussed. PMID:24353747

Investigation of protein selectivity in multimodal chromatography using in silico designed Fab fragment variants.

PubMed

Karkov, Hanne Sophie; Krogh, Berit Olsen; Woo, James; Parimal, Siddharth; Ahmadian, Haleh; Cramer, Steven M

2015-11-01

In this study, a unique set of antibody Fab fragments was designed in silico and produced to examine the relationship between protein surface properties and selectivity in multimodal chromatographic systems. We hypothesized that multimodal ligands containing both hydrophobic and charged moieties would interact strongly with protein surface regions where charged groups and hydrophobic patches were in close spatial proximity. Protein surface property characterization tools were employed to identify the potential multimodal ligand binding regions on the Fab fragment of a humanized antibody and to evaluate the impact of mutations on surface charge and hydrophobicity. Twenty Fab variants were generated by site-directed mutagenesis, recombinant expression, and affinity purification. Column gradient experiments were carried out with the Fab variants in multimodal, cation-exchange, and hydrophobic interaction chromatographic systems. The results clearly indicated that selectivity in the multimodal system was different from the other chromatographic modes examined. Column retention data for the reduced charge Fab variants identified a binding site comprising light chain CDR1 as the main electrostatic interaction site for the multimodal and cation-exchange ligands. Furthermore, the multimodal ligand binding was enhanced by additional hydrophobic contributions as evident from the results obtained with hydrophobic Fab variants. The use of in silico protein surface property analyses combined with molecular biology techniques, protein expression, and chromatographic evaluations represents a previously undescribed and powerful approach for investigating multimodal selectivity with complex biomolecules. © 2015 Wiley Periodicals, Inc.

Multimodal recording of brain activity in term newborns during photic stimulation by near-infrared spectroscopy and electroencephalography

NASA Astrophysics Data System (ADS)

Biallas, Martin; Trajkovic, Ivo; Hagmann, Cornelia; Scholkmann, Felix; Jenny, Carmen; Holper, Lisa; Beck, Andreas; Wolf, Martin

2012-08-01

In this study 14 healthy term newborns (postnatal mean age 2.1 days) underwent photic stimulation during sleep on two different days. Near-infrared spectroscopy (NIRS) and electroencephalography (EEG) was acquired simultaneously. The aims of the study were: to determine (i) the sensitivity and (ii) the repeatability of NIRS to detect the hemodynamic response, (iii) the sensitivity and (iv) the repeatability of EEG to detect a visual evoked potential (VEP), (v) to analyze optical data for the optical neuronal signal, and (vi) to test whether inadequate stimulation could be reason for absent hemodynamic responses. The results of the study were as follows. (i) Sensitivity of NIRS was 61.5% to detect hemodynamic responses; (ii) their reproducibility was 41.7%. A VEP was detected (iii) in 96.3% of all subjects with (iv) a reproducibility of 92.3%. (v) In two measurements data met the criteria for an optical neuronal signal. The noise level was 9.6.10-5% change in optical density. (vi) Insufficient stimulation was excluded as reason for absent hemodynamic responses. We conclude that NIRS is an promising tool to study cognitive activation and development of the brain. For clinical application, however, the sensitivity and reproducibility on an individual level needs to be improved.

Delivery of ultrashort spatially focused pulses through a multimode fiber

NASA Astrophysics Data System (ADS)

Morales-Delgado, Edgar E.; Papadopoulos, Ioannis N.; Farahi, Salma; Psaltis, Demetri; Moser, Christophe

2015-08-01

Multimode optical fibers potentially allow the transmission of larger amounts of information than their single mode counterparts because of their high number of supported modes. However, propagation of a light pulse through a multimode fiber suffers from spatial distortions due to the superposition of the various exited modes and from time broadening due to modal dispersion. We present a method based on digital phase conjugation to selectively excite in a multimode fiber specific optical fiber modes that follow similar optical paths as they travel through the fiber. The excited modes interfere constructively at the fiber output generating an ultrashort spatially focused pulse. The excitation of a limited number of modes following similar optical paths limits modal dispersion, allowing the transmission of the ultrashort pulse. We have experimentally demonstrated the delivery of a focused spot of pulse width equal to 500 fs through a 30 cm, 200 micrometer core step index multimode fiber. The results of this study show that two-photon imaging capability can be added to ultra-thin lensless endoscopy using commercial multimode fibers.

Delivery of an ultrashort spatially focused pulse to the other end of a multimode fiber using digital phase conjugation

NASA Astrophysics Data System (ADS)

Morales Delgado, Edgar E.; Papadopoulos, Ioannis N.; Farahi, Salma; Psaltis, Demetri; Moser, Christophe

2015-03-01

Multimode optical fibers potentially allow the transmission of larger amounts of information than their single mode counterparts because of their high number of supported modes. However, propagation of a light pulse through a multimode fiber suffers from spatial distortions due to the superposition of the various exited modes and from time broadening due to modal dispersion. We present a method based on digital phase conjugation to selectively excite in a multimode fiber specific optical fiber modes that follow similar optical paths as they travel through the fiber. The excited modes interfere constructively at the fiber output generating an ultrashort spatially focused pulse. The excitation of a limited number of modes following similar optical paths limits modal dispersion, allowing the transmission of the ultrashort pulse. We have experimentally demonstrated the delivery of a focused spot of pulse width equal to 500 fs through a 30 cm, 200 micrometer core step-index multimode fiber. The results of this study show that two-photon imaging capability can be added to ultra-thin lensless endoscopy using commercial multimode fibers.

Auditory Evoked Potentials as a Function of Sleep Deprivation and Recovery Sleep

DTIC Science & Technology

1985-09-29

present research: They relate to the effects of: a) 48-hours of sleep deprivation on endogenous event related potentials (ERPs); b) circadian rhythms on...the study were: decreases in amplitude for N2, P3 and N2P3 across the reprivation period; a circadian rhythm was apparent for both ERP recordings and...of cortical evoked response potentials (ERPs)? 2) How do circadian rhythms affect ERPS under conditions of sleep deprivation? 3) How do different

Matched Filtering of Visual Evoked Potentials to Detect Acceleration (+Gz) Induced Blackout

DTIC Science & Technology

1985-01-03

FILTERING OF VISUAL EVOKED POTENTIALS rO DETECT ACCELERATION ( + Gz) INDUCED BLACKOUT John Q. Nelson, Leonid Hrebien and Joseph P. Cammarota Aircraft...8217: , r .,.V -. 1-». .v. IE •> _"->.-"*« A^V :j% _"«;_"V X~«. _~»^"V.i.~» iuTtuTii i."»..-^. .-*._> r /; NOTICES REPORT NUMBERING SYSTEM - The...Potentials to Detect Acceleration (+G2) Induced Blackout 12 PERSONAL AUTHOR(S) John G. Nelson, Leonid Hrebien, Joseph P. Cammarota 13* TYPE OF REPORT

Waveform Similarity Analysis: A Simple Template Comparing Approach for Detecting and Quantifying Noisy Evoked Compound Action Potentials.

PubMed

Potas, Jason Robert; de Castro, Newton Gonçalves; Maddess, Ted; de Souza, Marcio Nogueira

2015-01-01

Experimental electrophysiological assessment of evoked responses from regenerating nerves is challenging due to the typical complex response of events dispersed over various latencies and poor signal-to-noise ratio. Our objective was to automate the detection of compound action potential events and derive their latencies and magnitudes using a simple cross-correlation template comparison approach. For this, we developed an algorithm called Waveform Similarity Analysis. To test the algorithm, challenging signals were generated in vivo by stimulating sural and sciatic nerves, whilst recording evoked potentials at the sciatic nerve and tibialis anterior muscle, respectively, in animals recovering from sciatic nerve transection. Our template for the algorithm was generated based on responses evoked from the intact side. We also simulated noisy signals and examined the output of the Waveform Similarity Analysis algorithm with imperfect templates. Signals were detected and quantified using Waveform Similarity Analysis, which was compared to event detection, latency and magnitude measurements of the same signals performed by a trained observer, a process we called Trained Eye Analysis. The Waveform Similarity Analysis algorithm could successfully detect and quantify simple or complex responses from nerve and muscle compound action potentials of intact or regenerated nerves. Incorrectly specifying the template outperformed Trained Eye Analysis for predicting signal amplitude, but produced consistent latency errors for the simulated signals examined. Compared to the trained eye, Waveform Similarity Analysis is automatic, objective, does not rely on the observer to identify and/or measure peaks, and can detect small clustered events even when signal-to-noise ratio is poor. Waveform Similarity Analysis provides a simple, reliable and convenient approach to quantify latencies and magnitudes of complex waveforms and therefore serves as a useful tool for studying evoked compound action potentials in neural regeneration studies.

[Effects of sevoflurane and propofol on evoked potentials during neurosurgical anesthesia].

PubMed

Nakagawa, Itsuo; Hidaka, Syozo; Okada, Hironori; Kubo, Takashi; Okamura, Kenta; Kato, Takahiro

2006-06-01

The effect of anesthetics on somatosensory evoked potential (SEP) and auditory brain stem response (ABR) has been a subject of intense reseach over the last two decades. In fact, volatile anesthetics have been repeatedly shown to decrease cortical amplitude in a dose-dependent fashion but the information regarding the effect of propofol is incomplete. The purpose of this study was to compare the effects of sevoflurane and propofol on evoked potentials during comparable depth of anesthesia guided by bispectral index (BIS). Forty four patients scheduled for neurosurgery were studied. Anesthesia was maintained with intravenous propofol using target controlled infusion (TCI). We measured the change of amplitude and latency of SEP(N20-P25), ABR (V wave) and visual evoked potential (VEP: P100) at three sets of sevoflurane (0%, 1%, 2%) or propofol concentrations (effect site concentration of 1.5, 2.0, 3.0 microug x ml(-1)). BIS monitor was used to measure relative depth of hypnosis. With increasing concentrations of sevoflurane (0, 1% and 2%), SEP showed dose-related reduction in its amplitude, ABR produced less marked changes and VEP showed a significant reduction at 1%. VEP at the propofol concentration of 3.0 microg x ml(-1) was decreased significantly compared with the amplitude at 1.5 microg x ml(-1) concentration. No significant change was observed with SEP and ABR during the change of propofol dosages. BIS values were almost the same with each anesthetics. VEP was most strongly affected with anesthetics, and ABR showed less marked influence of sevoflurane and propofol. Propofol based TIVA technique would induce less change in evoked potentials than sevoflurane.

Waveform Similarity Analysis: A Simple Template Comparing Approach for Detecting and Quantifying Noisy Evoked Compound Action Potentials

PubMed Central

Potas, Jason Robert; de Castro, Newton Gonçalves; Maddess, Ted; de Souza, Marcio Nogueira

2015-01-01

Experimental electrophysiological assessment of evoked responses from regenerating nerves is challenging due to the typical complex response of events dispersed over various latencies and poor signal-to-noise ratio. Our objective was to automate the detection of compound action potential events and derive their latencies and magnitudes using a simple cross-correlation template comparison approach. For this, we developed an algorithm called Waveform Similarity Analysis. To test the algorithm, challenging signals were generated in vivo by stimulating sural and sciatic nerves, whilst recording evoked potentials at the sciatic nerve and tibialis anterior muscle, respectively, in animals recovering from sciatic nerve transection. Our template for the algorithm was generated based on responses evoked from the intact side. We also simulated noisy signals and examined the output of the Waveform Similarity Analysis algorithm with imperfect templates. Signals were detected and quantified using Waveform Similarity Analysis, which was compared to event detection, latency and magnitude measurements of the same signals performed by a trained observer, a process we called Trained Eye Analysis. The Waveform Similarity Analysis algorithm could successfully detect and quantify simple or complex responses from nerve and muscle compound action potentials of intact or regenerated nerves. Incorrectly specifying the template outperformed Trained Eye Analysis for predicting signal amplitude, but produced consistent latency errors for the simulated signals examined. Compared to the trained eye, Waveform Similarity Analysis is automatic, objective, does not rely on the observer to identify and/or measure peaks, and can detect small clustered events even when signal-to-noise ratio is poor. Waveform Similarity Analysis provides a simple, reliable and convenient approach to quantify latencies and magnitudes of complex waveforms and therefore serves as a useful tool for studying evoked compound action potentials in neural regeneration studies. PMID:26325291

Cortical Auditory Evoked Potentials with Simple (Tone Burst) and Complex (Speech) Stimuli in Children with Cochlear Implant

PubMed Central

Martins, Kelly Vasconcelos Chaves; Gil, Daniela

2017-01-01

Introduction  The registry of the component P1 of the cortical auditory evoked potential has been widely used to analyze the behavior of auditory pathways in response to cochlear implant stimulation. Objective  To determine the influence of aural rehabilitation in the parameters of latency and amplitude of the P1 cortical auditory evoked potential component elicited by simple auditory stimuli (tone burst) and complex stimuli (speech) in children with cochlear implants. Method  The study included six individuals of both genders aged 5 to 10 years old who have been cochlear implant users for at least 12 months, and who attended auditory rehabilitation with an aural rehabilitation therapy approach. Participants were submitted to research of the cortical auditory evoked potential at the beginning of the study and after 3 months of aural rehabilitation. To elicit the responses, simple stimuli (tone burst) and complex stimuli (speech) were used and presented in free field at 70 dB HL. The results were statistically analyzed, and both evaluations were compared. Results  There was no significant difference between the type of eliciting stimulus of the cortical auditory evoked potential for the latency and the amplitude of P1. There was a statistically significant difference in the P1 latency between the evaluations for both stimuli, with reduction of the latency in the second evaluation after 3 months of auditory rehabilitation. There was no statistically significant difference regarding the amplitude of P1 under the two types of stimuli or in the two evaluations. Conclusion  A decrease in latency of the P1 component elicited by both simple and complex stimuli was observed within a three-month interval in children with cochlear implant undergoing aural rehabilitation. PMID:29018498

Gadolinium-Conjugated Gold Nanoshells for Multimodal Diagnostic Imaging and Photothermal Cancer Therapy

PubMed Central

Coughlin, Andrew J.; Ananta, Jeyarama S.; Deng, Nanfu; Larina, Irina V.; Decuzzi, Paolo

2014-01-01

Multimodal imaging offers the potential to improve diagnosis and enhance the specificity of photothermal cancer therapy. Toward this goal, we have engineered gadolinium-conjugated gold nanoshells and demonstrated that they enhance contrast for magnetic resonance imaging, X-Ray, optical coherence tomography, reflectance confocal microscopy, and two-photon luminescence. Additionally, these particles effectively convert near-infrared light to heat, which can be used to ablate cancer cells. Ultimately, these studies demonstrate the potential of gadolinium-nanoshells for image-guided photothermal ablation. PMID:24115690

Suppressive Effects of Resveratrol Treatment on The Intrinsic Evoked Excitability of CA1 Pyramidal Neurons

PubMed Central

Meftahi, Gholamhossein; Ghotbedin, Zohreh; Eslamizade, Mohammad Javad; Hosseinmardi, Narges; Janahmadi, Mahyar

2015-01-01

Objective Resveratrol, a phytoalexin, has a wide range of desirable biological actions. Despite a growing body of evidence indicating that resveratrol induces changes in neu- ronal function, little effort, if any, has been made to investigate the cellular effect of res- veratrol treatment on intrinsic neuronal properties. Materials and Methods This experimental study was performed to examine the acute effects of resveratrol (100 µM) on the intrinsic evoked responses of rat Cornu Ammonis (CA1) pyramidal neurons in brain slices, using whole cell patch clamp re- cording under current clamp conditions. Results Findings showed that resveratrol treatment caused dramatic changes in evoked responses of pyramidal neurons. Its treatment induced a significant (P<0.05) increase in the after hyperpolarization amplitude of the first evoked action potential. Resveratrol-treated cells displayed a significantly broader action potential (AP) when compared with either control or vehicle-treated groups. In addition, the mean instantaneous firing frequency between the first two action potentials was significantly lower in resveratrol-treated neurons. It also caused a significant reduction in the time to maximum decay of AP. The rheobase current and the utilization time were both significantly greater following resveratrol treatment. Neurons exhibited a significantly depolarized voltage threshold when exposed to resveratrol. Conclusion Results provide direct electrophysiological evidence for the inhibitory effects of resveratrol on pyramidal neurons, at least in part, by reducing the evoked neural activity. PMID:26464825

Arguing for Democracy: A Multimodal Approach to Argumentative Writing Instruction in the Social Studies Classroom

ERIC Educational Resources Information Center

Dingler, Matt

2017-01-01

Democratic societies require a citizenry skilled in argumentation. At present, the written argument maintains primacy among communicative modes. Because of its cognitive demands, written argumentation is often difficult to teach. A multimodal approach to writing instruction carries the potential to assist struggling learners. This article outlines…

A Standardization Evaluation Potential Study of the Common Multi-Mode Radar Program.

DTIC Science & Technology

1979-11-01

Radar, the RX (RF-16 etc.), Enhanced Tactical Fighter ( ETF ), and A-7. Candidate radar systems applicable to the Common Multi-Mode Radar Program...RSTC R Resupply Time to Overseas Located Bases (hours) RSTO R Depot Stock Safety Factor (standard deviations) DLY R Shipping Time to Depot from CONUS

Vibration-Induced Kinesthetic Illusions and Corticospinal Excitability Changes.

PubMed

Mancheva, Kapka; Rollnik, Jens D; Wolf, Werner; Dengler, Reinhard; Kossev, Andon

2017-01-01

The authors' aim was to investigate the changes of corticospinal excitability during kinesthetic illusions induced by tendon vibration. Motor-evoked potentials in response to transcranial magnetic stimulation were recorded from the vibrated flexor carpi radialis and its antagonist, extensor carpi radialis. The illusions were evoked under vision conditions without feedback for the position of the wrist (open or closed eyes). In these two conditions motor-evoked potential changes during vibration in the antagonist were not identical. This discrepancy may be a result of 2 simultaneously acting, different and opposite influences and the balance between them depends on visual conditions. Thus, the illusion was accompanied by the facilitation of corticospinal excitability in both vibrated muscle and its antagonist.

Cellular generators of the cortical auditory evoked potential initial component.

PubMed

Steinschneider, M; Tenke, C E; Schroeder, C E; Javitt, D C; Simpson, G V; Arezzo, J C; Vaughan, H G

1992-01-01

Cellular generators of the initial cortical auditory evoked potential (AEP) component were determined by analyzing laminar profiles of click-evoked AEPs, current source density, and multiple unit activity (MUA) in primary auditory cortex of awake monkeys. The initial AEP component is a surface-negative wave, N8, that peaks at 8-9 msec and inverts in polarity below lamina 4. N8 is generated by a lamina 4 current sink and a deeper current source. Simultaneous MUA is present from lower lamina 3 to the subjacent white matter. Findings indicate that thalamocortical afferents are a generator of N8 and support a role for lamina 4 stellate cells. Relationships to the human AEP are discussed.

Adaptive regularization network based neural modeling paradigm for nonlinear adaptive estimation of cerebral evoked potentials.

PubMed

Zhang, Jian-Hua; Böhme, Johann F

2007-11-01

In this paper we report an adaptive regularization network (ARN) approach to realizing fast blind separation of cerebral evoked potentials (EPs) from background electroencephalogram (EEG) activity with no need to make any explicit assumption on the statistical (or deterministic) signal model. The ARNs are proposed to construct nonlinear EEG and EP signal models. A novel adaptive regularization training (ART) algorithm is proposed to improve the generalization performance of the ARN. Two adaptive neural modeling methods based on the ARN are developed and their implementation and performance analysis are also presented. The computer experiments using simulated and measured visual evoked potential (VEP) data have shown that the proposed ARN modeling paradigm yields computationally efficient and more accurate VEP signal estimation owing to its intrinsic model-free and nonlinear processing characteristics.

Auditory and visual P300 evoked potentials do not predict response to valproate treatment of aggression in patients with borderline and antisocial personality disorders.

PubMed

Reeves, Roy R; Struve, Frederick A; Patrick, Gloria

2005-01-01

In this study of patients with borderline personality disorder (BPD) or antisocial personality disorder (ASPD) hospitalized because of aggressive behavior, auditory and visual P300 evoked potentials were obtained prior to treatment with valproate. Eight ASPD patients (8 males, 0 females) and 11 BPD patients (2 males, 9 females) showed improvement, while in 7 patients with ASPD (7 males, 0 females) and 10 patients with BPD (2 males, 8 females), aggression was not improved. Differences in auditory and visual P300 latencies and amplitudes were not significant for either diagnosis, or for both diagnoses combined. These findings suggest that auditory or visual P300 evoked potentials may not be useful for predicting response of aggressive behavior to valproate treatment in patients with BPD or ASPD.

Brain state-dependence of electrically evoked potentials monitored with head-mounted electronics.

PubMed

Richardson, Andrew G; Fetz, Eberhard E

2012-11-01

Inferring changes in brain connectivity is critical to studies of learning-related plasticity and stimulus-induced conditioning of neural circuits. In addition, monitoring spontaneous fluctuations in connectivity can provide insight into information processing during different brain states. Here, we quantified state-dependent connectivity changes throughout the 24-h sleep-wake cycle in freely behaving monkeys. A novel, head-mounted electronic device was used to electrically stimulate at one site and record evoked potentials at other sites. Electrically evoked potentials (EEPs) revealed the connectivity pattern between several cortical sites and the basal forebrain. We quantified state-dependent changes in the EEPs. Cortico-cortical EEP amplitude increased during slow-wave sleep, compared to wakefulness, while basal-cortical EEP amplitude decreased. The results demonstrate the utility of using portable electronics to document state-dependent connectivity changes in freely behaving primates.

Direct detection of a single evoked action potential with MRS in Lumbricus terrestris.

PubMed

Poplawsky, Alexander J; Dingledine, Raymond; Hu, Xiaoping P

2012-01-01

Functional MRI (fMRI) measures neural activity indirectly by detecting the signal change associated with the hemodynamic response following brain activation. In order to alleviate the temporal and spatial specificity problems associated with fMRI, a number of attempts have been made to detect neural magnetic fields (NMFs) with MRI directly, but have thus far provided conflicting results. In this study, we used MR to detect axonal NMFs in the median giant fiber of the earthworm, Lumbricus terrestris, by examining the free induction decay (FID) with a sampling interval of 0.32 ms. The earthworm nerve cords were isolated from the vasculature and stimulated at the threshold of action potential generation. FIDs were acquired shortly after the stimulation, and simultaneous field potential recordings identified the presence or absence of single evoked action potentials. FIDs acquired when the stimulus did not evoke an action potential were summed as background. The phase of the background-subtracted FID exhibited a systematic change, with a peak phase difference of (-1.2 ± 0.3) × 10(-5) radians occurring at a time corresponding to the timing of the action potential. In addition, we calculated the possible changes in the FID magnitude and phase caused by a simulated action potential using a volume conductor model. The measured phase difference matched the theoretical prediction well in both amplitude and temporal characteristics. This study provides the first evidence for the direct detection of a magnetic field from an evoked action potential using MR. Copyright © 2011 John Wiley & Sons, Ltd.

The Direct Detection of a Single Evoked Action Potential with Magnetic Resonance Spectroscopy in Lumbricus Terrestris

PubMed Central

Poplawsky, Alexander J.; Dingledine, Raymond

2011-01-01

Functional MRI (fMRI) indirectly measures neural activity by detecting the signal change associated with the hemodynamic response following brain activation. In order to alleviate the temporal and spatial specificity problems associated with fMRI, a number of attempts have been made to detect neural magnetic fields (NMFs) with MRI directly, but have thus far provided conflicting results. In the present study, we used magnetic resonance to detect axonal NMFs in the median giant fiber of the earthworm, Lumbricus terrestris, by examining the free-induction decay (FID) with a sampling interval of 0.32 ms. The earthworm nerve cords were isolated from the vasculature and stimulated at the threshold of action potential generation. FIDs were acquired shortly after the stimulation and simultaneous field potential recordings identified the presence or absence of single evoked action potentials. FIDs acquired when the stimulus did not evoke an action potential were summed as background. The phase of the background-subtracted FID exhibited a systematic change, with a peak phase difference of [-1.2 ± 0.3] ×10-5 radians occurring at a time corresponding to the timing of the action potential. In addition, we calculated the possible changes in the FID magnitude and phase due to a simulated action potential using a volume conductor model. The measured phase difference matched the theoretical prediction well in both amplitude and temporal characteristics. This study provides the first evidence for the direct detection of a magnetic field from an evoked action potential using magnetic resonance. PMID:21728204

Does navigated transcranial stimulation increase the accuracy of tractography? A prospective clinical trial based on intraoperative motor evoked potential monitoring during deep brain stimulation.

PubMed

Forster, Marie-Therese; Hoecker, Alexander Claudius; Kang, Jun-Suk; Quick, Johanna; Seifert, Volker; Hattingen, Elke; Hilker, Rüdiger; Weise, Lutz Martin

2015-06-01

Tractography based on diffusion tensor imaging has become a popular tool for delineating white matter tracts for neurosurgical procedures. To explore whether navigated transcranial magnetic stimulation (nTMS) might increase the accuracy of fiber tracking. Tractography was performed according to both anatomic delineation of the motor cortex (n = 14) and nTMS results (n = 9). After implantation of the definitive electrode, stimulation via the electrode was performed, defining a stimulation threshold for eliciting motor evoked potentials recorded during deep brain stimulation surgery. Others have shown that of arm and leg muscles. This threshold was correlated with the shortest distance between the active electrode contact and both fiber tracks. Results were evaluated by correlation to motor evoked potential monitoring during deep brain stimulation, a surgical procedure causing hardly any brain shift. Distances to fiber tracks clearly correlated with motor evoked potential thresholds. Tracks based on nTMS had a higher predictive value than tracks based on anatomic motor cortex definition (P < .001 and P = .005, respectively). However, target site, hemisphere, and active electrode contact did not influence this correlation. The implementation of tractography based on nTMS increases the accuracy of fiber tracking. Moreover, this combination of methods has the potential to become a supplemental tool for guiding electrode implantation.

Origin and Properties of Striatal Local Field Potential Responses to Cortical Stimulation: Temporal Regulation by Fast Inhibitory Connections

PubMed Central

Galiñanes, Gregorio L.; Braz, Barbara Y.; Murer, Mario Gustavo

2011-01-01

Evoked striatal field potentials are seldom used to study corticostriatal communication in vivo because little is known about their origin and significance. Here we show that striatal field responses evoked by stimulating the prelimbic cortex in mice are reduced by more than 90% after infusing the AMPA receptor antagonist CNQX close to the recording electrode. Moreover, the amplitude of local field responses and dPSPs recorded in striatal medium spiny neurons increase in parallel with increasing stimulating current intensity. Finally, the evoked striatal fields show several of the basic known properties of corticostriatal transmission, including paired pulse facilitation and topographical organization. As a case study, we characterized the effect of local GABAA receptor blockade on striatal field and multiunitary action potential responses to prelimbic cortex stimulation. Striatal activity was recorded through a 24 channel silicon probe at about 600 µm from a microdialysis probe. Intrastriatal administration of the GABAA receptor antagonist bicuculline increased by 65±7% the duration of the evoked field responses. Moreover, the associated action potential responses were markedly enhanced during bicuculline infusion. Bicuculline enhancement took place at all the striatal sites that showed a response to cortical stimulation before drug infusion, but sites showing no field response before bicuculline remained unresponsive during GABAA receptor blockade. Thus, the data demonstrate that fast inhibitory connections exert a marked temporal regulation of input-output transformations within spatially delimited striatal networks responding to a cortical input. Overall, we propose that evoked striatal fields may be a useful tool to study corticostriatal synaptic connectivity in relation to behavior. PMID:22163020

Time Perception and Evoked Potentials

DTIC Science & Technology

1988-07-01

ARI Research Note 88-69 0 MitnS.Ktohe U.0 ... Ann-r (. Time Perception and Evoked Potentials Paul FraisseDT ( Lfniversit6 Rene Descartes E LECTE...JOHNSON 00L, [N Technical Dicctojr Cmad Research accomplished under contract for the Department of the Army C. Universite Rene Descartes , Paris )r...ORGANIZATION NAME AND ADDRESS 10. PROGRAM ELEMENT. PROJECT. TASK Labrato-ire de Psychologie Experimental AREA• WORK UNIT NUMBERS Universite Rene Descartes

Corticomotor excitability during a noxious stimulus before and after exercise in women with fibromyalgia.

PubMed

Hoeger Bement, Marie K; Weyer, Andy D; Yoon, Tejin; Hunter, Sandra K

2014-02-01

The purposes of this study were to assess corticomotor excitability in people with fibromyalgia during a noxious stimulus before and after fatiguing exercise and examine associations with pain perception. Fifteen women with fibromyalgia completed three sessions: one familiarization and two experimental. The experimental sessions were randomized and involved measurement of pain perception and motor evoked potentials before and after (1) quiet rest and (2) isometric contraction of the elbow flexor muscles. Motor evoked potential amplitude of brachioradialis muscle was measured following transcranial magnetic stimulation delivered before, during, and after a noxious mechanical stimulus. After quiet rest, there was no change in pain perception. After the submaximal contraction, there was considerable variability in the pain response. Based on the changes in the experimental pain, subjects were divided into three groups (increase, decrease, and no change in pain). There was an interaction between pain response and the pain-induced change in motor evoked potentials. Those individuals who had an increase in motor evoked potentials during the pain test had an increase in pain after exercise. Thus, women with fibromyalgia were classified based on their pain response to exercise, and this response was associated with the change in corticomotor excitability during the application of a noxious stimulus.

Intraoperative Subcortical Fiber Mapping with Subcortico-Cortical Evoked Potentials.

PubMed

Enatsu, Rei; Kanno, Aya; Ohtaki, Shunya; Akiyama, Yukinori; Ochi, Satoko; Mikuni, Nobuhiro

2016-02-01

During brain surgery, there are difficulties associated with identifying subcortical fibers with no clear landmarks. We evaluated the usefulness of cortical evoked potentials with subcortical stimuli (subcortico-cortical evoked potential [SCEP]) in identifying subcortical fibers intraoperatively. We used SCEP to identify the pyramidal tract in 4 patients, arcuate fasciculus in 1 patient, and both in 2 patients during surgical procedures. After resection, a 1 × 4-electrode plate was placed on the floor of the removal cavity and 1-Hz alternating electrical stimuli were delivered to this electrode. A 4 × 5 recording electrode plate was placed on the central cortical areas to map the pyramidal tract and temporoparietal cortical areas for the arcuate fasciculus. SCEPs were obtained by averaging electrocorticograms time locked to the stimulus onset. The subcortical stimulation within 15 mm of the target fiber induced cortical evoked potentials in the corresponding areas, whereas the stimulation apart from 20 mm did not. Five patients showed transient worsening of neurologic symptoms after surgery. However, all patients recovered. SCEP was useful for identifying subcortical fibers and confirmed the preservation of these fibers. This technique is expected to contribute to the effectiveness and safety of resective surgery in patients with lesions close to eloquent areas. Copyright © 2016 Elsevier Inc. All rights reserved.

Effects of maternal inhalation of gasoline evaporative ...

EPA Pesticide Factsheets

In order to assess potential health effects resulting from exposure to ethanol-gasoline blend vapors, we previously conducted neurophysiological assessment of sensory function following gestational exposure to 100% ethanol vapor (Herr et al., Toxicologist, 2012). For comparison purposes, the current study investigated the same measures after gestational exposure to 100% gasoline evaporative condensates (GVC). Pregnant Long-Evans rats were exposed to 0, 3K, 6K, or 9K ppm GVC vapors for 6.5 h/day over GD9 – GD20. Sensory evaluations of male offspring began around PND106. Peripheral nerve function (compound action potentials, NCV), somatosensory (cortical and cerebellar evoked potentials), auditory (brainstem auditory evoked responses), and visual evoked responses were assessed. Visual function assessment included pattern elicited visual evoked potentials (VEP), VEP contrast sensitivity, and electroretinograms (ERG) recorded from dark-adapted (scotopic) and light-adapted (photopic) flashes, and UV and green flicker. Although some minor statistical differences were indicated for auditory and somatosensory responses, these changes were not consistently dose- or stimulus intensity-related. Scotopic ERGs had a statistically significant dose-related decrease in the b-wave implicit time. All other parameters of ERGs and VEPs were unaffected by treatment. All physiological responses showed changes related to stimulus intensity, and provided an estimate of detectable le

Roles of N-methyl-d-aspartate receptors during the sensory stimulation-evoked field potential responses in mouse cerebellar cortical molecular layer.

PubMed

Xu, Yin-Hua; Zhang, Guang-Jian; Zhao, Jing-Tong; Chu, Chun-Ping; Li, Yu-Zi; Qiu, De-Lai

2017-11-01

The functions of N-methyl-d-aspartate receptors (NMDARs) in cerebellar cortex have been widely studied under in vitro condition, but their roles during the sensory stimulation-evoked responses in the cerebellar cortical molecular layer in living animals are currently unclear. We here investigated the roles of NMDARs during the air-puff stimulation on ipsilateral whisker pad-evoked field potential responses in cerebellar cortical molecular layer in urethane-anesthetized mice by electrophysiological recording and pharmacological methods. Our results showed that cerebellar surface administration of NMDA induced a dose-dependent decrease in amplitude of the facial stimulation-evoked inhibitory responses (P1) in the molecular layer, accompanied with decreases in decay time, half-width and area under curve (AUC) of P1. The IC 50 of NMDA induced inhibition in amplitude of P1 was 46.5μM. In addition, application of NMDA induced significant increases in the decay time, half-width and AUC values of the facial stimulation-evoked excitatory responses (N1) in the molecular layer. Application of an NMDAR blocker, D-APV (250μM) abolished the facial stimulation-evoked P1 in the molecular layer. These results suggested that NMDARs play a critical role during the sensory information processing in cerebellar cortical molecular layer in vivo in mice. Copyright © 2017 Elsevier B.V. All rights reserved.

Steady-state evoked potentials possibilities for mental-state estimation

NASA Technical Reports Server (NTRS)

Junker, Andrew M.; Schnurer, John H.; Ingle, David F.; Downey, Craig W.

1988-01-01

The use of the human steady-state evoked potential (SSEP) as a possible measure of mental-state estimation is explored. A method for evoking a visual response to a sum-of-ten sine waves is presented. This approach provides simultaneous multiple frequency measurements of the human EEG to the evoking stimulus in terms of describing functions (gain and phase) and remnant spectra. Ways in which these quantities vary with the addition of performance tasks (manual tracking, grammatical reasoning, and decision making) are presented. Models of the describing function measures can be formulated using systems engineering technology. Relationships between model parameters and performance scores during manual tracking are discussed. Problems of unresponsiveness and lack of repeatability of subject responses are addressed in terms of a need for loop closure of the SSEP. A technique to achieve loop closure using a lock-in amplifier approach is presented. Results of a study designed to test the effectiveness of using feedback to consciously connect humans to their evoked response are presented. Findings indicate that conscious control of EEG is possible. Implications of these results in terms of secondary tasks for mental-state estimation and brain actuated control are addressed.

Mecamylamine, dihydro-β-erythroidine, and dextromethorphan block conditioned responding evoked by the conditional stimulus effects of nicotine

PubMed Central

Struthers, Amanda M.; Wilkinson, Jamie L.; Dwoskin, Linda P.; Crooks, Peter A.; Bevins, Rick A.

2009-01-01

Current smokers express the desire to quit. However, the majority find it difficult to remain abstinent. As such, research efforts continually seek to develop more effective treatment. One such area of research involves the interoceptive stimulus effects of nicotine as either a discriminative stimulus in an operant drug discrimination task, or more recently as a conditional stimulus (CS) in a discriminated goal-tracking task. The present work investigated the potential role nicotinic acetylcholine receptors in the CS effects of nicotine (0.4 mg/kg) using antagonists with differential selectivity for β2*, α7*, α6β2*, and α3β4* receptors. Methyllycaconitine (MLA) had no effect on nicotine-evoked conditioned responding. Mecamylamine and dihydro-β-erythroidine (DHβE) dose dependently blocked responding evoked by the nicotine CS. In a time-course assessment of mecamylamine and DHβE, each blocked conditioned responding when given 5 min before testing and still blocked conditioned responding when administered 200 min before testing. Two novel bis-picolinium analogs (N, N’-(3, 3′-(dodecan-1,12-diyl)-bis-picolinium dibromide [bPiDDB], and N, N’-(decan-1,10-diyl)-bis-picolinium diiodide [bPiDI]) did not block nicotine-evoked conditioned responding. Finally, pretreatment with low dose combinations of mecamylamine, dextromethorphan, and/or bupropion were used to target α3β4* receptors. No combination blocked conditioned responding evoked by the training dose of nicotine. However, a combination of mecamylamine and dextromethorphan partially blocked nicotine-evoked conditioned responding to a lower dose of nicotine (0.1 mg/kg). These results indicate that β2* and potentially α3β4* nicotinic acetylcholine receptors play a role in the CS effects of nicotine and are potential targets for the development of nicotine cessation aids. PMID:19778551

Experience-dependent increase in spine calcium evoked by backpropagating action potentials in layer 2/3 pyramidal neurons in rat somatosensory cortex.

PubMed

Krieger, Patrik

2009-11-01

In spines on basal dendrites of layer 2/3 pyramidal neurons in somatosensory barrel cortex, calcium transients evoked by back-propagating action potentials (bAPs) were investigated (i) along the length of the basal dendrite, (ii) with postnatal development and (iii) with sensory deprivation during postnatal development. Layer 2/3 pyramidal neurons were investigated at three different ages. At all ages [postnatal day (P)8, P14, P21] the bAP-evoked calcium transient amplitude increased with distance from the soma with a peak at around 50 microm, followed by a gradual decline in amplitude. The effect of sensory deprivation on the bAP-evoked calcium was investigated using two different protocols. When all whiskers on one side of the rat snout were trimmed daily from P8 to P20-24 there was no difference in the bAP-evoked calcium transient between cells in the contralateral hemisphere, lacking sensory input from the whisker, and cells in the ipsilateral barrel cortex, with intact whisker activation. When, however, only the D-row whiskers on one side were trimmed the distribution of bAP-evoked calcium transients in spines was shifted towards larger amplitudes in cells located in the deprived D-column. In conclusion, (i) the bAP-evoked calcium transient gradient along the dendrite length is established at P8, (ii) the calcium transient increases in amplitude with age and (iii) this increase is enhanced in layer 2/3 pyramidal neurons located in a sensory-deprived barrel column that is bordered by non-deprived barrel columns.

Rapid Screening of Cancer Margins in Tissue with Multimodal Confocal Microscopy

PubMed Central

Gareau, Daniel S.; Jeon, Hana; Nehal, Kishwer S.; Rajadhyaksha, Milind

2012-01-01

Background Complete and accurate excision of cancer is guided by the examination of histopathology. However, preparation of histopathology is labor intensive and slow, leading to insufficient sampling of tissue and incomplete and/or inaccurate excision of margins. We demonstrate the potential utility of multimodal confocal mosaicing microscopy for rapid screening of cancer margins, directly in fresh surgical excisions, without the need for conventional embedding, sectioning or processing. Materials/Methods A multimodal confocal mosaicing microscope was developed to image basal cell carcinoma margins in surgical skin excisions, with resolution that shows nuclear detail. Multimodal contrast is with fluorescence for imaging nuclei and reflectance for cellular cytoplasm and dermal collagen. Thirtyfive excisions of basal cell carcinomas from Mohs surgery were imaged, and the mosaics analyzed by comparison to the corresponding frozen pathology. Results Confocal mosaics are produced in about 9 minutes, displaying tissue in fields-of-view of 12 mm with 2X magnification. A digital staining algorithm transforms black and white contrast to purple and pink, which simulates the appearance of standard histopathology. Mosaicing enables rapid digital screening, which mimics the examination of histopathology. Conclusions Multimodal confocal mosaicing microscopy offers a technology platform to potentially enable real-time pathology at the bedside. The imaging may serve as an adjunct to conventional histopathology, to expedite screening of margins and guide surgery toward more complete and accurate excision of cancer. PMID:22721570

Complexin Mutants Reveal Partial Segregation between Recycling Pathways That Drive Evoked and Spontaneous Neurotransmission

PubMed Central

Sabeva, Nadezhda; Cho, Richard W.; Vasin, Alexander; Gonzalez, Agustin; Littleton, J. Troy

2017-01-01

Synaptic vesicles fuse at morphological specializations in the presynaptic terminal termed active zones (AZs). Vesicle fusion can occur spontaneously or in response to an action potential. Following fusion, vesicles are retrieved and recycled within nerve terminals. It is still unclear whether vesicles that fuse spontaneously or following evoked release share similar recycling mechanisms. Genetic deletion of the SNARE-binding protein complexin dramatically increases spontaneous fusion, with the protein serving as the synaptic vesicle fusion clamp at Drosophila synapses. We examined synaptic vesicle recycling pathways at complexin null neuromuscular junctions, where spontaneous release is dramatically enhanced. We combined loading of the lipophilic dye FM1–43 with photoconversion, electron microscopy, and electrophysiology to monitor evoked and spontaneous recycling vesicle pools. We found that the total number of recycling vesicles was equal to those retrieved through spontaneous and evoked pools, suggesting that retrieval following fusion is partially segregated for spontaneous and evoked release. In addition, the kinetics of FM1–43 destaining and synaptic depression measured in the presence of the vesicle-refilling blocker bafilomycin indicated that spontaneous and evoked recycling pools partially intermix during the release process. Finally, FM1–43 photoconversion combined with electron microscopy analysis indicated that spontaneous recycling preferentially involves synaptic vesicles in the vicinity of AZs, whereas vesicles recycled following evoked release involve a larger intraterminal pool. Together, these results suggest that spontaneous and evoked vesicles use separable recycling pathways and then partially intermix during subsequent rounds of fusion. SIGNIFICANCE STATEMENT Neurotransmitter release involves fusion of synaptic vesicles with the plasma membrane in response to an action potential, or spontaneously in the absence of stimulation. Upon fusion, vesicles are retrieved and recycled, and it is unclear whether recycling pathways for evoked and spontaneous vesicles are segregated after fusion. We addressed this question by taking advantage of preparations lacking the synaptic protein complexin, which have elevated spontaneous release that enables reliable tracking of the spontaneous recycling pool. Our results suggest that spontaneous and evoked recycling pathways are segregated during the retrieval process but can partially intermix during stimulation. PMID:28077717

Experimental human pain models in gastro-esophageal reflux disease and unexplained chest pain

PubMed Central

Drewes, Asbjørn Mohr; Arendt-Nielsen, Lars; Funch-Jensen, Peter; Gregersen, Hans

2006-01-01

Methods related to experimental human pain research aim at activating different nociceptors, evoke pain from different organs and activate specific pathways and mechanisms. The different possibilities for using mechanical, electrical, thermal and chemical methods in visceral pain research are discussed with emphasis of combinations (e.g., the multimodal approach). The methods have been used widely in assessment of pain mechanisms in the esophagus and have contributed to our understanding of the symptoms reported in these patients. Hence abnormal activation and plastic changes of central pain pathways seem to play a major role in the symptoms in some patients with gastro-esophageal reflux disease and in patients with functional chest pain of esophageal origin. These findings may lead to an alternative approach for treatment in patients that does not respond to conventional medical or surgical therapy. PMID:16718803

Contemporary Strategies for Rapid Recovery Total Hip Arthroplasty.

PubMed

Stambough, Jeffrey B; Beaulé, Paul E; Nunley, Ryan M; Clohisy, John

2016-01-01

Over the past several years, rapid recovery protocols for total hip arthroplasty have evolved in parallel with advancements in pain management, regional anesthesia, focused rehabilitation, and the patient selection process. As fiscal pressures from payers of health care increase, surgical outcomes and complications are being scrutinized, which evokes a sense of urgency for arthroplasty surgeons as well as hospitals. The implementation of successful accelerated recovery pathways for total hip arthroplasty requires the coordinated efforts of surgeons, practice administrators, anesthesiologists, nurses, physical and occupational therapists, case managers, and postacute care providers. To optimize performance outcomes, it is important for surgeons to select patients who are eligible for rapid recovery. The fundamental tenets of multimodal pain control, regional anesthesia, prudent perioperative blood management, venous thromboembolic prophylaxis, and early ambulation and mobility should be collectively addressed for all patients who undergo primary total hip replacement.

Using the Interactive Whiteboard to Resource Continuity and Support Multimodal Teaching in a Primary Science Classroom

ERIC Educational Resources Information Center

Gillen, J.; Littleton, K.; Twiner, A.; Staarman, J. K.; Mercer, N.

2008-01-01

All communication is inherently multimodal, and understandings of science need to be multidimensional. The interactive whiteboard offers a range of potential benefits to the primary science classroom in terms of relative ease of integration of a number of presentational and ICT functions, which, taken together, offers new opportunities for…

Drawing Near and Pushing Away: Critical Positioning in Multimodal Composition

ERIC Educational Resources Information Center

Doerr-Stevens, Candance

2016-01-01

As the tools and modes of literate practice continually emerge, so too must our critical approaches to understanding their expression. While media production has been praised for its potential to provide youth a voice to challenge dominant narratives, various questions remain as to what happens at the multimodal levels of composition in terms of…

Writing as Embodied, College Football Plays as Embodied: Extracurricular Multimodal Composing

ERIC Educational Resources Information Center

Rifenburg, J. Michael

2014-01-01

Recent explorations position multimodality as a largely curricular practice wherein the body typically is not figured as a potential mode of meaning making. Such a projection not only fails to acknowledge extracurricular uses of such a rhetoric but also fails to acknowledge the role of the body in and especially for composing. In hopes of…

Meaning-Making with Colour in Multimodal Texts: An 11-Year-Old Student's Purposeful "Doing"

ERIC Educational Resources Information Center

Pantaleo, Sylvia

2012-01-01

Colour, a visual element of art and design, is a semiotic mode that is used strategically by sign-makers to communicate meaning. Understanding the meaning-making potential of colour can enhance students' understanding, appreciation, interpretation and composition of multimodal texts. This article features a case study of Anya, an 11-year-old…

Nanoparticles in Higher-Order Multimodal Imaging

NASA Astrophysics Data System (ADS)

Rieffel, James Ki

Imaging procedures are a cornerstone in our current medical infrastructure. In everything from screening, diagnostics, and treatment, medical imaging is perhaps our greatest tool in evaluating individual health. Recently, there has been tremendous increase in the development of multimodal systems that combine the strengths of complimentary imaging technologies to overcome their independent weaknesses. Clinically, this has manifested in the virtually universal manufacture of combined PET-CT scanners. With this push toward more integrated imaging, new contrast agents with multimodal functionality are needed. Nanoparticle-based systems are ideal candidates based on their unique size, properties, and diversity. In chapter 1, an extensive background on recent multimodal imaging agents capable of enhancing signal or contrast in three or more modalities is presented. Chapter 2 discusses the development and characterization of a nanoparticulate probe with hexamodal imaging functionality. It is my hope that the information contained in this thesis will demonstrate the many benefits of nanoparticles in multimodal imaging, and provide insight into the potential of fully integrated imaging.

Effect of head circumference on parameters of pattern reversal visual evoked potential in healthy adults of central India.

PubMed

Kothari, R; Singh, R; Singh, S; Bokariya, P

2012-06-01

Visual evoked response testing has been one of the most exciting clinical tools to be developed from neurophysiologic research in recent years and has provided us with an objective method of identifying abnormalities of the afferent visual pathways. Investigation were carried out to see whether the head circumference influence the pattern reversal visual evoked potential (PRVEP) parameters. The study comprised of pattern reversal visual evoked potential (PRVEP) recordings in 400 eyes of 200 normal subjects. Two hundred fourty eight eyes were males and 152 eyes were from 76 female subjects recruited from the Central Indian population in the age range of 40-79 years. Visual evoked potential (VEP) recordings were performed in accordance to the standardized methodology of International Federation of Clinical Neurophysiology (IFCN) Committee Recommendations and International Society for Clinical Electrophysiology of Vision (ISCEV) Guidelines and montages were kept as per 10-20 International System of EEG Electrode placements. The stimulus configuration in this study consisted of the transient pattern reversal method in which a black and white checker board was generated (full field) and displayed on a VEP Monitor by an electronic pattern regenerator inbuilt in an Evoked Potential Recorder (RMS EMG EP MARK II). VEP latencies, duration and amplitude were measured in all subjects and the data were analyzed. The correlation of all the electrophysiological parameters with head circumference was evaluated by Pearson's correlation co-efficient (r) and its statistical significance was evaluated. The prediction equations for all the VEP parameters with respect to head circumference were derived. We found a positive correlation of P 100 latency and N 155 latency with mean head circumference, while a highly significant negative correlation were noted of P 100 amplitude with head circumference. N 70 latency was significantly correlated with head circumference. P 100 duration showed in negative correlation with head circumference. These findings suggest that VEP latencies, duration and amplitude are influenced by the head circumference of the individual in a sample of healthy subjects and head circumference can be a useful predictor of VEP peak latencies, amplitude and duration.

The effects of click and tone-burst stimulus parameters on the vestibular evoked myogenic potential (VEMP).

PubMed

Akin, Faith Wurm; Murnane, Owen D; Proffitt, Tina M

2003-11-01

Vestibular evoked myogenic potentials (VEMP) are short latency electromyograms (EMG) evoked by high-level acoustic stimuli and recorded from surface electrodes over the tonically contracted sternocleidomastoid (SCM) muscle and are presumed to originate in the saccule. The present experiments examined the effects of click and tone-burst level and stimulus frequency on the latency, amplitude, and threshold of the VEMP in subjects with normal hearing sensitivity and no history of vestibular disease. VEMPs were recorded in all subjects using 100 dB nHL click stimuli. Most subjects had VEMPs present at 500, 750, and 1000 Hz, and few subjects had VEMPs present at 2000 Hz. The response amplitude of the VEMP increased with click and tone-burst level, whereas VEMP latency was not influenced by the stimulus level. The largest tone-burst-evoked VEMPs and lowest thresholds were obtained at 500 and 750 Hz. VEMP latency was independent of stimulus frequency when tone-burst duration was held constant.

Evoked potential application to study of echolocation in cetaceans

NASA Astrophysics Data System (ADS)

Supin, Alexander Ya.; Nactigall, Paul E.; Pawloski, Jeffrey; Au, Whitlow W. L.

2002-05-01

The evoked-potential (EP) method is effective in studies of hearing capabilities of cetaceans. However, until now EP studies in cetaceans were performed only in conditions of passive hearing by recording EP to external stimuli. Can this method be applied to study active echolocation in odontocetes? To answer this question, auditory brainstem evoked responses (ABR) were recorded in a false killer whale while the animal echolocated a target within an experiment in which the animal reported the target present or absent. The ABR collection was triggered by echolocation clicks. In these conditions, the recorded ABR pattern contained a duplicate set of waves. A comparison of ABR wave delays recorded during echolocation with those recorded during regular external stimulation has shown that the first set of waves is a response to the emitted click whereas the second one is a response to the echo. Both responses, to the emitted click and to the echo, were of comparable amplitude in spite of the intensity difference of these two sounds of more than 40 dB near the animal's head. This finding indicates some mechanisms releasing responses to echoes from masking by loud emitted clicks. The evoked-potential method may be productive to investigate these mechanisms.

Brainstem auditory-evoked potentials as an objective tool for evaluating hearing dysfunction in traumatic brain injury.

PubMed

Lew, Henry L; Lee, Eun Ha; Miyoshi, Yasushi; Chang, Douglas G; Date, Elaine S; Jerger, James F

2004-03-01

Because of the violent nature of traumatic brain injury, traumatic brain injury patients are susceptible to various types of trauma involving the auditory system. We report a case of a 55-yr-old man who presented with communication problems after traumatic brain injury. Initial results from behavioral audiometry and Weber/Rinne tests were not reliable because of poor cooperation. He was transferred to our service for inpatient rehabilitation, where review of the initial head computed tomographic scan showed only left temporal bone fracture. Brainstem auditory-evoked potential was then performed to evaluate his hearing function. The results showed bilateral absence of auditory-evoked responses, which strongly suggested bilateral deafness. This finding led to a follow-up computed tomographic scan, with focus on bilateral temporal bones. A subtle transverse fracture of the right temporal bone was then detected, in addition to the left temporal bone fracture previously identified. Like children with hearing impairment, traumatic brain injury patients may not be able to verbalize their auditory deficits in a timely manner. If hearing loss is suspected in a patient who is unable to participate in traditional behavioral audiometric testing, brainstem auditory-evoked potential may be an option for evaluating hearing dysfunction.

Early-Stage Visual Processing and Cortical Amplification Deficits in Schizophrenia

PubMed Central

Butler, Pamela D.; Zemon, Vance; Schechter, Isaac; Saperstein, Alice M.; Hoptman, Matthew J.; Lim, Kelvin O.; Revheim, Nadine; Silipo, Gail; Javitt, Daniel C.

2005-01-01

Background Patients with schizophrenia show deficits in early-stage visual processing, potentially reflecting dysfunction of the magnocellular visual pathway. The magnocellular system operates normally in a nonlinear amplification mode mediated by glutamatergic (N-methyl-d-aspartate) receptors. Investigating magnocellular dysfunction in schizophrenia therefore permits evaluation of underlying etiologic hypotheses. Objectives To evaluate magnocellular dysfunction in schizophrenia, relative to known neurochemical and neuroanatomical substrates, and to examine relationships between electrophysiological and behavioral measures of visual pathway dysfunction and relationships with higher cognitive deficits. Design, Setting, and Participants Between-group study at an inpatient state psychiatric hospital and out-patient county psychiatric facilities. Thirty-three patients met DSM-IV criteria for schizophrenia or schizoaffective disorder, and 21 nonpsychiatric volunteers of similar ages composed the control group. Main Outcome Measures (1) Magnocellular and parvocellular evoked potentials, analyzed using nonlinear (Michaelis-Menten) and linear contrast gain approaches; (2) behavioral contrast sensitivity measures; (3) white matter integrity; (4) visual and nonvisual neuropsychological measures, and (5) clinical symptom and community functioning measures. Results Patients generated evoked potentials that were significantly reduced in response to magnocellular-biased, but not parvocellular-biased, stimuli (P=.001). Michaelis-Menten analyses demonstrated reduced contrast gain of the magnocellular system (P=.001). Patients showed decreased contrast sensitivity to magnocellular-biased stimuli (P<.001). Evoked potential deficits were significantly related to decreased white matter integrity in the optic radiations (P<.03). Evoked potential deficits predicted impaired contrast sensitivity (P=.002), which was in turn related to deficits in complex visual processing (P≤.04). Both evoked potential (P≤.04) and contrast sensitivity (P=.01) measures significantly predicted community functioning. Conclusions These findings confirm the existence of early-stage visual processing dysfunction in schizophrenia and provide the first evidence that such deficits are due to decreased nonlinear signal amplification, consistent with glutamatergic theories. Neuroimaging studies support the hypothesis of dysfunction within low-level visual pathways involving thalamocortical radiations. Deficits in early-stage visual processing significantly predict higher cognitive deficits. PMID:15867102

The action of ether and methoxyflurane on synaptic transmission in isolated preparations of the mammalian cortex.

PubMed Central

Richards, C D; Russell, W J; Smaje, J C

1975-01-01

1. The actions of ether and methoxyflurane on the evoked potentials of in vitro preparations of the guinea-pig olfactory cortex were studied. Following stimulation of the lateral olfactory tract (l.o.t.) evoked potentials could be recorded from the cortical surface; these potentials consisted of an initial wave (the compound action potential of the l.o.t.) followed by a negative field potential which was associated with the synchronous excitation of many superficial excitatory synapses (population e.p.s.p.). Superimposed on the population e.p.s.p. was a number of positive peaks. These positive peaks reflect the synchronous discharge of many neurones and so have been called population spikes. 2. When ether or methoxyflurane was added to the gas stream that superfused the surface of the preparations, the population e.p.s.p.s. and population spikes were depressed at lower concentrations than those required to depress the compound action potential of the afferent fibres. 3. The evoked activity of individual cells in the cortex was depressed by ether and methoxyflurane. However, five of the twelve cells tested in ether showed an increase in their evoked activity at concentrations below 4-5%, but at higher concentrations these cells also became depressed. 4. Both ether and methoxyflurane depressed the sensitivity of cortical neurones to iontophoretically applied L-glutamate and may similarly depress the sensitivity of the post-synaptic membrane to the released transmitter substance. 5. Neither anaesthetic appeared to increase the threshold depolarization required for nerve impulse generation. Thus, the decrease of the discharge of the post-synaptic cells was primarily caused by a depression of chemical transmission. 6. Ether caused some cells in the cortex to alter their normal pattern of synaptically evoked discharge and both anaesthetics induced similar changes during excitation by glutamate. PMID:168356

Cortical Auditory Evoked Potentials to Evaluate Cochlear Implant Candidacy in an Ear With Long-standing Hearing Loss: A Case Report.

PubMed

Patel, Tirth R; Shahin, Antoine J; Bhat, Jyoti; Welling, D Bradley; Moberly, Aaron C

2016-10-01

We describe a novel use of cortical auditory evoked potentials in the preoperative workup to determine ear candidacy for cochlear implantation. A 71-year-old male was evaluated who had a long-deafened right ear, had never worn a hearing aid in that ear, and relied heavily on use of a left-sided hearing aid. Electroencephalographic testing was performed using free field auditory stimulation of each ear independently with pure tones at 1000 and 2000 Hz at approximately 10 dB above pure-tone thresholds for each frequency and for each ear. Mature cortical potentials were identified through auditory stimulation of the long-deafened ear. The patient underwent successful implantation of that ear. He experienced progressively improving aided pure-tone thresholds and binaural speech recognition benefit (AzBio score of 74%). Findings suggest that use of cortical auditory evoked potentials may serve a preoperative role in ear selection prior to cochlear implantation. © The Author(s) 2016.

Stability of Evoked Potentials during Auditory Attention

DTIC Science & Technology

1988-12-01

attention ef- (S2), to which the subject made a behavioral response and fects upon NI components of the evoked potential received food reinforcement for a... food dipper mounted in the floor, and a driver, with a sound tube attached, mounted in the top of the box. Histology Four weeks after surgery, the cats...response paradigm dose of intravenous sodium pentobarbital. Electrolytic lesions were using food reinforcement. They were gradually deprived of food

Applications of pain-related evoked potentials and short-latency somatosensory evoked potentials in acupuncture research: a narrative review.

PubMed

Lin, Chi; Ma, Liangxiao; Zhu, Shipeng; Hu, Nijuan; Wang, Pei; Zhang, Peng; Qi, Dandan; Hao, Jie; Li, Jing; Xin, Siyuan; Zhu, Jiang

2015-10-01

To review and discuss the Chinese and English literature on the use of pain-related evoked potentials (PREP) and short-latency somatosensory EP (SLSEP) in acupuncture research. China National Knowledge Infrastructure Database and MEDLINE were searched for the following key words: acupuncture and PREP or SLSEP. Thirty-seven articles were included in the review. Researchers usually use PREPs to study the analgesic effect of acupuncture, observe influential factors, or for mechanistic exploration. In the SLSEP studies, researchers focused on response characteristics of acupuncture, acupoint specificity, and influential factors of the treatment. There were some problems with the study design and conclusions. Researchers could use PREP and SLSEP to objectively validate the effects of acupuncture and explore its mechanisms using nerve electrophysiology. Further studies can benefit from observing more acupoints' effects using PREPs or SLSEPs and investigating the placebo effect of acupuncture.

Multifocal visual evoked potentials for early glaucoma detection.

PubMed

Weizer, Jennifer S; Musch, David C; Niziol, Leslie M; Khan, Naheed W

2012-07-01

To compare multifocal visual evoked potentials (mfVEP) with other detection methods in early open-angle glaucoma. Ten patients with suspected glaucoma and 5 with early open-angle glaucoma underwent mfVEP, standard automated perimetry (SAP), short-wave automated perimetry, frequency-doubling technology perimetry, and nerve fiber layer optical coherence tomography. Nineteen healthy control subjects underwent mfVEP and SAP for comparison. Comparisons between groups involving continuous variables were made using independent t tests; for categorical variables, Fisher's exact test was used. Monocular mfVEP cluster defects were associated with an increased SAP pattern standard deviation (P = .0195). Visual fields that showed interocular mfVEP cluster defects were more likely to also show superior quadrant nerve fiber layer thinning by OCT (P = .0152). Multifocal visual evoked potential cluster defects are associated with a functional and an anatomic measure that both relate to glaucomatous optic neuropathy. Copyright 2012, SLACK Incorporated.

Substance P analogues potentiate the pressor response to microinjection of L-glutamate into laminas I and II of the cat dorsal horn.

PubMed

Beyaert, C A; Hill, J M; Kaufman, M P

1997-06-06

Microinjection of a substance P analogue (1 mM; 7 or 10 nl) into laminae I and II of the L7 dorsal horn of decerebrate cats significantly potentiated (P < 0.05) the increase in arterial pressure evoked by microinjection of L-glutamate (109 mM; 7 or 10 nl) into these spinal sites. Microinjection of the substance P analogues (i.e., GR73638 and [Sar9,Met(O2)11]-substance P) which were selective NK-1 receptor agonists, had no impact on the cardioacceleration evoked by microinjection of L-glutamate (P > 0.05). In addition, microinjection of these analogues had no effect on the modest and non-significant increase in phrenic nerve discharge evoked by L-glutamate. We conclude that stimulation of NK-1 receptors in the superficial laminae of the dorsal horn potentiates the pressor responses to microinjection of L-glutamate.

Cholesterol-dependent balance between evoked and spontaneous synaptic vesicle recycling

PubMed Central

Wasser, Catherine R; Ertunc, Mert; Liu, Xinran; Kavalali, Ege T

2007-01-01

Cholesterol is a prominent component of nerve terminals. To examine cholesterol's role in central neurotransmission, we treated hippocampal cultures with methyl-β-cyclodextrin, which reversibly binds cholesterol, or mevastatin, an inhibitor of cholesterol biosynthesis, to deplete cholesterol. We also used hippocampal cultures from Niemann-Pick type C1-deficient mice defective in intracellular cholesterol trafficking. These conditions revealed an augmentation in spontaneous neurotransmission detected electrically and an increase in spontaneous vesicle endocytosis judged by horseradish peroxidase uptake after cholesterol depletion by methyl-β-cyclodextrin. In contrast, responses evoked by action potentials and hypertonicity were severely impaired after the same treatments. The increase in spontaneous vesicle recycling and the decrease in evoked neurotransmission were reversible upon cholesterol addition. Cholesterol removal did not impact on the low level of evoked neurotransmission seen in the absence of synaptic vesicle SNARE protein synaptobrevin-2 whereas the increase in spontaneous fusion remained. These results suggest that synaptic cholesterol balances evoked and spontaneous neurotransmission by hindering spontaneous synaptic vesicle turnover and sustaining evoked exo-endocytosis. PMID:17170046

Clinical applications of cognitive event-related potentials in Alzheimer's disease.

PubMed

Olichney, John M; Hillert, Dieter G

2004-02-01

This article has reviewed several abnormalities in the cognitive ERPs of AD patients. These abnormalities are prominent from latencies of approximately 200 msec and later. In contrast, sensory-dependent evoked potentials, such as N100, are generally normal in AD. This finding is as one familiar with the neuropathology of AD would predict. Predilection sites in early AD include the medial temporal lobe, other limbic areas, and multimodal association cortices with sparing of primary sensory areas. Unimodal association cortex is involved in AD, but not as heavily as multimodal cortex. Particular advantages of studying a given ERP paradigm or component depend largely on the specific application or hypothesis being tested. A P300 paradigm can be useful in detecting a disorder of attention or in quantifying the effects of drugs that improve attention, such as the cholinesterase inhibitors. For the early diagnosis of AD or other memory disorders, a word-repetition paradigm with an explicit recognition task or one that fosters associative learning would be recommended. This article has discussed potential use of N400 in tracking disease progression. ERPs provide a flexible and powerful technique, with superb temporal resolution, which can be used as a probe into subtle "subclinical" abnormalities of cognitive processes. Despite being applied to AD for about 25 years since the early P300 studies, the full potential of ERPs in helping diagnose and treat AD patients has yet to be realized. In this era of rapidly evolving brain-imaging techniques, electrophysiologic data are important in advancing understanding of cognition. Brain-mapping techniques that can inform where and when key cognitive processes occur are finally emerging. A final example of potential clinical application of cognitive ERPs is in the development of rational combinational treatment of cognitive enhancing drugs. Along these lines, P300 investigations in epilepsy proved helpful in ranking the cognitive side effects of anticonvulsant drugs. Drug studies that use 2 x 2 combinational designs, which compare the effects of drug A, drug B, with A + B, are currently prohibitively expensive for full-scale clinical trials in AD. It is likely that precise ERP measures could hasten drug development in several ways. Smaller samples could be used, at lower cost, to test the cognitive effects of each specific drug combination. Optimal doses of combinational therapy perhaps could be identified by repeated within-subject ERP measures. Longitudinal changes in the ERP hold promise as a marker of individual responsivity to a particular agent, which could have diagnostic utility (eg, testing response to cholinergic or dopaminergic therapy). This horizon and many others remain wide open for well-planned explorations.

Patterned light flash evoked short latency activity in the visual system of visually normal and in amblyopic subjects.

PubMed

Sjöström, A; Abrahamsson, M

1994-04-01

In a previous experimental study on anaesthetized cat it was shown that a short latency (35-40 ms) cortical potential changed polarity due to the presence or absence of a pattern in the flash stimulus. The results suggested one pathway of neuronal activation in the cortex to a pattern that was within the level of resolution and another to patterns that were not. It was implied that a similar difference in impulse transmission to pattern and non-pattern stimuli may be recorded in humans. The present paper describes recordings of the short-latency visual evoked response to varying light flash checkerboard pattern stimuli of high intensity in visually normal and amblyopic children and adults. When stimulating the normal eye a visual evoked response potential with a peak latency between 35 to 40 ms showed a polarity change to patterned compared to non-patterned stimulation. The visual evoked response resolution limit could be correlated to a visual acuity of 0.5 and below. In amblyopic eyes the shift in polarity was recorded at the acuity limit level. The latency of the pattern depending potential was increased in patients with amblyopia compared to normal, but not directly related to amblyopic degree. It is concluded that the short latency, visual evoked response that mainly represents the retino-geniculo-cortical activation may be used to estimate visual resolution below 0.5 in acuity level.(ABSTRACT TRUNCATED AT 250 WORDS)

Interhemispheric Asymmetries in Visual Evoked Potential Amplitude

DTIC Science & Technology

1980-06-12

Layne, 1965) and of patients with Korsakoff’s syndrome (Malerstein and Callaway, 1969) . In the schizophrenics, the high variability is related to poor...communication. Malerstein, A. J., Callaway, E. Two-tone average evoked response in Korsakoff patients. J. Psychiatr. Res. 6: 253-260, 1969. Marsh, G

Augmenting responses evoked in area 17 of the cat by intracortical axon collaterals of cortico-geniculate cells.

PubMed Central

Ferster, D; Lindström, S

1985-01-01

Evoked potentials were recorded in the visual cortex of the cat after electrical stimulation of the lateral geniculate nucleus (l.g.n.). The primary response, mediated by geniculo-cortical fibres, was depressed at stimulation frequencies above 7 Hz and replaced by a late potential, the incremental response, which gradually increased in amplitude with successive stimuli. The incremental response was a negative-positive potential in the depth of the cortex with the negative component having maximal amplitude in layer 4. The response reversed polarity in layer 1 to become a positive-negative potential at the surface. The latency of the negative component of the incremental response was about 3.5-4 ms in layer 4, compared to about 1.5 and 2.5 ms for the mono- and disynaptic components of the primary response. The incremental response could only be evoked from the l.g.n. and the optic radiation, not from the optic tract, superior colliculus or other surrounding structures. Within the l.g.n., the effect was only evoked from stimulation sites in approximate retinotopic register with the recording site in the cortex. Low threshold points were found in the A laminae, completely overlapping with the low threshold points for the primary response. Thresholds increased steeply when the stimulation electrode was lowered into the C laminae. The incremental response could still be evoked ten days after the destruction of all cells in the l.g.n. complex by kainic acid. It is concluded that the described incremental response is identical to the augmenting response of Dempsey & Morison (1943) and is mediated by intracortical axon collaterals of antidromically activated cortico-geniculate neurones. Images Plate 1 PMID:4057097

Drawing Bodies and Spaces in Telecollaboration: A View of Research Potential in Synaesthesia and Multimodality, from the Outside

ERIC Educational Resources Information Center

Malinowski, David

2014-01-01

While much scholarship on the multisensory and transmodal phenomenon of synaesthesia seeks to uncover its psychophysiological and neurological bases, recent research in multimodal literacy and language acquisition addresses it largely in terms of agentive processes of meaning-making and design. This paper takes as its starting point the latter's…

Multimodality and interactivity: connecting properties of serious games with educational outcomes.

PubMed

Ritterfeld, Ute; Shen, Cuihua; Wang, Hua; Nocera, Luciano; Wong, Wee Ling

2009-12-01

Serious games have become an important genre of digital media and are often acclaimed for their potential to enhance deeper learning because of their unique technological properties. Yet the discourse has largely remained at a conceptual level. For an empirical evaluation of educational games, extra effort is needed to separate intertwined and confounding factors in order to manipulate and thus attribute the outcome to one property independent of another. This study represents one of the first attempts to empirically test the educational impact of two important properties of serious games, multimodality and interactivity, through a partial 2 x 3 (interactive, noninteractive by high, moderate, low in multimodality) factorial between-participants follow-up experiment. Results indicate that both multimodality and interactivity contribute to educational outcomes individually. Implications for educational strategies and future research directions are discussed.

Multimodal Estimation of Distribution Algorithms.

PubMed

Yang, Qiang; Chen, Wei-Neng; Li, Yun; Chen, C L Philip; Xu, Xiang-Min; Zhang, Jun

2016-02-15

Taking the advantage of estimation of distribution algorithms (EDAs) in preserving high diversity, this paper proposes a multimodal EDA. Integrated with clustering strategies for crowding and speciation, two versions of this algorithm are developed, which operate at the niche level. Then these two algorithms are equipped with three distinctive techniques: 1) a dynamic cluster sizing strategy; 2) an alternative utilization of Gaussian and Cauchy distributions to generate offspring; and 3) an adaptive local search. The dynamic cluster sizing affords a potential balance between exploration and exploitation and reduces the sensitivity to the cluster size in the niching methods. Taking advantages of Gaussian and Cauchy distributions, we generate the offspring at the niche level through alternatively using these two distributions. Such utilization can also potentially offer a balance between exploration and exploitation. Further, solution accuracy is enhanced through a new local search scheme probabilistically conducted around seeds of niches with probabilities determined self-adaptively according to fitness values of these seeds. Extensive experiments conducted on 20 benchmark multimodal problems confirm that both algorithms can achieve competitive performance compared with several state-of-the-art multimodal algorithms, which is supported by nonparametric tests. Especially, the proposed algorithms are very promising for complex problems with many local optima.

All-optical universal logic gates on nonlinear multimode interference coupler using tunable input intensity

NASA Astrophysics Data System (ADS)

Tajaldini, Mehdi; Jafri, Mohd Zubir Mat

2015-04-01

The theory of Nonlinear Modal Propagation Analysis Method (NMPA) have shown significant features of nonlinear multimode interference (MMI) coupler with compact dimension and when launched near the threshold of nonlinearity. Moreover, NMPA have the potential to allow studying the nonlinear MMI based the modal interference to explorer the phenomenon that what happen due to the natural of multimode region. Proposal of all-optical switch based NMPA has approved its capability to achieving the all-optical gates. All-optical gates have attracted increasing attention due to their practical utility in all-optical signal processing networks and systems. Nonlinear multimode interference devices could apply as universal all-optical gates due to significant features that NMPA introduce them. In this Paper, we present a novel Ultra-compact MMI coupler based on NMPA method in low intensity compared to last reports either as a novel design method and potential application for optical NAND, NOR as universal gates on single structure for Boolean logic signal processing devices and optimize their application via studding the contrast ratio between ON and OFF as a function of output width. We have applied NMPA for several applications so that the miniaturization in low nonlinear intensities is their main purpose.

A multimodal image sensor system for identifying water stress in grapevines

NASA Astrophysics Data System (ADS)

Zhao, Yong; Zhang, Qin; Li, Minzan; Shao, Yongni; Zhou, Jianfeng; Sun, Hong

2012-11-01

Water stress is one of the most common limitations of fruit growth. Water is the most limiting resource for crop growth. In grapevines, as well as in other fruit crops, fruit quality benefits from a certain level of water deficit which facilitates to balance vegetative and reproductive growth and the flow of carbohydrates to reproductive structures. A multi-modal sensor system was designed to measure the reflectance signature of grape plant surfaces and identify different water stress levels in this paper. The multi-modal sensor system was equipped with one 3CCD camera (three channels in R, G, and IR). The multi-modal sensor can capture and analyze grape canopy from its reflectance features, and identify the different water stress levels. This research aims at solving the aforementioned problems. The core technology of this multi-modal sensor system could further be used as a decision support system that combines multi-modal sensory data to improve plant stress detection and identify the causes of stress. The images were taken by multi-modal sensor which could output images in spectral bands of near-infrared, green and red channel. Based on the analysis of the acquired images, color features based on color space and reflectance features based on image process method were calculated. The results showed that these parameters had the potential as water stress indicators. More experiments and analysis are needed to validate the conclusion.

Single-trial extraction of cognitive evoked potentials by combination of third-order correlation and wavelet denoising.

PubMed

Zhang, Z; Tian, X

2005-01-01

The application of a recently proposed denoising implementation for obtaining cognitive evoked potentials (CEPs) at the single-trial level is shown. The aim of this investigation is to develop the technique of extracting CEPs by combining both the third-order correlation and the wavelet denoising methods. First, the noisy CEPs was passed through a finite impulse response filter whose impulse response is matched with the shape of the noise-free signal. It was shown that it is possible to estimate the filter impulse response on basis of a select third-order correlation slice (TOCS) of the input noisy CEPs. Second, the output from the third-order correlation filter is decomposed with bi-orthogonal splines at 5 levels. The CEPs is reconstructed by wavelet final approximation a5. We study its performance in simulated data as well as in cognitive evoked potentials of normal rat and Alzheimer's disease (AD) model rat. For the simulated data, the method gives a significantly better reconstruction of the single-trial cognitive evoked potentials responses in comparison with the simulated data. Moreover, with this approach we obtain a significantly better estimation of the amplitudes and latencies of the simulated CEPs. For the real data, the method clearly improves the visualization of single-trial CEPs. This allows the calculation of better averages as well as the study of systematic or unsystematic variations between trials.

Sensitivity of visual evoked potentials and spectral domain optical coherence tomography in early relapsing remitting multiple sclerosis.

PubMed

Behbehani, Raed; Ahmed, Samar; Al-Hashel, Jasem; Rousseff, Rossen T; Alroughani, Raed

2017-02-01

Visual evoked potentials and spectral-domain optical coherence tomography are common ancillary studies that assess the visual pathways from a functional and structural aspect, respectively. To compare prevalence of abnormalities of Visual evoked potentials (VEP) and spectral-domain optical coherence tomography (SDOCT) in patients with relapsing remitting multiple sclerosis (RRMS). A cross-sectional study of 100 eyes with disease duration of less than 5 years since the diagnosis. Correlation between retinal nerve fiber layer and ganglion-cell/inner plexiform layer with pattern-reversal visual evoked potentials amplitude and latency and contrast sensitivity was performed. The prevalence of abnormalities in pattern-reversal visual VEP was 56% while that of SOCT was 48% in all eyes. There was significant negative correlations between the average RNFL (r=-0.34, p=0.001) and GCIPL (r=-0.39, p<0.001) with VEP latency. In eyes with prior optic neuritis, a significant negative correlation was seen between average RNFL (r=-0.33, p=0.037) and GCIPL (r=-0.40, p=0.010) with VEP latency. We have found higher prevalence of VEP abnormalities than SCOCT in early relapsing-remitting multiple sclerosis. This suggests that VEP has a higher sensitivity for detecting lesions of the visual pathway in patients with early RRMS. Copyright © 2016 Elsevier B.V. All rights reserved.

Objective Assessment of Spectral Ripple Discrimination in Cochlear Implant Listeners Using Cortical Evoked Responses to an Oddball Paradigm

PubMed Central

Lopez Valdes, Alejandro; Mc Laughlin, Myles; Viani, Laura; Walshe, Peter; Smith, Jaclyn; Zeng, Fan-Gang; Reilly, Richard B.

2014-01-01

Cochlear implants (CIs) can partially restore functional hearing in deaf individuals. However, multiple factors affect CI listener's speech perception, resulting in large performance differences. Non-speech based tests, such as spectral ripple discrimination, measure acoustic processing capabilities that are highly correlated with speech perception. Currently spectral ripple discrimination is measured using standard psychoacoustic methods, which require attentive listening and active response that can be difficult or even impossible in special patient populations. Here, a completely objective cortical evoked potential based method is developed and validated to assess spectral ripple discrimination in CI listeners. In 19 CI listeners, using an oddball paradigm, cortical evoked potential responses to standard and inverted spectrally rippled stimuli were measured. In the same subjects, psychoacoustic spectral ripple discrimination thresholds were also measured. A neural discrimination threshold was determined by systematically increasing the number of ripples per octave and determining the point at which there was no longer a significant difference between the evoked potential response to the standard and inverted stimuli. A correlation was found between the neural and the psychoacoustic discrimination thresholds (R2 = 0.60, p<0.01). This method can objectively assess CI spectral resolution performance, providing a potential tool for the evaluation and follow-up of CI listeners who have difficulty performing psychoacoustic tests, such as pediatric or new users. PMID:24599314

Use of NK1 receptor antagonists in the exploration of physiological functions of substance P and neurokinin A.

PubMed

Otsuka, M; Yoshioka, K; Yanagisawa, M; Suzuki, H; Zhao, F Y; Guo, J Z; Hosoki, R; Kurihara, T

1995-07-01

Tachykinin NK1 receptor antagonists were used to explore the physiological functions of substance P (SP) and neurokinin A (NKA). Pharmacological profiles of three NK1 receptor antagonists, GR71251, GR82334, and RP 67580, were examined in the isolated spinal cord preparation of the neonatal rat. These tachykinin receptor antagonists exhibited considerable specificities and antagonized the actions of both SP and NKA to induce the depolarization of ventral roots. Electrical stimulation of the saphenous nerve with C-fiber strength evoked a depolarization lasting about 30 s of the ipsilateral L3 ventral root. This response, which is referred to as saphenous-nerve-evoked slow ventral root potential (VRP), was depressed by these NK1 receptor antagonists. In contrast, the saphenous-nerve-evoked slow VRP was potentiated by application of a mixture of peptidase inhibitors, including thiorphan, actinonin, and captopril in the presence of naloxone, but not after further addition of GR71251. Likewise, in the isolated coeliac ganglion of the guinea pig, electrical stimulation of the mesenteric nerves evoked in some ganglionic cells slow excitatory postsynaptic potentials (EPSPs), which were depressed by GR71251 and potentiated by peptidase inhibitors. These results further support the notion that SP and NKA serve as neurotransmitters producing slow EPSPs in the neonatal rat spinal cord and guinea pig prevertebral ganglia.

Objective assessment of spectral ripple discrimination in cochlear implant listeners using cortical evoked responses to an oddball paradigm.

PubMed

Lopez Valdes, Alejandro; Mc Laughlin, Myles; Viani, Laura; Walshe, Peter; Smith, Jaclyn; Zeng, Fan-Gang; Reilly, Richard B

2014-01-01

Cochlear implants (CIs) can partially restore functional hearing in deaf individuals. However, multiple factors affect CI listener's speech perception, resulting in large performance differences. Non-speech based tests, such as spectral ripple discrimination, measure acoustic processing capabilities that are highly correlated with speech perception. Currently spectral ripple discrimination is measured using standard psychoacoustic methods, which require attentive listening and active response that can be difficult or even impossible in special patient populations. Here, a completely objective cortical evoked potential based method is developed and validated to assess spectral ripple discrimination in CI listeners. In 19 CI listeners, using an oddball paradigm, cortical evoked potential responses to standard and inverted spectrally rippled stimuli were measured. In the same subjects, psychoacoustic spectral ripple discrimination thresholds were also measured. A neural discrimination threshold was determined by systematically increasing the number of ripples per octave and determining the point at which there was no longer a significant difference between the evoked potential response to the standard and inverted stimuli. A correlation was found between the neural and the psychoacoustic discrimination thresholds (R2=0.60, p<0.01). This method can objectively assess CI spectral resolution performance, providing a potential tool for the evaluation and follow-up of CI listeners who have difficulty performing psychoacoustic tests, such as pediatric or new users.

Passive attenuation of cortical pattern evoked potentials with increasing body weight in young male rhesus macaques.

PubMed

Komaromy, Andras M; Brooks, Dennis E; Kallberg, Maria E; Dawson, William W; Sapp, Harold L; Sherwood, Mark B; Lambrou, George N; Percicot, Christine L

2003-05-01

The purpose of our study was to determine changes in amplitudes and implicit times of retinal and cortical pattern evoked potentials with increasing body weight in young, growing rhesus macaques (Macaca mulatta). Retinal and cortical pattern evoked potentials were recorded from 29 male rhesus macaques between 3 and 7 years of age. Thirteen animals were reexamined after 11 months. Computed tomography (CT) was performed on two animals to measure the distance between the location of the skin electrode and the surface of the striate cortex. Spearman correlation coefficients were calculated to describe the relationship between body weights and either root mean square (rms) amplitudes or implicit times. For 13 animals rms amplitudes and implicit times were compared with the Wilcoxon matched pairs signed rank test for recordings taken 11 months apart. Highly significant correlations between increases in body weights and decreases in cortical rms amplitudes were noted in 29 monkeys (p < 0.0005). No significant changes were found in the cortical rms amplitudes in thirteen monkeys over 11 months. Computed tomography showed a large increase of soft tissue thickness over the skull and striate cortex with increased body weight. The decreased amplitude in cortical evoked potentials with weight gain associated with aging can be explained by the increased distance between skin electrode and striate cortex due to soft tissue thickening (passive attenuation).

The Theoretical Distribution of Evoked Brainstem Activity in Preterm, High-Risk, and Healthy Infants.

ERIC Educational Resources Information Center

Salamy, A.

1981-01-01

Determines the frequency distribution of Brainstem Auditory Evoked Potential variables (BAEP) for premature babies at different stages of development--normal newborns, infants, young children, and adults. The author concludes that the assumption of normality underlying most "standard" statistical analyses can be met for many BAEP…

The Middle Latency Response (MLR) and Steady State Evoked Potential (SSEP) in Neonates.

DTIC Science & Technology

1985-05-01

diagnostic audiologic information will enhance habilitation efforts in prescribing hearing aids and designing appropriate language intervention strategies...auditory evoked brain stem response. A study of patients with sensory hearing loss. SCANDINAVIAN AUDIOLOGY 8: 67-70, 1979. Page 165 "- FILMED 10-85 DTIC * 4 N . . -. N

Functional ligand-gated purinergic receptors (P2X) in rat vestibular ganglion neurons.

PubMed

Ito, Ken; Chihara, Yasuhiro; Iwasaki, Shinichi; Komuta, Yukari; Sugasawa, Masashi; Sahara, Yoshinori

2010-08-01

The expression of purinergic receptors (P2X) on rat vestibular ganglion neurons (VGNs) was examined using whole-cell patch-clamp recordings. An application of adenosine 5'-triphosphate (ATP; 100microM) evoked inward currents in VGNs at a holding potential of -60mV. The decay time constant of the ATP-evoked currents was 2-4s, which is in between the values for rapidly desensitizing subgroups (P2X1 and P2X3) and slowly desensitizing subgroups (P2X2, P2X4, etc.), suggesting the heterogeneous expression of P2X receptors. A dose-response experiment showed an EC(50) of 11.0microM and a Hill's coefficient of 0.82. Suramin (100microM) reversibly inhibited the ATP-evoked inward currents. Alpha, beta-methylene ATP (100microM), a P2X-specific agonist, also evoked inward currents but less extensively than ATP. An application of adenosine 5'-dihosphate (ADP; 100microM) evoked similar, but much smaller, currents. The current-voltage relationship of the ATP-evoked conductance showed pronounced inward rectification with a reversal potential more positive than 0mV, suggesting non-selective cation conductance. However, the channel was not permeable to a large cation (N-methyl-d-glucamine) and acidification (pH 6.3) had little effect on the ATP-evoked conductance. RT-PCR confirmed the expression of five subtypes (P2X2-P2X6) in VGNs. The physiological role of P2X receptors includes the modulation of excitability at the synapses between hair cells and dendrites and/or trophic support (or also neuromodulation) from supporting cells surrounding the VGNs. Copyright 2010 Elsevier B.V. All rights reserved.

Spectrum pattern resolution after noise exposure in a beluga whale, Delphinapterus leucas: Evoked potential study.

PubMed

Popov, Vladimir V; Nechaev, Dmitry I; Sysueva, Evgenia V; Rozhnov, Viatcheslav V; Supin, Alexander Ya

2015-07-01

Temporary threshold shift (TTS) and the discrimination of spectrum patterns after fatiguing noise exposure (170 dB re 1 μPa, 10 min duration) was investigated in a beluga whale, Delphinapterus leucas, using the evoked potential technique. Thresholds were measured using rhythmic (1000/s) pip trains of varying levels and recording the rhythmic evoked responses. Discrimination of spectrum patterns was investigated using rippled-spectrum test stimuli of various levels and ripple densities, recording the rhythmic evoked responses to ripple phase reversals. Before noise exposure, the greatest responses to rippled-spectrum probes were evoked by stimuli with a low ripple density with a decrease in the response magnitude occurring with an increasing ripple density. After noise exposure, both a TTS and a reduction of the responses to rippled-spectrum probes appeared and recovered in parallel. The reduction of the responses to rippled-spectrum probes was maximal for high-magnitude responses at low ripple densities and was negligible for low-magnitude responses at high ripple densities. It is hypothesized that the impacts of fatiguing sounds are not limited by increased thresholds and decreased sensitivity results in reduced ability to discriminate fine spectral content with the greatest impact on the discrimination of spectrum content that may carry the most obvious information about stimulus properties.

Gender differences in binaural speech-evoked auditory brainstem response: are they clinically significant?

PubMed

Jalaei, Bahram; Azmi, Mohd Hafiz Afifi Mohd; Zakaria, Mohd Normani

2018-05-17

Binaurally evoked auditory evoked potentials have good diagnostic values when testing subjects with central auditory deficits. The literature on speech-evoked auditory brainstem response evoked by binaural stimulation is in fact limited. Gender disparities in speech-evoked auditory brainstem response results have been consistently noted but the magnitude of gender difference has not been reported. The present study aimed to compare the magnitude of gender difference in speech-evoked auditory brainstem response results between monaural and binaural stimulations. A total of 34 healthy Asian adults aged 19-30 years participated in this comparative study. Eighteen of them were females (mean age=23.6±2.3 years) and the remaining sixteen were males (mean age=22.0±2.3 years). For each subject, speech-evoked auditory brainstem response was recorded with the synthesized syllable /da/ presented monaurally and binaurally. While latencies were not affected (p>0.05), the binaural stimulation produced statistically higher speech-evoked auditory brainstem response amplitudes than the monaural stimulation (p<0.05). As revealed by large effect sizes (d>0.80), substantive gender differences were noted in most of speech-evoked auditory brainstem response peaks for both stimulation modes. The magnitude of gender difference between the two stimulation modes revealed some distinct patterns. Based on these clinically significant results, gender-specific normative data are highly recommended when using speech-evoked auditory brainstem response for clinical and future applications. The preliminary normative data provided in the present study can serve as the reference for future studies on this test among Asian adults. Copyright © 2018 Associação Brasileira de Otorrinolaringologia e Cirurgia Cérvico-Facial. Published by Elsevier Editora Ltda. All rights reserved.

Vertebral Column Resection for Kyphoscoliosis in a Patient with Ehlers-Danlos Syndrome: An Intraoperative Neurophysiological Monitoring Alert.

PubMed

Jahangiri, Faisal R; Al Eissa, Sami; Sayegh, Samir; Al Helal, Fahad; Al-Sharif, Shomoukh A; Annaim, Monerah M; Muhammad, Sheryar; Aziz, Tanweer

2016-08-31

A 16-year-old male patient with Ehler-Danlos syndrome (EDS) and a back deformity since birth presented with severe kyphoscoliosis. The patient was neurologically intact but had respiratory and cardiac insufficiencies. A two-stage vertebral column resection (VCR) at T9-T10 with multiple level fusion with multimodality intraoperative neurophysiological monitoring (IONM) was planned.  During the first stage, pedicle screws were placed at multiple spinal levels above and below the VCR level. Upper and lower somatosensory evoked potentials (SSEP), transcranial electrical motor evoked potentials (TCeMEP), and electromyography were monitored continuously and showed no significant changes. The second stage was performed one week later. Baseline SSEP and TCeMEP responses were present in all extremities. The surgeon was informed of a sudden 70% amplitude drop in TCeMEP in the lower limbs with stable SSEP after ligating one of the left nerves/vessels fully stretching the spinal cord. The surgeon removed the ligation, and an improvement in motor responses followed. Surgery proceeded with the highest levels of caution. Later, there was a sudden loss of TCeMEP and SSEP in the lower limbs bilaterally. The correction was released, mean arterial pressure was increased, and intravenous dexamethasone was administered. The surgical correction was aborted, and the decision was made to close the site. Lower SSEP and TCeMEP responses remained absent until closing, while upper SSEP and TCeMEP responses remained stable. A wake-up test was done after closing. The patient moved his upper limbs but was unable to move his lower limbs bilaterally. The patient was sent for a magnetic resonance imaging scan while intubated and then sent to the intensive care unit. At 24 hours and 36 hours post-operation, the patient had no sensory and motor function below the T8 level. Forty-eight hours post-operation, the patient started to feel sensory stimuli at the T10 level. At one week post-operation, the patient regained sphincter functions, and at four weeks postoperatively, the patient's hip flexors started to recover. VCR in patients with EDS has a very high risk of damaging the spinal cord due to the fragile vasculature of the spinal cord. Real-time IONM is useful in the early identification of spinal cord injury in cases of this nature.

Vertebral Column Resection for Kyphoscoliosis in a Patient with Ehlers-Danlos Syndrome: An Intraoperative Neurophysiological Monitoring Alert

PubMed Central

Al Eissa, Sami; Sayegh, Samir; Al Helal, Fahad; Al-Sharif, Shomoukh A; Annaim, Monerah M; Muhammad, Sheryar; Aziz, Tanweer

2016-01-01

A 16-year-old male patient with Ehler-Danlos syndrome (EDS) and a back deformity since birth presented with severe kyphoscoliosis. The patient was neurologically intact but had respiratory and cardiac insufficiencies. A two-stage vertebral column resection (VCR) at T9-T10 with multiple level fusion with multimodality intraoperative neurophysiological monitoring (IONM) was planned.  During the first stage, pedicle screws were placed at multiple spinal levels above and below the VCR level. Upper and lower somatosensory evoked potentials (SSEP), transcranial electrical motor evoked potentials (TCeMEP), and electromyography were monitored continuously and showed no significant changes. The second stage was performed one week later. Baseline SSEP and TCeMEP responses were present in all extremities. The surgeon was informed of a sudden 70% amplitude drop in TCeMEP in the lower limbs with stable SSEP after ligating one of the left nerves/vessels fully stretching the spinal cord. The surgeon removed the ligation, and an improvement in motor responses followed. Surgery proceeded with the highest levels of caution. Later, there was a sudden loss of TCeMEP and SSEP in the lower limbs bilaterally. The correction was released, mean arterial pressure was increased, and intravenous dexamethasone was administered. The surgical correction was aborted, and the decision was made to close the site. Lower SSEP and TCeMEP responses remained absent until closing, while upper SSEP and TCeMEP responses remained stable. A wake-up test was done after closing. The patient moved his upper limbs but was unable to move his lower limbs bilaterally. The patient was sent for a magnetic resonance imaging scan while intubated and then sent to the intensive care unit. At 24 hours and 36 hours post-operation, the patient had no sensory and motor function below the T8 level. Forty-eight hours post-operation, the patient started to feel sensory stimuli at the T10 level. At one week post-operation, the patient regained sphincter functions, and at four weeks postoperatively, the patient’s hip flexors started to recover. VCR in patients with EDS has a very high risk of damaging the spinal cord due to the fragile vasculature of the spinal cord. Real-time IONM is useful in the early identification of spinal cord injury in cases of this nature.  PMID:27766191

The effects of video-game training on broad cognitive transfer in multiple sclerosis: A pilot randomized controlled trial.

PubMed

Janssen, Alisha; Boster, Aaron; Lee, HyunKyu; Patterson, Beth; Prakash, Ruchika Shaurya

2015-01-01

Multiple sclerosis (MS) is a neurodegenerative disease of the central nervous system that results in diffuse nerve damage and associated physical and cognitive impairments. Of the few comprehensive rehabilitation options that exist for populations with lower baseline cognitive functioning, those that have been successful at eliciting broad cognitive improvements have focused on a multimodal training approach, emphasizing complex cognitive processing that utilizes multiple domains simultaneously. The current study sought to determine the feasibility of an 8-week, hybrid-variable priority training (HVT) program, with a secondary aim to assess the success of this training paradigm at eliciting broad cognitive transfer effects. Capitalizing on the multimodal training modalities offered by the Space Fortress platform, we compared the HVT strategy-based intervention with a waitlist control group, to primarily assess skill acquisition and secondarily determine presence of cognitive transfer. Twenty-eight participants met inclusionary criteria for the study and were randomized to either training or waitlist control groups. To assess broad transfer effects, a battery of neuropsychological tests was administered pre- and post-intervention. The results indicated an overall improvement in skill acquisition and evidence for the feasibility of the intervention, but a lack of broad transfer to tasks of cognitive functioning. Participants in the training group, however, did show improvements on a measure of spatial short-term memory. The current investigation provided support for the feasibility of a multimodal training approach, using the HVT strategy, within the MS population, but lacked broad transfer to multiple domains of cognitive functioning. Future improvements to obtain greater cognitive transfer efficacy would include a larger sample size, a longer course of training to evoke greater game score improvement, the inclusion of only cognitively impaired individuals, and integration of subjective measures of improvement in addition to objective tests of cognitive performance.

Take-over again: Investigating multimodal and directional TORs to get the driver back into the loop.

PubMed

Petermeijer, Sebastiaan; Bazilinskyy, Pavlo; Bengler, Klaus; de Winter, Joost

2017-07-01

When a highly automated car reaches its operational limits, it needs to provide a take-over request (TOR) in order for the driver to resume control. The aim of this simulator-based study was to investigate the effects of TOR modality and left/right directionality on drivers' steering behaviour when facing a head-on collision without having received specific instructions regarding the directional nature of the TORs. Twenty-four participants drove three sessions in a highly automated car, each session with a different TOR modality (auditory, vibrotactile, and auditory-vibrotactile). Six TORs were provided per session, warning the participants about a stationary vehicle that had to be avoided by changing lane left or right. Two TORs were issued from the left, two from the right, and two from both the left and the right (i.e., nondirectional). The auditory stimuli were presented via speakers in the simulator (left, right, or both), and the vibrotactile stimuli via a tactile seat (with tactors activated at the left side, right side, or both). The results showed that the multimodal TORs yielded statistically significantly faster steer-touch times than the unimodal vibrotactile TOR, while no statistically significant differences were observed for brake times and lane change times. The unimodal auditory TOR yielded relatively low self-reported usefulness and satisfaction ratings. Almost all drivers overtook the stationary vehicle on the left regardless of the directionality of the TOR, and a post-experiment questionnaire revealed that most participants had not realized that some of the TORs were directional. We conclude that between the three TOR modalities tested, the multimodal approach is preferred. Moreover, our results show that directional auditory and vibrotactile stimuli do not evoke a directional response in uninstructed drivers. More salient and semantically congruent cues, as well as explicit instructions, may be needed to guide a driver into a specific direction during a take-over scenario. Copyright © 2017 Elsevier Ltd. All rights reserved.

Evoked potential correlates of selective attention with multi-channel auditory inputs

NASA Technical Reports Server (NTRS)

Schwent, V. L.; Hillyard, S. A.

1975-01-01

Ten subjects were presented with random, rapid sequences of four auditory tones which were separated in pitch and apparent spatial position. The N1 component of the auditory vertex evoked potential (EP) measured relative to a baseline was observed to increase with attention. It was concluded that the N1 enhancement reflects a finely tuned selective attention to one stimulus channel among several concurrent, competing channels. This EP enhancement probably increases with increased information load on the subject.

Auditory Evoked Potentials for the Evaluation of Hearing Sensitivity in Navy Dolphins. Assessment of Hearing Sensitivity in Adult Male Elephant Seals

DTIC Science & Technology

2006-12-01

Biology of Marine Mammals, San Diego, California, 12 - 16 December. Finneran, J. J. and Houser, D. S. 2004. Objective measures of steady-state...Gervais’ beaked whale auditory evoked potential hearing measurements. 16th Biennial Conference on the Biology of Marine Mammals, San Diego, California...Biennial Conference on the Biology of Marine Mammals, San Diego, California, 12 - 16 December. 16 FTR N00014-04-1-0455 BIOMIMETICA Invited Lectures

Human lateral geniculate nucleus and visual cortex respond to screen flicker.

PubMed

Krolak-Salmon, Pierre; Hénaff, Marie-Anne; Tallon-Baudry, Catherine; Yvert, Blaise; Guénot, Marc; Vighetto, Alain; Mauguière, François; Bertrand, Olivier

2003-01-01

The first electrophysiological study of the human lateral geniculate nucleus (LGN), optic radiation, striate, and extrastriate visual areas is presented in the context of presurgical evaluation of three epileptic patients (Patients 1, 2, and 3). Visual-evoked potentials to pattern reversal and face presentation were recorded with depth intracranial electrodes implanted stereotactically. For Patient 1, electrode anatomical registration, structural magnetic resonance imaging, and electrophysiological responses confirmed the location of two contacts in the geniculate body and one in the optic radiation. The first responses peaked approximately 40 milliseconds in the LGN in Patient 1 and 60 milliseconds in the V1/V2 complex in Patients 2 and 3. Moreover, steady state visual-evoked potentials evoked by the unperceived but commonly experienced video-screen flicker were recorded in the LGN, optic radiation, and V1/V2 visual areas. This study provides topographic and temporal propagation characteristics of steady state visual-evoked potentials along human visual pathways. We discuss the possible relationship between the oscillating signal recorded in subcortical and cortical areas and the electroencephalogram abnormalities observed in patients suffering from photosensitive epilepsy, particularly video-game epilepsy. The consequences of high temporal frequency visual stimuli delivered by ubiquitous video screens on epilepsy, headaches, and eyestrain must be considered.

Direct sensorimotor corticospinal modulation of dorsal horn neuronal C-fiber responses in the rat.

PubMed

Rojas-Piloni, Gerardo; Martínez-Lorenzana, Guadalupe; Condés-Lara, Miguel; Rodríguez-Jiménez, Javier

2010-09-10

Clinically, the stimulation of motor cortical areas has been used to alleviate certain pain conditions. However, the attempts to understand the mechanisms of cortical nociceptive modulation at the spinal cord level have yielded controversial results. The objectives of the present work were to: 1) determine the effects of activating and suppressing the activity of sensorimotor cortical neurons on the nociceptive electrophysiological responses of the segmental C-fibers, and 2) evaluate the contribution of direct and indirect corticospinal projections in segmental nociceptive modulation. By means of a bipolar matrix of stimulation electrodes we mapped the stimulation of cortical areas that modulate C-fiber evoked field potentials in the dorsal horn. In addition, suppressing the cortical activity by means of cortical spreading depression, we observed that the C-fiber evoked field potentials in the dorsal horn are facilitated when cortical activity is suppressed specifically in sensorimotor cortex. Moreover, the C-fiber evoked field potentials were inhibited during spontaneous activation of cortical projecting neurons. Furthermore, after a lesion of the pyramidal tract contralateral to the spinal cord recording sites, the cortical action was suppressed. Our results show that corticospinal tract fibers arising from the sensorimotor cortex modulate directly the nociceptive C-fiber evoked responses of the dorsal horn. 2010. Published by Elsevier B.V.

Oxaloacetate decreases the infarct size and attenuates the reduction in evoked responses after photothrombotic focal ischemia in the rat cortex.

PubMed

Nagy, David; Marosi, Mate; Kis, Zsolt; Farkas, Tamas; Rakos, Gabriella; Vecsei, Laszlo; Teichberg, Vivian I; Toldi, Jozsef

2009-09-01

A traumatic brain injury or a focal brain lesion is followed by acute excitotoxicity caused by the presence of abnormally high glutamate (Glu) levels in the cerebrospinal and interstitial fluids. It has recently been demonstrated that this excess Glu in the brain can be eliminated into the blood following the intravenous administration of oxaloacetate (OxAc), which, by scavenging the blood Glu, induces an enhanced and neuroprotective brain-to-blood Glu efflux. In this study, we subjected rats to a photothrombotic lesion and treated them after the illumination with a single 30-min-long administration of OxAc (1.2 mg/100 g, i.v.). Following induction of the lesion, we measured the infarct size and the amplitudes of the somatosensory evoked potentials (SEPs) as recorded from the skull surface. The photothrombotic lesion resulted in appreciably decreased amplitudes of the evoked potentials, but OxAc administration significantly attenuated this reduction, and also the infarct size assessed histologically. We suggest that the neuroprotective effects of OxAc are due to its blood Glu-scavenging activity, which, by increasing the brain-to-blood Glu efflux, reduces the excess Glu responsible for the anatomical and functional correlates of the ischemia, as evaluated by electrophysiological evoked potential (EP) measurements.

Investigation of Abnormal Left Temporal Functioning in Dyslexia through rCBF, Auditory Evoked Potentials, and Positron Emission Tomography.

ERIC Educational Resources Information Center

Wood, Frank; And Others

1991-01-01

Investigates the proposed left hemisphere dysfunction in dyslexia by reviewing four studies using regional cerebral blood flow (RCBF) and combined auditory evoked responses with positron emission tomography. Emphasizes methodological issues. Finds that dyslexics showed a positive correlation between Heschl's gyrus activation and phonemic…

Non-provocative diagnostics of photosensitivity using visual evoked potentials.

PubMed

Vermeulen, Joost; Kalitzin, Stiliyan; Parra, Jaime; Dekker, Erwin; Vossepoel, Albert; da Silva, Fernando Lopes

2008-04-01

Photosensitive epilepsy (PSE) is the most common form of reflex epilepsy. Usually, to find out whether a patient is sensitive, he/she is stimulated visually with, e.g. a stroboscopic light stimulus at variable frequency and intensity until a photo paroxysmal response (PPR) occurs. The research described in this work aims to find whether photosensitivity can be detected without provoking a PPR. Twenty-two subjects, 15 with known photosensitivity, were stimulated with visual stimuli that did not provoke a PPR. Using an "evoked response representation", 18 features were analytically derived from EEG signals. Single- and multi-feature classification paradigms were applied to extract those features that separate best subjects with PSE from controls. Two variables in the "evoked response representation", a frequency term and a goodness of fit term to a particular template, appeared to be best suited to make a prediction about the photosensitivity of a subject. Evoked responses appear to carry information about potential PSE. This result can be useful for screening patients for photosensitivity and it may also help to assess in a quantitative way the effectiveness of medical therapy.

The hybrid BCI system for movement control by combining motor imagery and moving onset visual evoked potential.

PubMed

Ma, Teng; Li, Hui; Deng, Lili; Yang, Hao; Lv, Xulin; Li, Peiyang; Li, Fali; Zhang, Rui; Liu, Tiejun; Yao, Dezhong; Xu, Peng

2017-04-01

Movement control is an important application for EEG-BCI (EEG-based brain-computer interface) systems. A single-modality BCI cannot provide an efficient and natural control strategy, but a hybrid BCI system that combines two or more different tasks can effectively overcome the drawbacks encountered in single-modality BCI control. In the current paper, we developed a new hybrid BCI system by combining MI (motor imagery) and mVEP (motion-onset visual evoked potential), aiming to realize the more efficient 2D movement control of a cursor. The offline analysis demonstrates that the hybrid BCI system proposed in this paper could evoke the desired MI and mVEP signal features simultaneously, and both are very close to those evoked in the single-modality BCI task. Furthermore, the online 2D movement control experiment reveals that the proposed hybrid BCI system could provide more efficient and natural control commands. The proposed hybrid BCI system is compensative to realize efficient 2D movement control for a practical online system, especially for those situations in which P300 stimuli are not suitable to be applied.

[Effect of the novel dipeptide nootropic agent noopept and its metabolite cyclo-L-prolylglycine on the transcallosal evoked potential in the rat brain].

PubMed

Molodavkin, G M; Borlikova, G G; Voronina, T A; Gudasheva, T A; Ostrovskaia, R U; Tushmalova, N A; Seredenin, S B

2002-01-01

The effect of new nootropic dipeptides--noopept (N-phenylacetyl-L-prolylglycine, GVS-111) and its metabolite (cyclo-L-prolylglycine)--and a standard nootrope piracetam on the transcallosal evoked potential (TEP) in rat brain was studied. In the dose range from 150 to 300 mg/kg, piracetam increased the TEP amplitude, which exhibited a maximum after 1.5-2 h and then gradually decreased. Both noopept and cyclo-L-prolylglycine also increased the TEP amplitude, which attained a plateau and retained this level over the entire observation time (above 3.5 h). All the nootropes studied increased both components of the evoked potential. Piracetam and cyclo-L-prolylglycine led to an approximately equal increase in both waves, while noopept induced a somewhat greater increase in the negative TEP wave amplitude. It is suggested that the positive effect of noopept and cyclo-L-prolylglycine upon the interhemispheric signal transfer (indicated by the improved transcallosal response) can be considered as a potential neurophysiological basis for a positive drug influence on the behavioral level.

Auditory effects of aircraft noise on people living near an airport.

PubMed

Chen, T J; Chen, S S; Hsieh, P Y; Chiang, H C

1997-01-01

Two groups of randomly chosen individuals who lived in two communities located different distances from the airport were studied. We monitored audiometry and brainstem auditory-evoked potentials to evaluate cochlear and retrocochlear functions in the individuals studied. The results of audiometry measurements indicated that hearing ability was reduced significantly in individuals who lived near the airport and who were exposed frequently to aircraft noise. Values of pure-tone average, high pure-tone average, and threshold at 4 kHz were all higher in individuals who lived near the airport, compared with those who lived farther away. With respect to brainstem auditory-evoked potentials, latencies between the two groups were not consistently different; however, the abnormality rate of such potentials was significantly higher in volunteers who lived near the airport, compared with less-exposed counterparts. In addition, a positive correlation was found between brainstem auditory-evoked potential latency and behavioral hearing threshold of high-frequency tone in exposed volunteers. We not only confirmed that damage to the peripheral cochlear organs occurred in individuals exposed frequently to aircraft noise, but we demonstrated involvement of the central auditory pathway.

Mapping the vestibular evoked myogenic potential (VEMP).

PubMed

Colebatch, James G

2012-01-01

Effects of different electrode placements and indifferent electrodes were investigated for the vestibular evoked myogenic potential (VEMP) recorded from the sternocleidomastoid muscle (SCM). In 5 normal volunteers, the motor point of the left SCM was identified and an electrode placed there. A grid of 7 additional electrodes was laid out, along and across the SCM, based upon the location of the motor point. One reference electrode was placed over the sternoclavicular joint and another over C7. There were clear morphological changes with differing recording sites and for the two reference electrodes, but the earliest and largest responses were recorded from the motor point. The C7 reference affected the level of rectified EMG and was associated with an initial negativity in some electrodes. The latencies of the p13 potentials increased with distance from the motor point but the n23 latencies did not. Thus the p13 potential behaved as a travelling wave whereas the n23 behaved as a standing wave. The C7 reference may be contaminated by other evoked myogenic activity. Ideally recordings should be made with an active electrode over the motor point.

Effects of musical training on the auditory cortex in children.

PubMed

Trainor, Laurel J; Shahin, Antoine; Roberts, Larry E

2003-11-01

Several studies of the effects of musical experience on sound representations in the auditory cortex are reviewed. Auditory evoked potentials are compared in response to pure tones, violin tones, and piano tones in adult musicians versus nonmusicians as well as in 4- to 5-year-old children who have either had or not had extensive musical experience. In addition, the effects of auditory frequency discrimination training in adult nonmusicians on auditory evoked potentials are examined. It was found that the P2-evoked response is larger in both adult and child musicians than in nonmusicians and that auditory training enhances this component in nonmusician adults. The results suggest that the P2 is particularly neuroplastic and that the effects of musical experience can be seen early in development. They also suggest that although the effects of musical training on cortical representations may be greater if training begins in childhood, the adult brain is also open to change. These results are discussed with respect to potential benefits of early musical training as well as potential benefits of musical experience in aging.

Detection of asymptomatic cranial neuropathies in patients with systemic lupus erythematosus and their relation to antiribosomal P antibody levels and disease activity.

PubMed

Gaber, Wafaa; Ezzat, Yasser; El Fayoumy, Neveen M; Helmy, Hanan; Mohey, Abeer M

2014-01-01

The objectives of this study are to assess the risk of asymptomatic cranial neuropathy among patients with systemic lupus erythematosus (SLE) and find any association with disease activity and antiribosomal P antibodies. This study is a case-control study including 60 female patients and 30 healthy female controls. Disease activity was measured with the SLE disease activity index (SLEDAI). All patients were evaluated using evoked potentials, blink reflex, and levels of antiribosomal P antibodies. Patients with abnormal electrophysiological parameters had significantly higher levels of antiribosomal P antibodies (P = 0.034) and secondary antiphospholipid syndrome (P = 0.044). Antiribosomal P antibodies (odds ratio 5.4, 95 % confidence interval 1.002-1.03, P = 0.002) and presence of anti-DNA antibodies (odds ratio 1.01, 95 % confidence interval 1.2-24.8, P = 0.032) were independent risk factors for the presence of the abnormal electrophysiological parameters. Disease duration was positively correlated with wave 1 of the auditory brain reflex (P < 0.001) and a latency of the evoked blink reflex (component R1, P = 0.013). SLEDAI scores were positively correlated with latencies of the visually evoked potential (P100, P = 0.02), wave 1 of the auditory brain reflex (P < 0.001), and a latency of the evoked blink reflex (R2c, P = 0.005). Steroid dosage was negatively correlated with P100 latencies (P = 0.042) and components of the evoked blink reflex (R1, P = 0.042; R2i, P = 0.041; R2c, P < 0.001). Because abnormalities in the visually evoked potential and blink reflex were associated with antiribosomal P antibodies, they can be useful for detecting asymptomatic cranial neuropathy. Further studies on large number of patients should be done to determine any association.

Long latency auditory evoked potentials in children with cochlear implants: systematic review.

PubMed

Silva, Liliane Aparecida Fagundes; Couto, Maria Inês Vieira; Matas, Carla Gentile; Carvalho, Ana Claudia Martinho de

2013-11-25

The aim of this study was to analyze the findings on Cortical Auditory Evoked Potentials in children with cochlear implant through a systematic literature review. After formulation of research question and search of studies in four data bases with the following descriptors: electrophysiology (eletrofisiologia), cochlear implantation (implante coclear), child (criança), neuronal plasticity (plasticidade neuronal) and audiology (audiologia), were selected articles (original and complete) published between 2002 and 2013 in Brazilian Portuguese or English. A total of 208 studies were found; however, only 13 contemplated the established criteria and were further analyzed; was made data extraction for analysis of methodology and content of the studies. The results described suggest rapid changes in P1 component of Cortical Auditory Evoked Potentials in children with cochlear implants. Although there are few studies on the theme, cochlear implant has been shown to produce effective changes in central auditory path ways especially in children implanted before 3 years and 6 months of age.

Artifacts produced during electrical stimulation of the vestibular nerve in cats. [autonomic nervous system components of motion sickness

NASA Technical Reports Server (NTRS)

Tang, P. C.

1973-01-01

Evidence is presented to indicate that evoked potentials in the recurrent laryngeal, the cervical sympathetic, and the phrenic nerve, commonly reported as being elicited by vestibular nerve stimulation, may be due to stimulation of structures other than the vestibular nerve. Experiments carried out in decerebrated cats indicated that stimulation of the petrous bone and not that of the vestibular nerve is responsible for the genesis of evoked potentials in the recurrent laryngeal and the cervical sympathetic nerves. The phrenic response to electrical stimulation applied through bipolar straight electrodes appears to be the result of stimulation of the facial nerve in the facial canal by current spread along the petrous bone, since stimulation of the suspended facial nerve evoked potentials only in the phrenic nerve and not in the recurrent laryngeal nerve. These findings indicate that autonomic components of motion sickness represent the secondary reactions and not the primary responses to vestibular stimulation.

A computer-controlled, closed-loop infusion system for infusing muscle relaxants: its use during motor-evoked potential monitoring.

PubMed

Stinson, L W; Murray, M J; Jones, K A; Assef, S J; Burke, M J; Behrens, T L; Lennon, R L

1994-02-01

A microcomputer-controlled closed-loop infusion system (MCCLIS) has been developed that provides stable intraoperative levels of partial neuromuscular blockade. Complete neuromuscular blockade interferes with intraoperative motor-evoked potential (MEP) monitoring used for patients undergoing surgical procedures that place them at risk for spinal cord ischemia. Nine patients were studied during which the MCCLIS maintained stable levels of partial neuromuscular blockade and allowed transcranial magnetic motor-evoked potential (TcM-MEP) monitoring during thoracoabdominal aortic aneurysmectomy. The use of TcM-MEP for monitoring intraoperative spinal cord function was balanced against surgical considerations for muscle relaxation with 80% to 90% neuromuscular blockade fulfilling each requirement. Intraoperative adjustment of partial neuromuscular blockade to facilitate TcM-MEP monitoring was also possible with the MCCLIS. The MCCLIS should allow for further investigation into the sensitivity, specificity, and predictability of TcM-MEP monitoring for any patient at risk for intraoperative spinal cord ischemia including those undergoing thoracoabdominal aortic aneurysmectomy.

Brain function monitoring during off-pump cardiac surgery: a case report

PubMed Central

Zanatta, Paolo; Bosco, Enrico; Di Pasquale, Piero; Nivedita, Agarwal; Valfrè, Carlo; Sorbara, Carlo

2008-01-01

Background Early postoperative stroke is an adverse syndrome after coronary bypass surgery. This report focuses on overcoming of cerebral ischemia as a result of haemodynamic instability during heart enucleation in off-pump procedure. Case presentation A 67 year old male patient, Caucasian race, with a body mass index of 28, had a recent non-Q posterolateral myocardial infarction one month before and recurrent instable angina. His past history includes an uncontrolled hypertension, dyslipidemia, insulin dependent diabetes mellitus, epiaortic vessel stenosis. The patient was scheduled for an off-pump procedure and monitored with bilateral somatosensory evoked potentials, whose alteration signalled the decrement of the cardiac index during operation. The somatosensory evoked potentials appeared when the blood pressure was increased with a pharmacological treatment. Conclusion During the off-pump coronary bypass surgery, a lower cardiac index, predisposes patients, with multiple stroke risk factors, to a reduction of the cerebral blood flow. Intraoperative somatosensory evoked potentials monitoring provides informations about the functional status of somatosensory cortex to reverse effects of brain ischemia. PMID:18706094

Changes in visual-evoked potential habituation induced by hyperventilation in migraine.

PubMed

Coppola, Gianluca; Currà, Antonio; Sava, Simona Liliana; Alibardi, Alessia; Parisi, Vincenzo; Pierelli, Francesco; Schoenen, Jean

2010-12-01

Hyperventilation is often associated with stress, an established trigger factor for migraine. Between attacks, migraine is associated with a deficit in habituation to visual-evoked potentials (VEP) that worsens just before the attack. Hyperventilation slows electroencephalographic (EEG) activity and decreases the functional response in the occipital cortex during visual stimulation. The neural mechanisms underlying deficient-evoked potential habituation in migraineurs remain unclear. To find out whether hyperventilation alters VEP habituation, we recorded VEPs before and after experimentally induced hyperventilation lasting 3 min in 18 healthy subjects and 18 migraine patients between attacks. We measured VEP P100 amplitudes in six sequential blocks of 100 sweeps and habituation as the change in amplitude over the six blocks. In healthy subjects, hyperventilation decreased VEP amplitude in block 1 and abolished the normal VEP habituation. In migraine patients, hyperventilation further decreased the already low block 1 amplitude and worsened the interictal habituation deficit. Hyperventilation worsens the habituation deficit in migraineurs possibly by increasing dysrhythmia in the brainstem-thalamo-cortical network.

Interaction between visual and chemical cues in a Liolaemus lizard: a multimodal approach.

PubMed

Vicente, Natalin S; Halloy, Monique

2017-12-01

Multimodal communication involves the use of signals and cues across two or more sensory modalities. The genus Liolaemus (Iguania: Liolaemidae) offers a great potential for studies on the ecology and evolution of multimodal communication, including visual and chemical signals. In this study, we analyzed the response of male and female Liolaemus pacha to chemical, visual and combined (multimodal) stimuli. Using cue-isolation tests, we registered the number of tongue flicks and headbob displays from exposure to signals in each modality. Number of tongue flicks was greater when a chemical stimulus was presented alone than in the presence of visual or multimodal stimuli. In contrast, headbob displays were fewer in number with visual and chemical stimuli alone, but significantly higher in number when combined. Female signallers triggered significantly more tongue flicks than male signallers, suggesting that chemical cues are involved in sexual recognition. We did not find an inhibition between chemical and visual cues. On the contrary, we observed a dominance of the chemical modality, because when presented with visual stimuli, lizards also responded with more tongue flicks than headbob displays. The total response produced by multimodal stimuli was similar to that of the chemical stimuli alone, possibly suggesting non-redundancy. We discuss whether the visual component of a multimodal signal could attract attention at a distance, increasing the effectiveness of transmission and reception of the information in chemical cues. Copyright © 2017 Elsevier GmbH. All rights reserved.

Auditory evoked potential could reflect emotional sensitivity and impulsivity

PubMed Central

Kim, Ji Sun; Kim, Sungkean; Jung, Wookyoung; Im, Chang-Hwan; Lee, Seung-Hwan

2016-01-01

Emotional sensitivity and impulsivity could cause interpersonal conflicts and neuropsychiatric problems. Serotonin is correlated with behavioral inhibition and impulsivity. This study evaluated whether the loudness dependence of auditory evoked potential (LDAEP), a potential biological marker of central serotonergic activity, could reflect emotional sensitivity and impulsivity. A total of 157 healthy individuals were recruited, who performed LDAEP and Go/Nogo paradigms during electroencephalogram measurement. Barratt impulsivity scale (BIS), Conners’ Adult ADHD rating scale (CAARS), and affective lability scale (ALS) were evaluated. Comparison between low and high LDAEP groups was conducted for behavioural, psychological, and event-related potential (ERP) measures. The high LDAEP group showed significantly increased BIS, a subscale of the CAARS, ALS, and false alarm rate of Nogo stimuli compared to the low LDAEP group. LDAEP showed significant positive correlations with the depression scale, ALS scores, subscale of the CAARS and Nogo-P3 amplitude. In the source activity of Nogo-P3, the cuneus, lingual gyrus, and precentral gyrus activities were significantly increased in the high LDAEP group. Our study revealed that LDAEP could reflect emotional sensitivity and impulsivity. LDAEP, an auditory evoked potential could be a useful tool to evaluate emotional regulation. PMID:27910865

Ion diffusion may introduce spurious current sources in current-source density (CSD) analysis.

PubMed

Halnes, Geir; Mäki-Marttunen, Tuomo; Pettersen, Klas H; Andreassen, Ole A; Einevoll, Gaute T

2017-07-01

Current-source density (CSD) analysis is a well-established method for analyzing recorded local field potentials (LFPs), that is, the low-frequency part of extracellular potentials. Standard CSD theory is based on the assumption that all extracellular currents are purely ohmic, and thus neglects the possible impact from ionic diffusion on recorded potentials. However, it has previously been shown that in physiological conditions with large ion-concentration gradients, diffusive currents can evoke slow shifts in extracellular potentials. Using computer simulations, we here show that diffusion-evoked potential shifts can introduce errors in standard CSD analysis, and can lead to prediction of spurious current sources. Further, we here show that the diffusion-evoked prediction errors can be removed by using an improved CSD estimator which accounts for concentration-dependent effects. NEW & NOTEWORTHY Standard CSD analysis does not account for ionic diffusion. Using biophysically realistic computer simulations, we show that unaccounted-for diffusive currents can lead to the prediction of spurious current sources. This finding may be of strong interest for in vivo electrophysiologists doing extracellular recordings in general, and CSD analysis in particular. Copyright © 2017 the American Physiological Society.

Can Vestibular-Evoked Myogenic Potentials Help Differentiate Ménière Disease from Vestibular Migraine?

PubMed Central

Zuniga, M. Geraldine; Janky, Kristen L.; Schubert, Michael C.; Carey, John P.

2013-01-01

Objectives To characterize both cervical and ocular vestibular-evoked myogenic potential (cVEMP, oVEMP) responses to air-conducted sound (ACS) and midline taps in Ménière disease (MD), vestibular migraine (VM), and controls, as well as to determine if cVEMP or oVEMP responses can differentiate MD from VM. Study Design Prospective cohort study. Setting Tertiary referral center. Subjects and Methods Unilateral definite MD patients (n = 20), VM patients (n = 21) by modified Neuhauser criteria, and age-matched controls (n = 28). cVEMP testing used ACS (clicks), and oVEMP testing used ACS (clicks and 500-Hz tone bursts) and midline tap stimuli (reflex hammer and Mini-Shaker). Outcome parameters were cVEMP peak-to-peak amplitudes and oVEMP n10 amplitudes. Results Relative to controls, MD and VM groups both showed reduced click-evoked cVEMP (P < .001) and oVEMP (P < .001) amplitudes. Only the MD group showed reduction in tone-evoked amplitudes for oVEMP. Tone-evoked oVEMPs differentiated MD from controls (P = .001) and from VM (P = .007). The oVEMPs in response to the reflex hammer and Mini-Shaker midline taps showed no differences between groups (P > .210). Conclusions Using these techniques, VM and MD behaved similarly on most of the VEMP test battery. A link in their pathophysiology may be responsible for these responses. The data suggest a difference in 500-Hz tone burst–evoked oVEMP responses between MD and MV as a group. However, no VEMP test that was investigated segregated individuals with MD from those with VM. PMID:22267492

The ventricular intracardiac unipolar paced-evoked potential in an isolated animal heart.

PubMed

Economides, A P; Walton, C; Gergely, S

1988-02-01

The endocardial unipolar paced evoked response has excited a great deal of interest due to its possible use in the measurement of the metabolic state of the body and other pacer-related areas. Although rate-responsive pacing utilizing this signal has been clinically evaluated, little is known regarding the behavior of the components of this waveform under normal physiological conditions. We have developed an electronic circuit which allows the recording of the evoked response within a few milliseconds of a pacing stimulus of 5 V and 0.5 ms duration being applied using a single unipolar, smooth platinum electrode of 14 mm2 surface area. The paced evoked response was measured using a total of 20 isolated rabbit heart preparations. Five were run for 8 hours and the remaining fifteen were run for 5 hours. Our results indicate that the waveform components of the evoked response remain stable while the preparation is viable, but that two of the time-related measurements change with loss of viability. A significant lengthening of the stimulus-R interval was seen together with a dramatic shortening of the R-T period. The net result of these changes was an overall reduction of 17% in the complex duration. In addition, we found the R-T shortening to be a sensitive measure of myocardial integrity. We conclude that the combination of our interface charge elimination circuit and the isolated heart preparation has proved a useful system for the investigation of the paced evoked potential. Furthermore, the loss of myocardial viability has a complex action on this response.

A short latency vestibular evoked potential (VsEP) produced by bone-conducted acoustic stimulation

NASA Astrophysics Data System (ADS)

McAngus Todd, Neil P.; Rosengren, Sally M.; Colebatch, James G.

2003-12-01

In this paper data are presented from an experiment which provides evidence for the existence of a short latency, acoustically evoked potential of probable vestibular origin. The experiment was conducted in two phases using bone-conducted acoustic stimulation. In the first phase subjects were stimulated with 6-ms, 500-Hz tone bursts in order to obtain the threshold VT for vestibular evoked myogenic potentials (VEMP). It was confirmed that the difference between bone-conducted auditory and acoustic vestibular thresholds was slightly over 30 dB. The estimated threshold was then used as a reference value in the second part of the experiment to stimulate subjects over a range of intensities from -6 to +18 dB (re:VT). Averaged EEG recordings were made with eight Ag/AgCl electrodes placed on the scalp at Fpz, F3, F4, F7, F8, Cz, T3, and T4 according to the 10-20 system. Below VT auditory midlatency responses (MLRs) were observed. Above VT two additional potentials appeared: a positivity at about 10 ms (P10) which was maximal at Cz, and a negativity at about 15 ms (N15) which was maximal at Fpz. Extrapolation of the growth functions for the P10 and N15 indicated a threshold close to VT, consistent with a vestibular origin of these potentials. Given the low threshold of vestibular acoustic sensitivity it is possible that this mode may make a contribution to the detection of and affective responses to loud low frequency sounds. The evoked potentials may also have application as a noninvasive and nontraumatic test of vestibular projections to the cortex.

Effects of phloretin and phloridzin on Ca2+ handling, the action potential, and ion currents in rat ventricular myocytes.

PubMed

Olson, Marnie L; Kargacin, Margaret E; Ward, Christopher A; Kargacin, Gary J

2007-06-01

The effects of the phytoestrogens phloretin and phloridzin on Ca(2+) handling, cell shortening, the action potential, and Ca(2+) and K(+) currents in freshly isolated cardiac myocytes from rat ventricle were examined. Phloretin increased the amplitude and area and decreased the rate of decline of electrically evoked Ca(2+) transients in the myocytes. These effects were accompanied by an increase in the Ca(2+) load of the sarcoplasmic reticulum, as determined by the area of caffeine-evoked Ca(2+) transients. An increase in the extent of shortening of the myocytes in response to electrically evoked action potentials was also observed in the presence of phloretin. To further examine possible mechanisms contributing to the observed changes in Ca(2+) handling and contractility, the effects of phloretin on the cardiac action potential and plasma membrane Ca(2+) and K(+) currents were examined. Phloretin markedly increased the action potential duration in the myocytes, and it inhibited the Ca(2+)-independent transient outward K(+) current (I(to)). The inwardly rectifying K(+) current, the sustained outward delayed rectifier K(+) current, and L-type Ca(2+) currents were not significantly different in the presence and absence of phloretin, nor was there any evidence that the Na(+)/Ca(2+) exchanger was affected. The effects of phloretin on Ca(2+) handling in the myocytes are consistent with its effects on I(to). Phloridzin did not significantly alter the amplitude or area of electrically evoked Ca(2+) transients in the myocytes, nor did it have detectable effects on the sarcoplasmic reticulum Ca(2+) load, cell shortening, or the action potential.

Cerebellar interaction with the acoustic reflex.

PubMed

Jastreboff, P J

1981-01-01

The involvement of the cerebellar vermis in the acoustic reflex was analyzed in 12 cats, decerebrated or in pentobarbital anesthesia. Anatomical data suggested the existence of a connection of lobules VIII with the ventral cochlear nucleus. Single cell recording and evoked potential techniques demonstrated the existence of the acoustic projection to lobulus VIII. Electrical stimulation of this area changed the tension of the middle ear muscle and caused evoked potential responses in the caudal part of the ventral cochlear nucleus. Electrical stimulation of the motor nucleus of the facial nerve evoked a slow wave in the recording taken from the surrounding of the cochlear round window. A hypothesis is proposed which postulates the involvement of the acoustic reflex in space localization of acoustic stimuli and the action of cerebellar vermis in order to assure the stability and plasticity of the acoustic reflex arc.

Diagnostic value of conventional visual evoked potentials applied to patients with multiple sclerosis.

PubMed

Balnytė, Renata; Ulozienė, Ingrida; Rastenytė, Daiva; Vaitkus, Antanas; Malcienė, Lina; Laučkaitė, Kristina

2011-01-01

The aim of this study was to determine the sensitivity and specificity of this classical technique employed at the Hospital of Lithuanian University of Health Sciences for the patients with multiple sclerosis and to assess its possible correlations with affected neurological systems. Pattern shift visual evoked potentials were recorded in 63 patients with multiple sclerosis, 17 (27%) of whom had a history of optic neuritis, and in 63 control patients with other neurological diseases. The latencies and amplitudes of P100 were measured. In total, 126 patients were referred to the inpatient department of neurology for differential diagnosis of demyelinating disorders between January and December of 2007. Abnormalities of visual evoked potentials were observed by 73% more frequently in patients with multiple sclerosis than in control patients (α=0.05, β<0.01). The combined monocular/interocular test showed a specificity of 90.5% and a sensitivity of 82.5%. The probability of an affection of the pyramidal system was 5 times greater (95% CI, 2.2-11.0; P<0.01) and the probability of the optic pathways involvement was 4.8 times greater (95% CI, 1.9-11.9; P<0.01) in patients with multiple sclerosis than in controls. Conventional visual evoked potentials must be reappraised in light of their diagnostic value in multiple sclerosis given their high diagnostic efficiency, relatively easy, short, and cheap implementation, and easy availability in everyday clinical practice.

Evolving Role of Local Anesthetics in Managing Postsurgical Analgesia.

PubMed

Golembiewski, Julie; Dasta, Joseph

2015-06-01

Opioid analgesics, the cornerstone of effective postsurgical pain management, may be associated with risk of opioid-related adverse drug events (ADEs) that may complicate the postsurgical experience. Perioperative multimodal analgesic regimens have the potential to improve postsurgical pain control and may permit use of lower analgesic doses and reduce the incidence of opioid-related ADEs. Utility of traditional local anesthetic formulations to provide analgesia over the entire postsurgical period is limited by their short duration of action. Liposome bupivacaine, a liposomal formulation of bupivacaine indicated for single-dose administration into the surgical site to produce postsurgical analgesia, was evaluated in multiple surgical models as part of multimodal analgesic regimens and was found in clinical trials to provide postsurgical analgesia for up to 72 hours. Here, we provide an overview of the available multimodal analgesic options and recent recommendations for optimal postsurgical pain management. A review of the literature was conducted, and results from recent clinical trials are included. The use of a multimodal analgesic regimen, including liposome bupivacaine, can extend the time to first postsurgical opioid use, may reduce postsurgical opioid consumption, and reduce hospital length of stay and costs compared with an opioid-only analgesic regimen. Use of multimodal analgesic regimens is a practical way to achieve good postsurgical analgesia while minimizing reliance on opioids and associated adverse events. Taken as a whole, evidence from the clinical studies of liposome bupivacaine suggests this local anesthetic formulation may be a useful component of multimodal analgesic regimens for managing postsurgical pain in select patients, with the potential to reduce opioid use and opioid-related ADEs in the postsurgical setting. As with bupivacaine, appropriate use of liposome bupivacaine to optimize clinical effects, economic implications, and patient tolerability will depend on appropriate patient selection, practitioner training, and institutional protocols. As a component of a multimodal analgesic regimen, liposome bupivacaine represents a new approach to extending the duration of postsurgical analgesia. Further studies across a range of surgical settings should help clarify the most appropriate roles for this prolonged-release formulation of bupivacaine. Copyright © 2015 Elsevier HS Journals, Inc. All rights reserved.

Detecting number processing and mental calculation in patients with disorders of consciousness using a hybrid brain-computer interface system.

PubMed

Li, Yuanqing; Pan, Jiahui; He, Yanbin; Wang, Fei; Laureys, Steven; Xie, Qiuyou; Yu, Ronghao

2015-12-15

For patients with disorders of consciousness such as coma, a vegetative state or a minimally conscious state, one challenge is to detect and assess the residual cognitive functions in their brains. Number processing and mental calculation are important brain functions but are difficult to detect in patients with disorders of consciousness using motor response-based clinical assessment scales such as the Coma Recovery Scale-Revised due to the patients' motor impairments and inability to provide sufficient motor responses for number- and calculation-based communication. In this study, we presented a hybrid brain-computer interface that combines P300 and steady state visual evoked potentials to detect number processing and mental calculation in Han Chinese patients with disorders of consciousness. Eleven patients with disorders of consciousness who were in a vegetative state (n = 6) or in a minimally conscious state (n = 3) or who emerged from a minimally conscious state (n = 2) participated in the brain-computer interface-based experiment. During the experiment, the patients with disorders of consciousness were instructed to perform three tasks, i.e., number recognition, number comparison, and mental calculation, including addition and subtraction. In each experimental trial, an arithmetic problem was first presented. Next, two number buttons, only one of which was the correct answer to the problem, flickered at different frequencies to evoke steady state visual evoked potentials, while the frames of the two buttons flashed in a random order to evoke P300 potentials. The patients needed to focus on the target number button (the correct answer). Finally, the brain-computer interface system detected P300 and steady state visual evoked potentials to determine the button to which the patients attended, further presenting the results as feedback. Two of the six patients who were in a vegetative state, one of the three patients who were in a minimally conscious state, and the two patients that emerged from a minimally conscious state achieved accuracies significantly greater than the chance level. Furthermore, P300 potentials and steady state visual evoked potentials were observed in the electroencephalography signals from the five patients. Number processing and arithmetic abilities as well as command following were demonstrated in the five patients. Furthermore, our results suggested that through brain-computer interface systems, many cognitive experiments may be conducted in patients with disorders of consciousness, although they cannot provide sufficient behavioral responses.

Parvalbumin interneuron mediated feedforward inhibition controls signal output in the deep layers of the perirhinal‐entorhinal cortex

PubMed Central

Willems, Janske G. P.; Wadman, Wytse J.

2018-01-01

Abstract The perirhinal (PER) and lateral entorhinal (LEC) cortex form an anatomical link between the neocortex and the hippocampus. However, neocortical activity is transmitted through the PER and LEC to the hippocampus with a low probability, suggesting the involvement of the inhibitory network. This study explored the role of interneuron mediated inhibition, activated by electrical stimulation in the agranular insular cortex (AiP), in the deep layers of the PER and LEC. Activated synaptic input by AiP stimulation rarely evoked action potentials in the PER‐LEC deep layer excitatory principal neurons, most probably because the evoked synaptic response consisted of a small excitatory and large inhibitory conductance. Furthermore, parvalbumin positive (PV) interneurons—a subset of interneurons projecting onto the axo‐somatic region of principal neurons—received synaptic input earlier than principal neurons, suggesting recruitment of feedforward inhibition. This synaptic input in PV interneurons evoked varying trains of action potentials, explaining the fast rising, long lasting synaptic inhibition received by deep layer principal neurons. Altogether, the excitatory input from the AiP onto deep layer principal neurons is overruled by strong feedforward inhibition. PV interneurons, with their fast, extensive stimulus‐evoked firing, are able to deliver this fast evoked inhibition in principal neurons. This indicates an essential role for PV interneurons in the gating mechanism of the PER‐LEC network. PMID:29341361

Exploring infrared neural stimulation with multimodal nonlinear imaging (Conference Presentation)

NASA Astrophysics Data System (ADS)

Adams, Wilson R.; Mahadevan-Jansen, Anita

2017-02-01

Infrared neural stimulation (INS) provides optical control of neural excitability using near to mid-infrared (mid-IR) light, which allows for spatially selective, artifact-free excitation without the introduction of exogenous agents or genetic modification. Although neural excitability is mediated by a transient temperature increase due to water absorption of IR energy, the molecular nature of IR excitability in neural tissue remains unknown. Current research suggests that transient changes in local tissue temperature give rise to a myriad of cellular responses that have been individually attributed to IR mediated excitability. To further elucidate the underlying biophysical mechanisms, we have begun work towards employing a novel multimodal nonlinear imaging platform to probe the molecular underpinnings of INS. Our imaging system performs coherent anti-Stokes Raman scattering (CARS), stimulated Raman scattering (SRS), two-photon excitation fluorescence (TPEF), second-harmonic generation (SHG) and thermal imaging into a single platform that allows for unprecedented co-registration of thermal and biochemical information in real-time. Here, we present our work leveraging CARS and SRS in acute thalamocortical brain slice preparations. We observe the evolution of lipid and protein-specific Raman bands during INS and electrically evoked activity in real-time. Combined with two-photon fluorescence and second harmonic generation, we offer insight to cellular metabolism and membrane dynamics during INS. Thermal imaging allows for the coregistration of acquired biochemical information with temperature information. Our work previews the versatility and capabilities of coherent Raman imaging combined with multiphoton imaging to observe biophysical phenomena for neuroscience applications.

Auditory Evoked Potentials from the Frog Eighth Nerve

DTIC Science & Technology

1989-09-01

superior olivary nucleus 6, 10-100 ms in torus semicircularis’ 2,4’ 14, 1618, 30-120 ms in thalamus 7’ 1,13,14, and greater than 30 ms in telencephalon 12...899. 12 Mudry, K.M. and Capranica, R.R., Evoked auditory activity within the telencephalon of the bullfrog (Rana catesbeiana), Brain Res., 182 (1980

Non-invasive mapping of deep-tissue lymph nodes in live animals using a multimodal PET/MRI nanoparticle

NASA Astrophysics Data System (ADS)

Thorek, Daniel L. J.; Ulmert, David; Diop, Ndeye-Fatou M.; Lupu, Mihaela E.; Doran, Michael G.; Huang, Ruimin; Abou, Diane S.; Larson, Steven M.; Grimm, Jan

2014-01-01

The invasion status of tumour-draining lymph nodes (LNs) is a critical indicator of cancer stage and is important for treatment planning. Clinicians currently use planar scintigraphy and single-photon emission computed tomography (SPECT) with 99mTc-radiocolloid to guide biopsy and resection of LNs. However, emerging multimodality approaches such as positron emission tomography combined with magnetic resonance imaging (PET/MRI) detect sites of disease with higher sensitivity and accuracy. Here we present a multimodal nanoparticle, 89Zr-ferumoxytol, for the enhanced detection of LNs with PET/MRI. For genuine translational potential, we leverage a clinical iron oxide formulation, altered with minimal modification for radiolabelling. Axillary drainage in naive mice and from healthy and tumour-bearing prostates was investigated. We demonstrate that 89Zr-ferumoxytol can be used for high-resolution tomographic studies of lymphatic drainage in preclinical disease models. This nanoparticle platform has significant translational potential to improve preoperative planning for nodal resection and tumour staging.

Multi-Modal Nano-Probes for Radionuclide and 5-color Near Infrared Optical Lymphatic Imaging

PubMed Central

Kobayashi, Hisataka; Koyama, Yoshinori; Barrett, Tristan; Hama, Yukihiro; Regino, Celeste A. S.; Shin, In Soo; Jang, Beom-Su; Le, Nhat; Paik, Chang H.; Choyke, Peter L.; Urano, Yasuteru

2008-01-01

Current contrast agents generally have one function and can only be imaged in monochrome, therefore, the majority of imaging methods can only impart uniparametric information. A single nano-particle has the potential to be loaded with multiple payloads. Such multi-modality probes have the ability to be imaged by more than one imaging technique, which could compensate for the weakness or even combine the advantages of each individual modality. Furthermore, optical imaging using different optical probes enables us to achieve multi-color in vivo imaging, wherein multiple parameters can be read from a single image. To allow differentiation of multiple optical signals in vivo, each probe should have a close but different near infrared emission. To this end, we synthesized nano-probes with multi-modal and multi-color potential, which employed a polyamidoamine dendrimer platform linked to both radionuclides and optical probes, permitting dual-modality scintigraphic and 5-color near infrared optical lymphatic imaging using a multiple excitation spectrally-resolved fluorescence imaging technique. PMID:19079788

Multimodal nanoprobes for radionuclide and five-color near-infrared optical lymphatic imaging.

PubMed

Kobayashi, Hisataka; Koyama, Yoshinori; Barrett, Tristan; Hama, Yukihiro; Regino, Celeste A S; Shin, In Soo; Jang, Beom-Su; Le, Nhat; Paik, Chang H; Choyke, Peter L; Urano, Yasuteru

2007-11-01

Current contrast agents generally have one function and can only be imaged in monochrome; therefore, the majority of imaging methods can only impart uniparametric information. A single nanoparticle has the potential to be loaded with multiple payloads. Such multimodality probes have the ability to be imaged by more than one imaging technique, which could compensate for the weakness or even combine the advantages of each individual modality. Furthermore, optical imaging using different optical probes enables us to achieve multicolor in vivo imaging, wherein multiple parameters can be read from a single image. To allow differentiation of multiple optical signals in vivo, each probe should have a close but different near-infrared emission. To this end, we synthesized nanoprobes with multimodal and multicolor potential, which employed a polyamidoamine dendrimer platform linked to both radionuclides and optical probes, permitting dual-modality scintigraphic and five-color near-infrared optical lymphatic imaging using a multiple-excitation spectrally resolved fluorescence imaging technique.

Evoking prescribed spike times in stochastic neurons

NASA Astrophysics Data System (ADS)

Doose, Jens; Lindner, Benjamin

2017-09-01

Single cell stimulation in vivo is a powerful tool to investigate the properties of single neurons and their functionality in neural networks. We present a method to determine a cell-specific stimulus that reliably evokes a prescribed spike train with high temporal precision of action potentials. We test the performance of this stimulus in simulations for two different stochastic neuron models. For a broad range of parameters and a neuron firing with intermediate firing rates (20-40 Hz) the reliability in evoking the prescribed spike train is close to its theoretical maximum that is mainly determined by the level of intrinsic noise.

Human auditory evoked potentials. I - Evaluation of components

NASA Technical Reports Server (NTRS)

Picton, T. W.; Hillyard, S. A.; Krausz, H. I.; Galambos, R.

1974-01-01

Fifteen distinct components can be identified in the scalp recorded average evoked potential to an abrupt auditory stimulus. The early components occurring in the first 8 msec after a stimulus represent the activation of the cochlea and the auditory nuclei of the brainstem. The middle latency components occurring between 8 and 50 msec after the stimulus probably represent activation of both auditory thalamus and cortex but can be seriously contaminated by concurrent scalp muscle reflex potentials. The longer latency components occurring between 50 and 300 msec after the stimulus are maximally recorded over fronto-central scalp regions and seem to represent widespread activation of frontal cortex.

Vestibular evoked myogenic potential (VEMP) in patients with acoustic neuromas.

PubMed

Takeichi, N; Sakamoto, T; Fukuda, S; Inuyama, Y

2001-05-01

To study the utility of VEMP (vestibular-evoked myogenic potential) in the diagnosis of acoustic neuromas. Eighteen patients with unilateral acoustic neuromas were subjected to this study. Myogenic potential responding to loud click stimuli was recorded at ipsilateral sternocleidomastoid muscle. A normal range of VEMP was obtained from 20 controls. VEMP responses were compared with both, clinical symptoms and results of caloric tests. Thirteen out of 18 patients showed decreased responses of VEMP at the affected side. VEMP responses seemed to have little relation with dysequilibrium, spontaneous nystagmus, canal paresis and pure-tone hearing. VEMP is useful for detecting dysfunction of inferior vestibular nerve in patients with acoustic neuromas.

The N-methyl-D-aspartate-evoked cytoplasmic calcium increase in adult rat dorsal root ganglion neuronal somata was potentiated by substance P pretreatment in a protein kinase C-dependent manner.

PubMed

Castillo, C; Norcini, M; Baquero-Buitrago, J; Levacic, D; Medina, R; Montoya-Gacharna, J V; Blanck, T J J; Dubois, M; Recio-Pinto, E

2011-03-17

The involvement of substance P (SP) in neuronal sensitization through the activation of the neurokinin-1-receptor (NK1r) in postsynaptic dorsal horn neurons has been well established. In contrast, the role of SP and NK1r in primary sensory dorsal root ganglion (DRG) neurons, in particular in the soma, is not well understood. In this study, we evaluated whether SP modulated the NMDA-evoked transient increase in cytoplasmic Ca2+ ([Ca2+]cyt) in the soma of dissociated adult DRG neurons. Cultures were treated with nerve growth factor (NGF), prostaglandin E2 (PGE2) or both NGF+PGE2. Treatment with NGF+PGE2 increased the percentage of N-methyl-D-aspartate (NMDA) responsive neurons. There was no correlation between the percentage of NMDA responsive neurons and the level of expression of the NR1 and NR2B subunits of the NMDA receptor or of the NK1r. Pretreatment with SP did not alter the percentage of NMDA responsive neurons; while it potentiated the NMDA-evoked [Ca2+]cyt transient by increasing its magnitude and by prolonging the period during which small- and some medium-sized neurons remained NMDA responsive. The SP-mediated potentiation was blocked by the SP-antagonist ([D-Pro4, D-Trp7,9]-SP (4-11)) and by the protein kinase C (PKC) blocker bisindolylmaleimide I (BIM); and correlated with the phosphorylation of PKCε. The Nk1r agonist [Sar9, Met(O2)11]-SP (SarMet-SP) also potentiated the NMDA-evoked [Ca2+]cyt transient. Exposure to SP or SarMet-SP produced a rapid increase in the labeling of phosphorylated-PKCε. In none of the conditions we detected phosphorylation of the NR2B subunit at Ser-1303. Phosphorylation of the NR2B subunit at Tyr1472 was enhanced to a similar extent in cells exposed to NMDA, SP or NMDA+SP, and that enhancement was blocked by BIM. Our findings suggest that NGF and PGE2 may contribute to the injury-evoked sensitization of DRG neurons in part by enhancing their NMDA-evoked [Ca2+]cyt transient in all sized DRG neurons; and that SP may further contribute to the DRG sensitization by enhancing and prolonging the NMDA-evoked increase in [Ca2+]cyt in small- and medium-sized DRG neurons. Copyright © 2011 IBRO. Published by Elsevier Ltd. All rights reserved.

The Emergence of Contrast-Invariant Orientation Tuning in Simple Cells of Cat Visual Cortex

PubMed Central

Finn, Ian M.; Priebe, Nicholas J.; Ferster, David

2007-01-01

Simple cells in primary visual cortex exhibit contrast-invariant orientation tuning, in seeming contradiction to feed-forward models relying on lateral geniculate nucleus (LGN) input alone. Contrast invariance has therefore been thought to depend on the presence of intracortical lateral inhibition. In vivo intracellular recordings instead suggest that contrast invariance can be explained by three properties of the excitatory pathway. 1) Depolarizations evoked by orthogonal stimuli are determined by the amount of excitation a cell receives from the LGN, relative to the excitation it receives from other cortical cells. 2) Depolarizations evoked by preferred stimuli saturate at lower contrasts than the spike output of LGN relay cells. 3) Visual stimuli evoke contrast-dependent changes in trial-to-trial variability, which lead to contrast-dependent changes in the relationship between membrane potential and spike rate. Thus, high-contrast, orthogonally-oriented stimuli that evoke significant depolarizations evoke few spikes. Together these mechanisms, without lateral inhibition, can account for contrast-invariant stimulus selectivity. PMID:17408583

Delta and gamma oscillations in operculo-insular cortex underlie innocuous cold thermosensation

PubMed Central

Vinding, Mikkel C.; Allen, Micah; Jensen, Troels Staehelin; Finnerup, Nanna Brix

2017-01-01

Cold-sensitive and nociceptive neural pathways interact to shape the quality and intensity of thermal and pain perception. Yet the central processing of cold thermosensation in the human brain has not been extensively studied. Here, we used magnetoencephalography and EEG in healthy volunteers to investigate the time course (evoked fields and potentials) and oscillatory activity associated with the perception of cold temperature changes. Nonnoxious cold stimuli consisting of Δ3°C and Δ5°C decrements from an adapting temperature of 35°C were delivered on the dorsum of the left hand via a contact thermode. Cold-evoked fields peaked at around 240 and 500 ms, at peak latencies similar to the N1 and P2 cold-evoked potentials. Importantly, cold-related changes in oscillatory power indicated that innocuous thermosensation is mediated by oscillatory activity in the range of delta (1–4 Hz) and gamma (55–90 Hz) rhythms, originating in operculo-insular cortical regions. We suggest that delta rhythms coordinate functional integration between operculo-insular and frontoparietal regions, while gamma rhythms reflect local sensory processing in operculo-insular areas. NEW & NOTEWORTHY Using magnetoencephalography, we identified spatiotemporal features of central cold processing, with respect to the time course, oscillatory profile, and neural generators of cold-evoked responses in healthy human volunteers. Cold thermosensation was associated with low- and high-frequency oscillatory rhythms, both originating in operculo-insular regions. These results support further investigations of central cold processing using magnetoencephalography or EEG and the clinical utility of cold-evoked potentials for neurophysiological assessment of cold-related small-fiber function and damage. PMID:28250150

Somatosensory evoked potentials in patients with hypocalcaemia after parathyroidectomy.

PubMed

Kanda, F; Jinnai, J; Fujita, T

1988-01-01

The effects of hypocalcaemia on somatosensory evoked potentials (SEPs) were studied in five patients after parathyroidectomy. Despite normal latencies the mean value of amplitudes of the SEPs in hypocalcaemic patients was greater than that in normocalcaemic subjects. Recovery functions of the SEPs showed a significant decrease in hypocalcaemic patients at interstimulus intervals of about 10 ms compared with those in normocalcaemic patients and in normal volunteers. Recovery functions appear to be a valid indicator of synaptic efficacy, especially for evaluation of the reduction in conduction efficacy of the central nervous system in hypocalcaemia.

The division of attention and the human auditory evoked potential

NASA Technical Reports Server (NTRS)

Hink, R. F.; Van Voorhis, S. T.; Hillyard, S. A.; Smith, T. S.

1977-01-01

The sensitivity of the scalp-recorded, auditory evoked potential to selective attention was examined while subjects responded to stimuli presented to one ear (focused attention) and to both ears (divided attention). The amplitude of the N1 component was found to be largest to stimuli in the ear upon which attention was to be focused, smallest to stimuli in the ear to be ignored, and intermediate to stimuli in both ears when attention was divided. The results are interpreted as supporting a capacity model of attention.

Intraoperative monitoring of somatosensory-evoked potential in the spinal cord rectification operation by means of wavelet analysis

NASA Astrophysics Data System (ADS)

Liu, W.; Du, M. H.; Chan, Francis H. Y.; Lam, F. K.; Luk, D. K.; Hu, Y.; Fung, Kan S. M.; Qiu, W.

1998-09-01

Recently there has been a considerable interest in the use of a somatosensory evoked potential (SEP) for monitoring the functional integrity of the spinal cord during surgery such as spinal scoliosis. This paper describes a monitoring system and signal processing algorithms, which consists of 50 Hz mains filtering and a wavelet signal analyzer. Our system allows fast detection of changes in SEP peak latency, amplitude and signal waveform, which are the main parameters of interest during intra-operative procedures.

The Role of Auditory Evoked Potentials in the Context of Cochlear Implant Provision.

PubMed

Hoth, Sebastian; Dziemba, Oliver Christian

2017-12-01

: Auditory evoked potentials (AEP) are highly demanded during the whole process of equipping patients with cochlear implants (CI). They play an essential role in preoperative diagnostics, intraoperative testing, and postoperative monitoring of auditory performance and success. The versatility of AEP's is essentially enhanced by their property to be evokable by acoustic as well as electric stimuli. Thus, the electric responses of the auditory system following acoustic stimulation and recorded by the conventional surface technique as well as by transtympanic derivation from the promontory (Electrocochleography [ECochG]) are used for the quantitative determination of hearing loss and, additionally, electrically evoked compound actions potentials (ECAP) can be recorded with the intracochlear electrodes of the implant just adjacent to the stimulation electrode to check the functional integrity of the device and its coupling to the auditory system. The profile of ECAP thresholds is used as basis for speech processor fitting, the spread of excitation (SOE) allows the identification of electrode mislocations such as array foldover, and recovery functions may serve to optimize stimulus pulse rate. These techniques as well as those relying on scalp surface activity originating in the brainstem or the auditory cortex accompany the CI recipient during its whole life span and they offer valuable insights into functioning and possible adverse effects of the CI for clinical and scientific purposes.

Normative data for Aδ contact heat evoked potentials in adult population: a multicenter study.

PubMed

Granovsky, Yelena; Anand, Praveen; Nakae, Aya; Nascimento, Osvaldo; Smith, Benn; Sprecher, Elliot; Valls-Solé, Josep

2016-05-01

There has been a significant increase over recent years in the use of contact heat evoked potentials (CHEPs) for the evaluation of small nerve fiber function. Measuring CHEP amplitude and latency has clinical utility for the diagnosis and assessment of conditions with neuropathic pain. This international multicenter study aimed to provide reference values for CHEPs to stimuli at 5 commonly examined body sites. Contact heat evoked potentials were recorded from 226 subjects (114 females), distributed per age decade between 20 and 79 years. Temperature stimuli were delivered by a thermode (32°C-51°C at a rate of 70°C/s). In phase I of the study, we investigated side-to-side differences and reported the maximum normal side-to-side difference in Aδ CHEP peak latency and amplitude for leg, forearm, and face. In phase II, we obtained normative data for 3 CHEP parameters (N2P2 amplitude, N2 latency, and P2 latency), stratified for gender and age decades from face, upper and lower limbs, and overlying cervical and lumbar spine. In general, larger CHEP amplitudes were associated with higher evoked pain scores. Females had CHEPs of larger amplitude and shorter latency than males. This substantive data set of normative values will facilitate the clinical use of CHEPs as a rapid, noninvasive, and objective technique for the assessment of patients presenting with neuropathic pain.

Synaptic potentials in respiratory neurones during evoked phase switching after NMDA receptor blockade in the cat

PubMed Central

Pierrefiche, O; Haji, A; Foutz, A S; Takeda, R; Champagnat, J; Denavit-Saubié, M

1998-01-01

Blockade of NMDA receptors by dizocilpine impairs the inspiratory off-switch (IOS) of central origin but not the IOS evoked by stimulation of sensory afferents. To investigate whether this difference was due to the effects of different patterns of synaptic interactions on respiratory neurones, we stimulated electrically the superior laryngeal nerve (SLN) or vagus nerve in decerebrate cats before and after i.v. administration of dizocilpine, whilst recording intracellularly. Phrenic nerve responses to ipsilateral SLN or vagal stimulation were: at mid-inspiration, a transient inhibition often followed by a brief burst of activity; at late inspiration, an IOS; and at mid-expiration, a late burst of activity. In all neurones (n = 16), SLN stimulation at mid-inspiration evoked an early EPSP during phase 1 (latency to the arrest of phrenic nerve activity), followed by an IPSP in inspiratory (I) neurones (n = 8) and by a wave of EPSPs in post-inspiratory (PI) neurones (n = 8) during phase 2 (inhibition of phrenic activity). An EPSP in I neurones and an IPSP in PI neurones occurred during phase 3 (brief phrenic burst) following phase 2. Evoked IOS was associated with a fast (phase 1) activation of PI neurones, whereas during spontaneous IOS, a progressive (30-50 ms) depolarization of PI neurones preceded the arrest of phrenic activity. Phase 3 PSPs were similar to those occurring during the burst of activity seen at the start of spontaneous inspiration. Dizocilpine did not suppress the evoked phrenic inhibition and the late burst of activity. The shapes and timing of the evoked PSPs and the changes in membrane potential in I and PI neurones during the phase transition were not altered. We hypothesize that afferent sensory pathways not requiring NMDA receptors (1) terminate inspiration through a premature activation of PI neurones, and (2) evoke a late burst of phrenic activity which might be the first stage of the inspiratory on-switch. PMID:9508816

Involuntary switching into the native language induced by electrocortical stimulation of the superior temporal gyrus: a multimodal mapping study.

PubMed

Tomasino, Barbara; Marin, Dario; Canderan, Cinzia; Maieron, Marta; Budai, Riccardo; Fabbro, Franco; Skrap, Miran

2014-09-01

We describe involuntary language switching from L2 to L1 evoked by electro-stimulation in the superior temporal gyrus in a 30-year-old right-handed Serbian (L1) speaker who was also a late Italian learner (L2). The patient underwent awake brain surgery. Stimulation of other portions of the exposed cortex did not cause language switching as did not stimulation of the left inferior frontal gyrus, where we evoked a speech arrest. Stimulation effects on language switching were selective, namely, interfered with counting behaviour but not with object naming. The coordinates of the positive site were combined with functional and fibre tracking (DTI) data. Results showed that the language switching site belonged to a significant fMRI cluster in the left superior temporal gyrus/supramarginal gyrus found activated for both L1 and L2, and for both the patient and controls, and did not overlap with the inferior fronto-occipital fasciculus (IFOF), the inferior longitudinal fasciculus (ILF) and the superior longitudinal fasciculus (SLF). This area, also known as Stp, has a role in phonological processing. Language switching phenomenon we observed can be partly explained by transient dysfunction of the feed-forward control mechanism hypothesized by the DIVA (Directions Into Velocities of Articulators) model (Golfinopoulos, E., Tourville, J. A., & Guenther, F. H. (2010). The integration of large-scale neural network modeling and functional brain imaging in speech motor control. Copyright © 2014 Elsevier Ltd. All rights reserved.

The integration of audio-tactile information is modulated by multimodal social interaction with physical contact in infancy.

PubMed

Tanaka, Yukari; Kanakogi, Yasuhiro; Kawasaki, Masahiro; Myowa, Masako

2018-04-01

Interaction between caregivers and infants is multimodal in nature. To react interactively and smoothly to such multimodal signals, infants must integrate all these signals. However, few empirical infant studies have investigated how multimodal social interaction with physical contact facilitates multimodal integration, especially regarding audio - tactile (A-T) information. By using electroencephalogram (EEG) and event-related potentials (ERPs), the present study investigated how neural processing involved in A-T integration is modulated by tactile interaction. Seven- to 8-months-old infants heard one pseudoword both whilst being tickled (multimodal 'A-T' condition), and not being tickled (unimodal 'A' condition). Thereafter, their EEG was measured during the perception of the same words. Compared to the A condition, the A-T condition resulted in enhanced ERPs and higher beta-band activity within the left temporal regions, indicating neural processing of A-T integration. Additionally, theta-band activity within the middle frontal region was enhanced, which may reflect enhanced attention to social information. Furthermore, differential ERPs correlated with the degree of engagement in the tickling interaction. We provide neural evidence that the integration of A-T information in infants' brains is facilitated through tactile interaction with others. Such plastic changes in neural processing may promote harmonious social interaction and effective learning in infancy. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

Calcium released by photolysis of DM-nitrophen stimulates transmitter release at squid giant synapse.

PubMed

Delaney, K R; Zucker, R S

1990-07-01

1. Transmitter release at the squid giant synapse was stimulated by photolytic release of Ca2+ from the 'caged' Ca2+ compound DM-nitrophen (Kaplan & Ellis-Davies, 1988) inserted into presynaptic terminals. 2. Competing binding reactions cause the amount of Ca2+ released by DM-nitrophen photolysis to depend on the concentrations of DM-nitrophen, total Ca2+, Mg+, ATP and native cytoplasmic Ca2+ buffer. Measurements of presynaptic [Ca2+] changes by co-injection of the fluorescent indicator dye Fura-2 show that DM-nitrophen photolysis causes a transient rise in Ca2+ followed by decay within about 150 ms to an increased steady-state level. 3. Rapid photolysis of Ca2(+)-loaded nitrophen within the presynaptic terminal was followed in less than a millisecond by depolarization of the postsynaptic membrane. As with action potential-evoked excitatory postsynaptic potentials (EPSPs), the light-evoked response was partially and reversibly blocked by 1-3 mM-kainic acid which desensitizes postsynaptic glutamate receptors. 4. Release was similar in magnitude and rate to normal action potential-mediated EPSPs. 5. The release of transmitter by photolysis of Ca2(+)-loaded DM-nitrophen was not affected by removal of Ca2+ from the saline or addition of tetrodotoxin. Photolysis of DM-nitrophen injected into presynaptic terminals without added Ca2+ did not stimulate release of transmitter nor did it interfere with normal action potential-mediated release. 6. Stimulation of presynaptic action potentials in Ca2(+)-free saline during the light-evoked response did not elicit increased release of transmitter if the ganglion was bathed in Ca2(+)-free saline, i.e. in the absence of Ca2+ influx. Increasing the intensity of the light or stimulating presynaptic action potentials in Ca2(+)-containing saline increased the release of transmitter. Therefore the failure of presynaptic voltage change to increase transmitter release resulting from release of caged Ca2+ was not due to saturation or inhibition of the release mechanism by light-released Ca2+. 7. Decreasing the temperature of the preparation increased the delay to onset of the light-evoked response and reduced its amplitude and rate of rise to an extent similar to that observed for action potential-evoked EPSPs.

Multimode waveguide speckle patterns for compressive sensing.

PubMed

Valley, George C; Sefler, George A; Justin Shaw, T

2016-06-01

Compressive sensing (CS) of sparse gigahertz-band RF signals using microwave photonics may achieve better performances with smaller size, weight, and power than electronic CS or conventional Nyquist rate sampling. The critical element in a CS system is the device that produces the CS measurement matrix (MM). We show that passive speckle patterns in multimode waveguides potentially provide excellent MMs for CS. We measure and calculate the MM for a multimode fiber and perform simulations using this MM in a CS system. We show that the speckle MM exhibits the sharp phase transition and coherence properties needed for CS and that these properties are similar to those of a sub-Gaussian MM with the same mean and standard deviation. We calculate the MM for a multimode planar waveguide and find dimensions of the planar guide that give a speckle MM with a performance similar to that of the multimode fiber. The CS simulations show that all measured and calculated speckle MMs exhibit a robust performance with equal amplitude signals that are sparse in time, in frequency, and in wavelets (Haar wavelet transform). The planar waveguide results indicate a path to a microwave photonic integrated circuit for measuring sparse gigahertz-band RF signals using CS.

Reduction hybrid artifacts of EMG-EOG in electroencephalography evoked by prefrontal transcranial magnetic stimulation

NASA Astrophysics Data System (ADS)

Bai, Yang; Wan, Xiaohong; Zeng, Ke; Ni, Yinmei; Qiu, Lirong; Li, Xiaoli

2016-12-01

Objective. When prefrontal-transcranial magnetic stimulation (p-TMS) performed, it may evoke hybrid artifact mixed with muscle activity and blink activity in EEG recordings. Reducing this kind of hybrid artifact challenges the traditional preprocessing methods. We aim to explore method for the p-TMS evoked hybrid artifact removal. Approach. We propose a novel method used as independent component analysis (ICA) post processing to reduce the p-TMS evoked hybrid artifact. Ensemble empirical mode decomposition (EEMD) was used to decompose signal into multi-components, then the components were separated with artifact reduced by blind source separation (BSS) method. Three standard BSS methods, ICA, independent vector analysis, and canonical correlation analysis (CCA) were tested. Main results. Synthetic results showed that EEMD-CCA outperformed others as ICA post processing step in hybrid artifacts reduction. Its superiority was clearer when signal to noise ratio (SNR) was lower. In application to real experiment, SNR can be significantly increased and the p-TMS evoked potential could be recovered from hybrid artifact contaminated signal. Our proposed method can effectively reduce the p-TMS evoked hybrid artifacts. Significance. Our proposed method may facilitate future prefrontal TMS-EEG researches.

Functional connectivity between right and left mesial temporal structures.

PubMed

Lacuey, Nuria; Zonjy, Bilal; Kahriman, Emine S; Kaffashi, Farhad; Miller, Jonathan; Lüders, Hans O

2015-09-01

The aim of this study is to investigate functional connectivity between right and left mesial temporal structures using cerebrocerebral evoked potentials. We studied seven patients with drug-resistant focal epilepsy who were explored with stereotactically implanted depth electrodes in bilateral hippocampi. In all patients cerebrocerebral evoked potentials evoked by stimulation of the fornix were evaluated as part of a research project assessing fornix stimulation for control of hippocampal seizures. Stimulation of the fornix elicited responses in the ipsilateral hippocampus in all patients with a mean latency of 4.6 ms (range 2-7 ms). Two patients (29 %) also had contralateral hippocampus responses with a mean latency of 7.5 ms (range 5-12 ms) and without involvement of the contralateral temporal neocortex or amygdala. This study confirms the existence of connections between bilateral mesial temporal structures in some patients and explains seizure discharge spreading between homotopic mesial temporal structures without neocortical involvement.

Activation of serotonin 2A receptors underlies the psilocybin-induced effects on α oscillations, N170 visual-evoked potentials, and visual hallucinations.

PubMed

Kometer, Michael; Schmidt, André; Jäncke, Lutz; Vollenweider, Franz X

2013-06-19

Visual illusions and hallucinations are hallmarks of serotonergic hallucinogen-induced altered states of consciousness. Although the serotonergic hallucinogen psilocybin activates multiple serotonin (5-HT) receptors, recent evidence suggests that activation of 5-HT2A receptors may lead to the formation of visual hallucinations by increasing cortical excitability and altering visual-evoked cortical responses. To address this hypothesis, we assessed the effects of psilocybin (215 μg/kg vs placebo) on both α oscillations that regulate cortical excitability and early visual-evoked P1 and N170 potentials in healthy human subjects. To further disentangle the specific contributions of 5-HT2A receptors, subjects were additionally pretreated with the preferential 5-HT2A receptor antagonist ketanserin (50 mg vs placebo). We found that psilocybin strongly decreased prestimulus parieto-occipital α power values, thus precluding a subsequent stimulus-induced α power decrease. Furthermore, psilocybin strongly decreased N170 potentials associated with the appearance of visual perceptual alterations, including visual hallucinations. All of these effects were blocked by pretreatment with the 5-HT2A antagonist ketanserin, indicating that activation of 5-HT2A receptors by psilocybin profoundly modulates the neurophysiological and phenomenological indices of visual processing. Specifically, activation of 5-HT2A receptors may induce a processing mode in which stimulus-driven cortical excitation is overwhelmed by spontaneous neuronal excitation through the modulation of α oscillations. Furthermore, the observed reduction of N170 visual-evoked potentials may be a key mechanism underlying 5-HT2A receptor-mediated visual hallucinations. This change in N170 potentials may be important not only for psilocybin-induced states but also for understanding acute hallucinatory states seen in psychiatric disorders, such as schizophrenia and Parkinson's disease.

Epileptiform activity induced by lowering extracellular [Mg2+] in combined hippocampal-entorhinal cortex slices: modulation by receptors for norepinephrine and N-methyl-D-aspartate.

PubMed

Stanton, P K; Jones, R S; Mody, I; Heinemann, U

1987-01-01

Reduction of extracellular Mg2+ concentration induced spontaneous and evoked epileptiform activity in the entorhinal cortex (EC) and dentate gyrus (DG) of combined hippocampus (HC)-EC slices. Extracellular field potentials, as well as changes in extracellular Ca2+ and K+ concentrations, were measured in EC and DG with ion-selective/reference electrodes during both repetitive and single stimuli. In the EC, lowering extracellular [Mg2+] induces both spontaneous and single stimulus evoked ictal events consisting of extracellular negative potential shifts (up to 5 mV, 30 sec), decreases in [Ca2+]0 and increases in [K+]0. In the DG, spontaneous events were much shorter, but similar changes in [Ca2+]0, [K+]0 and field potentials (FPs) could be evoked by brief high-frequency stimulation. In both areas, the N-methyl-D-aspartate (NMDA) receptor antagonist 2-aminophosphonovalerate (2-APV) completely blocked spontaneous as well as stimulus evoked epileptiform events. The neurotransmitter norepinephrine (NE), which has previously been shown to modulate long-term potentiation in the DG, was found to exhibit differential modulation of epileptiform activity in the EC and DG. In the EC, NE, acting via alpha 1-receptors, completely blocked low Mg2+-induced epileptiform activity. In contrast, in the DG, NE exhibited a beta-receptor mediated prolongation of the low Mg2+-induced ictal events, and enhanced the stimulus-induced ionic and field potential changes. From these results, we conclude that lowering extracellular [Mg2+], acting in large part through the removal of the Mg2+ voltage-dependent blockade of NMDA receptors, leads to induction of epileptiform activity in both the EC and DG.(ABSTRACT TRUNCATED AT 250 WORDS)

The developmental effects of extremely low frequency electric fields on visual and somatosensory evoked potentials in adult rats.

PubMed

Gok, Deniz Kantar; Akpinar, Deniz; Hidisoglu, Enis; Ozen, Sukru; Agar, Aysel; Yargicoglu, Piraye

2016-01-01

The purpose of our study was to investigate the developmental effects of extremely low frequency electric fields (ELF-EFs) on visual evoked potentials (VEPs) and somatosensory-evoked potentials (SEPs) and to examine the relationship between lipid peroxidation and changes of these potentials. In this context, thiobarbituric acid reactive substances (TBARS) levels were determined as an indicator of lipid peroxidation. Wistar albino female rats were divided into four groups; Control (C), gestational (prenatal) exposure (Pr), gestational+ postnatal exposure (PP) and postnatal exposure (Po) groups. Pregnant rats of Pr and PP groups were exposed to 50 Hz electric field (EF) (12 kV/m; 1 h/day), while those of C and Po groups were placed in an inactive system during pregnancy. Following parturition, rats of PP and Po groups were exposed to ELF-EFs whereas rats of C and Pr groups were kept under the same experimental conditions without being exposed to any EF during 68 days. On postnatal day 90, rats were prepared for VEP and SEP recordings. The latencies of VEP components in all experimental groups were significantly prolonged versus C group. For SEPs, all components of PP group, P2, N2 components of Pr group and P1, P2, N2 components of Po group were delayed versus C group. As brain TBARS levels were significantly increased in Pr and Po groups, retina TBARS levels were significantly elevated in all experimental groups versus C group. In conclusion, alterations seen in evoked potentials, at least partly, could be explained by lipid peroxidation in the retina and brain.

A novel component of cannabis extract potentiates excitatory synaptic transmission in rat olfactory cortex in vitro.

PubMed

Whalley, Benjamin J; Wilkinson, Jonathan D; Williamson, Elizabeth M; Constanti, Andrew

2004-07-15

Cannabis is a potential treatment for epilepsy, although the few human studies supporting this use have proved inconclusive. Previously, we showed that a standardized cannabis extract (SCE), isolated Delta9-tetrahydrocannabinol (Delta9-THC), and even Delta9-THC-free SCE inhibited muscarinic agonist-induced epileptiform bursting in rat olfactory cortical brain slices, acting via CB1 receptors. The present work demonstrates that although Delta9-THC (1 microM) significantly depressed evoked depolarizing postsynaptic potentials (PSPs) in rat olfactory cortex neurones, both SCE and Delta9-THC-free SCE significantly potentiated evoked PSPs (all results were fully reversed by the CB1 receptor antagonist SR141716A, 1 microM); interestingly, the potentiation by Delta9-THC-free SCE was greater than that produced by SCE. On comparing the effects of Delta9-THC-free SCE upon evoked PSPs and artificial PSPs (aPSPs; evoked electrotonically following brief intracellular current injection), PSPs were enhanced, whereas aPSPs were unaffected, suggesting that the effect was not due to changes in background input resistance. Similar recordings made using CB1 receptor-deficient knockout mice (CB1-/-) and wild-type littermate controls revealed cannabinoid or extract-induced changes in membrane resistance, cell excitability and synaptic transmission in wild-type mice that were similar to those seen in rat neurones, but no effect on these properties were seen in CB1-/- cells. It appears that the unknown extract constituent(s) effects over-rode the suppressive effects of Delta9-THC on excitatory neurotransmitter release, which may explain some patients' preference for herbal cannabis rather than isolated Delta9-THC (due to attenuation of some of the central Delta9-THC side effects) and possibly account for the rare incidence of seizures in some individuals taking cannabis recreationally.

Contralateral Inhibition of Click- and Chirp-Evoked Human Compound Action Potentials

PubMed Central

Smith, Spencer B.; Lichtenhan, Jeffery T.; Cone, Barbara K.

2017-01-01

Cochlear outer hair cells (OHC) receive direct efferent feedback from the caudal auditory brainstem via the medial olivocochlear (MOC) bundle. This circuit provides the neural substrate for the MOC reflex, which inhibits cochlear amplifier gain and is believed to play a role in listening in noise and protection from acoustic overexposure. The human MOC reflex has been studied extensively using otoacoustic emissions (OAE) paradigms; however, these measurements are insensitive to subsequent “downstream” efferent effects on the neural ensembles that mediate hearing. In this experiment, click- and chirp-evoked auditory nerve compound action potential (CAP) amplitudes were measured electrocochleographically from the human eardrum without and with MOC reflex activation elicited by contralateral broadband noise. We hypothesized that the chirp would be a more optimal stimulus for measuring neural MOC effects because it synchronizes excitation along the entire length of the basilar membrane and thus evokes a more robust CAP than a click at low to moderate stimulus levels. Chirps produced larger CAPs than clicks at all stimulus intensities (50–80 dB ppeSPL). MOC reflex inhibition of CAPs was larger for chirps than clicks at low stimulus levels when quantified both in terms of amplitude reduction and effective attenuation. Effective attenuation was larger for chirp- and click-evoked CAPs than for click-evoked OAEs measured from the same subjects. Our results suggest that the chirp is an optimal stimulus for evoking CAPs at low stimulus intensities and for assessing MOC reflex effects on the auditory nerve. Further, our work supports previous findings that MOC reflex effects at the level of the auditory nerve are underestimated by measures of OAE inhibition. PMID:28420960

Vestibular Evoked Myogenic Potential Produced by Bone-Conducted Stimuli: A Study on its Basics and Clinical Applications in Patients with Conductive and Sensorineural Hearing Loss and a Group with Vestibular Schawannoma.

PubMed

Mahdi, Parvane; Amali, Amin; Pourbakht, Akram; Karimi Yazdi, Alireza; Bassam, Ali

2013-06-01

Vestibular evoked myogenic potential (VEMP) has recently been broadly studied in vestibular disorders. As it is evoked by loud sound stimulation, even mild conductive hearing loss may affect VEMP results. Bone-conducted (BC) stimulus is an alternative stimulation for evoking this response. This study aims to assess the characteristics of BC-VEMP in different groups of patients. We performed a cross sectional analysis on 20 healthy volunteers with normal pure-tone audiometry as a control group; and on a group of patients consisted of 20 participants with conductive hearing loss, five with bilateral sensorineural hearing loss and four with vestibular schawannoma. AC and BC-VEMP were performed in all participants. In control group the VEMP responses to both kinds of stimuli had an acceptable morphology and consisted of p13 and n23 waves. Latency value of these main components in each type of stimulus was not significantly different (P>0.05). However, the mean amplitude was larger in BC modality than AC stimulation (P=0.025). In the group with conductive hearing loss, the VEMP response was absent in fifteen (46.87%) of the 32 ears using the AC method, whereas all (100%) displayed positive elicitability of VEMP by BC method. Normal VEMP responses in both stimuli were evoked in all patients with sensorineural hearing loss. In patients with unilateral vestibular schwannomas (VS), 2 (50.00%) had neither AC-VEMP nor BC-VEMP. Auditory stimuli delivered by bone conduction can evoke VEMP response. These responses are of vestibular origin and can be used in vestibular evaluation of patients with conductive hearing loss.

Vestibular Evoked Myogenic Potential Produced by Bone-Conducted Stimuli: A Study on its Basics and Clinical Applications in Patients with Conductive and Sensorineural Hearing Loss and a Group with Vestibular Schawannoma

PubMed Central

Mahdi, Parvane; Amali, Amin; Pourbakht, Akram; Karimi Yazdi, Alireza; Bassam, Ali

2013-01-01

Introduction: Vestibular evoked myogenic potential (VEMP) has recently been broadly studied in vestibular disorders. As it is evoked by loud sound stimulation, even mild conductive hearing loss may affect VEMP results. Bone-conducted (BC) stimulus is an alternative stimulation for evoking this response. This study aims to assess the characteristics of BC-VEMP in different groups of patients. Materials and Methods: We performed a cross sectional analysis on 20 healthy volunteers with normal pure-tone audiometry as a control group; and on a group of patients consisted of 20 participants with conductive hearing loss, five with bilateral sensorineural hearing loss and four with vestibular schawannoma. AC and BC-VEMP were performed in all participants. Results: In control group the VEMP responses to both kinds of stimuli had an acceptable morphology and consisted of p13 and n23 waves. Latency value of these main components in each type of stimulus was not significantly different (P>0.05). However, the mean amplitude was larger in BC modality than AC stimulation (P=0.025). In the group with conductive hearing loss, the VEMP response was absent in fifteen (46.87%) of the 32 ears using the AC method, whereas all (100%) displayed positive elicitability of VEMP by BC method. Normal VEMP responses in both stimuli were evoked in all patients with sensorineural hearing loss. In patients with unilateral vestibular schwannomas (VS), 2 (50.00%) had neither AC-VEMP nor BC-VEMP. Conclusion: Auditory stimuli delivered by bone conduction can evoke VEMP response. These responses are of vestibular origin and can be used in vestibular evaluation of patients with conductive hearing loss. PMID:24303434

Mismatch negativity to the patient's own name in chronic disorders of consciousness.

PubMed

Qin, Pengmin; Di, Haibo; Yan, Xiaodan; Yu, Senming; Yu, Dan; Laureys, Steven; Weng, Xuchu

2008-12-19

Previous studies implicated potential value of mismatch negativity (MMN) in predicting recovery of consciousness in patients with disorders of consciousness (DOC). We have adopted a novel MMN evoked by subject's own name (SON), a self-referential stimulus thought to be powerful in evoking residual brain activity, and examined the correlation between the MMN and recovery of consciousness in patients with chronic (>1 month) DOC. Twelve patients and 12 age-matched healthy controls were investigated. The patients were diagnosed as coma (n=4), vegetative state (VS, n=6), and minimally conscious state (MCS, n=2), mainly based on the JFK Coma Recovery Scale-Revised. The SON-evoked MMN (SON-MMN) was present in seven patients. Critically, the presence of SON-MMN was significantly correlated with recovery of consciousness. While four of the five patients (three VS and two coma) showing SON-MMN changed to MCS 3 months later, the rest of the patients (three VS and two coma) without SON-MMN failed to show any clinical improvement. Our study thus illustrates that the subject's own name is effective in evoking MMN in patients with DOC, and that SON-MMN has potential prognostic values in predicting recovery of consciousness.

The hybrid BCI system for movement control by combining motor imagery and moving onset visual evoked potential

NASA Astrophysics Data System (ADS)

Ma, Teng; Li, Hui; Deng, Lili; Yang, Hao; Lv, Xulin; Li, Peiyang; Li, Fali; Zhang, Rui; Liu, Tiejun; Yao, Dezhong; Xu, Peng

2017-04-01

Objective. Movement control is an important application for EEG-BCI (EEG-based brain-computer interface) systems. A single-modality BCI cannot provide an efficient and natural control strategy, but a hybrid BCI system that combines two or more different tasks can effectively overcome the drawbacks encountered in single-modality BCI control. Approach. In the current paper, we developed a new hybrid BCI system by combining MI (motor imagery) and mVEP (motion-onset visual evoked potential), aiming to realize the more efficient 2D movement control of a cursor. Main result. The offline analysis demonstrates that the hybrid BCI system proposed in this paper could evoke the desired MI and mVEP signal features simultaneously, and both are very close to those evoked in the single-modality BCI task. Furthermore, the online 2D movement control experiment reveals that the proposed hybrid BCI system could provide more efficient and natural control commands. Significance. The proposed hybrid BCI system is compensative to realize efficient 2D movement control for a practical online system, especially for those situations in which P300 stimuli are not suitable to be applied.

Network activity influences the subthreshold and spiking visual responses of pyramidal neurons in the three-layer turtle cortex.

PubMed

Wright, Nathaniel C; Wessel, Ralf

2017-10-01

A primary goal of systems neuroscience is to understand cortical function, typically by studying spontaneous and stimulus-modulated cortical activity. Mounting evidence suggests a strong and complex relationship exists between the ongoing and stimulus-modulated cortical state. To date, most work in this area has been based on spiking in populations of neurons. While advantageous in many respects, this approach is limited in scope: it records the activity of a minority of neurons and gives no direct indication of the underlying subthreshold dynamics. Membrane potential recordings can fill these gaps in our understanding, but stable recordings are difficult to obtain in vivo. Here, we recorded subthreshold cortical visual responses in the ex vivo turtle eye-attached whole brain preparation, which is ideally suited for such a study. We found that, in the absence of visual stimulation, the network was "synchronous"; neurons displayed network-mediated transitions between hyperpolarized (Down) and depolarized (Up) membrane potential states. The prevalence of these slow-wave transitions varied across turtles and recording sessions. Visual stimulation evoked similar Up states, which were on average larger and less reliable when the ongoing state was more synchronous. Responses were muted when immediately preceded by large, spontaneous Up states. Evoked spiking was sparse, highly variable across trials, and mediated by concerted synaptic inputs that were, in general, only very weakly correlated with inputs to nearby neurons. Together, these results highlight the multiplexed influence of the cortical network on the spontaneous and sensory-evoked activity of individual cortical neurons. NEW & NOTEWORTHY Most studies of cortical activity focus on spikes. Subthreshold membrane potential recordings can provide complementary insight, but stable recordings are difficult to obtain in vivo. Here, we recorded the membrane potentials of cortical neurons during ongoing and visually evoked activity. We observed a strong relationship between network and single-neuron evoked activity spanning multiple temporal scales. The membrane potential perspective of cortical dynamics thus highlights the influence of intrinsic network properties on visual processing. Copyright © 2017 the American Physiological Society.

Electrocortical amplification for emotionally arousing natural scenes: The contribution of luminance and chromatic visual channels

PubMed Central

Miskovic, Vladimir; Martinovic, Jasna; Wieser, Matthias M.; Petro, Nathan M.; Bradley, Margaret M.; Keil, Andreas

2015-01-01

Emotionally arousing scenes readily capture visual attention, prompting amplified neural activity in sensory regions of the brain. The physical stimulus features and related information channels in the human visual system that contribute to this modulation, however, are not known. Here, we manipulated low-level physical parameters of complex scenes varying in hedonic valence and emotional arousal in order to target the relative contributions of luminance based versus chromatic visual channels to emotional perception. Stimulus-evoked brain electrical activity was measured during picture viewing and used to quantify neural responses sensitive to lower-tier visual cortical involvement (steady-state visual evoked potentials) as well as the late positive potential, reflecting a more distributed cortical event. Results showed that the enhancement for emotional content was stimulus-selective when examining the steady-state segments of the evoked visual potentials. Response amplification was present only for low spatial frequency, grayscale stimuli, and not for high spatial frequency, red/green stimuli. In contrast, the late positive potential was modulated by emotion regardless of the scene’s physical properties. Our findings are discussed in relation to neurophysiologically plausible constraints operating at distinct stages of the cortical processing stream. PMID:25640949

Simultaneous diffuse near-infrared imaging of hemodynamic and oxygenation changes and electroencephalographic measurements of neuronal activity in the human brain

NASA Astrophysics Data System (ADS)

Noponen, Tommi; Kicic, Dubravko; Kotilahti, Kalle; Kajava, Timo; Kahkonen, Seppo; Nissila, Ilkka; Merilainen, Pekka; Katila, Toivo

2005-04-01

Visually evoked hemodynamic responses and potentials were simultaneously measured using a 16-channel optical imaging instrument and a 60-channel electroencephalography instrument during normo-, hypo- and hypercapnia from three subjects. Flashing and pattern-reversed checkerboard stimuli were used. The study protocol included two counterbalanced measurements during both normo- and hypocapnia and normo- and hypercapnia. Hypocapnia was produced by controlled hyperventilation and hypercapnia by breathing carbon dioxide enriched air. Near-infrared imaging was also used to monitor the concentration changes of oxy- and deoxyhaemoglobin due to hypo- and hypercapnia. Hemodynamic responses and evoked potentials were successfully detected for each subject above the visual cortex. The latencies of the hemodynamic responses during hypocapnia were shorter whereas during hypercapnia they were longer when compared to the latencies during normocapnia. Hypocapnia tended to decrease the latencies of visually evoked potentials compared to those during normocapnia while hypercapnia did not show any consistent effect to the potentials. The developed measurement setup and the study protocol provide the opportunity to investigate the neurovascular coupling and the links between the baseline level of blood flow, electrical activity and hemodynamic responses in the human brain.

Electrocortical amplification for emotionally arousing natural scenes: the contribution of luminance and chromatic visual channels.

PubMed

Miskovic, Vladimir; Martinovic, Jasna; Wieser, Matthias J; Petro, Nathan M; Bradley, Margaret M; Keil, Andreas

2015-03-01

Emotionally arousing scenes readily capture visual attention, prompting amplified neural activity in sensory regions of the brain. The physical stimulus features and related information channels in the human visual system that contribute to this modulation, however, are not known. Here, we manipulated low-level physical parameters of complex scenes varying in hedonic valence and emotional arousal in order to target the relative contributions of luminance based versus chromatic visual channels to emotional perception. Stimulus-evoked brain electrical activity was measured during picture viewing and used to quantify neural responses sensitive to lower-tier visual cortical involvement (steady-state visual evoked potentials) as well as the late positive potential, reflecting a more distributed cortical event. Results showed that the enhancement for emotional content was stimulus-selective when examining the steady-state segments of the evoked visual potentials. Response amplification was present only for low spatial frequency, grayscale stimuli, and not for high spatial frequency, red/green stimuli. In contrast, the late positive potential was modulated by emotion regardless of the scene's physical properties. Our findings are discussed in relation to neurophysiologically plausible constraints operating at distinct stages of the cortical processing stream. Copyright © 2015 Elsevier B.V. All rights reserved.

Controlling a stream of paranoia evoking events in a virtual reality environment.

PubMed

Isnanda, Reza Giga; Brinkman, Willem-Paul; Veling, Wim; van der Gaag, Mark; Neerincx, Mark

2014-01-01

Although virtual reality exposure has been reported as a method to induce paranoid thought, little is known about mechanisms to control specific virtual stressors. This paper reports on a study that examines the effect of controlling the stream of potential paranoia evoking events in a virtual restaurant world. A 2-by-2 experiment with a non-clinical group (n = 24) was conducted with as two within-subject factors: (1) the cycle time (short/long) for when the computer considers activation of a paranoia evoking event and (2) the probability that a paranoia-evoking event (low/high) would be triggered at the completion of a cycle. The results showed a significant main effect for the probability factor and two-way interaction effect with the cycle time factor on the number of paranoid comments participants made and their self-reported anxiety.

Entanglement and Wigner Function Negativity of Multimode Non-Gaussian States

NASA Astrophysics Data System (ADS)

Walschaers, Mattia; Fabre, Claude; Parigi, Valentina; Treps, Nicolas

2017-11-01

Non-Gaussian operations are essential to exploit the quantum advantages in optical continuous variable quantum information protocols. We focus on mode-selective photon addition and subtraction as experimentally promising processes to create multimode non-Gaussian states. Our approach is based on correlation functions, as is common in quantum statistical mechanics and condensed matter physics, mixed with quantum optics tools. We formulate an analytical expression of the Wigner function after the subtraction or addition of a single photon, for arbitrarily many modes. It is used to demonstrate entanglement properties specific to non-Gaussian states and also leads to a practical and elegant condition for Wigner function negativity. Finally, we analyze the potential of photon addition and subtraction for an experimentally generated multimode Gaussian state.

Entanglement and Wigner Function Negativity of Multimode Non-Gaussian States.

PubMed

Walschaers, Mattia; Fabre, Claude; Parigi, Valentina; Treps, Nicolas

2017-11-03

Non-Gaussian operations are essential to exploit the quantum advantages in optical continuous variable quantum information protocols. We focus on mode-selective photon addition and subtraction as experimentally promising processes to create multimode non-Gaussian states. Our approach is based on correlation functions, as is common in quantum statistical mechanics and condensed matter physics, mixed with quantum optics tools. We formulate an analytical expression of the Wigner function after the subtraction or addition of a single photon, for arbitrarily many modes. It is used to demonstrate entanglement properties specific to non-Gaussian states and also leads to a practical and elegant condition for Wigner function negativity. Finally, we analyze the potential of photon addition and subtraction for an experimentally generated multimode Gaussian state.

A big-data model for multi-modal public transportation with application to macroscopic control and optimisation

NASA Astrophysics Data System (ADS)

Faizrahnemoon, Mahsa; Schlote, Arieh; Maggi, Lorenzo; Crisostomi, Emanuele; Shorten, Robert

2015-11-01

This paper describes a Markov-chain-based approach to modelling multi-modal transportation networks. An advantage of the model is the ability to accommodate complex dynamics and handle huge amounts of data. The transition matrix of the Markov chain is built and the model is validated using the data extracted from a traffic simulator. A realistic test-case using multi-modal data from the city of London is given to further support the ability of the proposed methodology to handle big quantities of data. Then, we use the Markov chain as a control tool to improve the overall efficiency of a transportation network, and some practical examples are described to illustrate the potentials of the approach.

A Multimodal Search Engine for Medical Imaging Studies.

PubMed

Pinho, Eduardo; Godinho, Tiago; Valente, Frederico; Costa, Carlos

2017-02-01

The use of digital medical imaging systems in healthcare institutions has increased significantly, and the large amounts of data in these systems have led to the conception of powerful support tools: recent studies on content-based image retrieval (CBIR) and multimodal information retrieval in the field hold great potential in decision support, as well as for addressing multiple challenges in healthcare systems, such as computer-aided diagnosis (CAD). However, the subject is still under heavy research, and very few solutions have become part of Picture Archiving and Communication Systems (PACS) in hospitals and clinics. This paper proposes an extensible platform for multimodal medical image retrieval, integrated in an open-source PACS software with profile-based CBIR capabilities. In this article, we detail a technical approach to the problem by describing its main architecture and each sub-component, as well as the available web interfaces and the multimodal query techniques applied. Finally, we assess our implementation of the engine with computational performance benchmarks.

Monitoring auditory cortical plasticity in hearing aid users with long latency auditory evoked potentials: a longitudinal study.

PubMed

Leite, Renata Aparecida; Magliaro, Fernanda Cristina Leite; Raimundo, Jeziela Cristina; Bento, Ricardo Ferreira; Matas, Carla Gentile

2018-02-19

The objective of this study was to compare long-latency auditory evoked potentials before and after hearing aid fittings in children with sensorineural hearing loss compared with age-matched children with normal hearing. Thirty-two subjects of both genders aged 7 to 12 years participated in this study and were divided into two groups as follows: 14 children with normal hearing were assigned to the control group (mean age 9 years and 8 months), and 18 children with mild to moderate symmetrical bilateral sensorineural hearing loss were assigned to the study group (mean age 9 years and 2 months). The children underwent tympanometry, pure tone and speech audiometry and long-latency auditory evoked potential testing with speech and tone burst stimuli. The groups were assessed at three time points. The study group had a lower percentage of positive responses, lower P1-N1 and P2-N2 amplitudes (speech and tone burst), and increased latencies for the P1 and P300 components following the tone burst stimuli. They also showed improvements in long-latency auditory evoked potentials (with regard to both the amplitude and presence of responses) after hearing aid use. Alterations in the central auditory pathways can be identified using P1-N1 and P2-N2 amplitude components, and the presence of these components increases after a short period of auditory stimulation (hearing aid use). These findings emphasize the importance of using these amplitude components to monitor the neuroplasticity of the central auditory nervous system in hearing aid users.

Monitoring auditory cortical plasticity in hearing aid users with long latency auditory evoked potentials: a longitudinal study

PubMed Central

Leite, Renata Aparecida; Magliaro, Fernanda Cristina Leite; Raimundo, Jeziela Cristina; Bento, Ricardo Ferreira; Matas, Carla Gentile

2018-01-01

OBJECTIVE: The objective of this study was to compare long-latency auditory evoked potentials before and after hearing aid fittings in children with sensorineural hearing loss compared with age-matched children with normal hearing. METHODS: Thirty-two subjects of both genders aged 7 to 12 years participated in this study and were divided into two groups as follows: 14 children with normal hearing were assigned to the control group (mean age 9 years and 8 months), and 18 children with mild to moderate symmetrical bilateral sensorineural hearing loss were assigned to the study group (mean age 9 years and 2 months). The children underwent tympanometry, pure tone and speech audiometry and long-latency auditory evoked potential testing with speech and tone burst stimuli. The groups were assessed at three time points. RESULTS: The study group had a lower percentage of positive responses, lower P1-N1 and P2-N2 amplitudes (speech and tone burst), and increased latencies for the P1 and P300 components following the tone burst stimuli. They also showed improvements in long-latency auditory evoked potentials (with regard to both the amplitude and presence of responses) after hearing aid use. CONCLUSIONS: Alterations in the central auditory pathways can be identified using P1-N1 and P2-N2 amplitude components, and the presence of these components increases after a short period of auditory stimulation (hearing aid use). These findings emphasize the importance of using these amplitude components to monitor the neuroplasticity of the central auditory nervous system in hearing aid users. PMID:29466495

Neurophysiological assessment of auditory, peripheral nerve, somatosensory, and visual system functions after developmental exposure to ethanol vapors.

PubMed

Boyes, William K; Degn, Laura L; Martin, Sheppard A; Lyke, Danielle F; Hamm, Charles W; Herr, David W

2014-01-01

Ethanol-blended gasoline entered the market in response to demand for domestic renewable energy sources, and may result in increased inhalation of ethanol vapors in combination with other volatile gasoline constituents. It is important to understand potential risks of inhalation of ethanol vapors by themselves, and also as a baseline for evaluating the risks of ethanol combined with a complex mixture of hydrocarbon vapors. Because sensory dysfunction has been reported after developmental exposure to ethanol, we evaluated the effects of developmental exposure to ethanol vapors on neurophysiological measures of sensory function as a component of a larger project evaluating developmental ethanol toxicity. Pregnant Long-Evans rats were exposed to target concentrations 0, 5000, 10,000, or 21,000 ppm ethanol vapors for 6.5h/day over GD9-GD20. Sensory evaluations of male offspring began between PND106 and PND128. Peripheral nerve function (compound action potentials, nerve conduction velocity (NCV)), somatosensory (cortical and cerebellar evoked potentials), auditory (brainstem auditory evoked responses), and visual evoked responses were assessed. Visual function assessment included pattern elicited visual evoked potentials (VEPs), VEP contrast sensitivity, and electroretinograms recorded from dark-adapted (scotopic), light-adapted (photopic) flashes, and UV flicker and green flicker. No consistent concentration-related changes were observed for any of the physiological measures. The results show that gestational exposure to ethanol vapor did not result in detectable changes in peripheral nerve, somatosensory, auditory, or visual function when the offspring were assessed as adults. Published by Elsevier Inc.

Short latency vestibular evoked potentials in the chicken embryo

NASA Technical Reports Server (NTRS)

Jones, S. M.; Jones, T. A.

1996-01-01

Electrophysiological responses to pulsed linear acceleration stimuli were recorded in chicken embryos incubated for 19 or 20 days (E19/E20). Responses occurred within the first 16 ms following the stimulus onset. The evoked potentials disappeared following bilateral labyrinthectomy, but persisted following cochlear destruction alone, thus demonstrating that the responses were vestibular. Approximately 8 to 10 response peaks could be identified. The first 4 positive and corresponding negative components (early peaks with latencies < 6.0 ms) were scored and latencies and amplitudes quantified. Vestibular response latencies were significantly longer (P < 0.01) and amplitudes significantly smaller (P < 0.001) than those observed in 2-week-old birds. Mean response threshold for anesthetized embryos was -15.9dBre 1.0 g/ms, which was significantly higher (P < 0.03) than those observed in 2-week-old birds (-23.0dBre 1.0 g/ms). Latency/intensity functions (that is, slopes) were not significantly different between embryos and 2-week-old animals, but amplitude/intensity functions for embryos were significantly shallower than those for 2-week-old birds (P < 0.001). We presume that these differences reflect the refinement of sensory function that occurs following 19 to 20 days of incubation. The recording of vestibular evoked potentials provides an objective, direct and noninvasive measure of peripheral vestibular function in the embryo and, as such, the method shows promise as an investigative tool. The results of the present study form the definitive basis for using vestibular evoked potentials in the detailed study of avian vestibular ontogeny and factors that may influence it.

Cervical intraspinal microstimulation evokes robust forelimb movements before and after injury

NASA Astrophysics Data System (ADS)

Sunshine, Michael D.; Cho, Frances S.; Lockwood, Danielle R.; Fechko, Amber S.; Kasten, Michael R.; Moritz, Chet T.

2013-06-01

Objective. Intraspinal microstimulation (ISMS) is a promising method for reanimating paralyzed limbs following neurological injury. ISMS within the cervical and lumbar spinal cord is capable of evoking a variety of highly-functional movements prior to injury, but the ability of ISMS to evoke forelimb movements after cervical spinal cord injury is unknown. Here we examine the forelimb movements and muscles activated by cervical ISMS both before and after contusion injury. Approach. We documented the forelimb muscles activated and movements evoked via systematic stimulation of the rodent cervical spinal cord both before injury and three, six and nine weeks following a moderate C4/C5 lateralized contusion injury. Animals were anesthetized with isoflurane to permit construction of somatotopic maps of evoked movements and quantify evoked muscle synergies between cervical segments C3 and T1. Main results. When ISMS was delivered to the cervical spinal cord, a variety of responses were observed at 68% of locations tested, with a spatial distribution that generally corresponded to the location of motor neuron pools. Stimulus currents required to achieve movement and the number of sites where movements could be evoked were unchanged by spinal cord injury. A transient shift toward extension-dominated movements and restricted muscle synergies were observed at three and six weeks following injury, respectively. By nine weeks after injury, however, ISMS-evoked patterns were similar to spinally-intact animals. Significance. The results demonstrate the potential for cervical ISMS to reanimate hand and arm function following spinal cord injury. Robust forelimb movements can be evoked both before and during the chronic stages of recovery from a clinically relevant and sustained cervical contusion injury.

Anti-Aversive Effects of Cannabidiol on Innate Fear-Induced Behaviors Evoked by an Ethological Model of Panic Attacks Based on a Prey vs the Wild Snake Epicrates cenchria crassus Confrontation Paradigm

PubMed Central

Uribe-Mariño, Andrés; Francisco, Audrey; Castiblanco-Urbina, Maria Angélica; Twardowschy, André; Salgado-Rohner, Carlos José; Crippa, José Alexandre S; Hallak, Jaime Eduardo Cecílio; Zuardi, Antônio Waldo; Coimbra, Norberto Cysne

2012-01-01

Several pharmacological targets have been proposed as modulators of panic-like reactions. However, interest should be given to other potential therapeutic neurochemical agents. Recent attention has been given to the potential anxiolytic properties of cannabidiol, because of its complex actions on the endocannabinoid system together with its effects on other neurotransmitter systems. The aim of this study was to investigate the effects of cannabidiol on innate fear-related behaviors evoked by a prey vs predator paradigm. Male Swiss mice were submitted to habituation in an arena containing a burrow and subsequently pre-treated with intraperitoneal administrations of vehicle or cannabidiol. A constrictor snake was placed inside the arena, and defensive and non-defensive behaviors were recorded. Cannabidiol caused a clear anti-aversive effect, decreasing explosive escape and defensive immobility behaviors outside and inside the burrow. These results show that cannabidiol modulates defensive behaviors evoked by the presence of threatening stimuli, even in a potentially safe environment following a fear response, suggesting a panicolytic effect. PMID:21918503

Effects of Mental Load and Fatigue on Steady-State Evoked Potential Based Brain Computer Interface Tasks: A Comparison of Periodic Flickering and Motion-Reversal Based Visual Attention.

PubMed

Xie, Jun; Xu, Guanghua; Wang, Jing; Li, Min; Han, Chengcheng; Jia, Yaguang

Steady-state visual evoked potentials (SSVEP) based paradigm is a conventional BCI method with the advantages of high information transfer rate, high tolerance to artifacts and the robust performance across users. But the occurrence of mental load and fatigue when users stare at flickering stimuli is a critical problem in implementation of SSVEP-based BCIs. Based on electroencephalography (EEG) power indices α, θ, θ + α, ratio index θ/α and response properties of amplitude and SNR, this study quantitatively evaluated the mental load and fatigue in both of conventional flickering and the novel motion-reversal visual attention tasks. Results over nine subjects revealed significant mental load alleviation in motion-reversal task rather than flickering task. The interaction between factors of "stimulation type" and "fatigue level" also illustrated the motion-reversal stimulation as a superior anti-fatigue solution for long-term BCI operation. Taken together, our work provided an objective method favorable for the design of more practically applicable steady-state evoked potential based BCIs.

Auditory brain stem response and cortical evoked potentials in children with type 1 diabetes mellitus.

PubMed

Radwan, Heba Mohammed; El-Gharib, Amani Mohamed; Erfan, Adel Ali; Emara, Afaf Ahmad

2017-05-01

Delay in ABR and CAEPs wave latencies in children with type 1DM indicates that there is abnormality in the neural conduction in DM patients. The duration of DM has greater effect on auditory function than the control of DM. Diabetes mellitus (DM) is a common endocrine and metabolic disorder. Evoked potentials offer the possibility to perform a functional evaluation of neural pathways in the central nervous system. To investigate the effect of type 1 diabetes mellitus (T1DM) on auditory brain stem response (ABR) and cortical evoked potentials (CAEPs). This study included two groups: a control group (GI), which consisted of 20 healthy children with normal peripheral hearing, and a study group (GII), which consisted of 30 children with type I DM. Basic audiological evaluation, ABR, and CAEPs were done in both groups. Delayed absolute latencies of ABR and CAEPs waves were found. Amplitudes showed no significant difference between both groups. Positive correlation was found between ABR wave latencies and duration of DM. No correlation was found between ABR, CAEPs, and glycated hemoglobin.

Axono-cortical evoked potentials: A proof-of-concept study.

PubMed

Mandonnet, E; Dadoun, Y; Poisson, I; Madadaki, C; Froelich, S; Lozeron, P

2016-04-01

Awake surgery is currently considered the best method to tailor intraparenchymatous resections according to functional boundaries. However, the exact mechanisms by which electrical stimulation disturbs behavior remain largely unknown. In this case report, we describe a new method to explore the propagation toward cortical sites of a brief pulse applied to an eloquent white matter pathway. We present a patient, operated on in awake condition for removal of a cavernoma of the left ventral premotor cortex. At the end of the resection, the application of 60Hz stimulation in the white matter of the operculum induced anomia. Stimulating the same site at a frequency of 1Hz during 70seconds allowed to record responses on electrodes put over Broca's area and around the inferior part of central sulcus. Axono-cortical evoked potentials were then obtained by averaging unitary responses, time-locked to the stimulus. We then discuss the origin of these evoked axono-cortical potentials and the likely pathway connecting the stimulation site to the recorded cortical sites. Copyright © 2015 Elsevier Masson SAS. All rights reserved.

[Anticipatory postural adjustment in bimanual unloading: role of the motor cortex in motor learning].

PubMed

Kazennikov, O V; Solopova, I A; Talis, V L; Ioffe, M E

2006-01-01

The role of the motor cortex was investigated during learning unusual postural adjustment. Healthy subjects held their right (postural) forearm in a horizontal position while supporting a 1-kG load via an electromagnet. The postural forearm position was perturbed by the load release triggered by other elbow voluntary movement. Repetition of the imposed unloading test resulted in a progressive reduction of the maximal forearm rotation, accompanied by the anticipatory decrease in m. biceps brachii activity (learning). Control situation consisted of the voluntary forearm loading. Using the transcranial magnetic stimulation we examined changes in the motor evoked potential of the m. biceps brahii at the beginning and at the end of learning. The evoked potential amplitude did not significantly change in process of the decrease of m. biceps brachii activity. At the end of learning, motor evoked potential / baseline electromyogram ratio increased as compared to the beginning of learning and to the control situation. The results highlight the fundamental role of the motor cortex in suppression of synergies which interfere with formation of a new coordination during motor learning.

Auditory evoked potential (AEP) measurements in stranded rough-toothed dolphins (Steno bredanensis)

NASA Astrophysics Data System (ADS)

Cook, Mandy L. H.; Manire, Charles A.; Mann, David A.

2005-04-01

Thirty-six rough-toothed dolphins (Steno bredanensis) live-stranded on Hutchinson Island, FL on August 6, 2004. Seven animals were transported to Mote Marine Laboratory for rehabilitation. Two auditory evoked potential (AEP) measurements were performed on each of five of these dolphins in air using a jawphone to present acoustic stimuli. Modulation rate transfer functions (MRTFs) were measured to establish how well the auditory system follows the temporal envelope of acoustic stimuli. A 40 kHz stimulus carrier was amplitude modulated (AM) with varying rates ranging from 200 Hz to 1800 Hz, in 200 Hz steps. The best AM-rate from the first dolphin tested was 1500 Hz. This AM rate was used in subsequent AEP measurements to determine evoked-potential hearing thresholds between 5000 and 80000 Hz. These findings show that rough-toothed dolphins can detect sounds between 5 and 80 kHz, and are most likely capable of detecting frequencies much higher than 80 kHz. MRTF data suggest that rough-toothed dolphins have a high temporal resolution, similar to that of other cetaceans.

Construction of a multimodal CT-video chest model

NASA Astrophysics Data System (ADS)

Byrnes, Patrick D.; Higgins, William E.

2014-03-01

Bronchoscopy enables a number of minimally invasive chest procedures for diseases such as lung cancer and asthma. For example, using the bronchoscope's continuous video stream as a guide, a physician can navigate through the lung airways to examine general airway health, collect tissue samples, or administer a disease treatment. In addition, physicians can now use new image-guided intervention (IGI) systems, which draw upon both three-dimensional (3D) multi-detector computed tomography (MDCT) chest scans and bronchoscopic video, to assist with bronchoscope navigation. Unfortunately, little use is made of the acquired video stream, a potentially invaluable source of information. In addition, little effort has been made to link the bronchoscopic video stream to the detailed anatomical information given by a patient's 3D MDCT chest scan. We propose a method for constructing a multimodal CT-video model of the chest. After automatically computing a patient's 3D MDCT-based airway-tree model, the method next parses the available video data to generate a positional linkage between a sparse set of key video frames and airway path locations. Next, a fusion/mapping of the video's color mucosal information and MDCT-based endoluminal surfaces is performed. This results in the final multimodal CT-video chest model. The data structure constituting the model provides a history of those airway locations visited during bronchoscopy. It also provides for quick visual access to relevant sections of the airway wall by condensing large portions of endoscopic video into representative frames containing important structural and textural information. When examined with a set of interactive visualization tools, the resulting fused data structure provides a rich multimodal data source. We demonstrate the potential of the multimodal model with both phantom and human data.

Brain correlates of music-evoked emotions.

PubMed

Koelsch, Stefan

2014-03-01

Music is a universal feature of human societies, partly owing to its power to evoke strong emotions and influence moods. During the past decade, the investigation of the neural correlates of music-evoked emotions has been invaluable for the understanding of human emotion. Functional neuroimaging studies on music and emotion show that music can modulate activity in brain structures that are known to be crucially involved in emotion, such as the amygdala, nucleus accumbens, hypothalamus, hippocampus, insula, cingulate cortex and orbitofrontal cortex. The potential of music to modulate activity in these structures has important implications for the use of music in the treatment of psychiatric and neurological disorders.

Evaluation of electrical propagation delay with cardiomyocytes by photosensitization reaction in vitro

NASA Astrophysics Data System (ADS)

Doi, Marika; Ogawa, Emiyu; Arai, Tsunenori

2017-02-01

In order to study cardiomyocyte electrical conduction damage by a photosensitization reaction (PR) mostly comes from outside of the cells in a few minutes after the PR, we studied propagation delay of contact action potential with cardiomyocyte by the PR. To determine appropriate PR condition for tachyarrhythmia ablation, a precise electrophysiological experiment in vitro has been preferable. We measured the contact action potential using a microelectrode array system of which information may be correct than conventional Ca2+ measurement. We investigated the propagation delays of an evoked potential to evaluate the electrical conduction damage by the PR. Rat cardiomyocytes were cultivated for 5-7 days on a dish with which 64 electrodes were patterned, in an incubator controlled to 37°C, 5% CO2. The following conditions were used for the PR: 40 μg/ml talapordfin sodium and 290 mW/cm2, 40-78 J/cm2 for an irradiation. A 2D map was obtained to visualize the propagation delays of the evoked potential. The propagation speed, which was calculated based on the measured propagation delays, was decreased by about 30-50% on average of all electrodes after the PR. Therefore, we think 2D propagation delays measurement of the evoked potential with contact action potential measuring system might be available to evaluate the acute electrical conduction damage of cardiomyocyte by the PR.

Ventral tegmental ionotropic glutamate receptor stimulation of nucleus accumbens tonic dopamine efflux blunts hindbrain-evoked phasic neurotransmission: implications for dopamine dysregulation disorders.

PubMed

Tye, S J; Miller, A D; Blaha, C D

2013-11-12

Activation of glutamate receptors within the ventral tegmental area (VTA) stimulates extrasynaptic (basal) dopamine release in terminal regions, including the nucleus accumbens (NAc). Hindbrain inputs from the laterodorsal tegmental nucleus (LDT) are critical for elicitation of phasic VTA dopamine cell activity and consequent transient dopamine release. This study investigated the role of VTA ionotropic glutamate receptor (iGluR) stimulation on both basal and LDT electrical stimulation-evoked dopamine efflux in the NAc using in vivo chronoamperometry and fixed potential amperometry in combination with stearate-graphite paste and carbon fiber electrodes, respectively. Intra-VTA infusion of the iGluR agonists (±)-α-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid (AMPA; 1 μg/μl) or N-methyl-d-aspartic acid (NMDA; 2 μg/μl) enhanced basal NAc dopamine efflux. This iGluR-mediated potentiation of basal dopamine efflux was paralleled by an attenuation of LDT-evoked transient NAc dopamine efflux, suggesting that excitation of basal activity effectively inhibited the capacity of hindbrain afferents to elicit transient dopamine efflux. In line with this, post-NMDA infusion of the dopamine D2 autoreceptor (D2R) agonist quinpirole (1 μg/μl; intra-VTA) partially recovered NMDA-mediated attenuation of LDT-evoked NAc dopamine, while concurrently attenuating NMDA-mediated potentiation of basal dopamine efflux. Post-NMDA infusion of quinpirole (1 μg/μl) alone attenuated basal and LDT-evoked dopamine efflux. Taken together, these data reveal that hyperstimulation of basal dopamine transmission can stunt hindbrain burst-like stimulation-evoked dopamine efflux. Inhibitory autoreceptor mechanisms within the VTA help to partially recover the magnitude of phasic dopamine efflux, highlighting the importance of both iGluRs and D2 autoreceptors in maintaining the functional balance of tonic and phasic dopamine neurotransmission. Dysregulation of this balance may have important implications for disorders of dopamine dysregulation such as attention deficit hyperactivity disorder. Copyright © 2013 IBRO. Published by Elsevier Ltd. All rights reserved.

Middle ear muscle contractions and their relation to pulse and echo evoked potentials in the bat

NASA Technical Reports Server (NTRS)

Henson, O. W., Jr.; Henson, M. M.

1972-01-01

An analysis is made of pulse and echo orientation cries of the Mustache Bat. That bat's cries are characterized by a long, 60 to 30 msec, pure tone component and brief beginning and terminal FM sweeps. In addition to obvious echo overlap and middle ear muscle contractions, the following are examined: (1) characteristics of pulse- and echo-evoked potential under various conditions, (2) evidence of changes in hearing sensitivity during and after pulse emission, and (3) the role of the middle ear muscles in bringing about these changes.

Intraoperative Monitoring: Recent Advances in Motor Evoked Potentials.

PubMed

Koht, Antoun; Sloan, Tod B

2016-09-01

Advances in electrophysiological monitoring have improved the ability of surgeons to make decisions and minimize the risks of complications during surgery and interventional procedures when the central nervous system (CNS) is at risk. Individual techniques have become important for identifying or mapping the location and pathway of critical neural structures. These techniques are also used to monitor the progress of procedures to augment surgical and physiologic management so as to reduce the risk of CNS injury. Advances in motor evoked potentials have facilitated mapping and monitoring of the motor tracts in newer, more complex procedures. Copyright © 2016 Elsevier Inc. All rights reserved.

Melatonin potentiates tear secretion induced by diadenosine tetraphosphate in the rabbit.

PubMed

Hoyle, Charles H V; Peral, Assumpta; Pintor, Jesús

2006-12-15

Diadenosine tetraphosphate (Ap(4)A, 0.03 nmol) applied topically to the cornea of New Zealand white rabbits, evoked an increase in tear secretion of 9.7 +/- 2.60% (N=7). Melatonin (1 nmol) had no significant effect. Application of Ap(4)A in combination with melatonin, evoked a significantly greater increase in tear secretion of 34.2 +/- 5.8% (N=11). This potentiating effect of melatonin was blocked by pretreating the cornea with a topical application of the melatonin receptor antagonist, luzindole (240 nmol). Melatonin combined with Ap(4)A may be useful for treating dry eye conditions.

Intraoperative changes in transcranial motor evoked potentials and somatosensory evoked potentials predicting outcome in children with intramedullary spinal cord tumors.

PubMed

Cheng, Jason S; Ivan, Michael E; Stapleton, Christopher J; Quinones-Hinojosa, Alfredo; Gupta, Nalin; Auguste, Kurtis I

2014-06-01

Intraoperative dorsal column mapping, transcranial motor evoked potentials (TcMEPs), and somatosensory evoked potentials (SSEPs) have been used in adults to assist with the resection of intramedullary spinal cord tumors (IMSCTs) and to predict postoperative motor deficits. The authors sought to determine whether changes in MEP and SSEP waveforms would similarly predict postoperative motor deficits in children. The authors reviewed charts and intraoperative records for children who had undergone resection for IMSCTs as well as dorsal column mapping and TcMEP and SSEP monitoring. Motor evoked potential data were supplemented with electromyography data obtained using a Kartush microstimulator (Medtronic Inc.). Motor strength was graded using the Medical Research Council (MRC) scale during the preoperative, immediate postoperative, and follow-up periods. Reductions in SSEPs were documented after mechanical traction, in response to maneuvers with the cavitational ultrasonic surgical aspirator (CUSA), or both. Data from 12 patients were analyzed. Three lesions were encountered in the cervical and 7 in the thoracic spinal cord. Two patients had lesions of the cervicomedullary junction and upper spinal cord. Intraoperative MEP changes were noted in half of the patients. In these cases, normal polyphasic signals converted to biphasic signals, and these changes correlated with a loss of 1-2 grades in motor strength. One patient lost MEP signals completely and recovered strength to MRC Grade 4/5. The 2 patients with high cervical lesions showed neither intraoperative MEP changes nor motor deficits postoperatively. Dorsal columns were mapped in 7 patients, and the midline was determined accurately in all 7. Somatosensory evoked potentials were decreased in 7 patients. Two patients each had 2 SSEP decreases in response to traction intraoperatively but had no new sensory findings postoperatively. Another 2 patients had 3 traction-related SSEP decreases intraoperatively, and both had new postoperative sensory deficits that resolved. One additional patient had a CUSA-related SSEP decrease intraoperatively, which resolved postoperatively, and the last patient had 3 traction-related sensory deficits and a CUSA-related sensory deficit postoperatively, none of which resolved. Intraoperative TcMEPs and SSEPs can predict the degree of postoperative motor deficit in pediatric patients undergoing IMSCT resection. This technique, combined with dorsal column mapping, is particularly useful in resecting lesions of the upper cervical cord, which are generally considered to be high risk in this population. Furthermore, the spinal cord appears to be less tolerant of repeated intraoperative SSEP decreases, with 3 successive insults most likely to yield postoperative sensory deficits. Changes in TcMEPs and SSEP waveforms can signal the need to guard against excessive manipulation thereby increasing the safety of tumor resection.

Quantum interference between transverse spatial waveguide modes.

PubMed

Mohanty, Aseema; Zhang, Mian; Dutt, Avik; Ramelow, Sven; Nussenzveig, Paulo; Lipson, Michal

2017-01-20

Integrated quantum optics has the potential to markedly reduce the footprint and resource requirements of quantum information processing systems, but its practical implementation demands broader utilization of the available degrees of freedom within the optical field. To date, integrated photonic quantum systems have primarily relied on path encoding. However, in the classical regime, the transverse spatial modes of a multi-mode waveguide have been easily manipulated using the waveguide geometry to densely encode information. Here, we demonstrate quantum interference between the transverse spatial modes within a single multi-mode waveguide using quantum circuit-building blocks. This work shows that spatial modes can be controlled to an unprecedented level and have the potential to enable practical and robust quantum information processing.

Identification of spinal circuits involved in touch-evoked dynamic mechanical pain

PubMed Central

Cheng, Longzhen; Duan, Bo; Huang, Tianwen; Zhang, Yan; Chen, Yangyang; Britz, Olivier; Garcia-Campmany, Lidia; Ren, Xiangyu; Vong, Linh; Lowell, Bradford B.; Goulding, Martyn; Wang, Yun; Ma, Qiufu

2017-01-01

Mechanical hypersensitivity is a debilitating symptom associated with millions of chronic pain patients. It exists in distinct forms, including brush-evoked dynamic and filament-evoked punctate. Here we report that dynamic mechanical hypersensitivity induced by nerve injury or inflammation was compromised in mice with ablation of spinal VT3Lbx1 neurons defined by coexpression of VGLUT3Cre and Lbx1Flpo, as indicated by the loss of brush-evoked nocifensive responses and conditional place aversion. Electrophysiological recordings show that VT3Lbx1 neurons form morphine-resistant polysynaptic pathways relaying inputs from low-threshold Aβ mechanoreceptors to lamina I output neurons. Meanwhile, the subset of somatostatin (SOM) lineage neurons preserved in VT3Lbx1 neuron-ablated mice is largely sufficient to mediate von Frey filament-evoked punctate mechanical hypersensitivity, including both morphine-sensitive and morphine-resistant forms. Furthermore, acute silencing of VT3Lbx1 neurons attenuated pre-established dynamic mechanical hypersensitivity induced by nerve injury, suggesting these neurons as a potential cellular target for treating this form of neuropathic pain. PMID:28436981

Prospective Evaluation of Multimodal Optical Imaging with Automated Image Analysis to Detect Oral Neoplasia In Vivo.

PubMed

Quang, Timothy; Tran, Emily Q; Schwarz, Richard A; Williams, Michelle D; Vigneswaran, Nadarajah; Gillenwater, Ann M; Richards-Kortum, Rebecca

2017-10-01

The 5-year survival rate for patients with oral cancer remains low, in part because diagnosis often occurs at a late stage. Early and accurate identification of oral high-grade dysplasia and cancer can help improve patient outcomes. Multimodal optical imaging is an adjunctive diagnostic technique in which autofluorescence imaging is used to identify high-risk regions within the oral cavity, followed by high-resolution microendoscopy to confirm or rule out the presence of neoplasia. Multimodal optical images were obtained from 206 sites in 100 patients. Histologic diagnosis, either from a punch biopsy or an excised surgical specimen, was used as the gold standard for all sites. Histopathologic diagnoses of moderate dysplasia or worse were considered neoplastic. Images from 92 sites in the first 30 patients were used as a training set to develop automated image analysis methods for identification of neoplasia. Diagnostic performance was evaluated prospectively using images from 114 sites in the remaining 70 patients as a test set. In the training set, multimodal optical imaging with automated image analysis correctly classified 95% of nonneoplastic sites and 94% of neoplastic sites. Among the 56 sites in the test set that were biopsied, multimodal optical imaging correctly classified 100% of nonneoplastic sites and 85% of neoplastic sites. Among the 58 sites in the test set that corresponded to a surgical specimen, multimodal imaging correctly classified 100% of nonneoplastic sites and 61% of neoplastic sites. These findings support the potential of multimodal optical imaging to aid in the early detection of oral cancer. Cancer Prev Res; 10(10); 563-70. ©2017 AACR . ©2017 American Association for Cancer Research.

Label-aligned Multi-task Feature Learning for Multimodal Classification of Alzheimer’s Disease and Mild Cognitive Impairment

PubMed Central

Zu, Chen; Jie, Biao; Liu, Mingxia; Chen, Songcan

2015-01-01

Multimodal classification methods using different modalities of imaging and non-imaging data have recently shown great advantages over traditional single-modality-based ones for diagnosis and prognosis of Alzheimer’s disease (AD), as well as its prodromal stage, i.e., mild cognitive impairment (MCI). However, to the best of our knowledge, most existing methods focus on mining the relationship across multiple modalities of the same subjects, while ignoring the potentially useful relationship across different subjects. Accordingly, in this paper, we propose a novel learning method for multimodal classification of AD/MCI, by fully exploring the relationships across both modalities and subjects. Specifically, our proposed method includes two subsequent components, i.e., label-aligned multi-task feature selection and multimodal classification. In the first step, the feature selection learning from multiple modalities are treated as different learning tasks and a group sparsity regularizer is imposed to jointly select a subset of relevant features. Furthermore, to utilize the discriminative information among labeled subjects, a new label-aligned regularization term is added into the objective function of standard multi-task feature selection, where label-alignment means that all multi-modality subjects with the same class labels should be closer in the new feature-reduced space. In the second step, a multi-kernel support vector machine (SVM) is adopted to fuse the selected features from multi-modality data for final classification. To validate our method, we perform experiments on the Alzheimer’s Disease Neuroimaging Initiative (ADNI) database using baseline MRI and FDG-PET imaging data. The experimental results demonstrate that our proposed method achieves better classification performance compared with several state-of-the-art methods for multimodal classification of AD/MCI. PMID:26572145

Extrinsic Embryonic Sensory Stimulation Alters Multimodal Behavior and Cellular Activation

PubMed Central

Markham, Rebecca G.; Shimizu, Toru; Lickliter, Robert

2009-01-01

Embryonic vision is generated and maintained by spontaneous neuronal activation patterns, yet extrinsic stimulation also sculpts sensory development. Because the sensory and motor systems are interconnected in embryogenesis, how extrinsic sensory activation guides multimodal differentiation is an important topic. Further, it is unknown whether extrinsic stimulation experienced near sensory sensitivity onset contributes to persistent brain changes, ultimately affecting postnatal behavior. To determine the effects of extrinsic stimulation on multimodal development, we delivered auditory stimulation to bobwhite quail groups during early, middle, or late embryogenesis, and then tested postnatal behavioral responsiveness to auditory or visual cues. Auditory preference tendencies were more consistently toward the conspecific stimulus for animals stimulated during late embryogenesis. Groups stimulated during middle or late embryogenesis showed altered postnatal species-typical visual responsiveness, demonstrating a persistent multimodal effect. We also examined whether auditory-related brain regions are receptive to extrinsic input during middle embryogenesis by measuring postnatal cellular activation. Stimulated birds showed a greater number of ZENK-immunopositive cells per unit volume of brain tissue in deep optic tectum, a midbrain region strongly implicated in multimodal function. We observed similar results in the medial and caudomedial nidopallia in the telencephalon. There were no ZENK differences between groups in inferior colliculus or in caudolateral nidopallium, avian analog to prefrontal cortex. To our knowledge, these are the first results linking extrinsic stimulation delivered so early in embryogenesis to changes in postnatal multimodal behavior and cellular activation. The potential role of competitive interactions between the sensory and motor systems is discussed. PMID:18777564

SEPs to finger joint input lack the N20-P20 response that is evoked by tactile inputs: contrast between cortical generators in areas 3b and 2 in humans.

PubMed

Desmedt, J E; Ozaki, I

1991-01-01

A method using a DC servo motor is described to produce brisk angular movements at finger interphalangeal joints in humans. Small passive flexions of 2 degrees elicited sizable somatosensory evoked potentials (SEPs) starting with a contralateral positive P34 parietal response thought to reflect activation of a radial equivalent dipole generator in area 2 which receives joint inputs. By contrast, electric stimulation of tactile (non-joint) inputs from the distal phalanx evoked the usual contralateral negative N20 reflecting a tangential equivalent dipole generator in area 3b. Finger joint inputs also evoked a precentral positivity equivalent to the P22 of motor area 4, and a large frontal negativity equivalent to N30. It is suggested that natural stimulation allows human SEP components to be differentiated in conjunction with distinct cortical somatotopic projections.

Non-responders to cardiac resynchronization therapy: Insights from multimodality imaging and electrocardiography. A brief review.

PubMed

Carità, Patrizia; Corrado, Egle; Pontone, Gianluca; Curnis, Antonio; Bontempi, Luca; Novo, Giuseppina; Guglielmo, Marco; Ciaramitaro, Gianfranco; Assennato, Pasquale; Novo, Salvatore; Coppola, Giuseppe

2016-12-15

Cardiac resynchronization therapy (CRT) is a successful strategy for heart failure (HF) patients. The pre-requisite for the response is the evidence of electrical dyssynchrony on the surface electrocardiogram usually as left bundle branch block (LBBB). Non-response to CRT is a significant problem in clinical practice. Patient selection, inadequate delivery and sub-optimal left ventricle lead position may be important causes. In an effort to improve CRT response multimodality imaging (especially echocardiography, computed tomography and cardiac magnetic resonance) could play a decisive role and extensive literature has been published on the matter. However, we are so far from routinary use in clinical practice. Electrocardiography (with respect to left ventricle capture and QRS narrowing) may represent a simple and low cost approach for early prediction of potential non-responder, with immediate practical implications. This brief review covers the current recommendations for CRT in HF patients with particular attention to the potential benefits of multimodality imaging and electrocardiography in improving response rate. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Launch device using endlessly single-mode PCF for ultra-wideband WDM transmission in graded-index multi-mode fiber.

PubMed

Ma, Lin; Hanzawa, Nobutomo; Tsujikawa, Kyozo; Azuma, Yuji

2012-10-22

We demonstrated ultra-wideband wavelength division multiplexing (WDM) transmission from 850 to 1550 nm in graded-index multi-mode fiber (GI-MMF) using endlessly single-mode photonic crystal fiber (ESM-PCF) as a launch device. Effective single-mode guidance is obtained in multi-mode fiber at all wavelengths by splicing cm-order length ESM-PCF to the transmission fiber. We achieved 3 × 10 Gbit/s WDM transmission in a 1 km-long 50-μm-core GI-MMF. We also realized penalty free 10 Gbit/s data transmission at a wavelength of 850 nm by optimizing the PCF structure. This method has the potential to achieve greater total transmission capacity for MMF systems by the addition of more wavelength channels.

Focusing and imaging with increased numerical apertures through multimode fibers with micro-fabricated optics.

PubMed

Bianchi, S; Rajamanickam, V P; Ferrara, L; Di Fabrizio, E; Liberale, C; Di Leonardo, R

2013-12-01

The use of individual multimode optical fibers in endoscopy applications has the potential to provide highly miniaturized and noninvasive probes for microscopy and optical micromanipulation. A few different strategies have been proposed recently, but they all suffer from intrinsically low resolution related to the low numerical aperture of multimode fibers. Here, we show that two-photon polymerization allows for direct fabrication of micro-optics components on the fiber end, resulting in an increase of the numerical aperture to a value that is close to 1. Coupling light into the fiber through a spatial light modulator, we were able to optically scan a submicrometer spot (300 nm FWHM) over an extended region, facing the opposite fiber end. Fluorescence imaging with improved resolution is also demonstrated.

A Novel Multimode Waveguide Coupler for Accurate Power Measurement of Traveling Wave Tube Harmonic Frequencies

NASA Technical Reports Server (NTRS)

Wintucky, Edwin G.; Simons, Rainee N.

2014-01-01

This paper presents the design, fabrication and test results for a novel waveguide multimode directional coupler (MDC). The coupler fabricated from two dissimilar waveguides is capable of isolating the power at the second harmonic frequency from the fundamental power at the output port of a traveling-wave tube (TWT). In addition to accurate power measurements at harmonic frequencies, a potential application of the MDC is in the design of a beacon source for atmospheric propagation studies at millimeter-wave frequencies.

Effects of Multimodal Analgesia on the Success of Mouse Embryo Transfer Surgery

PubMed Central

Parker, John M.; Austin, Jamie; Wilkerson, James; Carbone, Larry

2011-01-01

Multimodal analgesia is promoted as the best practice pain management for invasive animal research procedures. Universal acceptance and incorporation of multimodal analgesia requires assessing potential effects on study outcome. The focus of this study was to assess effects on embryo survival after multimodal analgesia comprising an opioid and nonsteroidal antiinflammatory drug (NSAID) compared with opioid-only analgesia during embryo transfer procedures in transgenic mouse production. Mice were assigned to receive either carprofen (5 mg/kg) with buprenorphine (0.1 mg/kg; CB) or vehicle with buprenorphine (0.1 mg/kg; VB) in a prospective, double-blinded placebo controlled clinical trial. Data were analyzed in surgical sets of 1 to 3 female mice receiving embryos chimeric for a shared targeted embryonic stem-cell clone and host blastocyst cells. A total of 99 surgical sets were analyzed, comprising 199 Crl:CD1 female mice and their 996 offspring. Neither yield (pups weaned per embryo implanted in the surgical set) nor birth rate (average number of pups weaned per dam in the set) differed significantly between the CB and VB conditions. Multimodal opioid–NSAID analgesia appears to have no significant positive or negative effect on the success of producing novel lines of transgenic mice by blastocyst transfer. PMID:21838973

Objective measures of binaural masking level differences and comodulation masking release based on late auditory evoked potentials.

PubMed

Epp, Bastian; Yasin, Ifat; Verhey, Jesko L

2013-12-01

The audibility of important sounds is often hampered due to the presence of other masking sounds. The present study investigates if a correlate of the audibility of a tone masked by noise is found in late auditory evoked potentials measured from human listeners. The audibility of the target sound at a fixed physical intensity is varied by introducing auditory cues of (i) interaural target signal phase disparity and (ii) coherent masker level fluctuations in different frequency regions. In agreement with previous studies, psychoacoustical experiments showed that both stimulus manipulations result in a masking release (i: binaural masking level difference; ii: comodulation masking release) compared to a condition where those cues are not present. Late auditory evoked potentials (N1, P2) were recorded for the stimuli at a constant masker level, but different signal levels within the same set of listeners who participated in the psychoacoustical experiment. The data indicate differences in N1 and P2 between stimuli with and without interaural phase disparities. However, differences for stimuli with and without coherent masker modulation were only found for P2, i.e., only P2 is sensitive to the increase in audibility, irrespective of the cue that caused the masking release. The amplitude of P2 is consistent with the psychoacoustical finding of an addition of the masking releases when both cues are present. Even though it cannot be concluded where along the auditory pathway the audibility is represented, the P2 component of auditory evoked potentials is a candidate for an objective measure of audibility in the human auditory system. Copyright © 2013 Elsevier B.V. All rights reserved.

Chromatic spatial contrast sensitivity estimated by visual evoked cortical potential and psychophysics

PubMed Central

Barboni, M.T.S.; Gomes, B.D.; Souza, G.S.; Rodrigues, A.R.; Ventura, D.F.; Silveira, L.C.L.

2013-01-01

The purpose of the present study was to measure contrast sensitivity to equiluminant gratings using steady-state visual evoked cortical potential (ssVECP) and psychophysics. Six healthy volunteers were evaluated with ssVECPs and psychophysics. The visual stimuli were red-green or blue-yellow horizontal sinusoidal gratings, 5° × 5°, 34.3 cd/m2 mean luminance, presented at 6 Hz. Eight spatial frequencies from 0.2 to 8 cpd were used, each presented at 8 contrast levels. Contrast threshold was obtained by extrapolating second harmonic amplitude values to zero. Psychophysical contrast thresholds were measured using stimuli at 6 Hz and static presentation. Contrast sensitivity was calculated as the inverse function of the pooled cone contrast threshold. ssVECP and both psychophysical contrast sensitivity functions (CSFs) were low-pass functions for red-green gratings. For electrophysiology, the highest contrast sensitivity values were found at 0.4 cpd (1.95 ± 0.15). ssVECP CSF was similar to dynamic psychophysical CSF, while static CSF had higher values ranging from 0.4 to 6 cpd (P < 0.05, ANOVA). Blue-yellow chromatic functions showed no specific tuning shape; however, at high spatial frequencies the evoked potentials showed higher contrast sensitivity than the psychophysical methods (P < 0.05, ANOVA). Evoked potentials can be used reliably to evaluate chromatic red-green CSFs in agreement with psychophysical thresholds, mainly if the same temporal properties are applied to the stimulus. For blue-yellow CSF, correlation between electrophysiology and psychophysics was poor at high spatial frequency, possibly due to a greater effect of chromatic aberration on this kind of stimulus. PMID:23369980

A comparative study on long-term evoked auditory and visual potential responses between Schizophrenic patients and normal subjects

PubMed Central

2011-01-01

Background The electrical signals measuring method is recommended to examine the relationship between neuronal activities and measure with the event related potentials (ERPs) during an auditory and a visual oddball paradigm between schizophrenic patients and normal subjects. The aim of this study is to discriminate the activation changes of different stimulations evoked by auditory and visual ERPs between schizophrenic patients and normal subjects. Methods Forty-three schizophrenic patients were selected as experimental group patients, and 40 healthy subjects with no medical history of any kind of psychiatric diseases, neurological diseases, or drug abuse, were recruited as a control group. Auditory and visual ERPs were studied with an oddball paradigm. All the data were analyzed by SPSS statistical software version 10.0. Results In the comparative study of auditory and visual ERPs between the schizophrenic and healthy patients, P300 amplitude at Fz, Cz, and Pz and N100, N200, and P200 latencies at Fz, Cz, and Pz were shown significantly different. The cognitive processing reflected by the auditory and the visual P300 latency to rare target stimuli was probably an indicator of the cognitive function in schizophrenic patients. Conclusions This study shows the methodology of application of auditory and visual oddball paradigm identifies task-relevant sources of activity and allows separation of regions that have different response properties. Our study indicates that there may be slowness of automatic cognitive processing and controlled cognitive processing of visual ERPs compared to auditory ERPs in schizophrenic patients. The activation changes of visual evoked potentials are more regionally specific than auditory evoked potentials. PMID:21542917

Implementation of Intraoperative Neurophysiological Monitoring during Endovascular Procedures in the Central Nervous System.

PubMed

Martinez Piñeiro, Alicia; Cubells, Carles; Garcia, Pablo; Castaño, Carlos; Dávalos, Antonio; Coll-Canti, Jaume

2015-03-01

Intraoperative monitoring (IOM) has been used in different surgical disciplines since the 1980s. Nonetheless, regular routine use of IOM in interventional neuroradiology units has only been reported in a few centers. The aim of this study is to report our experience, 1 year after deciding to implement standardized IOM during endovascular treatment of vascular abnormalities of the central nervous system. Basic recordings included somatosensory-evoked potentials (SEPs) and motor-evoked potentials (MEPs). Corticobulbar motor-evoked potentials and flash-visual-evoked potentials were also recorded depending on the topography of the lesion. Intra-arterial provocative tests (PTs) with amobarbital and lidocaine were also performed. All patients except 1 were under total intravenous anesthesia. Clinical outcome was assessed prospectively and correlated with IOM events. Twelve patients and 15 procedures were monitored during the inclusion period. Significant IOM events were detected during 3 of the 15 procedures (20%). We observed temporary MEP changes in 2 cases which resolved after interruption of the embolization or application of corrective measures, leaving no postoperative neurological deficits. In 1 case, persistent SEP and MEP deterioration was detected secondary to a frontal hematoma, resulting in mild sensory-motor deficit in the right upper extremity after the procedure. Overall, 12 PTs (4 spinal cord and 8 brain abnormalities) were performed using lidocaine and sodium amytal injections. One positive result occurred after the injection of lidocaine. No false negatives were detected. IOM may provide continuous real-time data about the functional status of eloquent areas and pathways of the central nervous system in patients under general anesthesia. It therefore allows us to detect early neurological damage in time to perform specific actions that may prevent irreversible neurological deficits.

The cortical spatiotemporal correlate of otolith stimulation: Vestibular evoked potentials by body translations.

PubMed

Ertl, M; Moser, M; Boegle, R; Conrad, J; Zu Eulenburg, P; Dieterich, M

2017-07-15

The vestibular organ senses linear and rotational acceleration of the head during active and passive motion. These signals are necessary for bipedal locomotion, navigation, the coordination of eye and head movements in 3D space. The temporal dynamics of vestibular processing in cortical structures have hardly been studied in humans, let alone with natural stimulation. The aim was to investigate the cortical vestibular network related to natural otolith stimulation using a hexapod motion platform. We conducted two experiments, 1. to estimate the sources of the vestibular evoked potentials (VestEPs) by means of distributed source localization (n=49), and 2. to reveal modulations of the VestEPs through the underlying acceleration intensity (n=24). For both experiments subjects were accelerated along the main axis (left/right, up/down, fore/aft) while the EEG was recorded. We were able to identify five VestEPs (P1, N1, P2, N2, P3) with latencies between 38 and 461 ms as well as an evoked beta-band response peaking with a latency of 68 ms in all subjects and for all acceleration directions. Source localization gave the cingulate sulcus visual (CSv) area and the opercular-insular region as the main origin of the evoked potentials. No lateralization effects due to handedness could be observed. In the second experiment, area CSv was shown to be integral in the processing of acceleration intensities as sensed by the otolith organs, hinting at its potential role in ego-motion detection. These robust VestEPs could be used to investigate the mechanisms of inter-regional interaction in the natural context of vestibular processing and multisensory integration. Copyright © 2017 Elsevier Inc. All rights reserved.

Sensory transduction of weak electromagnetic fields: role of glutamate neurotransmission mediated by NMDA receptors.

PubMed

Frilot, C; Carrubba, S; Marino, A A

2014-01-31

Subliminal electromagnetic fields (EMFs) triggered nonlinear evoked potentials in awake but not anesthetized animals, and increased glucose metabolism in the hindbrain. Field detection occurred somewhere in the head and possibly was an unrecognized function of sensory neurons in facial skin, which synapse in the trigeminal nucleus and project to the thalamus via glutamate-dependent pathways. If so, anesthetic agents that antagonize glutamate neurotransmission would be expected to degrade EMF-evoked potentials (EEPs) to a greater extent than agents having different pharmacological effects. We tested the hypothesis using ketamine which blocks N-methyl-d-aspartate (NMDA) receptors (NMDARs), and xylazine which is an α₂-adrenoreceptor agonist. Electroencephalograms (EEGs) of rats were examined using recurrence analysis to observe EEPs in the presence and absence of ketamine and/or xylazine anesthesia. Auditory evoked potentials (AEPs) served as positive controls. The frequency of observation of evoked potentials in a given condition (wake or anesthesia) was compared with that due to chance using the Fisher's exact test. EEPs were observed in awake rats but not while they were under anesthesia produced using a cocktail of xylazine and ketamine. In another experiment each rat was measured while awake and while under anesthesia produced using either xylazine or ketamine. EEPs and AEPs were detected during wake and under xylazine (P<0.05 in each of the four measurements). In contrast, neither EEPs nor AEPs were observed when anesthesia was produced partly or wholly using ketamine. The duration and latency of the EEPs was unaltered by xylazine anesthesia. The afferent signal triggered by the transduction of weak EMFs was likely mediated by NMDAR-mediated glutamate neurotransmission. Copyright © 2013 IBRO. Published by Elsevier Ltd. All rights reserved.

[Effect of acoustic stimulus intensity on air-conducted sound elicited ocular vestibular-evoked myogenic potential and cervical vestibular-evoked myogenic potential].

PubMed

Zhang, Rui; Xu, Min; Zhang, Qing; Yang, Yin-Tong; Chen, Yanfei

2014-06-01

To observe the effect of acoustic stimulus intensity on air-conducted sound elicited ocular vestibular- evoked myogenic potential (oVEMP) and cervical vestibular-evoked myogenic potential (cVEMP) in normal young Chinese subjects. Thirty-five normal subjects aged 4-40 years (20.80∓8.89 years), including 16 males and 19 females, were recruited for conventional oVEMP and cVEMP examinations. The responses obtained from each side using 500 Hz tone bursts were divided into 6 groups according to different sound intensities (100, 95, 90, 85, 80 and 75dB nHL). The response rate and normal parameters of each stimulus intensity group were calculated. As the acoustic stimulus intensity decreased, the oVEMP response rate decreased from 100% in both 100 dB nHL and 95dB nHL groups to 97.14% (90 dB nHL), 54.29% (85 dB nHL), 14.29% (80 dB nHL), and 2.86% (75 dB nHL), and the response rate of cVEMP, 100% in both 100 dB nHL and 95dB nHL groups, was lowered to 97.14% (90 dB nHL), 84.29% (85 dB nHL), 38.57% (80 dB nHL) and 8.57% (75 dB nHL). The response rate and the parameters were comparable between 100 and 95 dB nHL groups. As the acoustic stimulus intensity decreases, both oVEMP and cVEMP show decreased response rate and amplitude. For Chinese subjects under 40 years of age, we recommend 95dB nHL as the maximum initial stimulus intensity in VEMPs test.

Electrophysiological measurement of human auditory function

NASA Technical Reports Server (NTRS)

Galambos, R.

1975-01-01

Contingent negative variations in the presence and amplitudes of brain potentials evoked by sound are considered. Evidence is produced that the evoked brain stem response to auditory stimuli is clearly related to brain events associated with cognitive processing of acoustic signals since their properties depend upon where the listener directs his attention, whether the signal is an expected event or a surprise, and when sound that is listened-for is heard at last.

The Evoked Potential. An Experimental Method for Biomechanical Analysis of Brain and Spinal Injury

DTIC Science & Technology

1980-01-01

Newtons produced marked changes in blood pressure, heart rate and distraction of the cervical spinal column with minimal ligamentous disruption...pathologic distraction and pathologic flexion of the thoracic ver- tebral column (8). Cerebral responses were lost within two minutes aftex complete...However, the immediate flexion and distraction responses were not altered. These findings suggest that mechanical trauma alters the spinal cord evoked

GABAergic Neural Activity Involved in Salicylate-Induced Auditory Cortex Gain Enhancement

PubMed Central

Lu, Jianzhong; Lobarinas, Edward; Deng, Anchun; Goodey, Ronald; Stolzberg, Daniel; Salvi, Richard J.; Sun, Wei

2011-01-01

Although high doses of sodium salicylate impair cochlear function, it paradoxically enhances sound-evoked activity in the auditory cortex (AC) and augments acoustic startle reflex responses, neural and behavioral metrics associated with hyperexcitability and hyperacusis. To explore the neural mechanisms underlying salicylate-induced hyperexcitability and “increased central gain”, we examined the effects of γ-aminobutyric acid (GABA) receptor agonists and antagonists on salicylate-induced hyperexcitability in the AC and startle reflex responses. Consistent with our previous findings, local or systemic application of salicylate significantly increased the amplitude of sound-evoked AC neural activity, but generally reduced spontaneous activity in the AC. Systemic injection of salicylate also significantly increased the acoustic startle reflex. S-baclofen or R-baclofen, GABA-B agonists, which suppressed sound-evoked AC neural firing rate and local field potentials, also suppressed the salicylate-induced enhancement of the AC field potential and the acoustic startle reflex. Local application of vigabatrin, which enhances GABA concentration in the brain, suppressed the salicylate-induced enhancement of AC firing rate. Systemic injection of vigabatrin also reduced the salicylate-induced enhancement of acoustic startle reflex. Collectively, these results suggest that the sound-evoked behavioral and neural hyperactivity induced by salicylate may arise from a salicylate-induced suppression GABAergic inhibition in the AC. PMID:21664433

Salicylate-Induced Auditory Perceptual Disorders and Plastic Changes in Nonclassical Auditory Centers in Rats

PubMed Central

Chen, Guang-Di; Radziwon, Kelly E.; Manohar, Senthilvelan

2014-01-01

Previous studies have shown that sodium salicylate (SS) activates not only central auditory structures, but also nonauditory regions associated with emotion and memory. To identify electrophysiological changes in the nonauditory regions, we recorded sound-evoked local field potentials and multiunit discharges from the striatum, amygdala, hippocampus, and cingulate cortex after SS-treatment. The SS-treatment produced behavioral evidence of tinnitus and hyperacusis. Physiologically, the treatment significantly enhanced sound-evoked neural activity in the striatum, amygdala, and hippocampus, but not in the cingulate. The enhanced sound evoked response could be linked to the hyperacusis-like behavior. Further analysis showed that the enhancement of sound-evoked activity occurred predominantly at the midfrequencies, likely reflecting shifts of neurons towards the midfrequency range after SS-treatment as observed in our previous studies in the auditory cortex and amygdala. The increased number of midfrequency neurons would lead to a relative higher number of total spontaneous discharges in the midfrequency region, even though the mean discharge rate of each neuron may not increase. The tonotopical overactivity in the midfrequency region in quiet may potentially lead to tonal sensation of midfrequency (the tinnitus). The neural changes in the amygdala and hippocampus may also contribute to the negative effect that patients associate with their tinnitus. PMID:24891959

Spontaneous and evoked release are independently regulated at individual active zones.

PubMed

Melom, Jan E; Akbergenova, Yulia; Gavornik, Jeffrey P; Littleton, J Troy

2013-10-30

Neurotransmitter release from synaptic vesicle fusion is the fundamental mechanism for neuronal communication at synapses. Evoked release following an action potential has been well characterized for its function in activating the postsynaptic cell, but the significance of spontaneous release is less clear. Using transgenic tools to image single synaptic vesicle fusion events at individual release sites (active zones) in Drosophila, we characterized the spatial and temporal dynamics of exocytotic events that occur spontaneously or in response to an action potential. We also analyzed the relationship between these two modes of fusion at single release sites. A majority of active zones participate in both modes of fusion, although release probability is not correlated between the two modes of release and is highly variable across the population. A subset of active zones is specifically dedicated to spontaneous release, indicating a population of postsynaptic receptors is uniquely activated by this mode of vesicle fusion. Imaging synaptic transmission at individual release sites also revealed general rules for spontaneous and evoked release, and indicate that active zones with similar release probability can cluster spatially within individual synaptic boutons. These findings suggest neuronal connections contain two information channels that can be spatially segregated and independently regulated to transmit evoked or spontaneous fusion signals.

Decreased Corticospinal Excitability after the Illusion of Missing Part of the Arm.

PubMed

Kilteni, Konstantina; Grau-Sánchez, Jennifer; Veciana De Las Heras, Misericordia; Rodríguez-Fornells, Antoni; Slater, Mel

2016-01-01

Previous studies on body ownership illusions have shown that under certain multimodal conditions, healthy people can experience artificial body-parts as if they were part of their own body, with direct physiological consequences for the real limb that gets 'substituted.' In this study we wanted to assess (a) whether healthy people can experience 'missing' a body-part through illusory ownership of an amputated virtual body, and (b) whether this would cause corticospinal excitability changes in muscles associated with the 'missing' body-part. Forty right-handed participants saw a virtual body from a first person perspective but for half of them the virtual body was missing a part of its right arm. Single pulse transcranial magnetic stimulation was applied before and after the experiment to left and right motor cortices. Motor evoked potentials (MEPs) were recorded from the first dorsal interosseous (FDI) and the extensor digitorum communis (EDC) of each hand. We found that the stronger the illusion of amputation and arm ownership, the more the reduction of MEP amplitudes of the EDC muscle for the contralateral sensorimotor cortex. In contrast, no association was found for the EDC amplitudes in the ipsilateral cortex and for the FDI amplitudes in both contralateral and ipsilateral cortices. Our study provides evidence that a short-term illusory perception of missing a body-part can trigger inhibitory effects on corticospinal pathways and importantly in the absence of any limb deafferentation or disuse.

Effects of changing the ionic environment on passive and active membrane properties of pregnant rat uterus

PubMed Central

Abe, Y.

1971-01-01

1. In pregnant rat myometrium electrotonic potentials, produced by externally applied current, were recorded intracellularly. 2. The space constant, λ, was 1·8 mm, the time constant, τm, 120 msec. The values obtained on the 7th day and on the 20th day of pregnancy were the same. 3. The magnitude of the electrotonic potential and the time constant of the membrane were increased in the absence of potassium from the external solution and decreased by excess potassium. 4. The magnitude of the electrotonic potential and the time constant of the membrane were increased by the replacement of chloride with C6H5SO3- or SO42-, and decreased with NO3- or I- replacement. 5. When the sodium chloride was replaced with sucrose (16·7 mM sodium remaining in the buffers) the spontaneous spikes deteriorated and activity stopped within 30 min. However, for periods up to 4 hr, a spike of larger amplitude and faster rate of rise than in normal solution could be evoked when a depolarizing current was applied. 6. When the external calcium concentration was raised (5 and 10 mM) the amplitude and the rate of rise of the evoked spike were increased. They were decreased by reducing calcium. In zero calcium spontaneous activity stopped within 15 min. 7. The effects of calcium deficiency were much less marked and slower in onset when, simultaneously, the sodium concentration was reduced to 16·7 mM. 8. When calcium was replaced with strontium (2·5 mM), the membrane was depolarized and the duration of the spontaneous and evoked action potential was prolonged, mainly due to a slowed rate of repolarization. When the concentration of strontium was raised to 7·5 or 12·5 mM the membrane was hyperpolarized, the duration of the action potential became short and the amplitude of the spike was increased. 9. Addition of barium or the replacement of calcium with barium caused depolarization and oscillatory membrane activity. However, a spike could be evoked by applying conditioning hyperpolarization. 10. Manganese abolished the spontaneous and evoked spike. Tetrodotoxin had no effect. 11. The results show that rat uterus has cable-like properties. The action potential may be due to calcium entry, while sodium, by influencing the membrane potential in competition with calcium, may be involved in the spontaneous spike generation and the spread of excitation. PMID:5103422

Optogenetic micro-electrocorticography for modulating and localizing cerebral cortex activity

PubMed Central

Richner, Thomas J.; Thongpang, Sanitta; Brodnick, Sarah K.; Schendel, Amelia A.; Falk, Ryan W.; Krugner-Higby, Lisa A.; Pashaie, Ramin; Williams, Justin C.

2014-01-01

Objective Spatial localization of neural activity from within the brain with electrocorticography (ECoG) and electroencephalography (EEG) remains a challenge in clinical and research settings, and while microfabricated ECoG (micro-ECoG) array technology continues to improve, complimentary methods to simultaneously modulate cortical activity while recording are needed. Approach We developed a neural interface utilizing optogenetics, cranial windowing, and micro-ECoG arrays fabricated on a transparent polymer. This approach enabled us to directly modulate neural activity at known locations around micro-ECoG arrays in mice expressing Channelrhodopsin-2 (ChR2). We applied photostimuli varying in time, space and frequency to the cortical surface, and we targeted multiple depths within the cortex using an optical fiber while recording micro-ECoG signals. Main Results Negative potentials of up to 1.5 mV were evoked by photostimuli applied to the entire cortical window, while focally applied photostimuli evoked spatially localized micro-ECoG potentials. Two simultaneously applied focal stimuli could be separated, depending on the distance between them. Photostimuli applied within the cortex with an optical fiber evoked more complex micro-ECoG potentials with multiple positive and negative peaks whose relative amplitudes depended on the depth of the fiber. Significance Optogenetic ECoG has potential applications in the study of epilepsy, cortical dynamics, and neuroprostheses. PMID:24445482

Automated single-trial assessment of laser-evoked potentials as an objective functional diagnostic tool for the nociceptive system.

PubMed

Hatem, S M; Hu, L; Ragé, M; Gierasimowicz, A; Plaghki, L; Bouhassira, D; Attal, N; Iannetti, G D; Mouraux, A

2012-12-01

To assess the clinical usefulness of an automated analysis of event-related potentials (ERPs). Nociceptive laser-evoked potentials (LEPs) and non-nociceptive somatosensory electrically-evoked potentials (SEPs) were recorded in 37 patients with syringomyelia and 21 controls. LEP and SEP peak amplitudes and latencies were estimated using a single-trial automated approach based on time-frequency wavelet filtering and multiple linear regression, as well as a conventional approach based on visual inspection. The amplitudes and latencies of normal and abnormal LEP and SEP peaks were identified reliably using both approaches, with similar sensitivity and specificity. Because the automated approach provided an unbiased solution to account for average waveforms where no ERP could be identified visually, it revealed significant differences between patients and controls that were not revealed using the visual approach. The automated analysis of ERPs characterized reliably and objectively LEP and SEP waveforms in patients. The automated single-trial analysis can be used to characterize normal and abnormal ERPs with a similar sensitivity and specificity as visual inspection. While this does not justify its use in a routine clinical setting, the technique could be useful to avoid observer-dependent biases in clinical research. Copyright © 2012 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.

Auditory attention in childhood and adolescence: An event-related potential study of spatial selective attention to one of two simultaneous stories.

PubMed

Karns, Christina M; Isbell, Elif; Giuliano, Ryan J; Neville, Helen J

2015-06-01

Auditory selective attention is a critical skill for goal-directed behavior, especially where noisy distractions may impede focusing attention. To better understand the developmental trajectory of auditory spatial selective attention in an acoustically complex environment, in the current study we measured auditory event-related potentials (ERPs) across five age groups: 3-5 years; 10 years; 13 years; 16 years; and young adults. Using a naturalistic dichotic listening paradigm, we characterized the ERP morphology for nonlinguistic and linguistic auditory probes embedded in attended and unattended stories. We documented robust maturational changes in auditory evoked potentials that were specific to the types of probes. Furthermore, we found a remarkable interplay between age and attention-modulation of auditory evoked potentials in terms of morphology and latency from the early years of childhood through young adulthood. The results are consistent with the view that attention can operate across age groups by modulating the amplitude of maturing auditory early-latency evoked potentials or by invoking later endogenous attention processes. Development of these processes is not uniform for probes with different acoustic properties within our acoustically dense speech-based dichotic listening task. In light of the developmental differences we demonstrate, researchers conducting future attention studies of children and adolescents should be wary of combining analyses across diverse ages. Copyright © 2015 The Authors. Published by Elsevier Ltd.. All rights reserved.

Auditory attention in childhood and adolescence: An event-related potential study of spatial selective attention to one of two simultaneous stories

PubMed Central

Karns, Christina M.; Isbell, Elif; Giuliano, Ryan J.; Neville, Helen J.

2015-01-01

Auditory selective attention is a critical skill for goal-directed behavior, especially where noisy distractions may impede focusing attention. To better understand the developmental trajectory of auditory spatial selective attention in an acoustically complex environment, in the current study we measured auditory event-related potentials (ERPs) in human children across five age groups: 3–5 years; 10 years; 13 years; 16 years; and young adults using a naturalistic dichotic listening paradigm, characterizing the ERP morphology for nonlinguistic and linguistic auditory probes embedded in attended and unattended stories. We documented robust maturational changes in auditory evoked potentials that were specific to the types of probes. Furthermore, we found a remarkable interplay between age and attention-modulation of auditory evoked potentials in terms of morphology and latency from the early years of childhood through young adulthood. The results are consistent with the view that attention can operate across age groups by modulating the amplitude of maturing auditory early-latency evoked potentials or by invoking later endogenous attention processes. Development of these processes is not uniform for probes with different acoustic properties within our acoustically dense speech-based dichotic listening task. In light of the developmental differences we demonstrate, researchers conducting future attention studies of children and adolescents should be wary of combining analyses across diverse ages. PMID:26002721

Two Sides of the Same Coin: ERP and Wavelet Analyses of Visual Potentials Evoked and Induced by Task-Relevant Faces.

PubMed

Van der Lubbe, Rob H J; Szumska, Izabela; Fajkowska, Małgorzata

2016-01-01

New analysis techniques of the electroencephalogram (EEG) such as wavelet analysis open the possibility to address questions that may largely improve our understanding of the EEG and clarify its relation with related potentials (ER Ps). Three issues were addressed. 1) To what extent can early ERERP components be described as transient evoked oscillations in specific frequency bands? 2) Total EEG power (TP) after a stimulus consists of pre-stimulus baseline power (BP), evoked power (EP), and induced power (IP), but what are their respective contributions? 3) The Phase Reset model proposes that BP predicts EP, while the evoked model holds that BP is unrelated to EP; which model is the most valid one? EEG results on NoGo trials for 123 individuals that took part in an experiment with emotional facial expressions were examined by computing ERPs and by performing wavelet analyses on the raw EEG and on ER Ps. After performing several multiple regression analyses, we obtained the following answers. First, the P1, N1, and P2 components can by and large be described as transient oscillations in the α and θ bands. Secondly, it appears possible to estimate the separate contributions of EP, BP, and IP to TP, and importantly, the contribution of IP is mostly larger than that of EP. Finally, no strong support was obtained for either the Phase Reset or the Evoked model. Recent models are discussed that may better explain the relation between raw EEG and ERPs.

Two Sides of the Same Coin: ERP and Wavelet Analyses of Visual Potentials Evoked and Induced by Task-Relevant Faces

PubMed Central

Van der Lubbe, Rob H. J.; Szumska, Izabela; Fajkowska, Małgorzata

2016-01-01

New analysis techniques of the electroencephalogram (EEG) such as wavelet analysis open the possibility to address questions that may largely improve our understanding of the EEG and clarify its relation with related potentials (ER Ps). Three issues were addressed. 1) To what extent can early ERERP components be described as transient evoked oscillations in specific frequency bands? 2) Total EEG power (TP) after a stimulus consists of pre-stimulus baseline power (BP), evoked power (EP), and induced power (IP), but what are their respective contributions? 3) The Phase Reset model proposes that BP predicts EP, while the evoked model holds that BP is unrelated to EP; which model is the most valid one? EEG results on NoGo trials for 123 individuals that took part in an experiment with emotional facial expressions were examined by computing ERPs and by performing wavelet analyses on the raw EEG and on ER Ps. After performing several multiple regression analyses, we obtained the following answers. First, the P1, N1, and P2 components can by and large be described as transient oscillations in the α and θ bands. Secondly, it appears possible to estimate the separate contributions of EP, BP, and IP to TP, and importantly, the contribution of IP is mostly larger than that of EP. Finally, no strong support was obtained for either the Phase Reset or the Evoked model. Recent models are discussed that may better explain the relation between raw EEG and ERPs. PMID:28154612

Single-trial laser-evoked potentials feature extraction for prediction of pain perception.

PubMed

Huang, Gan; Xiao, Ping; Hu, Li; Hung, Yeung Sam; Zhang, Zhiguo

2013-01-01

Pain is a highly subjective experience, and the availability of an objective assessment of pain perception would be of great importance for both basic and clinical applications. The objective of the present study is to develop a novel approach to extract pain-related features from single-trial laser-evoked potentials (LEPs) for classification of pain perception. The single-trial LEP feature extraction approach combines a spatial filtering using common spatial pattern (CSP) and a multiple linear regression (MLR). The CSP method is effective in separating laser-evoked EEG response from ongoing EEG activity, while MLR is capable of automatically estimating the amplitudes and latencies of N2 and P2 from single-trial LEP waveforms. The extracted single-trial LEP features are used in a Naïve Bayes classifier to classify different levels of pain perceived by the subjects. The experimental results show that the proposed single-trial LEP feature extraction approach can effectively extract pain-related LEP features for achieving high classification accuracy.

Stimulation of mucosal secretion by lubiprostone (SPI-0211) in guinea pig small intestine and colon

PubMed Central

Fei, Guijun; Wang, Yu-Zhong; Liu, Sumei; Hu, Hong-Zhen; Wang, Guo-Du; Qu, Mei-Hua; Wang, Xi-Yu; Xia, Yun; Sun, Xiaohong; Bohn, Laura M.; Cooke, Helen J.; Wood, Jackie D.

2009-01-01

Actions of lubiprostone, a selective type-2 chloride channel activator, on mucosal secretion were investigated in guinea pig small intestine and colon. Flat-sheet preparations were mounted in Ussing flux chambers for recording short-circuit current (Isc) as a marker for electrogenic chloride secretion. Lubiprostone, applied to the small intestinal mucosa in eight concentrations ranging from 1–3000 nM, evoked increases in Isc in a concentration-dependent manner with an EC50 of 42.5 nM. Lubiprostone applied to the mucosa of the colon in eight concentrations ranging from 1–3000 nM evoked increases in Isc in a concentration-dependent manner with an EC50 of 31.7 nM. Blockade of enteric nerves by tetrodotoxin did not influence stimulation of Isc by lubiprostone. Antagonists acting at prostaglandin (PG)E2, EP1–3, or EP4 receptors did not suppress stimulation of Isc by lubiprostone but suppressed or abolished PGE2-evoked responses. Substitution of gluconate for chloride abolished all responses to lubiprostone. The selective CFTR channel blocker, CFTR(inh)-172, did not suppress lubiprostone-evoked Isc. The broadly acting blocker, glibenclamide, suppressed (P < 0.001) lubiprostone-evoked Isc. Lubiprostone, in the presence of tetrodotoxin, enhanced carbachol-evoked Isc. The cholinergic component, but not the putative vasoactive intestinal peptide component, of neural responses to electrical field stimulation was enhanced by lubiprostone. Application of any of the prostaglandins, E2, F2, or I2, evoked depolarization of the resting membrane potential in enteric neurons. Unlike the prostaglandins, lubiprostone did not alter the electrical behavior of enteric neurons. Exposure to the histamine H2 receptor agonists increased basal Isc followed by persistent cyclical increases in Isc. Lubiprostone increased the peak amplitude of the dimaprit-evoked cycles. PMID:19179625

Stimulation of mucosal secretion by lubiprostone (SPI-0211) in guinea pig small intestine and colon.

PubMed

Fei, Guijun; Wang, Yu-Zhong; Liu, Sumei; Hu, Hong-Zhen; Wang, Guo-Du; Qu, Mei-Hua; Wang, Xi-Yu; Xia, Yun; Sun, Xiaohong; Bohn, Laura M; Cooke, Helen J; Wood, Jackie D

2009-04-01

Actions of lubiprostone, a selective type-2 chloride channel activator, on mucosal secretion were investigated in guinea pig small intestine and colon. Flat-sheet preparations were mounted in Ussing flux chambers for recording short-circuit current (Isc) as a marker for electrogenic chloride secretion. Lubiprostone, applied to the small intestinal mucosa in eight concentrations ranging from 1-3000 nM, evoked increases in Isc in a concentration-dependent manner with an EC50 of 42.5 nM. Lubiprostone applied to the mucosa of the colon in eight concentrations ranging from 1-3000 nM evoked increases in Isc in a concentration-dependent manner with an EC50 of 31.7 nM. Blockade of enteric nerves by tetrodotoxin did not influence stimulation of Isc by lubiprostone. Antagonists acting at prostaglandin (PG)E2, EP1-3, or EP4 receptors did not suppress stimulation of Isc by lubiprostone but suppressed or abolished PGE2-evoked responses. Substitution of gluconate for chloride abolished all responses to lubiprostone. The selective CFTR channel blocker, CFTR(inh)-172, did not suppress lubiprostone-evoked Isc. The broadly acting blocker, glibenclamide, suppressed (P<0.001) lubiprostone-evoked Isc. Lubiprostone, in the presence of tetrodotoxin, enhanced carbachol-evoked Isc. The cholinergic component, but not the putative vasoactive intestinal peptide component, of neural responses to electrical field stimulation was enhanced by lubiprostone. Application of any of the prostaglandins, E2, F2, or I2, evoked depolarization of the resting membrane potential in enteric neurons. Unlike the prostaglandins, lubiprostone did not alter the electrical behavior of enteric neurons. Exposure to the histamine H2 receptor agonists increased basal Isc followed by persistent cyclical increases in Isc. Lubiprostone increased the peak amplitude of the dimaprit-evoked cycles.

Sodium-bicarbonate cotransport in retinal Müller (glial) cells of the salamander.

PubMed

Newman, E A

1991-12-01

An electrogenic Na+/HCO3- cotransport system was studied in freshly dissociated Müller cells of the salamander retina. Cotransporter currents were recorded from isolated cells using the whole-cell, voltage-clamp technique following the block of K+ conductance with external Ba2+ and internal Cs+. At constant pHo, an outward current was evoked when extracellular HCO3- concentration was raised by pressure ejecting a HCO3(-)-buffered solution onto the surface of cells bathed in nominally HCO3(-)-free solution. The HCO3(-)-evoked outward current was reduced to 4.4% of control by 0.5 mM DIDS (4,4'-diisothiocyanatostilbene-2,2'-disulfonate), to 28.8% of control by 2 mM DNDS (4,4'-dinitrostilbene-2,2'-disulfonate), and to 28.4% of control by 2 mM harmaline. Substitution of choline for Na+ in bath and ejection solutions reduced the response to 1.3% of control. Bicarbonate-evoked currents of normal magnitude were recorded when methane sulfonate was substituted for Cl- in bath, ejection, and intracellular solutions. Similarly, an outward current was evoked when extracellular Na+ concentration was raised in the presence of HCO3-. The Na(+)-evoked response was reduced to 16.2% of control by 2 mM DNDS and was abolished by removal of HCO3- from bath and ejection solutions. Taken together, these results (block by stilbenes and harmaline, HCO3- and Na+ dependence, Cl- independence) indicate that salamander Müller cells possess an electrogenic Na+/HCO3- cotransport system. Na+/HCO3- cotransporter sites were localized primarily at the endfoot region of Müller cells. Ejection of HCO3- onto the endfoot evoked outward currents 10 times larger than currents evoked by ejections onto the opposite (distal) end of the cell. The reversal potential of the cotransporter was determined by DNDS block of cotransport current. In the absence of a transmembrane HCO3- gradient, the reversal potential varied systematically as a function of the transmembrane Na+ gradient. The reversal potential was -0.1 mV for a [Na+]o:[Na+]i ratio of 1:1 and -25.2 mV for a Na+ gradient ratio of 7.4:1. Based on these values, the estimated stoichiometry of the cotransporter was 2.80 +/- 0.13:1 (HCO3-:Na+). Possible functions of the glial cell Na+/HCO3- cotransporter, including the regulation of CO2 in the retina and the regulation of cerebral blood flow, are discussed.

Conductance changes associated with the secretory potential in the cockroach salivary gland.

PubMed

Ginsborg, B L; House, C R; Silinsky, E M

1974-02-01

1. Conductance changes in the acini of the cockroach salivary gland have been examined during nerve stimulation by means of two intracellular electrodes placed in the same acinus, the first electrode being used for recording membrane potential and the second for current injection.2. The transient hyperpolarization (secretory potential) in the acinus evoked by nerve stimuli is accompanied by a rise in membrane conductance. The conductance, however, remains high for a longer period than that of the response.3. Applying the analysis of Trautwein & Dudel (1958) to the secretory potentials recorded in the acinus (assumed to behave electrically like a single cell) gives estimates of the ;transmitter equilibrium potential'. The values indicate that the neurotransmitter increases the membrane potassium conductance.4. The hyperpolarization of the acinus evoked by 10(-6)M dopamine in the bathing fluid is also associated with an increase in membrane potassium conductance.

Control of humanoid robot via motion-onset visual evoked potentials

PubMed Central

Li, Wei; Li, Mengfan; Zhao, Jing

2015-01-01

This paper investigates controlling humanoid robot behavior via motion-onset specific N200 potentials. In this study, N200 potentials are induced by moving a blue bar through robot images intuitively representing robot behaviors to be controlled with mind. We present the individual impact of each subject on N200 potentials and discuss how to deal with individuality to obtain a high accuracy. The study results document the off-line average accuracy of 93% for hitting targets across over five subjects, so we use this major component of the motion-onset visual evoked potential (mVEP) to code people's mental activities and to perform two types of on-line operation tasks: navigating a humanoid robot in an office environment with an obstacle and picking-up an object. We discuss the factors that affect the on-line control success rate and the total time for completing an on-line operation task. PMID:25620918

Emotional body-word conflict evokes enhanced n450 and slow potential.

PubMed

Ma, Jianling; Liu, Chang; Zhong, Xin; Wang, Lu; Chen, Xu

2014-01-01

Emotional conflict refers to the influence of task irrelevant affective stimuli on current task set. Previously used emotional face-word tasks have produced certain electrophysiological phenomena, such as an enhanced N450 and slow potential; however, it remains unknown whether these effects emerge in other tasks. The present study used an emotional body-word conflict task to investigate the neural dynamics of emotional conflict as reflected by response time, accuracy, and event-related potentials, which were recorded with the aim of replicating the previously observed N450 and slow potential effect. Results indicated increased response time and decreased accuracy in the incongruent condition relative to the congruent condition, indicating a robust interference effect. Furthermore, the incongruent condition evoked pronounced N450 amplitudes and a more positive slow potential, which might be associated with conflict-monitoring and conflict resolution. The present findings extend our understanding of emotional conflict to the body-word domain.

Effect of neck flexion on somatosensory and motor evoked potentials in Hirayama disease.

PubMed

Abraham, A; Gotkine, M; Drory, V E; Blumen, S C

2013-11-15

Hirayama disease (HD) is a rare motor disorder mainly affecting young men, characterized by atrophy and weakness of forearm and hand muscles corresponding to a C7-T1 myotome distribution. The weakness is usually unilateral or asymmetric and progression usually stops within several years. The etiology of HD is not well understood. One hypothesis, mainly based on MRI findings, is that the weakness is a consequence of cervical flexion myelopathy. The aim of this study was to explore the function of corticospinal and ascending somatosensory pathways during neck flexion using evoked responses. 15 men with HD and 7 age-matched control male subjects underwent somatosensory evoked potentials (SSEP) and motor evoked potentials (MEP) studies with the neck in neutral position and fully flexed. SSEP studies included electrical stimulation of median and ulnar nerves at the wrist, and tibial nerve at the ankle with recording over the ipsilateral Erb's point, cervical spine, and contralateral sensory cortex. MEP recordings were obtained by magnetic stimulation of the motor cortex and the cervical lower spinal roots; the evoked responses were recorded from the contralateral thenar and abductor hallucis muscles. MEP recordings demonstrated significant lower amplitudes, and slightly prolonged latencies in HD patients on cervical stimulation, compared to control subjects. During neck flexion, MEP studies also demonstrated a statistically significant drop in mean upper limb amplitude on cervical stimulation in HD patients, as well as in control subjects, although to a lesser degree. In contrast, no significant differences were found in SSEP studies in HD patients compared to control subjects, or between neutral and flexed position in these groups. The study shows a negative effect of cervical flexion on MEP amplitudes in HD patients as well as in control subjects, requiring more studies to investigate its significance. Neck flexion did not have an influence on any SSEP parameters in patients or controls. © 2013 Elsevier B.V. All rights reserved.

Wavelet analysis can sensitively describe dynamics of ethanol evoked local field potentials of the slug (Limax marginatus) brain.

PubMed

Schütt, Atsuko; Ito, Iori; Rosso, Osvaldo A; Figliola, Alejandra

2003-10-30

Odorants evoke characteristic, but complex, local field potentials (LFPs) in the molluscan brain. Wavelet tools in combination with Fourier analysis can detect and characterize hitherto unknown discrete, slow potentials underlying the conspicuous oscillations. Ethanol was one of the odorants that we have extensively studied (J. Neurosci. Methods, 119 (2002) 89). To detect new features and to elucidate their functions, we tested the wavelet tools on the ethanol-evoked LFP responses of the slug (Limax) procerebrum. Recordings were made in vitro from the neuropile and the cell layer. The present study led to the following findings: (i) Mutual exclusion. Energy concentrated mainly in two ranges, (a) 0.1-0.4 Hz and (b) 1.56-12.5 Hz, and the sum of energy remained constant throughout experiments regardless of the condition. A redistribution of relative energy within this sum seemed to occur in the course of main, possible interactions between the two components excluding each other ('mutual exclusion'). (ii) Transient signal ordering and disordering. Ethanol stimulation alternatingly evoked periods of strongly time evolving oscillation dominated by the energy of 1.56-12.5 Hz (increase of entropy=disordered or complexly ordered state) and those of near-silence were predominated by the energy of 0.1-0.4 Hz (decrease of entropy=ordered state). (iii) About 0.1 Hz slow wave oscillation. It was robust. The dominant energy oscillation and the resulting large entropy fluctuation were negatively correlated to each other, and revealed strong frequency-tuning or synchronization at this frequency. Our findings suggest that discrete slow waves play functionally important roles in the invertebrate brain, as widely known in vertebrate EEG. Wavelet tools allow an easy interpretation of several minutes of frequency variations in a single display and give precise information on stimulus-evoked complex change of the neural system describing the new state 'more ordered' or 'non-ordered or more complexly ordered'.

Short- and long-latency auditory evoked potentials in individuals with vestibular dysfunction.

PubMed

Santos Filha, Valdete Alves Valentins Dos; Bruckmann, Mirtes; Garcia, Michele Vargas

2018-01-01

Purpose Evaluate the auditory pathway at the brainstem and cortical levels in individuals with peripheral vestibular dysfunction. Methods The study sample was composed 19 individuals aged 20-80 years that presented exam results suggestive of Peripheral Vestibular Disorder (PVD) or Vestibular Dysfunction (VD). Participants underwent evaluation of the auditory pathway through Brainstem Auditory Evoked Potentials (BAEP) (short latency) and P1, N1, P2, N2, and P300 cortical potentials (long latency). Results Nine individuals presented diagnosis of VD and 10 participants were diagnosed with PVD. The overall average of the long latency potentials of the participants was within the normal range, whereas an increased mean was observed in the short latency of waves III and V of the left ear, as well as in the I - III interpeak interval of both ears. Association of the auditory potentials with VD and PVD showed statistically significant correlation only in the III - V interpeak interval of the right ear for short latency. Comparison between the long and short latencies in the groups showed differences between VD and PVD, but without statistical significance. Conclusion No statistically significant correlation was observed between VD/PVD and the auditory evoked potentials; however, for the long latency potentials, individuals with VD presented higher latency in P1, N1, P2, and N2, where as participants with PVD showed higher latency in P300. In the short latency potentials, there was an increase in the absolute latencies in the VD group and in the interpeak intervals in the PVD group.

Activation of cannabinoid CB1 receptors modulates evoked action potentials in rat retinal ganglion cells.

PubMed

Jiang, Shu-Xia; Li, Qian; Wang, Xiao-Han; Li, Fang; Wang, Zhong-Feng

2013-08-25

Activation of cannabinoid CB1 receptors (CB1Rs) regulates a variety of physiological functions in the vertebrate retina through modulating various types of ion channels. The aim of the present study was to investigate the effects of this receptor on cell excitability of rat retinal ganglion cells (RGCs) in retinal slices using whole-cell patch-clamp techniques. The results showed that under current-clamped condition perfusing WIN55212-2 (WIN, 5 μmol/L), a CB1R agonist, did not significantly change the spontaneous firing frequency and resting membrane potential of RGCs. In the presence of cocktail synaptic blockers, including excitatory postsynaptic receptor blockers CNQX and D-APV, and inhibitory receptor blockers bicuculline and strychnine, perfusion of WIN (5 μmol/L) hardly changed the frequencies of evoked action potentials by a series of positive current injection (from +10 to +100 pA). Phase-plane plot analysis showed that both average threshold voltage for triggering action potential and delay time to reach threshold voltage were not affected by WIN. However, WIN significantly decreased +dV/dtmax and -dV/dtmax of action potentials, suggestive of reduced rising and descending velocities of action potentials. The effects of WIN were reversed by co-application of SR141716, a CB1R selective antagonist. Moreover, WIN did not influence resting membrane potential of RGCs with synaptic inputs being blocked. These results suggest that activation of CB1Rs may regulate intrinsic excitability of rat RGCs through modulating evoked action potentials.

Multimodal system for the planning and guidance of bronchoscopy

NASA Astrophysics Data System (ADS)

Higgins, William E.; Cheirsilp, Ronnarit; Zang, Xiaonan; Byrnes, Patrick

2015-03-01

Many technical innovations in multimodal radiologic imaging and bronchoscopy have emerged recently in the effort against lung cancer. Modern X-ray computed-tomography (CT) scanners provide three-dimensional (3D) high-resolution chest images, positron emission tomography (PET) scanners give complementary molecular imaging data, and new integrated PET/CT scanners combine the strengths of both modalities. State-of-the-art bronchoscopes permit minimally invasive tissue sampling, with vivid endobronchial video enabling navigation deep into the airway-tree periphery, while complementary endobronchial ultrasound (EBUS) reveals local views of anatomical structures outside the airways. In addition, image-guided intervention (IGI) systems have proven their utility for CT-based planning and guidance of bronchoscopy. Unfortunately, no IGI system exists that integrates all sources effectively through the complete lung-cancer staging work flow. This paper presents a prototype of a computer-based multimodal IGI system that strives to fill this need. The system combines a wide range of automatic and semi-automatic image-processing tools for multimodal data fusion and procedure planning. It also provides a flexible graphical user interface for follow-on guidance of bronchoscopy/EBUS. Human-study results demonstrate the system's potential.

"What-Where-Which" Episodic Retrieval Requires Conscious Recollection and Is Promoted by Semantic Knowledge

PubMed Central

Saive, Anne-Lise; Royet, Jean-Pierre; Garcia, Samuel; Thévenet, Marc; Plailly, Jane

2015-01-01

Episodic memory is defined as the conscious retrieval of specific past events. Whether accurate episodic retrieval requires a recollective experience or if a feeling of knowing is sufficient remains unresolved. We recently devised an ecological approach to investigate the controlled cued-retrieval of episodes composed of unnamable odors (What) located spatially (Where) within a visual context (Which context). By combining the Remember/Know procedure with our laboratory-ecological approach in an original way, the present study demonstrated that the accurate odor-evoked retrieval of complex and multimodal episodes overwhelmingly required conscious recollection. A feeling of knowing, even when associated with a high level of confidence, was not sufficient to generate accurate episodic retrieval. Interestingly, we demonstrated that the recollection of accurate episodic memories was promoted by odor retrieval-cue familiarity and describability. In conclusion, our study suggested that semantic knowledge about retrieval-cues increased the recollection which is the state of awareness required for the accurate retrieval of complex episodic memories. PMID:26630170

Iconic Gestures Facilitate Discourse Comprehension in Individuals With Superior Immediate Memory for Body Configurations.

PubMed

Wu, Ying Choon; Coulson, Seana

2015-11-01

To understand a speaker's gestures, people may draw on kinesthetic working memory (KWM)-a system for temporarily remembering body movements. The present study explored whether sensitivity to gesture meaning was related to differences in KWM capacity. KWM was evaluated through sequences of novel movements that participants viewed and reproduced with their own bodies. Gesture sensitivity was assessed through a priming paradigm. Participants judged whether multimodal utterances containing congruent, incongruent, or no gestures were related to subsequent picture probes depicting the referents of those utterances. Individuals with low KWM were primarily inhibited by incongruent speech-gesture primes, whereas those with high KWM showed facilitation-that is, they were able to identify picture probes more quickly when preceded by congruent speech and gestures than by speech alone. Group differences were most apparent for discourse with weakly congruent speech and gestures. Overall, speech-gesture congruency effects were positively correlated with KWM abilities, which may help listeners match spatial properties of gestures to concepts evoked by speech. © The Author(s) 2015.

"What-Where-Which" Episodic Retrieval Requires Conscious Recollection and Is Promoted by Semantic Knowledge.

PubMed

Saive, Anne-Lise; Royet, Jean-Pierre; Garcia, Samuel; Thévenet, Marc; Plailly, Jane

2015-01-01

Episodic memory is defined as the conscious retrieval of specific past events. Whether accurate episodic retrieval requires a recollective experience or if a feeling of knowing is sufficient remains unresolved. We recently devised an ecological approach to investigate the controlled cued-retrieval of episodes composed of unnamable odors (What) located spatially (Where) within a visual context (Which context). By combining the Remember/Know procedure with our laboratory-ecological approach in an original way, the present study demonstrated that the accurate odor-evoked retrieval of complex and multimodal episodes overwhelmingly required conscious recollection. A feeling of knowing, even when associated with a high level of confidence, was not sufficient to generate accurate episodic retrieval. Interestingly, we demonstrated that the recollection of accurate episodic memories was promoted by odor retrieval-cue familiarity and describability. In conclusion, our study suggested that semantic knowledge about retrieval-cues increased the recollection which is the state of awareness required for the accurate retrieval of complex episodic memories.

Enhancing Human Responses to Climate Change Risks through Simulated Flooding Experiences

NASA Astrophysics Data System (ADS)

Zaalberg, Ruud; Midden, Cees

Delta areas are threatened by global climate change. The general aims of our research were (1) to increase our understanding of climate and flood risk perceptions and the factors that influence these judgments, and (2) to seek for interventions that can contribute to a realistic assessment by laypersons of long-term flooding risks. We argue that awareness of one's own vulnerability to future flooding and insights into the effectiveness of coping strategies is driven by direct flooding experiences. In the current research multimodal sensory stimulation by means of interactive 3D technology is used to simulate direct flooding experiences at the experiential or sensory level, thereby going beyond traditional persuasion attempts using fear-evoking images. Our results suggest that future communication efforts should not only use these new technologies to transfer knowledge about effective coping strategies and flooding risks, but should especially be directed towards residents living in flood prone areas, but who lack direct flooding experiences as their guiding principle.

Optimizing the early phase development of new analgesics by human pain biomarkers.

PubMed

Arendt-Nielsen, Lars; Hoeck, Hans Christian

2011-11-01

Human pain biomarkers are based on standardized acute activation of pain pathways/mechanisms and quantitative assessment of the evoked responses. This approach can be applied to healthy volunteers, to pain patients, and before and after pharmacological interventions to help understanding and profile the mode of action (proof-of-concept) of new and existing analgesic compounds. Standardized stimuli of different modalities can be applied to different tissues (multimodal and multi-tissue) for profiling analgesic compounds with respect to modulation of pain transduction, transmission, specific mechanisms and processing. This approach substantiates which specific compounds may work in particular clinical pain conditions. Human pain biomarkers can be translational and may bridge animal findings in clinical pain conditions, which in turn can provide new possibilities for designing more successful clinical trials. Biomarker based proof-of-concept drug studies in either volunteers or selected patient populations provide inexpensive, fast and reliable mechanism-based information about dose-efficacy relationships. This is important information in the early drug development phase and for designing large expensive clinical trials.

A multimodal imaging platform with integrated simultaneous photoacoustic microscopy, optical coherence tomography, optical Doppler tomography and fluorescence microscopy

NASA Astrophysics Data System (ADS)

Dadkhah, Arash; Zhou, Jun; Yeasmin, Nusrat; Jiao, Shuliang

2018-02-01

Various optical imaging modalities with different optical contrast mechanisms have been developed over the past years. Although most of these imaging techniques are being used in many biomedical applications and researches, integration of these techniques will allow researchers to reach the full potential of these technologies. Nevertheless, combining different imaging techniques is always challenging due to the difference in optical and hardware requirements for different imaging systems. Here, we developed a multimodal optical imaging system with the capability of providing comprehensive structural, functional and molecular information of living tissue in micrometer scale. This imaging system integrates photoacoustic microscopy (PAM), optical coherence tomography (OCT), optical Doppler tomography (ODT) and fluorescence microscopy in one platform. Optical-resolution PAM (OR-PAM) provides absorption-based imaging of biological tissues. Spectral domain OCT is able to provide structural information based on the scattering property of biological sample with no need for exogenous contrast agents. In addition, ODT is a functional extension of OCT with the capability of measurement and visualization of blood flow based on the Doppler effect. Fluorescence microscopy allows to reveal molecular information of biological tissue using autofluoresce or exogenous fluorophores. In-vivo as well as ex-vivo imaging studies demonstrated the capability of our multimodal imaging system to provide comprehensive microscopic information on biological tissues. Integrating all the aforementioned imaging modalities for simultaneous multimodal imaging has promising potential for preclinical research and clinical practice in the near future.

Practical Designs of Brain-Computer Interfaces Based on the Modulation of EEG Rhythms

NASA Astrophysics Data System (ADS)

Wang, Yijun; Gao, Xiaorong; Hong, Bo; Gao, Shangkai

A brain-computer interface (BCI) is a communication channel which does not depend on the brain's normal output pathways of peripheral nerves and muscles [1-3]. It supplies paralyzed patients with a new approach to communicate with the environment. Among various brain monitoring methods employed in current BCI research, electroencephalogram (EEG) is the main interest due to its advantages of low cost, convenient operation and non-invasiveness. In present-day EEG-based BCIs, the following signals have been paid much attention: visual evoked potential (VEP), sensorimotor mu/beta rhythms, P300 evoked potential, slow cortical potential (SCP), and movement-related cortical potential (MRCP). Details about these signals can be found in chapter "Brain Signals for Brain-Computer Interfaces". These systems offer some practical solutions (e.g., cursor movement and word processing) for patients with motor disabilities.

Dynamics of feature categorization.

PubMed

Martí, Daniel; Rinzel, John

2013-01-01

In visual and auditory scenes, we are able to identify shared features among sensory objects and group them according to their similarity. This grouping is preattentive and fast and is thought of as an elementary form of categorization by which objects sharing similar features are clustered in some abstract perceptual space. It is unclear what neuronal mechanisms underlie this fast categorization. Here we propose a neuromechanistic model of fast feature categorization based on the framework of continuous attractor networks. The mechanism for category formation does not rely on learning and is based on biologically plausible assumptions, for example, the existence of populations of neurons tuned to feature values, feature-specific interactions, and subthreshold-evoked responses upon the presentation of single objects. When the network is presented with a sequence of stimuli characterized by some feature, the network sums the evoked responses and provides a running estimate of the distribution of features in the input stream. If the distribution of features is structured into different components or peaks (i.e., is multimodal), recurrent excitation amplifies the response of activated neurons, and categories are singled out as emerging localized patterns of elevated neuronal activity (bumps), centered at the centroid of each cluster. The emergence of bump states through sequential, subthreshold activation and the dependence on input statistics is a novel application of attractor networks. We show that the extraction and representation of multiple categories are facilitated by the rich attractor structure of the network, which can sustain multiple stable activity patterns for a robust range of connectivity parameters compatible with cortical physiology.

[Forensic application of brainstem auditory evoked potential in patients with brain concussion].

PubMed

Zheng, Xing-Bin; Li, Sheng-Yan; Huang, Si-Xing; Ma, Ke-Xin

2008-12-01

To investigate changes of brainstem auditory evoked potential (BAEP) in patients with brain concussion. Nineteen patients with brain concussion were studied with BAEP examination. The data was compared to the healthy persons reported in literatures. The abnormal rate of BAEP for patients with brain concussion was 89.5%. There was a statistically significant difference between the abnormal rate of patients and that of healthy persons (P<0.05). The abnormal rate of BAEP in the brainstem pathway for patients with brain concussion was 73.7%, indicating dysfunction of the brainstem in those patients. BAEP might be helpful in forensic diagnosis of brain concussion.

Clinical application of vestibular evoked myogenic potential (VEMP).

PubMed

Murofushi, Toshihisa

2016-08-01

The author reviewed clinical aspects of vestibular evoked myogenic potentials (VEMPs). Now two types of VEMPs are available. The first one is cervical VEMP, which is recorded in the sternocleidomastoid muscle and predominantly reflects sacculo-collic reflex. The other is ocular VEMP, which is usually recorded below the lower eye lid and predominantly reflects utriculo-ocular reflex. VEMPs play important roles not only for assessment of common vestibular diseases but also for establishment of new clinical entities. Clinical application in Meniere's disease, vestibular neuritis, benign paroxysmal positional vertigo, vestibular migraine, idiopathic otolithic vertigo, and central vertigo/dizziness was reviewed. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

Continuous time wavelet entropy of auditory evoked potentials.

PubMed

Cek, M Emre; Ozgoren, Murat; Savaci, F Acar

2010-01-01

In this paper, the continuous time wavelet entropy (CTWE) of auditory evoked potentials (AEP) has been characterized by evaluating the relative wavelet energies (RWE) in specified EEG frequency bands. Thus, the rapid variations of CTWE due to the auditory stimulation could be detected in post-stimulus time interval. This approach removes the probability of missing the information hidden in short time intervals. The discrete time and continuous time wavelet based wavelet entropy variations were compared on non-target and target AEP data. It was observed that CTWE can also be an alternative method to analyze entropy as a function of time. 2009 Elsevier Ltd. All rights reserved.

Unpredictable interference of new transcranial motor-evoked potential monitor against the implanted pacemaker.

PubMed

Hayashi, Kazuko

2016-12-01

Recently, NuVasive NV-M5 nerve monitoring system, a new transcranial motor-evoked potential (TcMEP) monitor, has been introduced with the spread of flank-approach spinal operations such as extreme lateral interbody fusion, to prevent nerve damage. Conventional TcMEP monitors use changes in MEP wave patterns, such as amplitude and/or latency, whereas the NV-M5 nerve monitor system first measures the MEP baseline waveform from the transcranial-evoked potential then measures the electric current necessary to obtain the standard of the previous baseline wave pattern at subsequent monitoring times. The NV-M5 monitor determines nerve damage according to the increase in necessary electric current threshold. The NV-M5 monitor also uses a local electrical stimulation mode to monitor the safety of setting screws into the lumbar vertebrae. In this way, various electrical stimulations with various durations and frequencies are used, and electrical noise may result in unpredictable interference with cardiac pacemakers. We performed anesthetic management of extreme lateral interbody fusion surgery using the NV-M5 in a patient with an implanted pacemaker, during which TcMEP stimulation caused interference with the implanted pacemaker. Copyright © 2016 Elsevier Inc. All rights reserved.

Functional abnormalities in the cortical processing of sound complexity and musical consonance in schizophrenia: evidence from an evoked potential study

PubMed Central

2013-01-01

Background Previous studies have demonstrated functional and structural temporal lobe abnormalities located close to the auditory cortical regions in schizophrenia. The goal of this study was to determine whether functional abnormalities exist in the cortical processing of musical sound in schizophrenia. Methods Twelve schizophrenic patients and twelve age- and sex-matched healthy controls were recruited, and participants listened to a random sequence of two kinds of sonic entities, intervals (tritones and perfect fifths) and chords (atonal chords, diminished chords, and major triads), of varying degrees of complexity and consonance. The perception of musical sound was investigated by the auditory evoked potentials technique. Results Our results showed that schizophrenic patients exhibited significant reductions in the amplitudes of the N1 and P2 components elicited by musical stimuli, to which consonant sounds contributed more significantly than dissonant sounds. Schizophrenic patients could not perceive the dissimilarity between interval and chord stimuli based on the evoked potentials responses as compared with the healthy controls. Conclusion This study provided electrophysiological evidence of functional abnormalities in the cortical processing of sound complexity and music consonance in schizophrenia. The preliminary findings warrant further investigations for the underlying mechanisms. PMID:23721126

Attention to emotion: auditory-evoked potentials in an emotional choice reaction task and personality traits as assessed by the NEO FFI.

PubMed

Mittermeier, Verena; Leicht, Gregor; Karch, Susanne; Hegerl, Ulrich; Möller, Hans-Jürgen; Pogarell, Oliver; Mulert, Christoph

2011-03-01

Several studies suggest that attention to emotional content is related to specific changes in central information processing. In particular, event-related potential (ERP) studies focusing on emotion recognition in pictures and faces or word processing have pointed toward a distinct component of the visual-evoked potential, the EPN ('early posterior negativity'), which has been shown to be related to attention to emotional content. In the present study, we were interested in the existence of a corresponding ERP component in the auditory modality and a possible relationship with the personality dimension extraversion-introversion, as assessed by the NEO Five-Factors Inventory. We investigated 29 healthy subjects using three types of auditory choice tasks: (1) the distinction of syllables with emotional intonation, (2) the identification of the emotional content of adjectives and (3) a purely cognitive control task. Compared with the cognitive control task, emotional paradigms using auditory stimuli evoked an EPN component with a distinct peak after 170 ms (EPN 170). Interestingly, subjects with high scores in the personality trait extraversion showed significantly higher EPN amplitudes for emotional paradigms (syllables and words) than introverted subjects.

Comparison of in-air evoked potential and underwater behavioral hearing thresholds in four bottlenose dolphins (Tursiops truncatus).

PubMed

Finneran, James J; Houser, Dorian S

2006-05-01

Traditional behavioral techniques for hearing assessment in marine mammals are limited by the time and access required to train subjects. Electrophysiological methods, where passive electrodes are used to measure auditory evoked potentials (AEPs), are attractive alternatives to behavioral techniques; however, there have been few attempts to compare AEP and behavioral results for the same subject. In this study, behavioral and AEP hearing thresholds were compared in four bottlenose dolphins. AEP thresholds were measured in-air using a piezoelectric sound projector embedded in a suction cup to deliver amplitude modulated tones to the dolphin through the lower jaw. Evoked potentials were recorded noninvasively using surface electrodes. Adaptive procedures allowed AEP hearing thresholds to be estimated from 10 to 150 kHz in a single ear in about 45 min. Behavioral thresholds were measured in a quiet pool and in San Diego Bay. AEP and behavioral threshold estimates agreed closely as to the upper cutoff frequency beyond which thresholds increased sharply. AEP thresholds were strongly correlated with pool behavioral thresholds across the range of hearing; differences between AEP and pool behavioral thresholds increased with threshold magnitude and ranged from 0 to + 18 dB.

A novel approach for automatic visualization and activation detection of evoked potentials induced by epidural spinal cord stimulation in individuals with spinal cord injury.

PubMed

Mesbah, Samineh; Angeli, Claudia A; Keynton, Robert S; El-Baz, Ayman; Harkema, Susan J

2017-01-01

Voluntary movements and the standing of spinal cord injured patients have been facilitated using lumbosacral spinal cord epidural stimulation (scES). Identifying the appropriate stimulation parameters (intensity, frequency and anode/cathode assignment) is an arduous task and requires extensive mapping of the spinal cord using evoked potentials. Effective visualization and detection of muscle evoked potentials induced by scES from the recorded electromyography (EMG) signals is critical to identify the optimal configurations and the effects of specific scES parameters on muscle activation. The purpose of this work was to develop a novel approach to automatically detect the occurrence of evoked potentials, quantify the attributes of the signal and visualize the effects across a high number of scES parameters. This new method is designed to automate the current process for performing this task, which has been accomplished manually by data analysts through observation of raw EMG signals, a process that is laborious and time-consuming as well as prone to human errors. The proposed method provides a fast and accurate five-step algorithms framework for activation detection and visualization of the results including: conversion of the EMG signal into its 2-D representation by overlaying the located signal building blocks; de-noising the 2-D image by applying the Generalized Gaussian Markov Random Field technique; detection of the occurrence of evoked potentials using a statistically optimal decision method through the comparison of the probability density functions of each segment to the background noise utilizing log-likelihood ratio; feature extraction of detected motor units such as peak-to-peak amplitude, latency, integrated EMG and Min-max time intervals; and finally visualization of the outputs as Colormap images. In comparing the automatic method vs. manual detection on 700 EMG signals from five individuals, the new approach decreased the processing time from several hours to less than 15 seconds for each set of data, and demonstrated an average accuracy of 98.28% based on the combined false positive and false negative error rates. The sensitivity of this method to the signal-to-noise ratio (SNR) was tested using simulated EMG signals and compared to two existing methods, where the novel technique showed much lower sensitivity to the SNR.

A novel approach for automatic visualization and activation detection of evoked potentials induced by epidural spinal cord stimulation in individuals with spinal cord injury

PubMed Central

Mesbah, Samineh; Angeli, Claudia A.; Keynton, Robert S.; Harkema, Susan J.

2017-01-01

Voluntary movements and the standing of spinal cord injured patients have been facilitated using lumbosacral spinal cord epidural stimulation (scES). Identifying the appropriate stimulation parameters (intensity, frequency and anode/cathode assignment) is an arduous task and requires extensive mapping of the spinal cord using evoked potentials. Effective visualization and detection of muscle evoked potentials induced by scES from the recorded electromyography (EMG) signals is critical to identify the optimal configurations and the effects of specific scES parameters on muscle activation. The purpose of this work was to develop a novel approach to automatically detect the occurrence of evoked potentials, quantify the attributes of the signal and visualize the effects across a high number of scES parameters. This new method is designed to automate the current process for performing this task, which has been accomplished manually by data analysts through observation of raw EMG signals, a process that is laborious and time-consuming as well as prone to human errors. The proposed method provides a fast and accurate five-step algorithms framework for activation detection and visualization of the results including: conversion of the EMG signal into its 2-D representation by overlaying the located signal building blocks; de-noising the 2-D image by applying the Generalized Gaussian Markov Random Field technique; detection of the occurrence of evoked potentials using a statistically optimal decision method through the comparison of the probability density functions of each segment to the background noise utilizing log-likelihood ratio; feature extraction of detected motor units such as peak-to-peak amplitude, latency, integrated EMG and Min-max time intervals; and finally visualization of the outputs as Colormap images. In comparing the automatic method vs. manual detection on 700 EMG signals from five individuals, the new approach decreased the processing time from several hours to less than 15 seconds for each set of data, and demonstrated an average accuracy of 98.28% based on the combined false positive and false negative error rates. The sensitivity of this method to the signal-to-noise ratio (SNR) was tested using simulated EMG signals and compared to two existing methods, where the novel technique showed much lower sensitivity to the SNR. PMID:29020054

Marine Mammals: Hearing and Echolocation at Coconut Island

DTIC Science & Technology

2009-09-30

113(5), 2408-2411 5 Supin, A. Ya., Nachtigall, P.E., and Breese, M. (2009) Forward masking based gain control in odontocete biosonar : an evoked...odontocete biosonar : an evoked-potential study. J Acous Soc Am (published, refereed) Mooney T.A., Nachtigall, P.E. Breese, M. Vlachos, S. and...Nachtigall, P.E. and Breese, M. (2008) Forward masking as a mechanism of automatic gain control in whale biosonar : a psychophysical study, Journal of the

Evidence that NMDA-dependent limbic neural plasticity in the right hemisphere mediates pharmacological stressor (FG-7142)-induced lasting increases in anxiety-like behavior. Study 1--Role of NMDA receptors in efferent transmission from the cat amygdala.

PubMed

Adamec, R E

1998-01-01

The anxiogenic beta-carboline, FG-7142, produces intense anxiety in humans and anxiety-like behavior in animals. FG-7142 also mimics the effects of exogenous stressors. In cats, FG-7142 lastingly changes defensive and aggressive behavior. Long-term potentiation (LTP) of neural transmission between limbic structures known to modulate feline defensive response to threat accompany behavioral changes. A series of three reports describes experiments designed to test the hypothesis that behavioral changes depend upon an N-methyl-D-aspartate (NMDA) receptor-based LTP of efferent transmission from the amygdala. This first study characterizes the dose and time effects of injection of the NMDA receptor blocker 7-amino-phosphono-heptanoic acid (AP7) on efferent transmission from the cat amygdala to the ventromedial hypothalamus (VMH). Effects of doses of 0.5-10mg/kg (i.v.) of AP7 on potentials evoked in the VMH by single pulse stimulation of the basal amygdala were examined. In order to localize the action of the drug, concurrent measurements were taken of potentials evoked in the VMH by stimulation of the efferent fibers from the amygdala to the VMH (ventral amygdalofugal pathway, VAF). There was a dose-dependent reduction in the amygdalo-VMH evoked potential. The greatest reduction occurred at 5 mg/kg. Effects peaked at 10 min, and persisted for at least 1 h after injection. In contrast, AP7 increased the VAF-VMH-evoked potential at 10 min after injection, with a maximal increase at 5mg/kg. The data suggest that NMDA receptors intrinsic to the amygdala modulate excitatory efferent transmission from amygdala to VMH in the cat. It is speculated that a glutamatergic projection to gamma-aminobutyric acid tonic inhibitory systems in the VMH accounts for the VAF-VMH results.

Two-photon quantum walk in a multimode fiber

PubMed Central

Defienne, Hugo; Barbieri, Marco; Walmsley, Ian A.; Smith, Brian J.; Gigan, Sylvain

2016-01-01

Multiphoton propagation in connected structures—a quantum walk—offers the potential of simulating complex physical systems and provides a route to universal quantum computation. Increasing the complexity of quantum photonic networks where the walk occurs is essential for many applications. We implement a quantum walk of indistinguishable photon pairs in a multimode fiber supporting 380 modes. Using wavefront shaping, we control the propagation of the two-photon state through the fiber in which all modes are coupled. Excitation of arbitrary output modes of the system is realized by controlling classical and quantum interferences. This report demonstrates a highly multimode platform for multiphoton interference experiments and provides a powerful method to program a general high-dimensional multiport optical circuit. This work paves the way for the next generation of photonic devices for quantum simulation, computing, and communication. PMID:27152325

Quantification of the proportion of motor neurons recruited by transcranial electrical stimulation during intraoperative motor evoked potential monitoring.

PubMed

Tsutsui, Shunji; Yamada, Hiroshi; Hashizume, Hiroshi; Minamide, Akihito; Nakagawa, Yukihiro; Iwasaki, Hiroshi; Yoshida, Munehito

2013-12-01

Transcranial motor evoked potentials (TcMEPs) are widely used to monitor motor function during spinal surgery. However, they are much smaller and more variable in amplitude than responses evoked by maximal peripheral nerve stimulation, suggesting that a limited number of spinal motor neurons to the target muscle are excited by transcranial stimulation. The aim of this study was to quantify the proportion of motor neurons recruited during TcMEP monitoring under general anesthesia. In twenty patients who underwent thoracic and/or lumbar spinal surgery with TcMEP monitoring, the triple stimulation technique (TST) was applied to the unilateral upper arm intraoperatively. Total intravenous anesthesia was employed. Trains of four stimuli were delivered with maximal intensity and an inter-pulse interval of 1.5 ms. TST responses were recorded from the abductor digiti minimi muscle, and the negative peak amplitude and area were measured and compared between the TST test (two collisions between transcranial and proximal and distal peripheral stimulation) and control response (two collisions between two proximal and one distal peripheral stimulation). The highest degree of superimposition of the TST test and control responses was chosen from several trials per patient. The average ratios (test:control) were 17.1 % (range 1.8-38 %) for the amplitudes and 21.6 % (range 2.9-40 %) for the areas. The activity of approximately 80 % of the motor units to the target muscle cannot be detected by TcMEP monitoring. Therefore, changes in evoked potentials must be interpreted cautiously when assessing segmental motor function with TcMEP monitoring.

Sustained signalling by PTH modulates IP3 accumulation and IP3 receptors through cyclic AMP junctions

PubMed Central

Meena, Abha; Tovey, Stephen C.; Taylor, Colin W.

2015-01-01

ABSTRACT Parathyroid hormone (PTH) stimulates adenylyl cyclase through type 1 PTH receptors (PTH1R) and potentiates the Ca2+ signals evoked by carbachol, which stimulates formation of inositol 1,4,5-trisphosphate (IP3). We confirmed that in HEK cells expressing PTH1R, acute stimulation with PTH(1-34) potentiated carbachol-evoked Ca2+ release. This was mediated by locally delivered cyclic AMP (cAMP), but unaffected by inhibition of protein kinase A (PKA), exchange proteins activated by cAMP, cAMP phosphodiesterases (PDEs) or substantial inhibition of adenylyl cyclase. Sustained stimulation with PTH(1-34) causes internalization of PTH1R–adenylyl cyclase signalling complexes, but the consequences for delivery of cAMP to IP3R within cAMP signalling junctions are unknown. Here, we show that sustained stimulation with PTH(1-34) or with PTH analogues that do not evoke receptor internalization reduced the potentiated Ca2+ signals and attenuated carbachol-evoked increases in cytosolic IP3. Similar results were obtained after sustained stimulation with NKH477 to directly activate adenylyl cyclase, or with the membrane-permeant analogue of cAMP, 8-Br-cAMP. These responses were independent of PKA and unaffected by substantial inhibition of adenylyl cyclase. During prolonged stimulation with PTH(1-34), hyperactive cAMP signalling junctions, within which cAMP is delivered directly and at saturating concentrations to its targets, mediate sensitization of IP3R and a more slowly developing inhibition of IP3 accumulation. PMID:25431134

β-Nicotinamide adenine dinucleotide acts at prejunctional adenosine A1 receptors to suppress inhibitory musculomotor neurotransmission in guinea pig colon and human jejunum

PubMed Central

Wang, Guo-Du; Wang, Xi-Yu; Liu, Sumei; Xia, Yun; Zou, Fei; Qu, Meihua; Needleman, Bradley J.; Mikami, Dean J.

2015-01-01

Intracellular microelectrodes were used to record neurogenic inhibitory junction potentials in the intestinal circular muscle coat. Electrical field stimulation was used to stimulate intramural neurons and evoke contraction of the smooth musculature. Exposure to β-nicotinamide adenine dinucleotide (β-NAD) did not alter smooth muscle membrane potential in guinea pig colon or human jejunum. ATP, ADP, β-NAD, and adenosine, as well as the purinergic P2Y1 receptor antagonists MRS 2179 and MRS 2500 and the adenosine A1 receptor agonist 2-chloro-N6-cyclopentyladenosine, each suppressed inhibitory junction potentials in guinea pig and human preparations. β-NAD suppressed contractile force of twitch-like contractions evoked by electrical field stimulation in guinea pig and human preparations. P2Y1 receptor antagonists did not reverse this action. Stimulation of adenosine A1 receptors with 2-chloro-N6-cyclopentyladenosine suppressed the force of twitch contractions evoked by electrical field stimulation in like manner to the action of β-NAD. Blockade of adenosine A1 receptors with 8-cyclopentyl-1,3-dipropylxanthine suppressed the inhibitory action of β-NAD on the force of electrically evoked contractions. The results do not support an inhibitory neurotransmitter role for β-NAD at intestinal neuromuscular junctions. The data suggest that β-NAD is a ligand for the adenosine A1 receptor subtype expressed by neurons in the enteric nervous system. The influence of β-NAD on intestinal motility emerges from adenosine A1 receptor-mediated suppression of neurotransmitter release at inhibitory neuromuscular junctions. PMID:25813057

EVOKED POTENTIALS, PHYSIOLOGICAL METHODS WITH HUMAN APPLICATIONS

EPA Science Inventory

A number of tests and test batteries have been developed and implemented for detecting potential neurotoxicity in humans. n some cases test results may suggest specific dysfunction. hile tests in laboratory animals are often used to project the potential for adverse health effect...

Effects of high-level pulse train stimulation on retinal function.

PubMed

Cohen, Ethan D

2009-06-01

We examined how stimulation of the local retina by high-level current pulse trains affected the light-evoked responses of the retinal ganglion cells. The spikes of retinal ganglion cell axons were recorded extracellularly using an in vitro eyecup preparation of the rabbit retina. Epiretinal electrical stimulation was delivered via a 500 microm inner diameter saline-filled, transparent tube positioned over the retinal surface forming the receptive field center. Spot stimuli were presented periodically to the receptive field center during the experiment. Trains of biphasic 1 ms current pulses were delivered to the retina at 50 Hz for 1 min. Pulse train charge densities of 1.3-442 microC/cm(2)/phase were examined. After pulse train stimulation with currents >or=300 microA (133 microC/cm(2)/phase), the ganglion cell's ability to respond to light was depressed and a significant time was required for recovery of the light-evoked response. During train stimulation, the ganglion cell's ability to spike following each current pulse fatigued. The current levels evoking train-evoked depression were suprathreshold to those evoking action potentials. Train-evoked depression was stronger touching the retinal surface, and in some cases impaired ganglion cell function for up to 30 min. This overstimulation could cause a transient refractory period for electrically stimulated perception in the retinal region below the electrode.

Ionic mechanisms underlying the responses of off-center bipolar cells in the carp retina. II. Studies on responses evoked by transretinal current stimulation.

PubMed

Kaneko, A; Saito, T

1983-04-01

Transretinal current pulses flowing from the receptor side to the vitreous side of the retina cause transient release of transmitter from the photoreceptor terminals, and in off-center bipolar cells they evoke transient depolarizations with a brief (less than 1 ms) synaptic delay. Since it is known that the presence of Na+ in the external medium is not essential for this type of transmitter release, we used this procedure to examine the role of [Na+]o in the generation of light-evoked responses (hyperpolarizing to spot illumination in the receptive field center and depolarizing to an annulus in the surround) of this type of bipolar cell. When the cell membrane was steadily depolarized by current injection through the recording microelectrode, the depolarizing response evoked by the transretinal current pulses decreased in amplitude and reversed its polarity at above +45 mV. Conversely, the response amplitude increased when the cell was steadily hyperpolarized. The reversal potential seems to be lowered in low [Na+]o (28 mM). Removal of Na+ from the superfusate hyperpolarized the cell and both the light-evoked and current-evoked responses disappeared. From these observations, it is hypothesized that the hyperpolarizing center response of the off-center bipolar cells is a result of removal of sustained depolarization produced by sodium permeability increase.

Measurements of evoked electroencephalograph by transcranial magnetic stimulation applied to motor cortex and posterior parietal cortex

NASA Astrophysics Data System (ADS)

Iwahashi, Masakuni; Koyama, Yohei; Hyodo, Akira; Hayami, Takehito; Ueno, Shoogo; Iramina, Keiji

2009-04-01

To investigate the functional connectivity, the evoked potentials by stimulating at the motor cortex, the posterior parietal cortex, and the cerebellum by transcranial magnetic stimulation (TMS) were measured. It is difficult to measure the evoked electroencephalograph (EEG) by the magnetic stimulation because of the large artifact induced by the magnetic pulse. We used an EEG measurement system with sample-and-hold circuit and an independent component analysis to eliminate the electromagnetic interaction emitted from TMS. It was possible to measure EEG signals from all electrodes over the head within 10 ms after applying the TMS. When the motor area was stimulated by TMS, the spread of evoked electrical activity to the contralateral hemisphere was observed at 20 ms after stimulation. However, when the posterior parietal cortex was stimulated, the evoked electrical activity to the contralateral hemisphere was not observed. When the cerebellum was stimulated, the cortical activity propagated from the stimulated point to the frontal area and the contralateral hemisphere at around 20 ms after stimulation. These results suggest that the motor area has a strong interhemispheric connection and the posterior parietal cortex has no interhemispheric connection.

Cortical Auditory Evoked Potentials Recorded From Nucleus Hybrid Cochlear Implant Users.

PubMed

Brown, Carolyn J; Jeon, Eun Kyung; Chiou, Li-Kuei; Kirby, Benjamin; Karsten, Sue A; Turner, Christopher W; Abbas, Paul J

2015-01-01

Nucleus Hybrid Cochlear Implant (CI) users hear low-frequency sounds via acoustic stimulation and high-frequency sounds via electrical stimulation. This within-subject study compares three different methods of coordinating programming of the acoustic and electrical components of the Hybrid device. Speech perception and cortical auditory evoked potentials (CAEP) were used to assess differences in outcome. The goals of this study were to determine whether (1) the evoked potential measures could predict which programming strategy resulted in better outcome on the speech perception task or was preferred by the listener, and (2) CAEPs could be used to predict which subjects benefitted most from having access to the electrical signal provided by the Hybrid implant. CAEPs were recorded from 10 Nucleus Hybrid CI users. Study participants were tested using three different experimental processor programs (MAPs) that differed in terms of how much overlap there was between the range of frequencies processed by the acoustic component of the Hybrid device and range of frequencies processed by the electrical component. The study design included allowing participants to acclimatize for a period of up to 4 weeks with each experimental program prior to speech perception and evoked potential testing. Performance using the experimental MAPs was assessed using both a closed-set consonant recognition task and an adaptive test that measured the signal-to-noise ratio that resulted in 50% correct identification of a set of 12 spondees presented in background noise. Long-duration, synthetic vowels were used to record both the cortical P1-N1-P2 "onset" response and the auditory "change" response (also known as the auditory change complex [ACC]). Correlations between the evoked potential measures and performance on the speech perception tasks are reported. Differences in performance using the three programming strategies were not large. Peak-to-peak amplitude of the ACC was not found to be sensitive enough to accurately predict the programming strategy that resulted in the best performance on either measure of speech perception. All 10 Hybrid CI users had residual low-frequency acoustic hearing. For all 10 subjects, allowing them to use both the acoustic and electrical signals provided by the implant improved performance on the consonant recognition task. For most subjects, it also resulted in slightly larger cortical change responses. However, the impact that listening mode had on the cortical change responses was small, and again, the correlation between the evoked potential and speech perception results was not significant. CAEPs can be successfully measured from Hybrid CI users. The responses that are recorded are similar to those recorded from normal-hearing listeners. The goal of this study was to see if CAEPs might play a role either in identifying the experimental program that resulted in best performance on a consonant recognition task or in documenting benefit from the use of the electrical signal provided by the Hybrid CI. At least for the stimuli and specific methods used in this study, no such predictive relationship was found.

Changes in event-related potentials in patients with first-episode schizophrenia and their siblings.

PubMed

Yang, Chengqing; Zhang, Tianhong; Li, Zezhi; Heeramun-Aubeeluck, Anisha; Liu, Na; Huang, Nan; Zhang, Jie; He, Leiying; Li, Hui; Tang, Yingying; Chen, Fazhan; Wang, Jijun; Lu, Zheng

2017-01-17

This study aimed to explore the characteristics of event-related potentials induced by facial emotion recognition in patients with first-episode schizophrenia and in their siblings. In this case-control study, 30 first-episode schizophrenia patients, 26 siblings, and 30 healthy controls were enrolled. They completed facial emotion recognition tasks from the Ekman Standard Faces Database as an induction for evoked potentials. Evoked potential data were obtained using a 64-channel electroencephalography system. Average evoked potential waveforms were computed from epochs for each stimulus type. The amplitudes and latency of the event-related potentials for P100 (positive potential 100 ms after stimulus onset), N170 (negative potential 170 ms after stimulus onset), and N250 (fronto-central peak) were investigated at O1, O2, P7, and P8 electrode locations. There were significant differences between the groups for P100 amplitude (F = 11.526, P < 0.001), electrode position (F = 450.592, P < 0.001), emotion (disgust vs. happiness vs. fear) (F = 1722.467, P < 0.001), and emotion intensity (low vs. moderate vs. high) (F = 1737.169, P < 0.001). Post hoc analysis showed significantly larger amplitudes in the schizophrenia group at the O1, O2, P7, and P8 electrode positions. There were no significant differences between the siblings of schizophrenia patients and the healthy controls. Patients with schizophrenia showed abnormalities in P100 amplitude, but similar results were not observed in their siblings. These results provide evidence of dysfunctional event-related potential patterns underlying facial emotion processing in patients with schizophrenia. P100 may be a characteristic index of schizophrenia.

Targeted delivery of cancer-specific multimodal contrast agents for intraoperative detection of tumor boundaries and therapeutic margins

NASA Astrophysics Data System (ADS)

Xu, Ronald X.; Xu, Jeff S.; Huang, Jiwei; Tweedle, Michael F.; Schmidt, Carl; Povoski, Stephen P.; Martin, Edward W.

2010-02-01

Background: Accurate assessment of tumor boundaries and intraoperative detection of therapeutic margins are important oncologic principles for minimal recurrence rates and improved long-term outcomes. However, many existing cancer imaging tools are based on preoperative image acquisition and do not provide real-time intraoperative information that supports critical decision-making in the operating room. Method: Poly lactic-co-glycolic acid (PLGA) microbubbles (MBs) and nanobubbles (NBs) were synthesized by a modified double emulsion method. The MB and NB surfaces were conjugated with CC49 antibody to target TAG-72 antigen, a human glycoprotein complex expressed in many epithelial-derived cancers. Multiple imaging agents were encapsulated in MBs and NBs for multimodal imaging. Both one-step and multi-step cancer targeting strategies were explored. Active MBs/NBs were also fabricated for therapeutic margin assessment in cancer ablation therapies. Results: The multimodal contrast agents and the cancer-targeting strategies were tested on tissue simulating phantoms, LS174 colon cancer cell cultures, and cancer xenograft nude mice. Concurrent multimodal imaging was demonstrated using fluorescence and ultrasound imaging modalities. Technical feasibility of using active MBs and portable imaging tools such as ultrasound for intraoperative therapeutic margin assessment was demonstrated in a biological tissue model. Conclusion: The cancer-specific multimodal contrast agents described in this paper have the potential for intraoperative detection of tumor boundaries and therapeutic margins.